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.
