6533b7d3fe1ef96bd125ff3d

RESEARCH PRODUCT

Acute toxicity of some chlorinated phenolic compounds toSelenastrum capricornutum and phytoplankton

subject

description

Acute toxicity of several chlorinated phenolic compounds detected in waste waters of bleached pulp was determined forSelenastrum capricornutum and indigenous phytoplankton using bioassays. Five of the phenolic compounds were chlorocatechols, four were chloroguaiacols and one was chlorosyringol. The response ofSelenastrum capricornutum to chemicals was measured by cell counting and phytoplankton14C-uptake. Chlorinated catechols inhibited the growth ofSelenastrum cultures in lower concentrations than chlorinated guaiacols. The increasing number of chlorine substituents on the phenolic ring increased the toxicity of both chlorinated catechols and guaiacols. The EC50-values (0-96 hr) of the compounds ranged from 3.2 × 10−4 mM to 1.6 × 10−2 mM, with tetrachlorocatechol being the most toxic toSelenastrum capricornutum. The response of indigenous phytoplankton to chemicals was less sensitive than that ofSelenastrum capricornutum in nutrient solution; the weaker response may be caused by different physico-chemical properties in lake water.