Comparison of eDNA with conventional infauna sampling when assessing pollution impacts

Environmental DNA (eDNA) methods are increasingly used to assess marine pollution, offering a promising tool for ecosystem monitoring. However, these approaches still require validation against traditional techniques, such as sediment fauna (macrobenthos) sampling using a van Veen grab to assess the effects of marine pollutants on the benthic assemblage. Using a suite of environmental and pollutant parameters sampled across southeastern Australia, we investigated the sensitivity of three metabarcoding assays (16S rRNA, 18S rRNA, and mitochondrial COI) versus traditional but labour-intensive macrobenthos sampling for detecting potential impacts of pollutants. Both eDNA metabarcoding and macrobenthos sampling detected pollutant-associated impacts, with eDNA more sensitive to heavy metals, and macrobenthos more responsive to organic pollutants.