Government of British Columbia: Ministry of Environment: Ambient Water Quality Guidelines for Zinc
Ambient Water Quality Guidelines for Zinc
Prepared pursuant to Section 2(e) of the
Environment Management Act, 1981
Original signed by Don Fast
Assistant Deputy Minister
Environment and Resource Management
March 15, 1999
TABLE OF CONTENTS
Application of the Guidelines
This document is one in a series that establishes ambient water quality guidelines, formerly known as criteria, for British Columbia (Table 1). This document is mainly based on a report prepared by the BC Ministry of Environment, Lands and Parks for the Canadian Council of Ministers of the Environment (CCME). It sets guidelines for zinc (Zn) to protect drinking water, recreational and aesthetics, freshwater and marine aquatic life, and agricultural water (irrigation and livestock watering) uses.
Zinc guidelines were not set for wildlife and industrial water uses, since suitable data documenting the effects of zinc for these uses were not available in the literature.
Zinc is most toxic to microscopic organisms in the aquatic environments. It is also an essential element for aquatic and terrestrial biota and its removal from the environment below certain levels can also be harmful due to its deficiency. Zinc guidelines, tabulated above, are summarized in the chapter on Recommended Guidelines. A more detailed discussion of the guidelines or criteria is presented in the main body of the report.
Zinc may bind to particulate matter. Soluble species of zinc are readily available for biological reactions and, therefore, considered as most toxic. It has been shown that zinc in water is a better predictor of fish tissue contamination than zinc in either sediment or invertebrates (i.e., food source). It is, therefore, recommended that the zinc guideline may be interpreted in terms of the dissolved metal fraction when the total zinc concentration in the environment exceeds the guideline due to particulate matter and adverse effects due to zinc are not obvious.