Temporal and spatial analysis of benomyl/carbendazim in water and its possible impact on Nile tilapia (Oreochromis niloticus) from Tenango dam, Puebla, Mexico

Activities like agriculture contribute to the pollution of aquatic systems by fungicides, such as benomyl/carbendazim. This chemical inhibits the activity of acetylcholinesterase (AChE), having teratogenic, oncogenic, reproductive, and hepatic effects on aquatic and soil organisms. This paper presents the results of a study conducted in the Tenango dam, Mexico, aimed at detecting and determining the spatial and temporal variability of benomyl/carbendazim fungicide in the dam’s water and its possible impact on Nile tilapia (Oreochromis niloticus), farmed and commercialized in the site. Five site visits were made during 2015. Benomyl/carbendazim was quantified at 34 georeferenced stations. Thirty O. niloticus specimens were collected per visit. The quality of water and O. niloticus specimens was evaluated according to the Mexican standards. The fungicide concentrations in the O. niloticus muscle and the AChE activity were measured. Seasonal and spatial variations of benomyl/carbendazim were determined using geostatistical methods (ordinary kriging [OK] and universal kriging [UK]). Geostatistical analyses demonstrated that agriculture contributes to the increased amounts of the chemical in specific areas. Even though the fungicide levels in water varied over time, they did not represent a risk to O. niloticus according to the current standards. The specimens met the quality criteria for their commercialization; however, they had low weights and small sizes. The benomyl/carbendazim concentration in the muscle increased with the size and exhibited a negative correlation with the AChE activity, thus indicating a potential harmful effect.