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Pesticide and methylmercury fluxes to a marine protected region of Australia influenced by agricultural expansion

Year: 2025
Type: article
Abstract: Blue carbon systems are important estuarine environments that provide a variety of ecological services, including carbon burial and the sequestration of pollutants. However, urban development and anthropogenic activities can impact the ability of estuarine systems to retain and store pollutants, with unknown consequences for marine communities. Here, we present dated sediment cores from within the Solitarily Island Marine Park, a marine life sanctuary in Australia subject to runoff from a highly developed catchment. We reveal historical accumulation rates of trace metals and pesticides associated with specific types of agricultural activities. Propiconazole and tebuconazole, fungicides highly reactive in marine habitats, were recorded throughout the site nearest the freshwater source. Furthermore, mercury content revealed elevated levels in the most recent sediments, up to 0.13 mg kg-1 in 1999, while methylmercury (MeHg) was found range from 0.1 mg kg-1 in 2017 to 0.2 mg kg-1 in 2019. Additionally, arsenic accumulation rates are shown to have significantly increased from 19.1 mg m-2 year-1 in 1930 to 259.6 mg m-2 year-1 in 2020. These substances were found not to be related to organic matter which was determined to be mostly of terrestrially derived sources, likely related to historical catchment deforestation, as indicated through δ13C and C:N molar ratios. This study highlights the importance in evaluating agriculture-derived pollutant discharge to protected coastal regions and provides a robust dataset that may be used to mitigate pollutant runoff in catchments impacted by expanding activities throughout Australia, and around the globe.
DOI: 10.1016/j.marpolbul.2025.118044
Language: English
Subfield: Pollution
Open Access status: hybrid
Estimated APC paid: $3,740
OpenAlex ID: W4410029932
FWCI: 0.449
Cites: 67
Cited by: 2
Related to: 10