Use of the Zebrafish Embryo Toxicity Test for Risk Assessment Purpose: Case Study
Fish embryotoxicity testing (FET) was performed in Zebrafish to identify toxicological hotspots on the Atoyac River, Mexico. This allowed for the detection of chemical substances that could have teratogenic effects and to establish a monitoring program. Eight stations were used to collect surface water samples. Each station was tested for toxicity using lethal dilution 50 (LDil50). We measured 18 physicochemical characteristics. Additional dilutions were used to evaluate malformations; delay development and heartbeat frequency were also recorded. Multivariate cluster analysis was used to identify pollution sources and improve environmental quality. Based on malformations, two groups of stations were identified. These correspond to cluster analysis. COD and phosphate levels were closely related. All samples were tested and all dilutions used. Heartbeat frequency decreased with increasing doses. Although the river’s movement reduced the toxic effects, lethality, and teratogenicity were still high at all stations. This indicates a risk to the entire zone where the river is used for agriculture and other human activities. FET is an easy way to monitor the progress of the Atoyac River, which is the most polluted in Mexico.