Assessment of emerging contaminants (ECs) in the marine environment of San Cristóbal Island, Galápagos

The Galápagos Islands face increasing anthropogenic pressures that threaten its unique biodiversity. While emerging contaminants (ECs) are a growing global concern, their presence and distribution in the island’s marine ecosystems are poorly understood. This study provides the first multi-contaminant assessment in the coastal waters of San Cristóbal Island, investigating the link between human activity and EC distribution. Water samples were collected from seven anthropogenically "impacted" sites (e.g., harbors and tourist beaches) and three relatively "pristine" sites. Using a semi-quantitative GC-MS analysis, a range of ECs—including hydrocarbons, petrochemical derivatives, plasticizers, and UV filters from personal care products—were identified. The results demonstrate a clear spatial pattern, with ECs detected almost exclusively in impacted areas, suggesting that proximity to urban centers, tourism, and maritime activities are the primary drivers of contamination. This conclusion is supported by the minimal variation in physico-chemical parameters across all sites, suggesting that natural environmental gradients are unlikely to be a major factor. Notably, the UV filter enzacamene (4-MBC) was the only contaminant detected in two “pristine” sites, suggesting the possibility that ocean currents may contribute to the dispersal of contaminants beyond their source. These findings provide preliminary evidence of anthropogenic chemical pollution in the Galápagos and underscore the need for quantitative monitoring and robust management strategies to protect this iconic marine reserve.