Mercury Dispersal to Arroyo and Coastal Sediments from Abandoned Copper Mine Operations, El Boléo, Baja California

Evidence for mercury dispersal in an arid coastal region of central Baja California (Mexico) suggests that abandoned copper mining operations are a noticeable source of mercury in the environment. There is a generally elevated level of mercury in alluvium of arroyos throughout the mining district (0.14–0.18 mg kg−1). In the first several dozen meters surrounding two of the biggest mines, mercury levels range from 0.26 to 3.16 mg kg−1, forming a halo of anomalously high concentrations. The coastal marine sediments, particularly those close to the copper smelter in the town of Santa Rosalia, also display some mercury enrichment.