Rather than just measuring chemicals in water samples, scientists increasingly use living organisms themselves as pollution detectors. This approach — biomonitoring — provides a more complete picture of how contaminants affect real ecosystems.
The Concept
Traditional chemical monitoring tells us what's in the water at a single point in time. But organisms integrate exposure over days, weeks, or months, accumulating chemicals in their tissues. By studying these organisms, we can understand not just what chemicals are present, but what biological effects they're having.
Sentinel Species
Mussels are the quintessential biomonitor. As filter feeders, they process vast quantities of water and accumulate pollutants in their tissues. The "Mussel Watch" programme, running since the 1980s, uses mussels to track pollution trends globally.
Fish are monitored for biomarkers — measurable biological responses to chemical exposure. Vitellogenin, an egg yolk protein normally found only in female fish, appears in males exposed to oestrogenic chemicals, serving as a clear indicator of endocrine disruption.
Seabirds and marine mammals, as top predators, reveal the cumulative burden of persistent pollutants through biomagnification.
Modern Biomonitoring
The CONTRAST project is advancing biomonitoring with cutting-edge techniques. Environmental DNA (eDNA) analysis can detect species and assess ecosystem health from water samples alone. "Omics" technologies — genomics, proteomics, metabolomics — reveal how organisms respond to pollutants at the molecular level.
In silico models use computer simulations to predict how chemicals will behave in organisms, reducing the need for animal testing while expanding our understanding.
Why It Matters
Biomonitoring bridges the gap between chemistry and ecology. A chemical might be present in water, but is it actually affecting life? Biomonitoring answers that question, helping policymakers set meaningful environmental standards based on real biological outcomes.
Citizen Science
You can contribute to biomonitoring efforts. Beach clean surveys, water quality testing kits, and species monitoring apps all generate valuable data. The more eyes on our coastlines, the better we can protect them.
This article is part of the CONTRAST project, funded by the European Union under Horizon Europe. Views expressed are those of the author(s) only.