An Integrated Approach for the Environmental Characterization of a Coastal Area in the Southern Atacama Desert

Desert areas in northern Chile are highly valuable ecosystems. While human activities are impacting the area in different ways, there are few environmental studies available. The current study analysed the ecological health status (water, sediment, biota) of a northern coastal area in the Atacama Region, including a national park (with a protected marine area), a tourist and benthic management area, and an industrial area. Results from the physical-chemical characterization and physiological state of organisms of ecological importance (macroalgae and microalgae) were integrated to determine pollution and toxic responses. The results identified high and moderate pollution levels for Bi, Ca, As, Ag and Cd in sediments. The As concentration in sediments is the leading environmental problem, with average values above the threshold effect level, associated with fine sediments. The stations showed increasing contamination and stress from north to south (national park > tourist and benthic management area > industrial area), associated with the proximity to the discharge of mining waste from the Salado River. The national park registered the poorest health status as demonstrated by high Cu bioaccumulation and high photosynthetic stress in the macroalgae and the lowest biomass concentration of the microalgae in water. The tourist and benthic management area demonstrated high As concentrations in sediments and Cd bioaccumulation. The industrial area was the least contaminated area, exhibiting lower photosynthetic stress and bioaccumulation.