Anions, organics, toxic, heavy metals

It is generally accepted that free ionic forms of heavy metals are generally more toxic to biota than chelated or precipitated forms. Several factors control metal bioavailability and, thus, toxicity in environmental samples. These factors include pH, redox potential, alkalinity, hardness, adsorption to suspended solids, cations and anions, as well as interaction with organic compounds (Kong et al., 1995). 

Effluents from the Annacis and Lulu Island STPs frequently contain higher levds of contaminants than permitted by the provincial government. For the Annacis plant permit, noncomphance is most apparent for Biochemical Oxygen Demand (BOD), toxicity, oil and grease, and dissolved oxygen. For example, in 1985 toxidty levels were exceeded 50 percent of the time for Annacis and 66.7 percent of the time for Lulu Island STPs. The toxic compotinds identified in municipal STP effluent include im-ionized ammonia, cyanide, sulfides, chlorine, chloramines, phenols, anionic siufactants, heavy metals, and organic compounds. Table P-5 provides a... 

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