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GeoInsighter Winter/Spring 2002 Newsletter

New Method 1 Standards Proposed

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On December 20, 2001, the Massachusetts Department of Environmental Protection (MADEP) released Draft Method 1 Standards "for discussion purposes only." The proposed changes to the standards, if approved, may significantly affect the response actions at Massachusetts Contingency Plan (MCP) sites. The revised standards will likely be issued in final form, after public comment, in the fall of 2002.

If the Draft changes are adopted, roughly half of Method 1 standards for ground water and over 80 percent of soil standards will change. New Method 1 standards are included for three additional compounds: the chlorinated solvent additive 1,4-dioxane and the explosives RDX and HMX. Soil and ground water standards for total chromium have been reduced to the hexavalent chromium standard instead of the higher trivalent standard, as is currently the case.

Proposed changes to selected individual standards are summarized below.

Method 1 Ground Water Standards [units are in parts per billion]: GW-1 and GW-3 standards for polycyclic aromatic hydrocarbons (PAHs) will generally be lower. For example, the GW-3 standard for benzo(a)pyrene will decrease from 3,000 to 10. The GW-1 standard for naphthalene, an important compound at fuel oil release sites, will increase from 20 to 140, and the GW-2 standard will increase from 6,000 to 20,000. However, the GW-3 naphthalene standard will decrease from 6,000 to 1,000, making it the limiting factor at sites outside drinking water areas. Similarly, the GW-2 benzene standard will increase from 2,000 to 40,000, but the GW-3 standard will decrease from 7,000 to 5,000. While the GW-1 and GW-3 standards for volatile petroleum hydrocarbons (VPHs) and extractable petroleum hydrocarbons (EPHs) will remain unchanged, the GW-2 standards (with the exception of C11 to C22 aromatics) will be higher by a factor of 5 to 10. GW-2 standards for many chlorinated hydrocarbons will be lower, with the exception of trichloroethylene, which increases from 300 to 500, and vinyl chloride, which increases from 2 to 8. 

Method 1 Soil Standards [units are in parts per million]. The often-problematic carcinogenic PAH soil standards, currently set at 0.7, will rise for all soil categories, except benzo(a,h)anthracene. Standards increase to 30 for S-3 soils, 7 for S-2 soils, and between 2 and 7 for S-1 soils. The general trend in VPH and EPH fractions and target analytes will be downward. For example, S-1/GW-1 standards for VPH/EPH aromatic fractions drop by 70 to 90 percent. Soil standards for naphthalene, which are often controlled by ground water classification, will remain at 4 in GW-1 areas, but will increase by a factor of 4 to 5 in other S-1 soils and decrease by 50 percent or more in other S-2 and S-3 soils. Soil standards for mercury, currently ranging between 20 and 60, will decrease to 1 for all soil categories. Cadmium values will drop from 30 to 3 in S-1 soils and 80 to 20 in S-2 and S-3 soils.

The full list of revisions can be found at 
http://www.state.ma.us/dep/bwsc/files/workgrps/numbers/numbers.htm.

Richard E. Doherty, P.E.
redoherty@geoinc.com

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