Accumulation and fluxes of potentially toxic elements in a large coastal lagoon (southern Gulf of Mexico) from 210Pb sediment chronologies

Three Pb-210-dated sediment cores were used to evaluate the contamination degree and flux ratios of potentially toxic elements (PTEs; As, Cd, Cr, Cu, Ni, Pb, V, and Zn) in seagrass meadows from the northern margin of Terminos Lagoon (TL), southern Gulf of Mexico. The sediments displayed minor Cd, Ni, V, and Zn enrichments but moderate to strong enrichment by As. Results from a chemometric analysis revealed that: 1) salinization and grain size, along with 2) the terrigenous inputs are the major factors influencing the PTEs accumulation. The historical trends of PTEs flux ratios nearly follow the large-scale land-use changes around TL, linked to the growth of the Mexican oil industry in the area since the 1970s. Our findings showed the critical role of seagrass meadows as PTEs sinks. This information is useful for decision-makers to develop restoration projects for a vulnerable site within the largest coastal lagoon ecosystem in Mexico.

Automated summary

Three Pb-210-dated sediment cores were used to assess the contamination level and flux ratios of potentially toxic elements (PTEs) in seagrass meadows from the northern margin of Terminos Lagoon in the southern Gulf of Mexico. The study revealed that salinization, grain size, and terrigenous inputs were major factors influencing the accumulation of PTEs. Historical trends of PTEs flux ratios were found to be correlated with land-use changes and the growth of the Mexican oil industry. The findings highlight the important role of seagrass meadows as sinks for PTEs and provide useful information for decision-makers in developing restoration projects.