Several studies show that many water bodies in developing countries are increasingly affected by anthropogenic pressure, such as agricultural activities, domestic and industrial wastewater. However, data is scarce in several of such countries, including Panama. Thus, in this work, the ecotoxicological status of selected rivers in Panama with distinct input sources were evaluated using the zebrafish (Danio rerio) embryo bioassays combined with a liquid chromatography-high resolution mass spectrometry screening of contaminants of emerging concern (CECs), using a library of over 3200 chemicals. A total of 68 CECs, including pharmaceuticals and metabolites, pesticides and several industrial chemicals, could be tentatively identified. Additionally, the zebrafish embryo bioassays showed a significant increase (p < 0.05) in embryo mortality/abnormalities when incubated with water samples from two rivers, Matasnillo and Curundú (47.5% and 32%, respectively). Importantly, a positive correlation between ecotoxicological endpoints and some of the detected CECs was observed. The findings demonstrate that both rivers are under strong anthropogenic pressure, and therefore, management actions are urgently needed to decrease their level of contamination. Overall, this study further supports the use of the zebrafish embryo bioassay as a fast, high throughput approach for screening the toxicity of water samples, and highlights the advantages of combining ecotoxicological assays with high-resolution mass spectrometry to an expedite assessment of the ecotoxicological status of water bodies.

Under a consent agreement among the Environmental Protection Agency (EPA) and proponents both for and against stricter regulation, EPA is to issue a new coal ash disposal rule by the end of 2014. Laboratory toxicity investigations often yield conservative estimates of toxicity because many standard test species are more sensitive than resident species, thus could provide information useful to the rule-making. However, few laboratory studies of coal ash toxicity are available; most studies reported in the literature are based solely on field investigations. This brief communication describes a broad range of toxicity studies conducted for the Tennessee Valley Authority (TVA) Kingston ash spill, results of which help provide additional perspective on the toxicity of coal ash.