Accumulation of heavy metals in leaf vegetables from agricultural soils and associated potential health risks in the Pearl River Delta, South China

Abstract

This study investigated the extent of heavy metal accumulation in leaf vegetables and associated potential health risks in agricultural areas of the Pearl River Delta (PRD), South China. Total concentrations of mercury (Hg), cadmium (Cd), lead (Pb), chromium (Cr) and arsenic (As) were determined in 92 pairs of soil and leaf vegetable (flowering Chinese cabbage, lettuce, pakchoi, Chinese cabbage, loose-leaf lettuce, and Chinese leaf mustard) samples collected from seven agricultural areas (cities). The bioconcentration factors (BCF) of heavy metals from soil to vegetables were estimated, and the potential health risks of heavy metal exposure to the PRD residents through consumption of local leaf vegetables were assessed. Results showed that among the six leaf vegetables, pakchoi had the lowest capacity for heavy metal enrichment, whereas among the five heavy metals, Cd had the highest capacity for transferring from soil into vegetables, with BCF values 30-fold those of Hg and 50-fold those of Cr, Pb and As. Sewage irrigation and fertilization were likely the main sources of heavy metals accumulated in leaf vegetables grown in agricultural areas of the PRD region. Different from previous findings, soil pH had no clear effect on metal accumulation in leaf vegetables. Despite a certain degree of metal enrichment from soil to leaf vegetables, the PRD residents were not exposed to significant health risks associated with consumption of local leaf vegetables. Nevertheless, more attention should be paid to children due to their sensitivity to metal pollutants.

Phytoextraction of heavy metals from a landfill in the metropolitan region of Belém-Pará-Brazil

“…The BF is an important quantitative indicator and has been used to generally estimate the transfer of metals from soils to plants (Chang et al, 2014).…”

“…where MCp corresponds to the heavy metal concentration in the plant, and MCs corresponds to the heavy metal concentration in the soil (Chang et al, 2014).…”

Metales pesados en leche de vacas alimentadas con alfalfa producida en suelos irrigados con aguas residuales en Puebla y Tlaxcala, México

“…La contaminación ambiental por metales pesados producida por la industria y el crecimiento urbano afecta el aire, agua y suelos (1) ; pudiéndose acumular a largo plazo a niveles tóxicos en los suelos, donde permanece por largos periodos debido a que no son degradados y pueden biotransformarse en la cadena alimentaria (2,3) . Esta acumulación puede provocar graves trastornos de salud en la población humana (4,5,6) .…”

Total and Bioaccessible Soil Arsenic and Lead Levels and Plant Uptake in Three Urban Community Gardens in Puerto Rico

“…Previous studies characterizing contaminant levels in urban garden produce have been conducted in regions throughout the world, including the United States [6,7], Great Britain [8][9][10], and China [11]. However, published research is limited on soil and plant As and Pb levels in the Caribbean region, including the U.S. territory of Puerto Rico.…”