Appears to be arsenic on both sides of the Clinton Newbury fault

1. Mapping Arsenic and Uranium Concentrations in Ground Water Using Correlations with Bedrock Geologic Formations in Massachusetts U.S. Geological Survey/Massachusetts Department of Environmental Protection funded project, with cooperative support from Massachusetts Department of Public Health

2. In Massachusetts, arsenic in ground water appears to be limited to a zone in the east central part of the state. Primary study area Secondary study area Clinton-Newbury fault Appears to be arsenic on both sides of the Clinton Newbury fault

3. Objectives • Guide testing of wells • Guide prospecting for new supplies • Evaluate the numbers of wells affected • Assess new mapping of geologic quadrangles

4. Arsenic Risk • The National Research Council review for the National Academy of Science estimated the lifetime bladder cancer risk at about 12-23/10,000 at 10 μg/L, the current drinking water standard, and lung cancer risk about 14-19/10,000 at 10 μg/L (NRC/NAS, 2001).

5. Uranium Risk • Primary risk is damage to the kidneys • Did not find an “increased risk” analysis. • In well water of the crystalline rocks of New England, uranium is correlated with radium and radon.

6. Correlations with geochronologic bedrock unit

7. High arsenic zone west of Clinton-Newbury fault Green/red =MaDEP Black/orange = USGS

8. 16 units in the high-arsenic zone

9. Sp and Dl--units that extend west from the high arsenic zone.

10. Arsenic within a unit extending west from the high-arsenic zone

11. East of the Clinton-Newbury fault

12. uranium

13. High As zone

14. arsenic

15. uranium

16. PROSPECTING--ARSENIC

17. PROSPECTING--URANIUM

18. NUMBER OF WELLS AFFECTED

20. Does remapping matter?

22. Arsenic concentrations (ug/L)

23. More on testing • The numbers of over-standard water supplies can be computed by using the fraction of households currently using water without treatment, for arsenic (66 percent of 11,690 = 7,715) and uranium (93 percent of 3639 = 3,384).

24. arsenic • By testing all wells that fall in bedrock units with probabilities of arsenic greater than 10 percent, 95 percent of the wells over the standard would be found out. • The 10 percent probability testing algorithm would result in testing of 53 percent of all of the wells estimated to be in the study areas.

25. uranium • For uranium, to determine 95 percent of wells greater than the standard, all units with above-standard probability of 4 percent or greater would need to be analyzed. This would involve testing about 48 per cent of the wells in the study area.

26. Comparison in and out of the high arsenic zone

27. PROSPECTING

28. TESTING

29. ESTIMATING IMPACT

30. Uranium concentration (ug/L)

31. QUALITY ASSURANCE

32. Low arsenic zone

33. Preliminary Results for Primary Study Area (342 wells) • 13 percent of the wells sampled were over the 10 ug/L standard for arsenic. • 3.9 percent of the wells sampled were over the 30 ug/L standard for uranium. For all wells (500) • For over-As-standard wells, 61 percent were using their supply without treatment. • For over-U-standard wells, 100 percent were using their supply without treatment.

34. Estimated number of wells affected • In the high-arsenic zone 39,000 wells x 0.25 = 9,750 wells over the arsenic limit. • In high-uranium zone (igneous rocks), 46,000 wells x 0.10 = 4,600 wells over the uranium limit.

35. Hydrothermal source of arsenic Huge hydrothermal vent spewing chemical-rich fluids that were 326 degrees.  About 2 meters across and 4 meters tall. Black smoker, Galapagos ridge undersea volcanic eruption