QUANTITATIVE STRUCTURE-TOXICITY RELATIONSHIPS FOR BENZALDEHYDES TO DAPHNIA-MAGNA

Acute toxicities of 17 substituted benzaldehydes to Daphnia magna were determined. The relationship between logarithm of the determined EC50 and E (the sum of Hammett sigma values of the substituent groups att ached to the carbon of benzene cycle) was parabolic. A quantitative st ructure-activity relationship was developed using E and quantum chemic al parameters, which showed that the toxicity was influenced mainly by the electronic effect. Except of E, the toxicities of benzaldehydes i ncreased as the second most negative net atomic charge on an atom (sq( -)) increased. This study further showed that benzaldehydes were react ive chemicals, which exhibited bioreactive toxicity. (C) 1998 Elsevier Science Ltd. All rights reserved.