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 σ* values of the substituent groups attached to the carbon of benzene cycle) was parabolic. A quantitative structure-activity relationship was developed using E and quantum chemical parameters, which showed that the toxicity was influenced mainly by the electronic effect. Except of E, the toxicities of benzaldehydes increased as the second most negative net atomic charge on an atom (sqʹ) increased. This study further showed that benzaldehydes were reactive chemicals, which exhibited bioreactive toxicity.