Death means the lack of reaction of a test organism to gentle prodding.
Flow-through means a continuous or an intermittent passage of test solution or dilution water through a test chamber or a holding or acclimation tank, with no recycling.
LC50 means the median lethal concentration, i.e., that concentration of a chemical in air or water killing 50 percent of the test batch of organisms within a particular period of exposure (which shall be stated).
Loading means the ratio of the biomass of gammarids (grams, wet weight) to the volume (liters) of test solution in either a test chamber or passing through it in a 24-hour period.
Solvent means a substance (e.g., acetone) which is combined with the test substance to facilitate introduction of the test substance into the dilution water.
Static system means a test chamber in which the test solution is not renewed during the period of the test.
Substance | Maximum concentration |
Particulate matter | 20 mg/L |
Total organic carbon (TOC) or | 2 mg/L |
chemical oxygen demand (COD) | 5 mg/L |
Boron, fluoride | 100 ug/L |
Un-ionized ammonia | 1 ug/L |
Aluminum, arsenic, chromium, cobalt, copper, iron, lead, nickel, zinc | 1 ug/L |
Residual chlorine | 3 ug/L |
Cadmium, mercury, silver | 100 ng/L |
Total organophosphorus pesticides | 50 ng/L |
Total organochlorine pesticides plus: | |
polychlorinated biphenyls (PCBs) or | 50 ng/L |
organic chlorine | 25 ng/L |
40 C.F.R. §795.120