D.C. Water Lead Levels Below Federal Limits Consumers Urged to Continue Precautions

By D'Vera Cohn Washington Post Staff Writer Wednesday, May 11, 2005;

Lead levels in the District's drinking water have fallen substantially in recent months and dropped below the federal action limit for the first time in four years, the general manager of the D.C. Water and Sewer Authority said yesterday.

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By Pierre Home-Douglas

FIRST, MARC EDWARDS DISCOVERED HIGH LEVELS OF LEAD IN WASHINGTON, D.C.'S, DRINKING WATER, THEN HE HAD TO PERSUADE THE BUREAUCRACY TO GET THE WORD OUT.

It was a problem that had baffled civil engineer Marc Edwards for a decade. By the time the Virginia Tech professor finally figured out the answer, he had stumbled across a health issue that ended up pitting him against the Environmental Protection Agency (EPA) and the utility that supplies Washington, D.C., with its drinking water. The resulting battle and stress affected his health, but Edwards persevered and was finally vindicated, assisted by three graduate students he credits with helping him through the ordeal.

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GAS WORKS PARK

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Lake Nyos

Solution lakes and streams

Scale formation in pipes

Stalactites

Stalagmites

FeS2 + 4O2 + 3H20 H2SO4 + Fe(OH)3

Hood Canal, Washington, USA

Newton, UW-APL

, pet waste, lawns, pet waste, lawns

Onsite Septic N ProjectState Legislature Appropriation to the PSAT

 

M. Brett et al

The objective of this project is to measure nitrogen removal rates from septic system drainfield plumes for OSSs located in the Hood Canal watershed. These data are needed to estimate the potential N loading to the Hood Canal from OSSs …. project report with the state legislature by the end of June, 2007.

Well Installation and Sampling

HouseS

1

2

34

5

6

7

8

11

13

12

9

Drainfield

KIT02

cutbank

125 34

XX

Tap

From: W.T. Edmondson (1994) Lake & Reservoir Management 10: 75-84.

The impact of waste water diversion on Lake Washington phosphorus loading

0

25

50

75

100

125

Dis

solv

ed P

Inp

uts

(met

ric

tons

yr.

-1)

1965 1970 1975 1980 1985 1990

Year

Watershed Loading

Sewage Effluent

From: W.T. Edmondson (1994) Lake & Reservoir Management 10: 75-84.

Change in Lake Washington phytoplankton composition and biomass

0

1

2

3

Phy

to. B

iovi

ol. (

mm

3 L-1)

1965 1970 1975 1980 1985 1990

Year

Other Phytoplankton

Cyanobacteria

0

25

50

75

100

125P

erce

nt o

f 19

64 V

alue

1965 1970 1975

Year

Phytoplankton

Phosphate

Nitrate

Inorganic Carbon

From: W.T. Edmondson (1991) The Uses of Ecology.

Change in Lake Washington nutrient concentrations, and phytoplankton biomass after waste water diversion

From: W.T. Edmondson (1994) Lake & Reservoir Management 10: 75-84.

The impact of waste water diversion on Lake Washington water clarity

0

5

10

15

20

Dap

hnia

L-1

0

2

4

6

8

10

Sec

chi (

m)

1965 1970 1975 1980 1985 1990

Year

Secchi Depth

Daphnia

Trophic Equilibrium

Global average temperature

1860 1880 1900 1920 1940 1960 1980 2000

0.8

0.4

0

-0.4

-0.8

degr

ees

Cel

sius

Consequences of Global Warming for the PNW

Shorter ski seasons More winter flooding Increased landslide risk due to rain on snow events Reduced summer flows Water supply shortages More catastrophic forest fires Agricultural water shortages in Eastern W Further-stressed salmon runs

1928

2000

The South Cascade glacier retreated dramatically in the 20th century

Courtesy of the USGS glacier group

Decrease Increase

Mote 2003(b)

Decrease Increase

As the West warms,winter flows rise and summer flows drop

Figure by Iris Stewart, Scripps Inst. of Oceanog. (UC San Diego)

Northwest warming

44

45

46

47

48

49

50

51

52

53

54

1900

s

1920

s

1940

s

1960

s

1980

s

2000

s

2020

s

2040

s

Deg

rees

F warmest scenarioaverage coolest scenarioobserved

Questions?