Environmental effects of manganese and proposed guidelines to protect freshwater life in British Columbia

Peter Samuel Reimer
Manganese is a naturally occurring substances that is present in surface waters and biota. Aquatic organisms have exhibited toxic responses to manganese in surface waters and regulatory bodies in some jurisdictions have established guidelines for levels of manganese in surface water to protect aquatic life. In British Columbia, a guideline of 0.1 mg/L was established by the Ministry of Environment, Lands and Parks, although it was recognized that the scientific data on which this guideline was
more » ... this guideline was based were weak. Toxicity tests applicable to aquatic life in B.C. waters were commissioned to strengthen the relevant data base and to apply the British Columbia procedures for deriving water quality criteria in an effort to establish more defensible guidelines for the protection of aquatic life in B.C. Acute and chronic toxicity tests were conducted on fish, invertebrates and freshwater algae. Acute tests included 48 and 96 hour LC50's, while chronic tests included reproduction, growth and survival endpoints. A range of organisms was chosen in order to evaluate the range of sensitivities to manganese.. The possible relationship between water hardness and toxicity to manganese was also investigated at water hardnesses of 25, 100 and 250 mg/L CaC03. Data were also gathered from literature sources in support of the new toxicity information. Both acute and chronic studies were identified for fish species resident in B.C. fresh waters. The collective data were evaluated for suitability with respect to the B.C. water quality guideline derivation process. Toxicity t test data that met the requirements for use in guideline derivation were screened for sensitivity in order to fulfill the objective of developing a guideline protective of the most sensitive aquatic organisms. A pattern emerged whereby the concentrations of manganese at which adverse effects were observed increased with increasing water hardness. This pattern was identified in both the literature data and all but one of the new toxicity tests commi [...]
doi:10.14288/1.0058589 fatcat:bvleyadjqjeinkupd4nkba2diy