1. MERCURY CONTAMINATION IN S-NEW ENGLAND AND LONG ISLAND SOUND, USA
JOHAN C. VAREKAMP
EARTH & ENVIRONMENTAL SCIENCES
WESLEYAN UNIVERSITY
MIDDLETOWN CT USA

2. Mercury droplets on cinnabar (HgS)

3. MERCURY AND HUMAN HEALTH
Mercury has no known biological function and binds tightly to sulfhydryl groups, inhibiting molecular functions
-SH
reduces membrane permeability
reacts with and disrupts phosphate bonds in ATP/ADP
replaces cations in important molecules

4. ENVIRONMENTAL
CONCERN
HUMAN HEALTH CONCERN:
HG IS A NEUROTOXIN

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

6. Eating fish or shellfish Breathing vapors (home, work)
Exposure to mercury?
Eating fish or shellfish
Breathing vapors (home, work)
Dental work and medical treatments
Religious rituals that include Hg inhalation (Santaria in Haiti)
Eating fish or shellfish contaminated with methylmercury.
Breathing vapors in air from spills, incinerators, and industries that burn mercury-containing fuels.
Release of mercury from dental work and medical treatments.
Breathing contaminated workplace air or skin contact during use in the workplace (dental, health services, chemical, and other industries that use mercury).
Practicing rituals that include mercury.

7. Fish Consumption
Primary 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/day
Maximum Hg-in-hair level is 1 ppm Hg

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

11. 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

13. Some important forms of Mercury in the environment:
CH3-Hg
organic, charged, lipophilic
Hg2+
oxidized
Hg0
reduced, elemental,volatile
CH3-Hg-CH3
organic, volatile, lipophilic

14. aerobic anaerobic Hg0 CH3-Hg+ Hg2+ (CH3)2-Hg volatilization
bioaccumulation
reduction
CH3-Hg+
Hg2+
demethylation
(CH3)2-Hg
Diagram is from Mark Coyne, Soil Microbiology text
methylation
(Sulfate reducing bacteria)
anaerobic

15. Hg Transport
Dissolved metals (e.g., in complexes with dissolved organic matter)
Attached to fine particles:
Inorganic
Organic

16. 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)

17. Sediment Cores Chemical mobility in the sediment column
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

21. 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

22. GRAIN SIZE EFFECT ON HG INVENTORIES

23. SR FI PI DB

24. Mercury profile core Chapman Pond, CT River, CT

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

31. THE STILL RIVER, WESTERN CONNECTICUT

34. ~1955

35. Fowler Island core, Housatonic River

36. Pope Island core, Housatonic River

38. Floods of 1955
Wooster Square, Danbury

39. The floods of 1955 in Waterbury, CT after two
hurricanes hit in a few weeks time

40. Norwalk River Core
1955
1900
1820

41. 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

42. Lee Hat Factory Mallory Hat Factory
Photos of Mallory Hat Factory and Lee Hat Factory

43. EVERYONE wore hats. Men, women,

45. 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.

46. Men working in Mallory’s carroting room

47. Benedict’s factory initially produced 3 hats per day

48. 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?

49. R/V UCONN

50. Sampling mud

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

54. 1975
1820
Core near Execution Rock near NYC peak is Hg-rich debris of unknown origin

55. Core in the delta of the Housatonic River
1955
1900
1820
Core in the delta of the Housatonic River

58. 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

61. How do we get rid of the Hg??
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??

62. 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

63. Growth Experiment
Brassica rapa P. (Mustard Spinach)

64. 1. Good correlation between Hg in leaves and Hg in spiked soils 2
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

65. Hg in Maple Trees Soils with 0
Hg in Maple Trees Soils with ppm Hg Hg in leaves increased over time Positive correlation Hg(leaves) with Hg(soil)

66. 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 yrs to clean up

70. 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

71. 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