Heavy metals content in sediments of several rivers in Costa Rica

Costa Rica has an abundance of water resources, however, it faces a high level of pollution. Heavy metals (PMs) stand out due to their harmful effects on the health of people, animals and plants, as well as their lack of biodegradability and their propensity to accumulate in organisms. This pollution comes from both direct discharges of domestic and industrial wastewater into rivers, as well as diffuse pollution originating from agricultural activities and atmospheric pollution. A recent study carried out in the rivers of Costa Rica revealed the presence of MPs, such as lead, chromium, copper, arsenic, nickel and mercury. The objective of this research was to evaluate the concentration of these metals in river sediments through 26 sampling sites distributed in various areas of the country, covering the period between 2017 and 2019. The toxicity levels for cadmium were classified as not probable, as were the majority of the places sampled for arsenic, lead, chromium and mercury. Regarding copper and nickel, levels ranged from unlikely to undefined toxicity were observed. However, some data related to nickel, copper and chromium were in the zone of probable toxicity.