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TOXICITY OF PULP AND PAPER MILL EFFLUENT, A LITERATURE REVIEW
Hutchins, F. TOXICITY OF PULP AND PAPER MILL EFFLUENT, A LITERATURE REVIEW. U.S. Environmental Protection Agency, Washington, D.C., EPA/600/3-79/013 (NTIS PB294287).
The review of pulp and paper mill effluents considers the need for additional toxicity data to insure effective effluent regulation. Effluent characteristics and problems of toxicity testing particular to pulp and paper mill effluents are discussed; however, the emphasis is on toxic effects of these effluents to aquatic life. Untreated pulp and paper mill effluents are very toxic to most aquatic life. Concentrations as low as two percent can be acutely toxic to fish. Sufficient treatment can render the effluent essentially nontoxic much of the time; however, treatment processes used by most mills reduce toxicity but do not eliminate it. Even effluents receiving good treatment may exhibit sporadic and dynamic increases in toxicity (due in part to spills or dumping of spent pulping chemicals). Sublethal exposures of aquatic organisms to pulp effluent may affect a number of their physiological and behavioral functions. The more sensitive functions, growth rate, coughing reflex, and temperature tolerance, are affected at concentrations less than 1/10th of the 96-hr LC50. Many other systems such as respiration, and circulation may be affected at concentrations near 1/10th of the 96-hr LC50. The principal toxic components in pulp and paper mill effluents are resin acids and fatty acids naturally occurring in the wood pulped, and in effluents from bleaching processes toxic chlorinated compounds predominate. Untreated effluents have caused considerable environmental damage, but well-treated effluents have had minimal effects on fish production, although shifts in biological diversity have occurred.