Diazinon negatively affects the integrity of environmental DNA stability: a case study with common carp (Cyprinus carpio).

Environmental DNA (eDNA) has been used to detect the presence of various species in aquatic ecosystems, but its degradation by several environmental factors can influence the correct identification of aquatic organisms. The present study examined the effects of a pesticide, diazinon, on breakage of Cyprinus carpio eDNA. The specimens were exposed to 0 (control), 0.06, 0.1, and 1 ppm of diazinon for 9 days. Water samples were collected at three time points (3, 6, and 9 days postexposure, dpe), and eDNA was extracted. The cytochrome oxidase I (COI) gene was successfully amplified by PCR, and a fuzzy inference system was used to convert DNA smears and breakage to numerical values. eDNA breakage percentage increased with diazinon concentration at all sampling times. At 3 dpe, the maximum eDNA breakage percentage occurred at 0.06 and 0.1 ppm of diazinon; whereas at 6 and 9 dpe, the maximum breakage was found at 1 ppm of diazinon, while exposure time had no significant effect. To the best of our knowledge, this is the first study to demonstrate that eDNA integrity can be compromised by a diazinon in surface waters. Hence, it is recommended that future eDNA studies take into account pesticide pollution when detecting aquatic species.