Toxicity of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) in embryos and larvae of the fathead minnow (Pimephales promelas)

This study evaluates the TCDD toxicity in embryos and larvae of the fathead minnow based on body burden. For the fish embryos, the LOAEL with mild lesions was at a tissue dose of 40 pg TCDD/g. The LD50 was 25,710 pg TCDD/g. Embryos exhibited gross lesions such as multifocal hemorrhages, edema, and lower jaw malformation. For the one-month-old larvae, the NOAEL was at 3,590 pg TCDD/g. The LD50 was 70,915 pg TCDD/g. Wasting-type syndrome was observed at a tissue dose of 20,000 pg TCDD/g, and 100% mortality at 163,000 pg TCDD/g.