Lead contamination and its potential sources in vegetables and soils of Fujian, China

Abstract

Lead (Pb) contents and partition in soils collected from eleven vegetable-growing lands in Fujian Province, China, were investigated using a modification of the BCR (Community Bureau of Reference) sequential extraction procedure coupled with the Pb isotope ratio technique. Pb contents in Chinese white cabbage (B. Chinensis L.) grown on the lands for this study were also measured. Results showed that Pb concentrations in fifty samples of topsoil ranged from 456 to 21.5 mg kg(-1), with each mean concentration of six sampling lands exceeding the national standard (50 mg kg(-1)); while Pb concentrations in edible portions of thirty-two vegetable samples ranged from 0.009 to 2.20 mg kg(-1), with four sampling sites exceeding the national sanitary standard (0.2 mg kg(-1)). A significant correlation (r = 0.971, P < 0.01) of Pb contents in the acid-extractable fractions by BCR approach and the vegetables was observed, which indicates that the acid-extractable Pb is useful for evaluating the metal bioavailability for plants and potential risk for human health in soils. The determination of lead isotope ratios in different chemical forms of soils by BCR sequential extraction procedures provides useful information on the Pb isotopic composition associated with different soil fractions (especially in the acid-extractable fractions), and the result is helpful for the further study on controlling and reducing Pb contamination in vegetable-growing soils.

Concentrations of lead, cadmium and barium in urban garden-grown vegetables: The impact of soil variables

“…For Pb, the highest levels in vegetables generally occur where soil Pb levels are the highest (Bielinska, 2009; Huang et al, 2012; Jorhem et al, 2000; Moir and Thornton, 1989; Samsøe-Petersen et al, 2002). Some studies using sensitive methods for analyzing vegetable metals concentrations have indicated a near-linear relationship between soil Pb and vegetable Pb concentrations, so that bioconcentration factors (BCFs) could be estimated (e.g., 0.001, 0.002 and 0.05 for lettuce, potato and carrot [with peel], respectively) (Samsøe-Petersen et al, 2002).…”

Evaluating specificity of sequential extraction for chemical forms of lead in artificially-contaminated and field-contaminated soils

“…Some studies suggest that plant availability of Pb is correlated to particular Pb fractions extracted in the sequential extraction procedure [6]. However, previous research has shown that the bulk of the Pb in contaminated soils is extracted in the “reducible” or “oxide” fraction, a strongly acidic extractant (pH near 2) of the 4-step BCR method [7,8].…”

Use of Sequential, Single and Kinetic Extractive Schemes to Assess Cadmium (Cd) and Lead (Pb) Availability in Vietnamese Urban Soils

“…Whatever the method used (BCR or single extraction), the exchangeable fraction of Cd decreased with pH increase indicating lower exchangeability in alkaline soils. Huang et al [6] reported that in alkaline soils, Cd is mostly released from carbonate-and Fe-/Mn-oxide bound fractions.…”