Tomato and parsley growth, arsenic uptake and translocation in a contaminated amended soil

Abstract

Mining is a source of trace element contamination of neighbouring soils. This study determined the influence of soil amendments (iron oxides, Fe; organic matter, OM; and calcium phosphate, PCa) on arsenic uptake and translocation by tomato and parsley growth in an As-contaminated soil. The original contaminated soil without amendments was collected in the vicinity of the abandoned Santo António mine (Penedono, Portugal), which was a very important gold and arsenic mining centre in the middle fifties of the last century. An uncontaminated soil was also used as control. Growth parameters measured were plant height, length of 4th leaf (tomato only) and dry matter accumulation. Arsenic concentration in plant components was also determined, and human health risks related to the edible tissues were calculated. Results showed that arsenic availability in the soil varied with the amendments applied: OM and PCa increased arsenic availability, while the opposite effect was found with Fe (at 3gkg−1). Soil amended with iron oxides showed no positive effect on plant growth compared with the original soil with no amendments. Amongst all the amendments, OM led to the best results relatively to all growth parameters measured in tomato, including dry matter accumulation and fruit yield. Parsley growth was very small except in the PCa at 12gkg−1. Parsley translocated more arsenic to shoots, while tomato retained a greater proportion in roots. The health risk for adults and adolescents was within acceptable limits with an average weekly intake of 500g of tomato and 20g of parsley, although the arsenic concentration in edible tissues was still considerable greater than in plants grown in the uncontaminated control soil.