MERCURY CONTAMINATION IN S-NEW ENGLAND AND LONG

ISLAND SOUND, USA

JOHAN C. VAREKAMP

EARTH & ENVIRONMENTAL SCIENCES

WESLEYAN UNIVERSITY

MIDDLETOWN CT USA

Mercury droplets on cinnabar (HgS)

MERCURY AND HUMAN HEALTHMercury has no known biological function and binds tightly to sulfhydryl groups, inhibiting molecular functions

•reduces membrane permeability

•reacts with and disrupts phosphate bonds in ATP/ADP

•replaces cations in important molecules

-SH

ENVIRONMENTALCONCERN

HUMAN HEALTH CONCERN:HG IS A NEUROTOXIN

Victim of the “Minamata Bay” (Japan) tragedy, the first documented disaster of Hg pollution (1954)

Exposure to mercury?

Eating fish or shellfish Breathing vapors (home, work)Dental work and medical treatmentsReligious rituals that include Hg

inhalation (Santaria in Haiti)

Fish ConsumptionPrimary form of human exposure to

methylmercury is through fish consumption.

Population at greatest risk: small children and pregnant women that consume fish

EPA - RfD is 0.1 ug MeHg/dayMaximum Hg-in-hair level is 1 ppm Hg

cumulative frequency distribution Hg in hair

0

10

20

30

40

50

60

70

80

90

100

0 250 500 750 1000 1250 1500 1750 2000 2250 2500 2750 3000

interval Hg in hair ppb

%

Series1

Wesleyan University study: 35%> EPA limit (nationwide random sample shows 20% above EPA limit)

EPA limit

Hg Sources – USA1998

Annual Hgemissions,

106 grams/yr.Oil-Gas Fired power plants 0.2

Coal-fired power plants 46.9Municipal waste incinerators 26.9Medical waste incinerators 14.6

Commercial/Industrial boilers 25.8Ore metal smelting 0.16

Other combustion sources 10.8Total combustion related 125.4Chlor-alkali production 6.5

Other sources 12.1TOTAL 144

Delivery pathways of Hg to the coastal environment

• Atmospheric deposition in the watersheds and fluvial transport to the coast

• Point source contamination on land with fluvial transport to the coast

• Direct discharge through outfall pipes of waste water treatment plants

• Dredge and sludge dumping

QuickTime™ and aNone decompressor

are needed to see this picture.

Some important forms of Mercury in the environment:

Hg2+

oxidized

CH3-Hg-CH3

organic, volatile, lipophilic

Hg0

reduced,

elemental,volatile

CH3-Hgorganic, charged,

lipophilic

Hg2+

Hg0

reductionbioaccumulation

demethylation

methylation

volatilization

CH3-Hg+

(CH3)2-Hg

anaerobic

aerobic

(Sulfate reducing bacteria)

Hg Transport• Dissolved metals (e.g., in complexes

with dissolved organic matter)

• Attached to fine particles:

• Inorganic

• Organic

Repositories of metals• Coastal subtidal sediments (delivery

mainly by particulate deposition)• Coastal salt marshes and estuarine

marshes (delivery mainly by particulate deposition and to some degree through in situ atmospheric deposition)

Sediment Cores

• Environmental archives that contain contamination records of metals

• Record can be blurred by

–Chemical mobility in the sediment column

–Discontinuous sediment deposition (flood deposits)

–Bioturbation

504030201000

0

1

2

3

4

5

6

Depth, cm

137Cs, dpm/gr1963

Mercury Levels

• Normal modern soil background levels for mercury in the northeast USA are around 200 to 300 parts per billion– Mostly due to atmospheric deposition

• Sediment samples with higher Hg suggest point sources of Hg in watershed

• Hg inventories: total amount of Hg deposited on 1 cm2 over the full pollution period

30002000100000

100

200

300Background

Hg pollution

Hg inventory,ng/cm2

GRAIN SIZE EFFECT ON HG INVENTORIES

RMRG

DBFI

PI

SR

Mercury profile core Chapman Pond, CT River, CT

Mercury profile from core BFB3A, Farm River marsh, Branford, CT

20001950190018501800175017001650160015500

100

200

300

400

500 GI-1

PTB100

Age AD

Hg ppb

20001950190018501800175017000

250

500

750

1000

1250

1500

1750

Age, years AD

Hg, ppb

onset of 'hatting' industry in Danbury

Onset of severeHg contamination

Knell's IslandCore KI 1

Flood Deposits

"normal" peak level of Hg contamination in CT

Natural background Hg level

Core Backgr. Onset Peak Peak ModernSSSaaallltttmmmaaarrrssshhheeesss

ppb Hg AD ppb Hg AD ppb Hg

BI2 38 1850 329 1970 218BI3 58 1850 243 1939 145BI5 93 1850 474 1974 206PTB/J100 54 1890 159 1956 107GI 35 1860 398 1960 146E 36 1900 293 1959 97GA 53 1870 415 1972 326GK 55 1860 420 1967 296BFB3a 44 1800 525 1940 236BFA3 37 1810 469 1944 249BFL8c 54 1790 333 1997 333KI1 68 1800 1544 1964 177FFFWWWMMMaaarrrssshhheeesssCP3 103 1820 414 1964 358DM - - 453 - 118MMMtttnnn bbbooogggsssTM 42 - 267 - 214LL 44 - 356 - 276Average 54 1842 441 1962 219

MarshCore

Peak Hg* dep. rate,ng Hg cm-2 yr-1 (peakyear)

Modern Hg*dep. rate, ngHg/cm-2 yr-1

% drop

Guilford 22.8 13.8 40 %GK 17.6 (1970) 10.8 40 %GA 28.0 (1970) 16.7 40 %

Barn Island 10 6 40 %BI-2 8.6 (1965) 6.4 25 %BI-3 12 (1940-1950) 5 58 %

BranfordBFA3 35 (1950 -1960) 15 57 %BFB3 13 (1930 -1940) 10 24 %Modernatmospheric HgDeposition rate

Fitzgerald et al. 1 - 2 Av. :

40 %

Barn IslandPataguanset Guilford Branford Atmosphere0

5

10

15

Mercury Deposition RatesMeasured Modern Atmospheric vs.Calculated from Inventories

ng/cm^2 yr

THE STILL RIVER, WESTERN CONNECTICUT

~1955

Fowler Island core, Housatonic River

1401201008060402000

0500

100015002000250030003500400045005000

Depth cm

Hg ppb

~1900

~1950

~ 1800

Pope Island core, Housatonic River

Floods of 1955Wooster Square, Danbury

The floods of 1955 in Waterbury, CT after twohurricanes hit in a few weeks time

Norwalk River CoreHg Concentration vs. Depth of Norwalk Core

0

1000

2000

3000

4000

5000

6000

0 10 20 30 40 50 60 70 80 90

Average Depth of Sample (cm)

Average Hg Concentration (ppb)

1820

1900

1955

Housatonic River, Still River, Norwalk River: strong evidence for Hg from hat-making sources

Source signals modified by floods

The return of the mad hatter

Lee Hat Factory

Mallory Hat Factory

EVERYONE wore hats. Men, women,

Danbury, CT"The Hatmaking Capital of the World"

• Hatmaki ngstarte d in Danbu ~ 1780ry• Th e" carrotage" solution (H g i n nitric

acid) isuse d t o mak e fel t fro mfur• Th efelt-makin g isdon e in asteam

saturate d environmen , t an d th esteam-condens ate wit h H -g nitrat edrip s fromth ewal lsan d ru ns offin to theenvironment

• Danbu ry Hat production:1808 - 100,000 hat / s year1850 - >1 milli onhat / s yea r wer e made;

65 h at factorie sacti ve in Danbury1920 - >5 milli onhat / s year1943 - 'carrotage ' proce ssoutlawed

The Carroting Solution…had nothing to do with vegetables.

This bright yellow-orange solution of mercury and nitric acid was used to treat animal fur from pelts. It made the fur fibers mat into felt more easily.

Men working in Mallory’s carroting room

Benedict’s factory initially produced 3 hats per day

Background Hg contamination in central and eastern Connecticut, much higher levels of Hg contamination in western Connecticut (Still River and Housatonic River wetlands)

How about sediments from Long Island Sound?

R/V UCONN

Sampling mud

HG IN LIS SEDIMENT: GREATEST ENRICHMENTS ON THE WEST SIDE NEAR NEW YORK

-72.30-72.55-72.80-73.05-73.30-73.55-73.80-73.80

0

100

200

300

400

500

600

70096017

96024

WLIS

Longitude

Hg ppb

Housatonic RiverConnecticut River

60504030201000

50

100

150

200

1

10

100

1000

10000Hg

C. perfringens

Depth (cm)

Hg (ppb)C. perfringens

core G1C1

(c)

Hg Concentration vs. Depth of WLIS 75GGC1 Core

0

500

1000

1500

2000

2500

3000

3500

0 20 40 60 80 100 120 140 160 180

Average Depth (cm)

Average Hg Concentration (ppb) 1820

1975

Core near Execution Rock near NYC - 1975 peak is Hg-rich debris of unknown origin

Hg Concentration vs. Depth of B1GGC1 Core

0

200

400

600

800

1000

1200

1400

0 10 20 30 40 50 60 70 80 90 100 110 120 130 140 150 160 170 180 190

Average Depth (cm)

Hg Concentration (ppb)

1820

1900

1955

Core in the delta of the Housatonic River

200019501900185018000

100

200

300

400

500

Cu

Pb

Zn

Hg

% Clay

Age years AD

Metals, ppm/ppb

A4C1 Housatonic Riversediment pulse?~1900 floods?

7000600050004000300020001000000

200

400

600

NYB

Westernmost SoundCentral-Western Sound

Eastern Sound

C. perfringens (spores/g dry sediment)

Hg (ppb)

R^2=0.98

R^2=0.78

First estimate of Hg sources for LIS

~30-35 % from Waste Water Treatment Plants

~20-25% from Housatonic River/Danbury (WLIS)

Rest from Connecticut River

Connecticut River watershedHousatonic River watershed

LONG ISLAND SOUNDFINE SEDIMENT TRANSPORTHG POINT SOURCESWWTPADADWESTEASTIN SITU AD

Hg ppbNatural Background Concentrations 50 – 100Peak Contamination, Atmospheric Deposition 400 – 700Modern Surface Sediments 200 – 300

Danbury: Old hatmaking sites/Still River 1000 – 60,000Ponds and wetlands in town 100 – 1000Still River Surface samples 1500 – 5500; 70,000Core samples near golf course 500 – 100,000Housatonic RiverPope IslandFowlers IslandLong Island HRCarting IslandPink House CoveKnells Island / Wheeler marsh

1000 – 5000500 – 2500100 – 2500100 – 2200100 – 1100100 – 2000

Long Island SoundCoresSurface sediment

50 – 120050 – 700

We have documented extensive Hg contamination in soils and sediments from a known point

source: hat-making!

How do we get rid of the Hg??

Phytoremediation

REMOVAL OF POLLUTANTS THROUGH PLANT UPTAKE:

STORAGE IN PLANT FOLLOWED BY PLANT REMOVAL

OR FOR HG

UPTAKE IN PLANT, REDUCTION TO Hgo AND THEN EMISSION OF VAPOR FROM LEAVES

Growth Experiment

Brassica rapa P. (Mustard Spinach)

1. Good correlation between Hg in leaves and Hg in spiked soils

2. No correlation between Hg leaves and Hg from ‘field contaminated soils’

3. Decrease in Hg in leaves over time

Hg in Maple Trees

Soils with 0.1 -- 75 ppm Hg

Hg in leaves increased over time

Positive correlation Hg(leaves) with Hg(soil)

Mean Hg loss from soils

Hg in ‘normal leaves’ minus Hg in ‘MER A leaves’

About 300 microgram Hg / m2 per growing season

Ten cm thick soil with 50 ppm Hg-about 103-104 yrs to clean up

CCCooonnncccllluuusssiiiooonnnsss

• Wetland sediments in CT have peak Hg contamination levels of 400-500 ppb Hg, with values 50-90,000 ppb Hg in the Housatonic & Still River Basins

• Most LIS sediments have 100-650

ppb Hg vs natural concentrations of ~ 50-100 ppb Hg

• Hg contamination started

~AD 1820-1850, coinciding with the Industrial Revolution (and hatting industry) and raised C.perfringens concentrationsË anthropogenic signals!

• Hg contamination hasdecreased by about 50 %since the 1960-1970's

• The Danbury hat-makingindustry has been animportant source of Hg forwestern CT and westernLIS, starting ~ 1800 AD

• The EË W increase in Hgconcentrations in LISsurface sediments:

1. More “fines” to the West2. Sediment inputs from the

Housatonic River, withppm levels Hg

3. Hg inputs from WWTP

PLANT EXPERIMENTS

HG UPTAKE DEPEND ON PLANT SPECIES AND HG SPECIATION IN SOIL

HG IN LEAVES FROM MAPLE TREES INCREASES WITH TIME AND REFLECTS SOIL HG

PHYTOREMEDIATION WORKS IN PRINCIPLE (MER A PLANTS DO NOT RETAIN MUCH HG IN LEAVES) BUT MAGNITUDE IS SMALL

ROLE OF PLANTS IN SOIL HG EMISSION IS NOT YET CLEAR

Thanks to CT Sea Grant College Program, CTDEP, USGS and the Mellon Foundation

for funding.

Much of the field and analytical work was done by Wesleyan University students Beth Goldoff,

Kate Lauriat, Bart Kreulen, Billo Jallow and Patrick Welsh.

THANKS TO YOU FOR LISTENING