Assessment of the embryotoxic potential of contaminated sediments using fish embryotoxicity tests for the river Buriganga, Dhaka, Bangladesh

Sediment samples from six different locations of Buriganga River following exposure to Zebrafish (Danio rerio) eggs and larvae displayed prominent effects on both whole sediments and sediment organic extracts. The acute and sublethal effects during 96 h exposure period included (i) a significant (P<0.05) increase in morality and abnormalities in zebrafish eggs and embryos; (ii) a significant (P<0.05) reduction in hatching success and heart rate; (iii) increased frequency of helical tail and lordosis after 96 h exposure to sediment extracts; (iv) developmental delay and yolk sac edema after exposed to whole sediments at 96h exposure period. Chemical analysis showed the increaseds concentrations of heavy metals (Zn, Cr, Cu, Pb, and Cd) in downstream (S1, S2, and S3) compared to upstream (S4, S5, and S6), where some ions such as Cd and Cr exceeded the Environmental Protection Agency’s Threshold Effect Level (EPA TEL). The current study delineates the contamination of extremely toxic compounds in the sediment of Buriganga River, which may initiate toxic effects on the early life stages of fish. Therefore, integrating zebrafish embryo toxicity tests may be crucial for evaluating the sediment quality of polluted rivers

A model of chlorpyrifos distribution and its biochemical effects on the liver and kidneys of rats

This study investigated the main target sites of chlorpyrifos (CPF), its effect on biochemical indices, and the pathological changes observed in rat liver and kidney function using gas chromatography/mass spectrometry. Adult female Wistar rats (n = 12) were randomly assigned into two groups (one control and one test group; n = 6 each). The test group received CPF via oral gavage for 21 days at 5 mg/kg daily. The distribution of CPF was determined in various organs (liver, brain, heart, lung, kidney, ovary, adipose tissue, and skeletal muscle), urine and stool samples using GCMS. Approximately 6.18% of CPF was distributed in the body tissues, and the highest CPF concentration (3.80%) was found in adipose tissue. CPF also accumulated in the liver (0.29%), brain (0.22%), kidney (0.10%), and ovary (0.03%). Approximately 83.60% of CPF was detected in the urine. CPF exposure resulted in a significant increase in plasma transaminases, alkaline phosphatase, and total bilirubin levels, a significant reduction in total protein levels and an altered lipid profile. Oxidative stress due to CPF administration was also evidenced by a significant increase in liver malondialdehyde levels. The detrimental effects of CPF on kidney function consisted of a significant increase in plasma urea and creatinine levels. Liver and kidney histology confirmed the observed biochemical changes. In conclusion, CPF bioaccumulates over time and exerts toxic effects on animals