Monitoring of copper, arsenic and antimony levels in agricultural soils impacted and non-impacted by mining activities, from three regions in Chile

Abstract

This paper reports a comparative study of the concentration of three important environmental elements that are often found together in mineral deposits and then associated with mining activities; copper, arsenic and antimony. These elements were determined in 26 different agricultural soils from regions I, II and V in Chile, zones where the most important and biggest copper industries of this country are located. As background levels of these elements in soils have not been well established, in this study, both, impacted and non-impacted agricultural soils from different regions were considered. The relationships between the concentrations of these elements in soils were also examined. The concentration ranges for copper, arsenic and antimony were 11-530; 2.7-202 and 0.42-11 mg kg(-1) respectively. The copper concentrations in non-polluted soils from the north and central zone of Chile were similar. However, three sites from the north region have copper concentration as higher as 100 mg kg(-1), values that exceed the critical concentration for copper in soils. The concentration of arsenic and antimony in the north soils were higher than in non-impacted ones and, in the case of arsenic, greatly exceeded the world average concentration reported for this element in soils. The highest arsenic and antimony concentrations were found in Calama and Quillagua soils, two different sites in the Loa valley. The arsenic/antimony concentration ratio was higher in Quillagua soil. The high concentrations of three elements determined in impacted soils from region V (Puchuncaví and Catemu valleys) clearly shows the impact produced in this zone by the industrial and mining activities developed in their proximities. At Puchuncaví valley a clear decrease was observed in copper, arsenic and antimony concentrations in soils on the function of the distance from the industrial complex "Las Ventanas", and all concentrations exceeded the reported critical values for this matrix. Instead at Catemu valley, only the copper concentration was higher than this value. Statistically significant correlation was found for Cu-Sb in all soils; more significant Cu-As, Cu-Sb and Sb-As correlations were evaluated for soils from Puchuncaví and Catemu valleys, corroborating that high concentrations of copper, arsenic and antimony in these soils coming from the same pollution sources, the copper industry and the thermoelectric power plant.

Arsenic Distribution in Shoots of the Halophyte Plant Species Atriplex atacamensis Growing in an Extreme Arid Mining Area from Northern Chile

“…Higher values (up to 1500 mg Kg -1 ) in Quillagua were reported by Romero et al [2] and Bugueño et al [9] but these authors studied sediments present in the river while our samples were taken on dry soil at least 30 m away from the river flow. De Gregori et al [28] analyzed soil sample from Quillagua and reported values similar to those quantified in this study. According to these authors, Quillagua is the most As contaminated site among 27 analyzed sites in Regions I, II and V in Chile.…”

“…DCB extraction showed that 50 ± 11 µg of As g -1 of soil were linked with iron oxide and that 22% of total As were not bioavailable. Despite the proximity of copper mining industry in this area, the recorded Cu concentration remained low and did not exceed the world average concentration (30 mg Kg -1 ) [28]. De Gregori et al [28] reported high concentration of antimony in Quillagua but this element was not analyzed in the present study.…”

“…Despite the proximity of copper mining industry in this area, the recorded Cu concentration remained low and did not exceed the world average concentration (30 mg Kg -1 ) [28]. De Gregori et al [28] reported high concentration of antimony in Quillagua but this element was not analyzed in the present study. A high concentration of B was also recorded in our soil samples (more than 500 ppm), confirming that Quillagua area is polluted by several elements.…”

Trace elements in bivalve shells from the Río Cruces, Chile

“…Cu is an important component in many fungicidal sprays (Brown et al 1996), the use of which is widespread in Chile, and is also a contaminant from mining activities (De Gregori et al 2003). If the record of Cu in these bivalves reflects agricultural activity, then it suggests that these sprays came into common usage along this watershed in the mid1970s.…”

Thresholds of copper toxicity to lettuce in field-collected agricultural soils exposed to copper mining activities in Chile

“…Environmental problems associated with copper mining in Central Chile are widely known, particularly in relation to the historical contamination of agricultural soils with metals, such as Cu, Zn, Pb, and Cd, and metalloids (As) (De Gregori et al, 2003;Ginocchio, 2000;González et al, 1984). It is well known that soil contamination with metals diminishes its quality and presents a risk for Thresholds of copper toxicity to lettuce soil functioning (Adriano, 2001).…”