Developmental Toxicity in Zebrafish Embryos after Exposure to Lead, Copper, and Lead-Copper Combination

Abstract

Toxicity of lead, copper and their combination were determined using zebrafish (Danio rerid). Zebrafish embryos were exposed to various concentrations of the fore mentioned heavy metals ranging from 5-, 10-. 15-, 20-, and 25 ppm. Reconstituted water served as the control (0 ppm). Sublethal endpoints such as egg and embryo mortality, egg coagulation, completion of gastrulation, somite formation, spontaneous contraction of trunk and tail, tail detachment, heartbeat and circulation, and hatching success were monitored at specific time points (/ = 2-4, 12, 24, 36, and 48h). Mortality, hatching and abnormalities such as pericardial edema, axial curvature, weak heartbeat and tail contraction were observed. Other sublethal endpoints were assessed relatively normal. Lead showed a concentration-related constancy for percent abnormality and percent mortality while copper exhibited a concentration-related decrease for both. Hatching was found to be inhibited more by copper than lead. There was a probable antagonistic interaction between lead and copper.