Heavy Metals in Soils: An Investigation of the Contaminated Floodplains Around the Sinu River, Colombia.

内容摘要

Heavy metal contamination in rivers mostly originates from anthropogenic sources such as industrial activities, mining, agriculture, and urban runoff. These metals accumulate in river sediments and impact living organisms and the surrounding ecosystem. Historically, some rivers in Colombia have faced issues related to heavy metal contamination, in particular from gold mining activities, which can lead to the release of heavy metals into waterways. To assess the current status of heavy metal presence in the Sinú River, one of the most important rivers in northern Colombia, we analyzed sediment samples collected in a section of the river between the towns of Santa Isabel and Montería. ICP-MS analysis found concentrations of Hg, Cd and Ni up to five times larger than the baseline concentrations, while concentrations of Pb, Zn and Cr were consistently below the baseline. The measured concentrations varied with both geographical location and sampling depth. During the dry season heavy metals accumulate near the surface, while rains spread them below the surface and into the groundwater, and across the surrounding land. These abnormal concentrations of potentially toxic elements are probably related to the widespread use of Hg in illegal gold mining activities, which are prevalent in the region, while Cd and Ni contamination probably derives from mining, as well as from agricultural practices and industrial discharges. The results point to the necessity to continuously monitor the state of the river and develop management strategies to reduce heavy metal contamination, protecting the health of the ecosystem and of the neighboring communities. Heavy metal contamination in rivers is a significant threat to the environment, and may affect the surrounding environment and the health of living organisms. The Sinú River is a vital waterway for northern Colombia, supplying water for the population and irrigation for agriculture and enabling the transport of goods. Here, we report our analysis of the presence of heavy metals in a section of the Sinú River between the towns of Santa Isabel and Montería. Soil samples were collected during the rainy and dry seasons of 2021 from the surface and at a depth of 0.5 m. ICP‐MS analysis found concentrations of Hg, Cd and Ni often much larger than the baseline, while those of Pb, Zn and Cr were consistently below these limits. Measured concentrations depend on the location and depth of the samples, and vary seasonally with rainfall due to surface runoff. The abnormal concentrations of these potentially toxic elements are related to anthropogenic activities, such as their widespread use in mining, agricultural practices and industrial discharges. The results point to the necessity of a continuous monitoring of the river and to the implementation of effective management strategies to protect the ecosystem and neighboring communities.