What levels of MTBE are safe for plants and animals that live in Canadian waters?
The Canadian Water Quality Guideline (CWQG) for the protection of freshwater life is 10 milligrams of MTBE per litre of water. This guideline is based on available toxicity data for six invertebrate species, three fish species, and three plant species. The interim CWQG for the protection of marine life is 5 milligrams of MTBE per litre of water. Only an interim guideline can be given at present because insufficient data are available on the chronic, or long-term, effects of MTBE on marine species. This interim guideline is based on available toxicity data for six invertebrate species, two fish species, and one plant species. If the levels of MTBE measured in fresh or salt water are less than the corresponding guideline, one would not expect to see adverse health effects in even the most sensitive species. In places where the CWQGs for MTBE are exceeded, adverse effects will not necessarily occur. Whether effects will occur depends on the amount by which the guideline levels are exceede
