Notes
A memorandum from Jim Laughlin of Parametrix, Inc. summarizing a phone conversation with Randall Marshall of the Washington State Department of Ecology (WADOE) regarding toxicity due to low water hardness and whether lab water hardness should be adjusted to match site water. The memo references a CH2MHill study showing chronic reproductive effects in C. dubia at low hardness levels, and notes WADOE’s opposition to adjusting lab water hardness for Whole Effluent Reporting (WER) studies. WADOE recommended testing against a gradient of hardness values with receiving water hardness as the lower limit.
