Long-term effects of dinoseb and paraquat, both individually and combined, on embryonic development and hatching success ofFasciola hepatica miracidia

Toxic effects of the herbicides dinoseb and paraquat, both individually and combined, on embryonic development and hatching ofFasciola hepatica miracidia were assessed by exposing the eggs to varying concentrations (0–20 μg/ml) of each of the herbicides. The results showed that dinoseb has an LC50 value of 4.3 μg/ml, paraquat has an LC50 of 4.9 μg/ml and the mixture of both dinoseb and paraquat has an LC50 of 7.1 μg/ml. Based on the LC50 values, dinoseb is slightly more toxic than paraquat on the tested organisms. The results also showed that the mixture of dinoseb and paraquat is significantly less toxic than the individual pesticides. Eggs ofF. hepatica cultured in either dinoseb or paraquat both individually and combined showed a delay of embryonic development and hatching of the miracidia. Eggs cultured in 0–2 μg/ml of dinoseb, paraquat and their mixture, fully embryonated and hatched within 14–16 days, while eggs cultured in 4–6 μg/ml of the same herbicides showed a delay of four days for embryonic development and hatching of their miracidia.