Assessment of trace metal bioavailability in garden soils and health risks via consumption of vegetables in the vicinity of Tongling mining area, China

• Published in: Ecotoxicology and environmental safety 2013-04, Vol.90, p.103-111
• Main Authors: Xu, Decong, Zhou, Ping, Zhan, Jing, Gao, Yi, Dou, Changming, Sun, Qingye
• Format: Article
• Language: English
• Subjects: ammonium nitrate; Animal, plant and microbial ecology; Applied ecology; aqueous solutions; Asteraceae; Bioavailability; Biological and medical sciences; Biological Availability; Cadmium; China; copper; Ecotoxicology, biological effects of pollution; EDTA (chelating agent); Food Contamination; Fundamental and applied biological sciences. Psychology; Garden soils; Gardening; gardens; Health risk; hydrochloric acid; lead; Lead (metal); Liliaceae; Metals, Heavy - analysis; Metals, Heavy - chemistry; Metals, Heavy - metabolism; Mining; polluted soils; pollution; Risk; Risk Assessment; Soil - chemistry; Soil Pollutants - analysis; Soil Pollutants - chemistry; Soil Pollutants - metabolism; soil sampling; Soils; Terrestrial environment, soil, air; Tongling mining area; Trace Elements - analysis; Trace Elements - chemistry; Trace Elements - metabolism; Trace metal bioavailability; Trace metals; vegetable consumption; Vegetables; Vegetables - chemistry; zinc
• ISSN: 0147-6513; 1090-2414
• DOI: 10.1016/j.ecoenv.2012.12.018

Environmental pollution due to mining activities has been reported in many countries. In this study, 283 vegetable and 44 corresponding garden soil samples were collected in the vicinity of the Tongling mining area, China. The aim was to evaluate the bioavailability of trace metals (Cu, Zn, Pb and Cd) to vegetables by comparing different methods (trace metals in DTPA, EDTA, HCl, NH4NO3, NH4OAC aqueous solutions and total metals in garden soils), and assess the potential health risks of trace metals to the local population via vegetable consumption. The results showed that the mean values of total Cu and Cd in the soil samples exceeded the Grade II national standard in China. Average concentrations of Cd and Pb in some vegetable samples were higher than the maximum permissible concentration in China. The transfer factors for trace metals in different vegetables showed a trend of Cd>Zn>Cu> Pb. Asteraceae vegetables had stronger metal uptake than Liliaceae. The total target hazard quotient (THQ) value was greater than 1, suggesting that trace metals in vegetables could present some potential health risks. The effectiveness of the studied methods for estimating soil metal bioavailability was generally dependent on the particular metal and vegetable species. Overall, 1.0M NH4OAC provided the best estimate of Cd and Zn bioavailability in multi-elemental contaminated soils. None of the studied soil metal extraction methods appeared suitable for measuring Cu or Pb bioavailability, especially for Pb, which showed almost no correlation between metal concentration in soil and vegetables. ► Asteraceae vegetables had stronger metal uptake than Liliaceae. ► Ammonium acetate was the best extractant. ► Lead concentrations in vegetables do not seem correlated to Pb contents in soil. ► Trace metals in vegetables could present some potential health risks.