When Goldilocks was snoopingaround the three-bear bungalow, shetested each chair (too high, too low),each bed (too soft, too hard), each bowlof porridge (too cold, too hot) until shefound those that felt just right. Mercurymay be more silver than gold, but it'sjust as picky as the fairytale heroine. It

comes in a lot of chemical shapes andsizes in our watershed, but it only turnsfrom your basic garden-variety to thekind doctors and scientists worry about— the methyl mercury that builds up infish and threatens the health of the peo-ple who eat them — when conditions arejust right. When there's just the right mixof bacteria, chemicals, soils, plants, andwater at just the right temperature, oxy-gen levels, and particle sizes to morphthe mercury left all over the place by theGold Rush into methyl mercury.

The places with just that right mixactually have a name down in theEverglades, where scientists and restora-tion managers have an airborne mercurythreat: "Goldilocks areas." Here inNorthern California, the threat is evenmore pervasive and longer-lived, but itssource is closer to the ground. More than

150 years ago, gold miners began liningtheir sluices and chutes with mercurybecause it drew the gold to its side. Themining and sorting and washing of goldin nearly every river and creek feedinginto the Sacramento and San Joaquinrivers spilled up to 13 million pounds ofmercury across the landscape, according

to state geologists, and runofffrom the Coast Range's 239mercury mines added stillmore (see Mining Mechanicsp. 2).

Everywhere else in theworld, the main source ofmercury is what falls from theskies, but in California, inputsfrom mines far exceed atmo-pheric sources. This spring,U.S. EPA issued new rules onpower plant emissions of mer-cury nationwide. Meanwhile

fish in Midwestern, Canadian, andEuropean lakes can have mercury levelsas high as those in California, and noone ever struck a gold vein in thoseareas. "It's everywhere, both from aregional and a global point of view,"says the U.S. Geological Survey's (USGS)Charlie Alpers, author of the first defini-tive fact sheet on mercury contamina-tion from gold mining in California.

The Bay-Delta's mining dose doesn'tmean we have a bigger problem thanmost everyoneelse— just amore compli-cated one.After a centuryof spreadingacross thelandscape,mercury can'tjust be cleanedup. Luckily,only a smallfraction of themercury in oursystem is reac-tive, the kindthat formsmethyl mercu-ry. But giventhe way this mer-cury magnifies asit climbs up thefood chain (seebelow), even a

small amount is cause for concern. Thetraces in our drinking water pose littlethreat, but many large sport fish fromthe Bay-Delta system carry body bur-dens near or above U.S. EPA criteria forthe protection of human health. Andunlike some other contaminants in estu-aries – cleaned, filtered, andsequestered by aquatic processes — thisone's not going away. Levels in fish havenot changed for 30 years.

Mercury is one of the most perturbingproblems to confront the California Bay-Delta Program (CALFED), one of themany government programs strugglingto address this pollutant. Californianscreated CALFED, a four-year-old cooper-ative state and federal program nowoverseen by the California Bay-DeltaAuthority, to maximize the state's watersupply while minimizing impacts onendangered fish and birds, and restor-ing the rivers, floodplains, and baysupstream of San Francisco Bay. Rightfrom the CALFED get-go, mercury sur-faced at the confluence of almost every-thing on the table.

"Mercury contamination is a long-standing problem that may or may notbe exacerbated by everything fromstoring and transferring water tostrengthening levees, controlling floods,dredging ship channels, removingdams, creating wetlands, and buildingmore cities and towns," says CALFEDEcosystem Restoration Program managerDan Castleberry. "For our part, we'vebeen carefully scrutinizing our own

MAY 2005

Gold mining dredge, Junction City district,Trinity River, 1935. Note the bucket linebehind the gantry at the near end (right side)of the dredge, the stacker conveyor discharg-ing coarse tailings at the far end, and the sidesluice discharging fine tailings to the rear.The dredge separated the coarse material in arotating trommel inside the housing, and finematerial passed through sluices and overtables charged with mercury to capture thegold. Gold dredging occurred on more than adozen Sacramento and San Joaquin river trib-utaries between 1898 and 1968, distributingmercury into the river system (see p.2).

Used with permission, California Department ofConservation, California Geogical Survey.

Methyl mercury biomagnifies in aquatic food webs. In Voyageurs NationalPark, Minnesota, concentrations in young yellow perch were more than onemillion times greater than those in the water, and in adult predatory pikemore than a ten million times greater. In the South Bay's Almaden Reservoir,near a historic mercury mine, concentrations were higher in the water thanin the Minnesota lakes, which is reflected in the elevated transfer up to zoo-plankton. Source: MN from Wiener et al, Univ. of Wisconsin-La Crosse; CA from Kuwabara et al, USGS

BIG PICTURE

Mercury in Every Mix

METHYL MERCURY BIOMAGNIFICATION (ng/g DRY WEIGHT)

Mukooda Ryan Almaden Lake, MN Lake, MN Reservoir, CA

Hg Source Atmospheric Atmospheric MiningWater (wet wt) 0.000018 0.00019 0.00037Seston (mostly algae) 3.5 8.3 4.1Zooplankton 17.0 197.0 640.0Young Fish (age 1) 181.0 943.0 4,830.0Largemouth bass CA x 2.6 millionYellow perch MN x 2.0 million x 1.0 millionNorthern pike (55 cm) 1,130.0 9,725.0

x 12.6 million x 10.2 millionx Bioaccum Factor (fish/water)

NEWS FROM THE CALIFORNIA BAY-DELTA AUTHORITY SCIENCE PROGRAM

SScciieenncceeAAccttiioonnScienceAction

restoration plans so that we don'tincrease mercury risks to the ecosys-tem, and trying to provide coordina-tion and critical data for the myriadother existing efforts to address mer-cury statewide."

Invaluable to this coordination,everyone agrees, was CALFED's invita-tion to a group of international expertsto develop a mercury strategy forNorthern California. The strategy —completed in 2003 with input fromdiverse stakeholders and more than adozen state, local and federal agencies— outlines a framework for scientificstudy of how mercury moves throughthe system and the food web, and sug-gests such actions as cleaning upmines, warning fish consumers, andmanaging landscapes to reducemethylation (see pp. 14-16).

"The strategy has been more than abook on the shelf," says CALFED Bay-Delta Authority water quality coordina-tor Donna Podger. "It's been a unifyingvision used by the wide group of peopleand agencies to tie together researchand management."

Even before the strategy, however,half a dozen teams of scientists hadbegun chasing mercury up and downcreeks, in and around mines, underdams, along river beds, through openwaters, and among pickleweed andtules — trying to pin down the condi-tions in all these places that eithermake them just right or not for mercu-ry methylation. They now know thatthe wet layer of sediments below wet-lands, where plant roots are oxygenat-ing the soil and certain kinds of bacte-ria are churning away, can be as hos-pitable to mercury methylation as LittleBear's bed was to Goldilocks. "All thethings that make wetlands and flood-plains good ecosystem components arethe same things that make them a juicyenvironment for mercury methylation.That's the devil's bargain we have tomake," says microbial ecologist MarkMarvin-DiPasquale of USGS.

In a 1999 national study, a team ofUSGS scientists led by DavisKrabbenhoft concluded that wetlanddensity was the single most watershedscale factor associated with methylmercury production. Here in the Bay-Delta region, Survey scientists aremoving from the regional watershed tothe local site specific scale, trying tofigure out which factors stimulate andwhich inhibit methylation. "There is no

one factor fix. It's all about the inter-play," says Marvin-DiPasquale.

The interplay becomes apparent inany reading of the mercury literature,where the word "biogeochemical"clogs every other sentence. But theresearch of the past six years seem tobe producing useful results: We'velearned that some fish are high in mer-cury but others, such as salmon, areless so; that some seasons are worsethan others — low summer flows seemto produce the biggest spikes; thatplant-rich wetlands may speed methy-lation while open sunlit waters mayactually reverse the process; that thedifference in methyl mercury exportedfrom two side-by-side wetlands can bedramatic — a few among many lessonsthat may help guide restoration in thefuture.

Some of these lessons derive fromthe $31 million in research now under-way and presented here that wasfunded by CALFED's EcosystemRestoration Program. The mercurychallenge is so complex that CALFED'sinvestment in science, as well as ineducation and remediation actions(see pp. 14-16), is just the tip of theiceberg. Many other agencies havechampioned and bankrolled essentialstudies as well, some of which aredescribed here in order to introduce allthe basic areas of inquiry, and some ofwhich had to be left out due to spaceconstraints.

"Time isrunning shortfor us on themercuryquestionworldwide,"says Marvin-DiPasquale."If we reallywant to dosomething,we can't foolaround inbeakers for-ever. We needto get out onthe ground,on an ecosys-tem scale. If itweren’t forCALFED, wewouldn't beable to dothis." ARO

MAY 2005 2

Mercury in Every MixDEFINITIONS

MINING MECHANICSWhen gold fever struck in the Sierra

Nevada, hungry fortune seekers quicklydiscovered that mercury — as liquidquicksilver — would help them recoverthe coveted metal. But first the mercuryhad to be mined from the Coast Ranges,which were rich with red cinnabar, theore that contains mercury. Miners wentto work on the Coast Ranges, includingthe South Bay's Almaden Hills, withpickaxes and blasting powder, chiselingout the cinnabar. They fed the cinnabarinto brick furnaces they built alongCoast Range creeks. The freed liquidquicksilver was poured into iron flasks,which were then shipped throughoutthe Pacific Rim and to other westernstates. An estimated 26 million poundswere used to mine gold from the SierraNevada and the Klamath-TrinityMountains.

Mercury helped extract gold fromtwo types of deposits: placer (alluvialdeposits) and lode (hardrock). Most ofthe mercury that ended up in the envi-ronment was from placer deposits,which were worked using three miningtechniques: hydraulic, drift (under-ground), and dredging. Hydraulicmining probably had the most directenvironmental impact: Enormous can-nons, called "monitors," shot high-pressure water at the deposits, strip-

ping soil,sand, andgravel fromthe bedrock.Miners thendirected thewater andsediment(slurry) intosluices —linear wood-en chutes —charged withquicksilver.The quicksil-ver and goldparticlescombined ina chemicalreaction toform gold-mercuryamalgam,which wouldsink, whilethe sand and

NORTHERN CALIFORNIA GOLD AND MERCURY MINES

Source: Alpers, USGS

MERCURY MINES

GOLD MINES

GOLD DREDGING

SanFrancisco

T Trinity RiverC Clear CreekBt Butte RiverF Feather River Y Yuba RiverB Bear RiverA American RiverCo Cosumnes RiverMo Mokelumne RiverTu Tuolomne RiverMe Merced River

Klamath -TrinityMountains

Sierra Nevada

TT

CcCc

X

Bt

FYBACo

MeTu

Mo

RESEARCH

Doing theGroundwork

Picture two mountain ranges, onefull of old gold diggings, the otherwith abandoned mercury mines.Imagine droplets of mercury andspecks of cinnabar hanging on to thefinest grains of sand and silt in thesewatersheds. Rain and runoff washthese grains downstream, leavingthem here and there on the sides andbottoms of creeks and rivers or to set-tle out in the wide-open waters ofDelta islands and north S.F. Bay wet-lands. Each year adds new layers ofthe silvery metal and deep red crystalsto old layers sent downstream by goldand mercury miners 150 years ago.Along the way, some gets buried,some changes chemical form, andsome settles, only to be stirred upagain by flows, tides, storms, andhumans rearranging the landscape.The question becomes, how much ofwhich kind of mercury is coming fromthe mountains and rivers, and howmuch from resuspension of bottomsediments and old deposits, not tomention how much is getting lostalong the way, out to sea or up thefood chain?

“It's the first time, to my knowl-edge, that anyone has tried to do amethyl mercury mass balance for thepurposes of regulating an estuary,"says biologist Chris Foe of the CentralValley Regional Water Quality ControlBoard. "We knew mercury was mov-ing from sediments to water to fish;what we needed to know was, wherewas it coming from and going?"

A team of 19 scientists, charged in1999 with answering this question,measured mercury in the water columnand sediments, and in various fish andbirds, throughout the watersheds ofthe Sacramento and San Joaquin riversand in the Delta. This first majorCALFED mercury study, managed byCalifornia Department of Fish & Gamebiologist Mark Stephenson of MossLanding Marine Labs, revealed a num-ber of things about Cache Creek, theSacramento River, the Delta, andSuisun Bay — some surprises, somemysteries, some fuzzy edges betweeninputs and outputs.

"Our expert science advisers told usnot to worry about methyl mercury

coming from the rivers. They told us toconcentrate on the Delta, with all itsmarshes, where they thought we'd seelots of methylation and associated lev-els in the biota," says Stephenson."What we found was a completely dif-ferent story."

Not surprising was confirmation thatthe Cache Creek watershed (see map. p.5), dotted with eroding old mercurymines, was one of the biggest sources ofnew mercury inputs to the Delta and S.F.Bay downstream. Scientists confirmednot only that nearly all sediments in his-toric mining areas had above-back-ground levels of total mercury (a meas-ure of all chemical forms-tk), but alsothat levels were acutely high below minesites. But Cache Creek's megadoses tothe system only come down after hugestorms. "We found very distinct season-al ups and downs in exposure," saysU.C. Davis biologist Darell Slotton, whotracked bioaccumulation in creek fish(see p. 9).

Comparing Coast Range creekssuch as Cache with Sierra creeks,researchers found that while themethylation potential starts out verydifferent in the two mountain rangesdue to the different types andamounts of mercury found there, bythe time it's transported to valleystreams and the Delta, it evens out.

More revolutionary, saysStephenson, was the discovery that in anormal year, Sacramento River inputsfar outweigh those of Cache Creek. Theriver loads go up in the winter anddown in the summer, he says. Butbecause the Sacramento supplies mostof the Estuary's water, it also supplies abig slug of mercury (60% to 85% of the

3

gravel passed over it and through thesluice. Finer-grained particles of goldand mercury often washed throughand out of the sluice, but some weretrapped in a second set of sluices,called undercurrents, which were cov-ered in copper plates coated with mer-cury. Despite efforts to catch the finestparticles, an estimated 10% to 30% ofthe mercury was lost at mine sites anddownstream during this process.

As the miners dug deeper, they builttunnels to remove debris and drainagefrom the bottom of the hydraulic minepits. The tunnels directed the processedsediments — placer tailings — intonearby streams and rivers. Between1850 and 1884 in the Sierra Nevada,more than 1.5 billion cubic yards ofplacer gravels loaded with gold weremined; during the processing, an esti-mated three to eight million pounds ofmercury (or more) may have been lostinto the environment. An 1884 legaldecision prohibited discharge of min-ing debris in the Sierra Nevada, effec-tively putting a halt to large-scalehydraulic mining, but the practicecontinued in the Klamath-TrinityMountains until the 1950s.

From the mid-1880s to the early1900s, most of California's gold camefrom drift mining of placer depositsand underground mining of hardrockgold-quartz vein deposits. Thehardrock mines used stamp mills tocrush the ore. In these mills, stamps —several-hundred-pound metal pestles— were lifted by a rotating cam anddropped onto the rocks. During thissmashing process, mercury was usedto recover the gold. The tailings fromthese stamp mills went downstream.

As recently as the 1960s, mercurywas used in dredging floodplaindeposits for gold. Today, large- andsmall-scale commercial gold miningoperations continue, including solominers working with small suctiondredges and old-fashioned pans.According to the CaliforniaDepartment of Conservation's DougCraig, modern dredgers probably pickup and sort more mercury than theyintroduce. The recovered mercury canbe turned in on mercury “drop-off”days in the Sierra foothills. It is themercury legacy of the rush for goldover a century ago that remainsirrecoverable. LOV

NEWS FROM THE CALIFORNIA BAY-DELTA AUTHORITY SCIENCE PROGRAM ScienceAction

Darell Slotton and Shaun Ayers of U.C. Davisin Sierra waters, collecting aquatic insects totest mercury uptake.

MAY 2005

total load). Big hits from these two heavy-

weights — Cache Creek and theSacramento River — are joined by somelesser but still notable hits from the SanJoaquin system to all flow through theDelta. Chris Foe found, for example,that methyl mercury concentrationsand loads increase threefold to fivefoldin the 300-mile transit of water downthe Sacramento River from ShastaReservoir to the state capital. Rightbelow Rio Vista, however, methyl mer-cury mysteriously diminishes by about50%, and stays that way as watersmigrate south and west down to theexport pumps and Suisun Bay.

"All our results suggest the loss ofmethyl mercury in transit from the trib-utaries through the Estuary. Mercury'sgetting dropped off in certain regionsof the Delta," says Texas A&M Universitygeochemist Gary Gill, part of the team.

Dropped off or not, methyl mercurycan also re-emerge in "flux" — to usethe science term for exchange betweensediments and water. To measure this,Gill used a device called a benthic fluxchamber. "We capture a piece of thebottom water in contact with sediment,then leave the device there, sampleperiodically, and watch for the buildupor loss of components like methyl mer-cury inside the chamber," he says. Gillfound that flux becomes the dominantsource of methyl mercury in the Delta

during summer low-flow conditions, whenriver inputs drop to amere quarter of ben-thic (bottom) inputs.Summer peaks wereconfirmed in sedi-ments across the Deltaby other investigators.

Chris Foe added thisresearch to his owntwo-year sampling atall major input andoutput sites in theDelta to come up withan estimated methylmercury mass balancefor the region. Theresult is a balance sheet suggesting thatthe Delta gets about 16 grams a day ininputs and loses about six grams inoutputs, leaving 10 grams unaccountedfor. "The Delta turns out to be a netmethyl mercury sink," says Foe.

This inputs and outputs balancesheet is a useful starting point in ourbig picture understanding of mercuryin the system. Much more remains tobe learned on a finer scale about theDelta's internal methyl mercury pro-duction and loss processes, and howthe region's complex hydrodynamicsaffect mercury movements and trans-formations. A lot has been learned,however, about another whole side ofthe ecosystem balance sheet: exposure.

The results of CALFEDstudies on where andhow bottom-dwelling organisms, andthe fish and birds that eat them, arepicking up mercury can be found indetail in later pages (seeBioaccumulation pp. 9-11). But as Foesums up, just as in sediments andwater, fish exhibited high concentra-tions at the mouths of tributaries; thesedecreased across the Delta and thenrose again around Suisun.

While it may be clear from the bigpicture side that the Delta is notpresently a methyl mercury hotspot,going down to ground level in itsmarshes the action heats up. The sci-ence team conducted a number of wet-land studies. Some did wetland tran-sects — measuring methyl mercury pro-duction in the inner, middle, and outermarsh areas of places like Weber Tract,Mandeville Cut, and 14-Mile Slough.Methyl mercury always proved higherin the inner marshes than outer chan-nels, and higher overall in the marshesthan in open water areas.

Another study comparing non-veg-etated deep water with tule marshand Egeria habitats along theCosumnes River and Frank's Tract (alarge flooded island) found that areascongested with submerged invasiveplants produced the most methylmercury. "Egeria sites are hotspotsrelative to others because the planttraps the fine-grained material andcreates a nice warm canopy over juicyorganic matter for the microbes to dotheir methylation work," says U.S.Geological Survey researcher MarkMarvin-DiPasquale.

Once the wetlands and the waterget saltier in Suisun Bay, mercurymethylation mounts again. In Suisunand the North Bay, USGS scientists

4

0 200 400 600 800 1000

12

10

8

6

4

2

0

TOTAL MERCURY (ng/g DRY SED)

MET

HYL

MER

CURY

(ng

/g D

RY S

ED)

FRESHWATER RESERVOIRFRESHWATER RIVERFRESHWATER STREAMDELTA REGIONESTUARY OPEN WATERESTUARY WETLANDS

TOTAL MERCURY V METHYL MERCURY IN S.F. BAY WATERSHED SEDIMENTS

This data, collected from surface sediments in multiple research projects throughout the S.F.Bay watershed between 1999 and 2004, suggests that habitat type may have more of an influ-ence on methyl mercury production and concentration than the amount total mercury.

Source: Marvin-DiPasquale, USGS

Source: FOE, CVRWQCB

+6 g/day

UNIDENTIFIEDLOSS PROCESSES

SEDIMENTPRODUCTION

RIVERINPUTS

EXPORTTOSF BAY

EXPORTTOS. CALIFORNIA

D E L T A

-5 g/day

-10 g/day

-1 g/day

+10 g/day

ESTIMATED DELTA METHYL MERCURY INPUTS & OUTPUTS

have long documented the erosion ofthe bayfloor, and the likely liberationof legacy mercury deposits. Somesuspect as much inorganic mercury iseroding off the floors of Suisun andGrizzly bays as is coming in from theCentral Valley.

Last year, Stephenson got moreinto the nitty-gritty of the Suisun sit-uation. In summer 2004, he monitoredmercury coming and going in waterand suspended solids at seven sta-tions in Suisun Marsh and Grizzly Bayand found methyl mercury concen-trations in the marsh five to 10 timeshigher than those down near GrizzlyBay in open water.

The twist this time, however, is themassive tidal to-and-fro. "The amounttraveling back and forth overwhelmsthe amount traveling down fromSuisun Marsh. So instead of the marshpolluting the Estuary, it looks like thereverse," he says.

These new findings come from amajor CALFED follow-up study onmercury, involving 17 scientists andstarted in 2003. The aim is to answerquestions raised by the first round ofresearch. Why, for example, do welose mercury in the Delta? Some spec-ulate that tides and salinity play arole; some that the rivers widen anddeepen just above Rio Vista, promot-ing more particle settling anddemethylation; some that there'ssomething else entirely going on thatwe've yet to fathom.

Amy Byington, a Moss Landing gradstudent, has begun gathering clues bychasing water masses down the riverwith drogues (a drifting device shecrafted out of a trash can); trackingsalinity, temperature, and turbidityusing a flow-through sensor; andfloating light and dark Teflon bottlesfilled with mercury-spiked surfacewater for hours at a time. All thesemethods are designed to see whether

mercury is beinglost by dilution,settling, long resi-dence time, food-web uptake, orphoto demethyla-tion — hence thebottles. Methylmercury can breakdown in sunlight.

Though resultsare highly prelimi-nary, Byingtonfound that particlesettling and photodemethylation dueto longer residencetime offered themost promisingexplanations formercury loss, whilewater dilutionalone could notexplain it. "I wassurprised to seesuch a high rate ofphoto demethlya-tion in this firststab," she says."Now I know it'sworth lookinginto." The resultsfrom her light anddark bottle floatexperiments sug-gest a summer lossof up to 22% of the methyl mercury inthe water during daylight hours.

Another looming question is thecontribution of wetlands in the mercu-ry balance sheet. Are they hoardingmethyl mercury or exporting it to thelarger Estuary? To answer this ques-tion, the science team is scrutinizing amix of natural and constructed marsh-es. These include the managed duckclubs of Suisun, the older tule marsheswith established root systems ofBrowns Island and Mandeville Cut, andtwo side-by-side human-engineeredwetlands built on Twitchell Island orig-inally for subsidence studies. "All thesesites have one big channel coming out,which gives us a good clear mercurysignal," says Stephenson.

The more uplifting news is thatsmall changes in wetland configura-tions and management may make bigchanges in such exports. On the side-by-side Twitchell wetlands, Stephen-son found that one exported ninetimes more methyl mercury than theother. The reason? Something to do

with the thickness of the tules and thewater movement through the channels,Stephenson speculates. On the sidewith 100% tule and cattail cover — thebigger exporter — water is forcedthrough the root zones where methyla-tion conditions are good. On the sidewith only 70% cover, water has theoption of flowing through channels.The different sizes and depths of theseponds may also play a role in terms ofdilution and photo demethylation.

"Wetlands may produce a lot ofmethyl mercury but they also catchand trap a lot of particles. Twitchelltells me that a blend of engineeringand science might someday design awetland that minimizes the export ofmercury," says Stephenson.

So looking at the whole landscape,what have we found? In a nutshell, the

5

Mokelum

ne

Cosu

mne

s Ri

ver

River

M

Cosu

M

su

MeHg IN SEDIMENT >1 PPB

MeHg IN LARGEMOUTH BASS >0.5PPM

MeHg IN SILVERSIDES>0.4 PPM

MeHg IN SILVERSIDES0.2 - 0.4 PPM

Sacr

amen

to R

iver

San Joaquin RiverSuisunBay

San

Joaqu

inR

iver

METHYL MERCURY HOT ZONES IN SEDIMENTS & FISHSACRAMENTO-SAN JOAQUIN RIVER WATERSHED, DELTA AND SUISUN BAY

NEWS FROM THE CALIFORNIA BAY-DELTA AUTHORITY SCIENCE PROGRAM

<0.2 PPM

>0.2 PPM

TOTAL MERCURY IN SEDIMENT

ScienceAction

Landings Kenneth Coale collecting a sediment sample for mercury.

CacheCreek

D E L T A

N O R T HS F B A Y

Inflowing tributaries consistently show thehighest biotic signals, with a secondary rise inthe west Delta and a notable low area in theDelta proper.

Source: Stephenson et al, Moss Landing(sediments: Hiem; silversides: Slotten; bass: Davis)

MAY 2005

concentration of methyl mercury inwater diminishes as the SacramentoRiver flows to the pumps, and the bioticdata show the same pattern, so the Deltasituation is what scientists call "tribu-tary dominated." In other words, themethyl mercury is coming from the trib-utaries, rather than being produced inthe Delta itself. Beyond the Delta, sedi-ment and water concentrations start torise again around the big North Baymarshes and over the eroding bayfloors.

On the horizon are studies that willlook more closely at where the two riversare making their methyl mercury andwhether marshes merely have localizedeffects on methyl mercury loads, orwhether they actually pollute the largersystem. Stephenson hopes to tackle theimport-export question via a multidisci-plinary study coordinating monitoringof flows, tides, suspended solids, andmethyl mercury concentrations. "It's theway the whole future of mercuryresearch has to go," he says. ARO

6

Biogeochemical BasicsChemistry, the blackboard kind

scratched with equations and transfor-mations, has never entered into CALFEDrestoration questions as much as it haswith mercury. Researchers have beentracing the myriad conversions andcombinations by which garden-vari-ety mercury becomes methyl mercu-ry. The biogeochemical "axis of evil"in these conversions, according toone scientist, is carbon, sulfur, andmercury. The evil occurs only whenthese elements interact, and only injust the right way. "They all fittogether; you pull on one and theother two get stretched," sayschemist George Aiken of the U.S.Geological Survey. Add water, andthe mercury goes mobile.

The biogeochemical basics arethese: Mercury comes in many forms,called "species." Whatever the species,they all derive from the earthy redcinnabar mined in the Coast Range(mercuric sulfide) or from elemental

mercury made byroastingcinnabar. Theroasting producesthe liquid "quick-silver" used ineveryday ther-mometers and inthe Sierra toamalgamategold.

The transfor-mation of thesespecies intomethyl mercury isa complicatedmulti-step,multi-factorprocess thatdefies simplifica-tion (see links formore technicalpapers p.16). Butat a basic level

the steps involve first oxidation (in thecase of elemental mercury only) andthen methylation. Once in an oxidizedform, the mercury can more easilyreact with things dissolved in water(sulfur, carbon, chloride, etc.) andcreate other gaseous, aqueous, andsolid species of mercury. The oxidationproduces a dissolved Hg(II) -- alsocalled mercuric ion or divalent mercu-ry.

The next transformation equation

on the blackboard adds a new player —the microbes that engineer and cat-alyze the methylation reaction with theHg(II). These "sulfate-reducing bacte-ria" thrive in the low oxygen zone

down at the bottom of our rivers,marshes, and bays. The bacteria con-vert sulfate into sulfide to "make theirliving," just as humans convert oxygento CO2, says microbial ecologist MarkMarvin-DiPasquale. In the process, theycan also take oxidized dissolved mer-cury species and convert them tomethyl mercury. If no sulfate is presentin their environment, the microbes mayswitch to other ways of making theirliving (via the fermentation of organicmatter) and still create methyl mercury.Other strains and kinds of bacteria,meanwhile, make their living in waysthat actually degrade methyl mercury.

The rate of methylation ordemethylation is influenced by awide variety of things in the aquaticenvironment: carbon (organic com-pounds from plants, algae, peat,etc.); sulfur and salinity levels (asso-ciated with marine influences, geot-hermal springs, or agriculturalrunoff); the amount of oxygen in thesoil; iron (which in combination withother elements can either stimulate orinhibit methylation); the depth of oldmining debris (buried under cleanersediments or eroding off the bayfloor); the depth of the water andamount of sunlight (see p.5); aquaticplants (the more roots, the more mer-cury methylation in many cases); andthe temperature. In general, low oxy-gen conditions, more organic carbon,and warmer (tk) temperatures will

USGS's Jennifer Agee sampling sediment in ananoxic glove bag. Photo: Mark Marvin-DiPasquale

Chemical terms: O2 = oxygen; Hg(II) or Hg2+ = dissolved oxydized mercury;

inorganic divalent mercury; MeHg = methyl mercury; SO = sulfur dioxide; elemental sulfurS2-= sulfide SO4

2-= sulfate Fe(II) = reduced iron or ferrous iron FeS & FeS2 = solid phase iron-sulfur minerals,

iron monosulfide and pyrite DOC=dissolved organic carbon; SRB = sulfate reducing bacteria.

METHYLATION ZONE IN A VEGETATED SALT MARSH

Oxygen in sediments

Methylation by sulfate reducingbacteria

No oxygen in sediments (anoxic)

Sulfates convert tosulfides, and team upwith iron, producingiron sulfide

Mercury buried in mining debris

Hydrogen sulfide(rotten egg smell)

Source: Marvin DiPasquale, USGS

O2 O2

O2

SO42-

SO42-

Fe(II)+s2-s2-

s0 Fe(III)DOC

Hg(II) MeHgmax

FeS & FeS2

SRB

SRB

S2-

7

increase methylation rates.Taken as a group, these biogeo-

chemical twists and turns become amind-bending puzzle not only for sci-entists, but also for restoration man-agers. But scientists are hopeful."We're just beginning to understandthe interplay between microbial activi-ty, sediment chemistry, and plantphysiology that controls methylation,"says Marvin-DiPasquale. "What's com-plicated is that controlling chemistriesdiffer from place to place, and seasonto season, within our Estuary."

Over the past ten years, within andoutside CALFED work, Marvin-DiPasquale has been analyzing bot-tom sediments from various ecosys-tems in terms of factors that controlmethylation and demethylation withthe help of radioactively tagged mer-cury compounds. These compoundssimulate natural mercury compoundsin the system, allowing him to moreeasily track the many microbial andchemical transformations mercury canundergo as a result of changing envi-ronmental conditions.

Based on this research, Marvin-DiPasquale estimates that less than 5%of legacy mercury in the Bay-Delta'sbackyard is "reactive," meaningavailable for microbial methylation. Itis this small fraction, and its pathwaysfor interaction with carbon and sulfur,that hold the key to future manage-ment. "Lots of things control reactivi-ty across the ecosystem. The trick is tofind those places along the way, thosecritical points in the process, thatcontrol the larger story," he says.

One critical point is the intersectionbetween the mining debris layer andwater. In a 2000 study of San PabloBay, where the debris is actually on orvery near the surface, Marvin-DiPasquale examined its depth relativeto the zone of maximum microbialactivity at three open water sites andone marsh site. Though total mercuryconcentrations derived from the debriswere similar at all sites, Marvin-DiPasquale saw a big difference inmethyl mercury production. "The take-home message is that sediment geo-chemistry is a much more importantcontrol than the amount of total mer-cury present," he says. The marsh siteon the periphery of the bay, wheremicrobes were more active and plantswere taking oxygen down to the debrislevel, produced 10 times more methylmercury than the other three sites.

On the sulfur corner of the black-board, Marvin-DiPasquale foundsome interesting things in a 2001study of Frank’s Tract (a Delta island),the Cosumnes River (last undammedriver in the system), and ProspectSlough (the connector from the YoloBypass -- where Cache Creek empties-- to the Sacramento River). He foundthat the SRB microbes that stimulatemethylation only do so when sulfidelevels are low to moderate. As thebacteria themselves produce moreand more sulfide end products,methylation decreases. "It's a dynam-ic cycle," says Marvin-DiPasquale,explaining how scientists must bal-ance processes controlling grossmethyl mercury production and thosecontrolling gross degradation to esti-mate net pro-duction in theenvironment(see chart).

On the car-bon side of theblackboard,even morepotential con-trolling factorson methylationare emerging.Dissolvedorganic carbon(DOC) — derivedfrom the break-down of plank-ton, peat soils,crops, and othervegetative mat-ter — actuallyhas the power toincrease theamount of mer-cury dissolvedin the water col-umn, accordingto studies doneby GeorgeAiken. DOC canaccomplish thissinister taskwithout anyhelp frommicrobes orminerals by dis-solving or solu-bilizing (ck)cinnabar ormercury associ-ated with soilsor sediments.

The dissolu-tion has to do

with certain key components in theDOC called "aromatic humic acids,"thinks Aiken. By measuring these andother key components, he hopes tofind a way to predict the reactivity ofdifferent kinds of DOC with mercuryand sulfur.

Part of the problem is how muchmercury likes to cozy up to passersby."Mercury really likes particles. If itbinds onto a soil grain, it won'tmethylate; but if it binds to DOC, itcan become available for methylationby microbes," says Aiken.

The quality or chemical nature ofthe DOC is much more important inthe mercury mix than the quantity.Alluding to our coffee culture, Aikensays, "You can either have double caf,

ScienceAction

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MeHg production, degradation and methylation-demethylation ratios atthree 2001 sampling sites in 0-2 cm of surface sediment. The dashed lineindicates where the ratio = 1 (theoretical net production and degradationare in balance). Source: Marvin-DiPasquale, USGS

NEWS FROM THE CALIFORNIA BAY-DELTA AUTHORITY SCIENCE PROGRAM

MAY 2005

Biogeochemical Basics

8

like you get in the Delta, or singlecaf, like you get in the SacramentoRiver." The more "caffeine," namelyreactive organic molecules, in thepresence of mercury and sulfate-reducing bacteria, the bigger thebioreactive buzz.

Aiken sees more promise in man-aging the DOC and sulfur in his axisthan the mercury. In the Everglades,the Goldilocks areas identified as hotfor methylation (see cover) are miss-ing one critical point in the axis —sulfur. But restoration plans to movea lot of water around this Florida wet-land could import the sulfur in runofffrom nearby sugarcane farms (animportant local source of sulfur inthis freshwater landscape). By beingaware of the sensitivity of some areas,and managing adaptively, resourcemanagers may be able to controlsome of the ecological backwash,Aiken says.

Plants, as a controlling factor, starin the next wave of research beingundertaken by various mercurysleuths, including Marvin-DiPasquale.Comparing methylation levels inpickleweed, bulrush, and non-vege-tated mudflats at the South Bay'sSteven's Creek Marsh, for example, hefound that in the summer, methyla-tion can be four to six times higher inthe root zone of the pickleweed vs.the mudflat just two meters away. Inthe winter, however, when migratorybirds arrive to poke for worms in theoozes, the mudflats were more activemethylators. "There's a seasonal flip-

flop," hesays."Birdsmay begettingtheir mer-cury fill inS.F. Bayduringtheir over-winteringperiod."

The plants themselves affect thesediment chemistry by pumping oxy-gen from the air down into the rootzone, which lowers sulfides and primesthe pump for methylation (see dia-gram p. 6). In an Army Corps studydone at the Hamilton Air Force Basewetland restoration site in MarinCounty, pickleweed outpaced cord-grass as a zone for mercury methyla-tion.

Scientists hasten to say that all theinformation on the impact of differ-ent wetland plant species on methy-lation rates is in its infancy. Questionsremain to be explored about theinfluence of different plant types, notto mention what goes on aboveground in the leaves. Do plants pullmercury up from down deep andthen excrete it into the air, or re-enrich the soil surface as they dieback each year, for example?

Back to the basics, more about thecarbon side of the axis evil may belearned soon. CALFED recently pro-vided $2 million to Aiken and RogerFujii, also of USGS, to delve deeperinto organic carbon interactions withmercury in different tidal wetlandenvironments.

So how will all this effort to followthe path of mercury through sedi-

ments, water, plants, and air help?Scientists hope to know enough in thenext five years to help Bay-Deltamanagers work on promoting onebiogeochemical process over anotheras they design wetlands, move water,staunch mine erosion, and treatwastewater.

On the distant horizon glimmernew computer models combiningcertain parameters of reactivity(among the DOC, mercury, and sul-fur) with data on methylation path-ways and processes. "Somewheredown the road, we should be able towrite a biogeochemical model thatcan predict the effect of tweaking acondition in the Delta or theEverglades or San Diego," says Aiken.

"If we can get areasonable num-ber at the end,

FOLLOWING THE FOODScientists have been scratching their

heads over why biota at the bottom ofDelta tributaries, on some islands, and inreservoirs in the South Bay's GuadalupeRiver watershed carry high methyl mercurylevels relative to aquatic critters hangingout elsewhere in the system. One hypothe-sis is that there's something differentabout the food chain in these areas —more trophic levels, different species orinterference from invaders.

In a CALFED-funded study now in itsthird year, Robin Stewart and MarkMarvin DiPasquale of the USGS are scruti-nizing two distinct habitats — riparianriver plain (Cosumnes) and flooded island(Frank's Tract) — and try to tease out notonly how mercury cycles through them,but also where and how organisms feedwithin each habitat. Stewart has beenusing stable isotopic fingerprints andecological methods to construct foodwebs. "I can get a measure of how longthey are, who's eating whom and where,and what is at the bottom of the foodchain," she says.

Based on the data gathered to datefrom this and past CALFED-funded stud-ies, Stewart suspects that epiphytic algae(algae attached to the surfaces of aquaticplants like the invasive Egeria densa) mayplay a critical role in the first transfersteps, particularly in the central Deltafood webs. In other food webs, organismseat phytoplankton instead of the algae, avariation in the mercury transfer path-way. To find out its significance, Stewart

is testing a new tech-nique that deploysTeflon sheets shapedlike egeria leaves tocollect the algae sothey can be tested formercury.

In another USGSstudy, independent ofCALFED, researchersexplored methyl mer-cury bioaccumulationin the food webs offour reservoirs and a

flooded quarry pit in the Guadalupe Riverwatershed, an area with some of thehighest mercury contamination in theBay-Delta system due to the presence ofthe New Almaden Quicksilver Mines.Sampling occurred in 2004 during thefall, a season when low reservoir waterlevels produce a combination of condi-tions scientists suspect promote methyla-tion and foodweb uptake (see p. 13).Snapshot measurements found thatmethyl mercury consistently representedless than 11 percent of the total mercury inphytoplankton, then leaped to 40-85percent in zooplankton. The relativemethyl mercury concentrations startedout low down at the bottom of the foodweb but then rose rapidly. "The criticaltransition step appears to be from thephytoplankton to the zooplankton, andit's much more complicated than hasbeen reported in other aquatic systemswhere atmospheric mercury sources dom-inate," says USGS' Jim Kuwabara. ARO

Photo: Rob E. Holt/MMS

USGS' Mark MarvinDiPasquale extract-ing sediment fromthe root zone oftules growing in theDelta's Franks Tract. Photo: Jennifer Agee

9

There's a perfect machine for meas-uring mercury buildup in the aquaticfoodweb, but it wasn't assembled inany high-tech instruments lab in Texas.The caddisfly, whose green caterpillar-like larvae never move far from underthe river rock where they were born, isone of the chosen. So is a slim silverfingerling called the inland silverside,and a number of equally diminutivecrayfish, gobies, and shiners. Thesesmall fry carry a big weight on theirbacks: standing sentinel in our creeks,rivers, and bays to warn us of mer-cury's spread.

"A large fish tells you the bottomline, if mercury levels are bad or good,better or worse, but not necessarilywhere it came from and when," saysDarell Slotton, explaining that big fishlike striped bass build up their mercuryacross several years and from diverselocations. "It's the short-lived, localizedorganisms that can help us answer thetricky questions of time and place."

Slotton, a U.C. Davis aquatic biolo-gist, has been putting these organismsto work as "biosentinels" — jumping orwading into the water to catch fish andinsects, then cleaning, freezing, dry-ing, and grinding them up into powderto measure their body burden ofmethyl mercury. These organisms notonly have to be small, young, and notlong for this world to make the biosen-tinel team, but also be abundant, pop-ular as lunch for larger fish, unimagi-native in their own diets, and stay-at-home types. "They allow us to pinpointmercury problems to place and time ofyear, which is something we might beable to do something about in terms ofmanagement," he says.

Everywhere he's been in the past 10years — polishing his biosentinel tech-niques in CALFED and other studiesacross the Sierra, the Coast Range, andthe Delta — Slotton's been chasing thelinks between mercury in the environ-ment, biosentinels, and big fish. "We'restarting to get a handle on how they allrelate to each other," he says. In amajor Cache Creek study, his researchgroup did some of the most compre-hensive sampling of mercury in water,biosentinel organisms, and fish everdone. What they found, among manyother things, was that methyl mercuryin the water correlated directly withmercury in fish, whereas total mercury

in water did not correlate well witheither. Their results have led to someinnovations in the state's regulatoryapproach to mercury (see pp. 14-15).

Slotton's biosentinel results also sug-gest, in a general way, just how muchthe warm season correlates withincreased mercury uptake by insects,fish, and other aquatic animals."Spring comes, bacterial activity heatsup, methylation increases, plants andfish grow, put on weight, pick up mer-cury," he says.

Isolating just how much of measuredchanges in mercury bioaccumulationare due to natural variability — thewildcard common to California's flashyclimate — vs. local methylationprocesses and hotspots is also impor-tant. In an older, bigger fish, mercurychanges are very muted year to year.But in silversides in the Delta, for exam-ple, Slotton saw changes of up to 30%?in the amount of exposure dependingon the wetness of the year and theassociated ups and downs in newannual inputs from tributaries.

"We all went into this whole mercuryproject thinking that it might be hope-

less, with this backlog of legacy mercu-ry everywhere," he says. "But now thatwe see these seasonal and spatialspikes, we're thinking it's the new inor-ganic mercury brought down frommining areas with winter storms, notthe old stuff lying around, that may bemore bioavailable for methylation."

The stuff may certainly be morebioavailable in wetlands. In researchcomparing gravel pits used to con-struct wetlands along Cache Creekwith the sloughs flowing in and out ofthem, Slotton found that anotherbiosentinel fish, red shiners, pickedup more than double the amount ofmethyl mercury in the restored wet-lands than in the inflowing sloughs.Summer and fall uptake were muchhigher than in late winter and spring.

Keeping Tabs on Bioaccumulation

50-65 MM RED SHINERS (SMALL FISH)MEANS ± 95% CONFIDENCE INTERVALS

SEASONAL SHIFTSIN EXPOSURE AND BIOACCUMULATIONWITHIN A SINGLE LOCATION

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IN RELATION TO A WETLAND RESTORATIONIN EXPOSURE AND BIOACCUMULATION,

Darell Slotton and Shaun Ayers of U.C. Davissiening for biosentinel fish in the Delta.

Yolo County hopes to eventually convert a string of 17 major gravel pits along lower Cache Creekinto healthy riparian corridor. In this pilot project, researchers found that restoring one pit to awetland almost doubled mercury exposure and bioaccumulation compared to inflowing waterlevels. The data and actual uptake patterns in red shiners show, however, that seasonal manage-ment of water releases from the wetland (limiting fall releases, for example) can dramaticallyreduce downstream exposure and discharges of mercury. Though funded by Yolo County, thisresearch builds significantly on prior CALFED studies.

Source: Slotton, UCDavis

EFFECTS OF GRAVEL PIT RESTORATION ON METHYLATION & WILDLIFE EXPOSURE, CACHE CREEK NATURE PRESERVEMERCURY (PPM WET WEIGHT) IN 50-65 MM RED SHINERS

ScienceActionNEWS FROM THE CALIFORNIA BAY-DELTA AUTHORITY SCIENCE PROGRAM

On the western slope of the Sierra,Slotton and colleagues have identifiednumerous mercury hot zones, includ-ing the Middle and South Yuba Rivers,locations of some of the largest GoldRush Era hydraulic mines. These riverreaches are also candidates for the re-introduction of endangered nativesteelhead and spring-run chinooksalmon, and resource managers eagerto improve fish passage upstream andover dams asked the U.S. GeologicalSurvey's Charlie Alpers and Slotton to

assess mercury risks. The two scientistsnarrowed the danger zone for migrat-ing fish to a 25-mile reach between3,000 feet in elevation and EnglebrightDam. In this reach, mercury levels inbiosentinel young trout were fivetimes higher than in upstream reaches.As a next step, Alpers hopes to take acloser look at methyl mercury inspawning redds (the gravel nest inwhich anadromous fish lay their eggs).

On a parallel track, other mercuryresearchers have been keeping tabs

on the bigger sport fish that anglerscatch and eat. According to the S.F.Estuary Institute's Jay Davis, whoconducted the first major CALFEDsport fish study on mercury, theoceangoing salmon that so manypeople like to eat aren't even on thehealth warning radar screen. It's thebass, catfish and pike minnow — bigpredator fish that hang out in deepspots, reservoirs, and flooded islandswaiting to lunch on littler guys —that are of greatest concern for preg-

MAY 2005 10

AVIAN TROPHICS A Caspian tern skimming the Bay for

fish might actually be healthier if itwere a dumpster-diving gull. RecentCALFED-funded studies of more than300 bird eggs revealed that birds thateat only fish (like terns), use special-ized habitats, or nest and forage in Bay"hotspots" are ingesting more methylmercury than birds that feed part-timein parking lots or dumps.

"We thought gulls being fish eaterswould have high mercury, but theydon't," says U.S. Fish & Wildlife's TomMaurer, although, he adds, their cho-lesterol may be bad from all thoseFrench fries. "In general, the higher upthe food chain, the more mercuryyou're ingesting."

Exposure to mercury is not onlyrelated to what birds eat, but also towhere they eat. Levels of mercury ineggs from great blue herons at fivelocations in the Delta correlated direct-ly with mercury in silversides (theirprey fish). Eggs from birds like black-necked stilts and snowy plovers thatfeed in potential methylation zones —around the Bay's perimeter, at theinterface of land and water, or near theSouth Bay salt ponds — also had ele-vated mercury concentrations.

Mercury can affect a bird's behavior,hearing, the growth of its nestlings,and the hatchability of its eggs. Someof those things are so subtle they aredifficult to measure — especially whenbirds are migrating and nesting else-where, and also being exposed to

many other contaminants. "Trying totease all these things out can be tricky,and there is no easy way to general-ize," says Maurer.

Birds can shunt these contaminantssuch as mercury into their eggs. As aresult, hatchlings may get a doubledose — one inherited from their moth-ers via the egg, the second from thefish their parents bring to feed them.

Further enlightenment should comefrom a new study in which USGS andU.S. Fish & Wildlife will track mercurythrough the entire lifecycle of somebirds, from egg to adulthood to nest-ing and reproduction. In the study,biologists will attach radiotransmittersto bird legs to confirm that they arebreeding locally and pinpoint wherethey feed in the Bay. They can then testthe food organisms in those areas, aswell as the eggs, feathers and blood ofthe locally nesting birds.

Bird biologists are also paying closeattention to the endangered clapperrail. In a recent study, U.S. Fish &Wildlife researchers concluded thatmercury concentrations in WildcatMarsh clapper rail eggs that had failedto hatch were likely embryotoxic.Diminished reproductive success, theysay, could mean trouble for future Bayclapper rail populations and for thosetrying to restore their habitats. Howmuch trouble mercury will cause noone quite knows.

Whatever the trouble, the $5 million CALFED’s EcosystemRestoration Program recently approvedfor further bird studies will helprestoration managers address it headon. "We know enough to know that weneed to know more," says Maurer. LOV

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PLOVER AVOCET W. GULL BITTERN BC HERON DC CORM CA TERN CASPIAN

MEDIAN25-75%NON-OUTLIER RANGE

HERBIVORE OBLIGATE PISCIVORE

Source: Maurer, USFWS

MERCURY CONCENTRATIONS IN BIRD EGGSPARTS PER MILLION, WET WEIGHT

Keeping Tabs on Bioaccumulation

nant women and children.Davis compared mercury levels in

10 sport fish with U.S.EPA screeningvalues for human health risk, andlargemouth bass were among themost-contaminated (see map p. 5).In the Delta, 80 percent of these basshad over 0.3 ppm of methyl mercury(EPA screening level) and 17 percenthad over 1 ppm (FDA screening level).As a result of studies by teams work-ing with Slotton, Davis, and Alpersthe state has issued new consumptionadvisories for Bear Creek (Cachewatershed), several northern Sierralakes, the Lower American River, andLake Natoma.

One place the health risk for fishconsumers seems low is the very heartof the Delta. Sport fish species in thisin this labyrinth of favorite fishingcoves and river bends frequently hadlevels below U.S. EPA health-risk crite-ria . "It's a ray of hope," says Davis. "Itmeans that mercury is not necessarilyhigh everywhere in the foodweb. Itmeans there may be other places wecan tell anglers it's safe to go fish."

More rays of hope, or at least light,are in the pipeline. This spring 2005,scientists began hammering out thedetails of an amibitious new CALFEDfish-monitoring program with inputfrom diverse advisers. The group ischoosing 12 long-term biosentinelindex sites for annual monitoring,paired with more intermittent sportfish monitoring, as well as surveys inmystery zones where there are no fishdata and spot checking as needed atlarge restoration and research sites."We're going out of our way to getbiosentinel data from right in the mid-dle of other mercury research proj-ects," says Slotton. Indeed, the entirefish-monitoring program should alsobenefit from tighter, stricter protocolsso that multi-species, multi-site datacan be better correlated.

"The bottom line in dealing withour mercury problem is always thefish. If it's not in the fish, it's not inthe fish," says Slotton. ARO

11

Tricky TailingsOnce upon a time, gold was our

region's most coveted resource, butthese days gravel seems equally pre-cious. Those trying to recreate flood-plains and salmon spawning beds —in rivers where most of the naturalgravel supply lies stuck behind dams,and where holes dug by gravel-min-ing operations gape to be filled —have been eyeing the big piles left bygold dredges. Gold dredges movedalong rivers, digging up the flood-plain and channel gravels, separatingout the gold (with the help of mercu-ry), and stacking tailings (cobbles,pebbles and other coarse materials) onthe banks. And while this form of min-ing may have left behind a cheap localgravel resource, it also ruined habitatand disrupted river processes along 11rivers and creeks in the Bay-Deltawatershed. In these areas, river restor-ers must not only find materials torebuild spawning and riverbeds, butalso shift the once-mined landscapearound to widen channels and recre-ate floodplains. Managers are worriedthat the disruption, and the reuse oftailings, may mobilize mercury.

In 2003, researchers, restorationmanagers and regulators joinedtogether to form a special work groupon tailings. In a major collaborativeeffort, this Dredge Tailings Work Group(including Bay-Delta Authority staff) isnow drafting an issue paper that laysout considerations for restorationmanagers.

Scientists, meanwhile, are learningmore every day about how mercury intailings might behave as a result ofvarious restoration uses. The CALFEDprogram, USGS, and other agencieshave launched diverse research proj-ects in recent years. The projects coverClear Creek and the American, Merced,Trinity (non-CALFED studies) rivers —comparing mercury levels in tailingspiles and surrounding waters to back-ground levels, tracking mercury'schemical transformations as tailingsare disturbed or exposed to differentecological processes, and experiment-ing with sorting and washing to elimi-nate the most contaminated material,among other topics.

"The coarse material is always verylow in mercury, but the fine materialcan be very high," says Roger Ashleyof the USGS. "What's interesting is thatwe're not really finding much of theelemental mercury used for goldamalgamation anymore. In the courseof a half century, it's been trans-formed into other species of mercury,some of which are more of a worry."

Ashley and James Rytuba, amongothers at USGS, have been scrutinizingthe Clear Creek and Trinity River situa-tions. They have been using a"sequential extraction" method toidentify different species of mercury intailings samples — enhancing under-standing of how and when mercurytransforms into more soluble, mobile,and bioavailable forms. (Rytuba andother researchers have also been simu-lating how natural waters containing

salts and organicacids may removemercury from tail-ings.)

Ashley, mean-while, can look at ariverbank wheredredge tailings wereleft behind andidentify whichdeposits and layerscame from the sluiceand which from thestacker (see left andcover photo). Someof the sluice tailingsmay contain morethan 100 times back-ground levels ofmercury, Ashleyfound, whereas thecoarser stacker tail-ings have close tobackground levels

TAILINGS SECTION, BUCKTAIL BRIDGE, TRINITY RIVERTOTAL MERCURY IN PARTS PER BILLION

SANDY STACKER TAILINGSSLUICE SAND

Sand 3950 ppb

SANDY STACKER TAILINGScoarse 20 ppbgravel 90 ppb

Sand & fines 560 ppbSTACKER TAILINGS

coarse 10 ppbgravel 20 ppb

Sand & fines 150 ppb

HYDRAULIC TAILINGS

Silversides. Photo: Slotton

Source: Ashley, USGS

ScienceAction

(see chart below). Results con-firm that the mercury associateswith the silt and clay fractions (lessthan 63 micrometers in diameter), andincludes forms which are mobile andreactive.

Despite the mercury levels,restoration using these materials willnot necessarily have obvious effectson biota because most projects arerecreating floodplains or activestream channels — environmentswhere methylation is low, saysAshley. Ponds in tailing piles, how-ever, can be methylators, especiallyif the water chemistry is favorable.

Not all rivers tell the same mercu-ry story. Along the Merced River,tailings tested by Maia Fleming-Singer of Stillwater Sciences turnedout to be close to natural back-ground levels, even within the sandsand fines (less than 2 millimeters).

On the state's Merced River Ranch,Fleming-Singer examined tailingspiles 6 to 15 feet high from base tocrest, and 20 to 30 feet deep in someplaces. A look at prickly sculpin andcaddisfly larvae found that thesebiosentinels picked up more mercuryupstream of the ranch than below."Finding a site where there actuallywasn't a huge mercury signal wasgreat news," says Fleming-Singer.Compared to levels in fish andinsects in other rivers, the Mercedtests came up relatively clean.

Just because levels proved low inranch site samples doesn't meanthere aren't mercury hotspots else-where along the river, or that dis-turbing the ranch's finer materials

isn't a problem.Sorting andwashing candi-date materialsfor restorationcan help, but todifferentdegrees, accord-ing to tests doneby Fleming-Singer. For thelarger-size frac-tions, washingmade little dif-ference to thetotal mercuryleached fromgravel surfaces,whereas in thesmaller size itdid (see chart).

"Dry sortingremoved 72% of the total mercury, sosize separation appears to be reallyworth it if you're just going afterbigger spawning gravels," she says.

As forwhy theMerced hadrelativelylow mercuryin testedtailings,Fleming-Singer admitsit's somethingof a mystery.But the take-home message is clear."You can't assume one way or anoth-er that mercury will be a problem atyour site. It can go both ways," shesays, suggesting that careful man-agement, as well as batch testingand sorting, should be done at everysite, regardless. "The good news isthat at the Merced River Ranch, ourcoarser material may be usable asspawning gravel resource, and we'renot necessarily stuck with a toxic pileof rocks." ARO

MAY 2005 12

Tricky Tailings

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LEACHED MERCURY FROM DRY SORTING VS. WASHINGMERCED RIVER RANCH SEDIMENT TESTS: THEORETICAL THg MAXIMUM RELEASED ng/g

Joshua Weinstein of URSseparates largest dredgermaterial at Merced RiverRanch.

Source: Fleming-Singer, Stillwater Sciences

Source: Ashley, USGS

13

Reservoirs have something in com-mon with old mercury mine sites:They're potential methylation facto-ries. But while abandoned mine sitestend to export mercury through ero-sion, reservoirs keep most of it allbottled up. And while the down-stream threat from mine sites comeslargely with big winter storms, it isthe lack of water in summer and fallthat can bring on mercury and methylmercury spikes in some reservoirs.

At mine sites, it's the old tunnels,canals, pits, and ponds — wherewater interacts with mercury in thepresence of sufficient sulfate andorganic carbon — that seem to loadresident bugs up with methyl mercu-ry. Non-CALFED studies at SierraNevada gold mines by Charlie Alpersand his USGS colleagues found consis-tently high levels in water striders —those long-legged bugs that seem toscissor across the water’s surface, andwhich eat other bugs that interactwith contaminated sediments.

Waters immediately downstream ofsome abandoned gold and mercurymines are acutely high in methyl mer-cury. The presence of nearby geother-mal springs, as in areas of Sulphurand Bear creeks in the Cache Creekwatershed, or of acid mine drainage,as in some parts of the Sierra Nevada,can exacerbate methlyation by intro-ducing more sulfate (see p. 6).

Downstream of mines, putting adam across the river may not havebeen an entirely disastrous thing fromthe mercury perspective. The damstrap and sequester the eroded miningsediments in their reservoirs. Whilethis may keep the harm in check, itcan also concentrate the mercuryproblem. "The reservoir itself is like alandfill; you wouldn't want to livethere," says Alpers. Tests above andbelow dams confirm lower total mer-cury and methyl mercury levels on thedownstream end.

Tests also confirm that as much, ormore, total mercury can flux out ofthe reservoir sediments into the wateras comes down the river into thereservoir. At Camp Far West Reservoiron the Bear River, one watershedsouth of the Yuba, a 2002 non-CALFEDstudy by the USGS' Jim Kuwabarafound that in an unusually dry year atleast, the reservoir bed was the domi-

nant source of dissolved mercury tothe water column. "You can't just useriverine discharge from station x, atflow y, and concentration z to deter-mine your mercury loads and risks,"he says.

Within reservoirs, mercury methy-lation and uptake into the food webmay have a lot to do with the devel-opment of different water layers inthe reservoir (stratification) and theduration of low oxygen (anoxic) con-ditions conducive to methlyation inthe summer and fall, when water lev-els get low. While methyl mercurymay largely be produced at the anox-ic sediment-water interface down atthe bottom, when there's a turnoverbetween upper layers and lower lay-ers the methyl mercury gets mixedinto the entire water column. In reser-voirs that stratify, upper and lowerlayers commonly turn over at leastonce each year, typically in the fall,as the upper layer cools down,changing the water's density.

The fall timing of these kinds ofmethyl mercury releases to the fullwater column can be bad timing forthe aquatic foodweb. Phytoplankton(tiny plants) tend to bloom in the falland winter, followed by blooms ofzooplankton (tiny animals) in thespring. "The critical seasonalsequence seems to be first reservoirstratification, then methyl mercuryproduction, then the lakes turn over,phytoplankton bloom, zooplanktonbloom, and you've got methyl mercu-ry headed onward and upward intothe foodweb," says Alpers, citingtrophic transfers monitored by hisUSGS colleague Robin Stewartin non-CALFED studies at CampFar West Reservoir.

As methyl mercury magnifiesup the reservoir food chain, thefish that live in the reservoirsmay become better candidatesfor catch and release thanSunday dinner. But when allthat's on the dinner table is aglass of water from a reservoir,the mercury levels scientists aremeasuring aren't enough toraise eyebrows.

Some dams and reservoirsdon't provide drinking waterbut do offer significant impedi-ments to fish migrating

upstream. Daguerre Point Dam (1907)and Englebright Dam (1940) werebuilt on the Yuba River to stem thetide of hydraulic mining debris. Nowthat restoration managers are consid-ering taking them down, or modify-ing them in ways that would releasesediment, Alpers and his colleagueshave been examining mercury intrapped sediment. As part of a aCALFED study at Englebright Lake,after drilling through the pile of post-reservoir sediments in six locations,including one site more than 100 feetthick, Alpers found a surprisingamount of methyl mercury way downdeep. Unlike conditions underMinnesota lakes, for example, wherebelow about five feet methyl mercurylevels are quite low, the methyl mer-cury in sediments buried underEnglebright Lake seems to have beenproduced continuously for the past 60years at great depth. "It's not like it'sbeen buried in a lockbox, and noth-ing happened to it. My gut feeling isthat because we have all the ingredi-ents down there — organic matter, theright chemistry — new methylationhas kept pace with demethylation,"says Alpers.

Those wishing to remove or modifythese or other dams should be pre-pared for a slug of fine material that,at least in the case of the Yuba Riverdams, contains about 300-1,000 partsper billion (ppb) total mercury andup to about 1-3 ppb methyl mercury.Scientists say such releases will prob-ably have more of an impact down-stream, especially in areas alreadysuffering from high mercury bioaccu-mulation levels, rather than immedi-ately below dams. ARO

Mine Sites, Reservoirs and DamsScienceAction

CAMP FAR WEST RESERVOIR IN THE SIERRA

APRIL

NOVEMBER

NEWS FROM THE CALIFORNIA BAY-DELTA AUTHORITY SCIENCE PROGRAM

Source: Kuwabara, USGS

14MAY 2005

MANAGEMENT

People First,Landscape ASAP

The wait for more science hasn'tkept the CALFED program and otheragencies wrestling with mercury fromgetting busy. In the three years sincethe the CALFED Mercury Strategybecame a unifying vision for mercuryresearch and management throughoutthe watershed, many of the actions atits heart have gotten underway, with apriority on tracking levels in the fishthat people eat most, and beefing upoutreach to at-risk Delta communities.In its work to implement the Strategy,CALFED has also helped identify thetruly bad actors among mercury minesfor priority cleanup, subsidizedstrapped state public health programs,investigated management options thatmight control the exposure of endan-gered and other wildlife to methylmercury, and supplied solid science toback up the region's water boards intheir efforts to regulate mercury dis-charges into streams, rivers, and theBay.

Central to the Strategy is educatingthose who are casting lines out intoBay-Delta waters, reeling in fresh fish,and taking them home to their familiesabout the mercury potentially on theirdinner plates. It is the children of thesefamilies – the unborn and the veryyoung – who are most at risk. For thedeveloping fetus, mercury can causemeasurable decreases in learning,attention, and memory. Other moreserious problems associated with mer-cury range from tremors and slurredspeech to kidney and neurological dis-orders. These days, most of the mercu-ry anyone accumulates comes fromeating large, long-lived fish of bothcommercial and sport derivation. Soit's no wonder fish consumption advi-sories for women of childbearing ageand children are the backbone of anyeducation effort on mercury.

The U.S. EPA and the state's Office ofEnvironmental Health HazardAssessment issued general advisoriesabout mercury in sport fish in the1970?s, and more recently, the FDAwarned of problems with tuna, shark,and other commercial fish. In 2004, thestate also released 10 local advisoriesfor Bay-Delta counties.

Whether state, regional, or local, thejob of creating these warnings isn't

easy. Bob Brodberg, a senior toxicolo-gist with the state's health hazardoffice, must patch together fish tissueinformation gathered by dozens ofdifferent agencies to create uniform,defensible advisories.

With CALFED and state funding,Brodberg will be laying the ground-work for a Cosumnes and Mokelumneriver advisory in 2005, and analyzingexisting Delta data for a San JoaquinRiver advisory. Next year, he'll work onthe area north of the San Joaquin upinto the Sacramento. River advisoriesare much more challenging than reser-voir advisories for the obvious geo-graphical reasons. "It's harder to com-municate risk when you have to saythat if you're fishing in the San Joaquinat Landers Ave., only eat one meal aweek of this species, but if you're atLaird Park, you can eat more," he says."The ultimate goal is to point peopleto fish they can eat more, not less, of."

Reaching the right people, with theright information, is the job of AlyceUjihara of the Department of HealthServices. "These communities are chal-lenging to reach, because of languageand cultural barriers. If you put up asign, they may not read it," she says.

Uhihara's agency began conduct-ing outreach to these communities infive counties of the Delta watershedwith support from CALFED, the DeltaTributaries Mercury Council, and theCentral Valley Regional Water QualityControl Board. She started by creatinglocal advisory groups within the Bay-Delta and Sacramento River water-shed, striving to enlist the assistancefrom people within targeted commu-nities. These groups help to develop,translate, and distribute educationalmaterial, and liaison with other moretechnical adviosry groups. Theseinclude a newly developed colorfulwarning postcard picturing both"safer" and "less safe" fish types, anddetailing how many meals of what sizefish are safe to eat per month. A Deltaposter has also been created in eightlanguages.

Ujihara’s agency isn't just trying toget the warnings to anglers. As shepoints out, those most at risk are thewives and children of anglers, not theanglers themselves. To this end, shebegan a survey in 2004 of 500 low-income women at a "WIC" (Women,Infants & Children) clinic in Stockton.In addition to the WIC survey, Ujiharawill survey boaters and anglers, con-

duct training sessions for county staffand community organizers, and col-laborate on the Food Stamp NutritionEducation Program in the Delta watershed.

CALFED has also helped her provide$10K mini-grants to groups fromCambodian, Russian, Latino, andAfrican-American communities to helpthem educate their own. "For the mostpart, when we went to these groups,they knew very little about the risks,"she says. "We think awareness is high-er now, but we aren't sure if we'vechanged behavior. It's hard to measureconcrete results unless you go intokitchens and monitor what they cookand eat."

Beyond the human health questionlies the question of how to gain controlof the places and processes thatexpose fish to mercury in the firstplace. As it moves from sediments towater to fish, mercury poses an unusu-al challenge to state water qualitymanagers used to setting concentra-tion limits for much less changeablepollutants. But set limits they must.Both the Delta and the Bay are on thefederal "303(d)" list of waterwayswhose beneficial uses are impaired bymercury, requiring the state to comeup with total maximum daily loads(TMDLs) allocated among all sources.

At press time, there were four mer-cury TMDLs in various stages ofapproval: two for watersheds believedto be the biggest polluters in terms ofmines, Cache Creek high in the CoastRange northwest of Sacramento andthe Guadalupe River watershed (homeof the New Almaden mercury mine)down in the South Bay. Two regionalTMDLs, one for the Delta and one forthe Bay, are also in progress. ThisMarch, the State Board asked the tworegional boards to integrate theTMDLs.

This integration shouldn't be toodifficult, according to the S.F. BayBoard's Dyan Whyte. Sediment leveltargets, source control actions, and theemphasis on commonly caught andconsumed sport fish as indicators all

Delta ddvisory postcard.

have "the same endpoints" in the vari-ous TMDLs, she says. The main differ-ence between the two regions is that theCentral Valley Board's proposed regula-tions are based on methyl, as opposedto total, mercury. For the S.F. Board, thetotal mercury approach seemed moreappropriate. "When you discharge mer-cury into an estuary vs. a freshwaterriver, the geochemistry is different. In ariver system, where you're only lookingat what's going past a specific point,you have a different mercury uptakeand degradation dynamic," she says."But other than that, we're pretty muchin sync in terms of where we need to gowith the TMDLs."

One place everyone wants to go is thesettling basin at the base of Cache Creek,which traps 50% of the mercury (total)headed downstream from this mine-dot-ted watershed, according to a 1998Central Valley Board study. Options forincreasingthe basin's capacity to stemthe spread of mercury downstream arenow being researched (see photo p. 16).Studies have identified a number ofother high-priority source control proj-ects: dredging and disposal of mine tail-ings in the bed of Sulfur Creek; andrerouting water around mine wastepiles, as well as curbing and containingerosion, at the Abbot and Turkey Runmines near Harley Gulch. "The most dif-ficult question is how to pay for minesite cleanup and long-term mainte-nance," says Central Valley Board seniorengineer Patrick Morris. Privatelandowners are fearful of such liabilities,which can overwhelm individual pocket-books. With Prop. 13 funds, CALFED willbe able to provide $15 million in financialsupport. TetraTech, which conducted areview of mine sites and their remedia-tion potential for CALFED, estimates theAbbott and Turkey Run projects alonecould cost between $2.6 and $5.9 million.

Upstream cleanup could prove morecost-effective than more wastewatertreatment downstream. "It would take agreat deal of money to get another gramor two of methyl mercury out of our dis-charges," says Vicki Fry of the Sacramen-to Regional County Sanitation District.The Sanitation District sees merit in "off-setting" any load reductions the TMDLplaces on dischargers by contributing toCache Creek settling basin improvementsor supporting a mine cleanup.Unfortunately, such offset programs, alsoknown as pollutant trading, have neverbeen tried for mercury in water.

An offset program feasibility study,submitted by the Sacramento County

discharger to the Central Valley Boardthis March, suggests load reductionupstream (through trading), support ofmore science on methylation processes,and outreach and education. "One ofthe biggest science questions for us interms of future trading is, how do weequate one methylation site with anoth-er? Can we combine bioavailability,location, and uncertainty factors in oneequation?" Fry says. However it's done,any trading proposal faces an uphillbattle with the U.S. EPA, which has apolicy against trading programs for anypersistent bioaccumulative substanceother than on a small pilot scale.

"In the end, what we really need toclean up mercury sources are resources(money) and some federal legislation toaddress liability problems – these arereally the two impediments to majorprogress in the mercury arena," saysCALFED's Donna Podger.

CALFED is only one of many programs,organizations, agencies, and individualsworking on the mercury problem.Recycling efforts have been gatheringsteam up and downstream, as dentalfillings, old thermometers, and mercuryfrom current gold mining activities arecollected and processed, rather thanentering the waste stream. Millions have

15

ScienceAction

Though reducing mercury methylationin their marshes may be a new priority forrestoration managers, scientists are stillbusy researching how different conditionsand habitats measure up in the mercurymix.

"The water depth at which you build awetland may turn out to be critical. Like-wise, certain elevation changes, certain flowcharacteristics, and certain vegetation typesmay decrease methylation," says geo-chemist Gary Gill of Texas A&M University.

These are the types of restoration detailsthat a new CALFED study launched thisspring hopes to uncover. Over the nextthree years, the eight-member multi-agency study team, led by Donald Yee ofthe S.F. Estuary Institute, will be compar-ing marsh habitats along the PetalumaRiver. Variations in environmental charac-teristics – marsh age, salinity and tidalregime, channel size, geomorphic fea-tures, vegetation, foodweb, total mercuryin sediments – will all be examined interms of their influence on the rate ofmethyl mercury production and bioaccu-mulation.

Prior studies have revealed noticeabledifferences between sediment concentra-tions of methyl mercury in large and smallchannels, and scientists have linked chan-nel size with reproductive failures in clap-per rails. "In smaller channels, the bound-ary of the anoxic environment is nearer thesurface of the marsh. The physical closenessof all parameters here – the anoxic bound-ary, the feeding wildlife, the methyl mercu-ry in the anoxic zone – may increase thechance of this toxin entering the foodweb,"says Institute wetland ecologist Josh Collins.

With the results of the study, CALFEDhopes to give more detailed advice abouthow and where to proceed with tidal wet-land restoration projects. For example, ifmethyl mercury production is elevatedwithin a particular range of sulfate con-centrations (Goldilocks areas), restorationprojects might be better pursued in areasoutside this range. Similarly, if wet-seasonflows deposit the most sediment-boundmercury, decisions about the timing ofdike breaching could be adjusted accord-ingly. And if methyl mercury is associatedwith certain landscape features withinwetlands, like small channels or shallowpools, projects may be designed to mini-mize these features.

The link between habitat design andmethyl mercury creation and uptake is notonly being researched through CALFED. AProp. 13-funded project, managed by theAssociation of Bay Area Governments andLevine-Fricke, will spend more than $1 mil-lion conducting a series of pilot projectsexploring the relationship between wet-land design, methylation, and foodwebuptake in the Bay region. In addition, wet-land restoration projects at Marin'sHamilton Air Force Base and on 16,500 acresof North and South bay salt ponds areactively collecting and analyzing moresite-specific information on mercury asthey begin reintroducing tides, plants, andlandscape diversity to former baylands.

Just because such projects are big doesn'tmean they will produce more methyl mercury than smaller ones, says Collins.Clearly the variables, and their effects onmethylation, are myriad in the restorationgame. In the meantime, "start slow, monitor, learn, correct" seems to be

MARSH DESIGN WITH MERCURY IN MIND

NEWS FROM THE CALIFORNIA BAY-DELTA AUTHORITY SCIENCE PROGRAM

CREDITS

Editor - Ariel Rubissow O

kamoto; Contributing W

riter - Lisa Ow

ens Viani; Proofreading - Kathryn Ankrum

; Illustration Support - Maiko Furusaw

a; Designer, Darren Campeau, w

ww

.dcampeau.com

been spent cleaning up the NewAlmaden mine state Superfund site inthe Guadalupe River watershed. And inone reservoir in that watershed, theSanta Clara Valley Water District willsoon be experimenting with aeratingthe lower layers of water during highmethylation seasons.

Despite all the action and research,scientists are quick to say they are stillabout five years away from knowingenough to give restoration managersany guidelines for minimizing mercuryrisks. "Mercury has dealt us a lot ofsurprises, so those of us who work inthe field are a little gun-shy of makingspecific recommendations," says MarkMarvin-DiPasquale of USGS. In themeantime, two documents offer twoplaces for restoration managers tostart. The CALFED Mercury Strategydetails a sound framework for organiz-ing adaptive management and moni-toring of restoration projects.

Beyond the printed word, there areother opportunities for researchers andthe public to learn about and shareprogress on mercury projects. Aboutsix years ago, three separate mercurystakeholder efforts came together andreformed to create the Delta TributariesMercury Council. As a sub-committeeof the Sacramento River WatershedProgram, this council provides a forumfor outreach, education, and exchangeof scientific data, identifies opportuni-ties to improve public policy on mer-cury management, and acts as asounding board for ideas. Projects likethose highlighted in these pages areoften presented and discussed at thebi-monthly meetings of the council.CALFED program staff actively partici-pate in this forum, and the two organi-zations have worked collaboratively on

various mercury advisory groups.Other active working groups includethe Sierra-Trinity Abandoned MineLands Agency Group, which consists ofagency staff collaborating on aban-doned mine restoration efforts and theDredge Tailings Workgroup, which isdeveloping an issue paper on the tech-nical, regulatory and managementchallenges of using dredge tailings forrestoration.

"In the last five years, our dialogueshave grown from the local to theregional scale," says Atkins, whoorganizes communication and meetingactivities for all three groups."Now we want to bring thediscussions up a notch, to alarger dialogue with morecross-talk among between dif-ferent disciplines and projects.We need to network the mer-cury issues with the organiccarbon and environmentalrestoration issues."

Networking requires infor-mation sharing not onlyamong landscape and waterquality managers, but alsoamong various research efforts.To make sure all its own pro-grams generate compatibledata, CALFED is now putting acomprehensive quality assur-ance program in place. Data isalso being fed into theCalifornia Environmental DataExchange Network – a collabo-rative project on the part ofstate and regional water quali-ty boards, the CaliforniaDepartment of Fish & Game,and the Department of WaterResources, among others – tomake data more accessible, viathe download button, to all.

"It's easy to get hung upon how complicated thebehavior of mercury in theenvironment can be, especial-ly in view of the extraordinaryvariation within the Bay-Deltaecosystem over space andtime, but communication isthe primary key to success,"says Jim Wiener, a professorat the University ofWisconsin-La Crosse, who ledthe development of theMercury Strategy and regardsits ongoing investigations asone of the most advancedefforts of its kind. "The bottom

line is that the scientists and man-agers involved with this contaminatedecosystem must find the time to sitdown and communicate; otherwise,they won't succeed in applying thisvery technical information to man-agement issues on the ground. Thegreatest strength of the MercuryStrategy is that everyone involved inits development has a sense of owner-ship about it, and is working togetherto address the problem."

16MAY 2005

Management

CONTACTS & WEBLINKS

George Aiken, U.S. Geological Survey graiken@usgs.govCharlie Alpers, U.S. Geological Survey cnalpers@usgs.govRoger Ashley, U.S. Geological Survey ashley@usgs.govBob Brodberg, Office Env.Health Hazard Assessement

rbrodber@oehha.ca.govAmy Byington, Moss Landing Marine Lab

abyington@mlml.calstate.eduJosh Collins, S.F. Estuary Institute josh@sfei.orgJay Davis, S.F. Estuary Institute jay@sfei.orgGary Gill, Texas A & M University gillg@tamug.eduMaia Fleming-Singer, Stillwater Sciences

maia@stillwatersci.comChris Foe, Central Valley RWQCB cfoe@waterboards.ca.govMark Marvin-DiPasquale, U.S.G.S. mmarvin@usgs.govPatrick Morris, Central Valley RWQCB

pmorris@waterboards.ca.govJohnnie Moore, CBDA johnniem@calwater.ca.govDonna Podger, CBDA dpodger@calwater.ca.govDarell Slotton, U.C. Davis dgslotton@ucdavis.eduMark Stephenson, Moss Landing Marine Lab

mstephenson@mlml.calstate.eduThomas Maurer, U.S. Fish & Wildlife Thomas_Maurer@fws.govAlyce Ujihara, Dept. Health Services aujihara@dhs.ca.govDyan Whyte, S.F. Bay RWQCB dwhyte@waterboards.ca.govJames Wiener, Univ. of Wisconsin, Lacrosse

wiener.jame@uwlax.eduRESOURCES & REPORTSBlood Mercury Levels in US Young Children & Women 1999- 2002, CDC

www.cdc.gov/mmwr/preview/mmwrhtml/mm5343a5.htmCALFED Mercury Strategy & Research http://calwater.ca.gov/Programs/Ecosystemrestoration/ecosystemmer-curyprojects.html

http://loer.tamug.tamu.edu/calfed/Frequently Asked Questions About Mercury in Fishbrochure (510)622-4500Guadalupe Watershed Mercury TMDL:

www.valleywater.org/Water/Watershedshttp://imcg.wr.usgs.gov/dmmrt/

SF Estuary Mercury News Website: sfmercurynews.orgTMDLs: www.waterboards.ca.govUSGS Mercury & Mining Fact Sheet:

http://pubs.usgs.gov/fs/fs2005-3014.html

COORDINATING GROUPSSierra Trinity Abandoned Mine Lands Agency Group

catkins@harriscompany.netDredge Tailings Work Group catkins@harriscompany.netDelta Tributaries Mercury Council www.sacriver.org/dtmc

This publication was paid for by the CALFED Science Program.

FISH CONSUMPTION ADVISORIESwww.oehha.ca.gov/fish.html, or (916)327-7319www.epa.gov/waterscience/fishadvice/advice.html

Raising the height of this outlet weir is one of a number of possible improvements to a1930s-era settling basin where Cache Creekempties into the Yolo Bypass near the city ofWoodland. The basin traps an estimateed halfof the mercury coming downstream in wetyears.