Development of a trace quantitative method to investigate caffeine distribution in the Yellow and Bohai Seas, China, and assessment of its potential neurotoxic effect on fish larvae.

Caffeine is an emerging contaminant in aquatic environments. The study utilized a validated method to investigate the presence and distribution of caffeine in the surface water of the Yellow and Bohai Seas, urban rivers, and the Yantai estuary area. The analytical method conforms to EPA guidelines and exhibits a limit of quantification that is 200 times lower than that of prior investigations. The study revealed that the highest concentration of 1436.4 ng/L was found in convergence of ocean currents in the Yellow and Bohai Seas. The presence of larger populations and the process of urban industrialization have been observed to result in elevated levels of caffeine in offshore regions, confirming that caffeine can serve as a potential indicator of anthropogenic contamination. Fish larvae exhibited hypoactivity in response to caffeine exposure at environmentally relevant concentrations. The study revealed that caffeine pollution can have adverse effects on marine and offshore ecosystems. This emphasizes the importance of decreasing neurotoxic pollution in the aquatic environment.