Complementary chemical and effect-based risk assessments reveal ecotoxicological risks in Caribbean coastal bays and coral reefs

Anthropogenic chemical pollution, though often overlooked, poses a significant risk to coral reef ecosystems. This research focused on three bays on Curacao and their adjacent coral reefs, examining chemical mixtures in both wet and dry seasons. Researchers utilized passive samplers and targeted chemical analysis, as well as effect-based methods, to analyze the samples. Each bay displayed its own chemical fingerprint, most likely influenced by nearby land use.

Concentrations of targeted chemicals were found to be higher during the wet season, particularly inside the bays. This suggests that rainfall helps mobilize terrestrial contaminants. A majority of these compounds exceeded their predicted no-effect concentrations, while the mixture's toxic pressure ranged from low to moderate, with the highest levels inside the bays.

Bioassays, which measured the effects of the entire mixture, indicated that mixture toxicity was relatively low to moderate, with the strongest impact observed on the reefs.

The two methods of analysis provided complementary information: targeted chemical analysis identified the bays as pollution sources, while bioassays revealed that the mixture effects were strongest on the reefs. Thus, relying solely on targeted chemical analysis would not suffice in evaluating ecotoxicological risks. This study demonstrates the value of a multidisciplinary approach, which can help prioritize key chemical indicators and bioassays for monitoring coral reef water quality.