BIOLOGICAL AND CHEMICAL CHARACTERIZATION OF NEWSPRINT SPECIALTY MILL EFFLUENTS

A survey of the biological and chemical characteristics of effluents without secondary (i.e. biological) treatment from Canadian newsprint/specialty mills was completed. The acute lethal toxicity of the effluents to rainbow trout, fathead minnows and Ceriodaphnia, expressed as LC50s, ranged from approximately 5 to approximately 50%. Sublethal effects on minnow growth occurred at approximately 2 to approximately 15% concentrations, whereas effects on Ceriodaphnia reproduction occurred at approximately 0.01 to approximately 2% levels. The impact of these effluents on Photobacterium phosphoreum (Microtox test) occurred at levels similar to those affecting minnow growth. The growth of algae was a less sensitive response than even acute lethal toxicity to fish or Ceriodaphnia. The concentrations of wood extractives in the effluents correlated well with acute lethal toxicity, but could not fully explain all toxic effects. The ranking of the impact of the effluent only on the basis of pulping process was not possible due to a range of other seemingly more important variables which could affect the effluent quality including the wood furnish, age of wood and other as yet unidentified factors.