ABSTRACT
The acute and chronic toxicities of whole mill effluents from a totally chlorine free (TCF) and elemental chlorine free (ECF) process, before and after secondary treatment, and an effluent from an unbleached process were assessed and compared. The tests performed were acute tests with Microtox® and the brackish water harpacticoid copepod Nitocra spinipes and two reproduction tests, one with N. spinipes and one with the marine red alga Ceramium strictum. All tests ranked the TCF effluent as the least toxic. The unbleached water was the most toxic according to all organisms except C. strictum. Both reproduction tests were 2–4 times more sensitive than Microtox and the acute test using N. spinipes. Secondary treatment of TCF and ECF effluents reduced the toxicity according to these tests by 2–5 times. The five effluents were separated into a lipophilic and a hydrophilic fraction using a filter with an impregnated reversed phase material (R18). The hydrophilic fractions were assessed in all tests, except the reproduction test with N. spinipes. This fraction did not cause any harmful responses to Microtox or the acute test with N. spinipes. In all effluents this fraction, however, contained a large amount of substances harmful to the reproduction of C. strictum.
