Concentration Level of Heavy Metals in Wheat Grains and the Health Risk Assessment to Local Inhabitants from Baiyin, Gansu, China

Abstract

In the present study, concentrations of heavy metals (Cu, Zn, Pb, Cd) in soil and wheat grains of the agricultural areas around Baiyin, a non-ferrous metals mining and smelting base, were detected. Meanwhile, the potential health risk of the heavy metals to adult males, adult females and children was estimated using non-carcinogenic health risk assessment model: Hazard Quotient (HQ) and Hazard Index (HI). The results showed that only the level of Cd in all soil samples exceeded the permissible limit of the environmental quality standard for soil, and its average level surpassed the standard value by 4 times. In wheat grains, the levels of Pb and Cd were 50 times and 8 times of the limited values of hygienic standard for grain respectively, while Cu and Zn concentrations did not surpass the standard value. The potential health risk due to single heavy metal for all the three investigated populations followed the sequence of HQPb＞HQCd＞HQCu＞HQZn＞1 (assumed the local inhabitants wholly food on wheats), suggesting that each of the four heavy metals were making negative effect on population health, of which the situation of Pb and Cd should be paid more attention due to their significant adverse effect. The total potential health risk due to the four heavy metals followed the sequence of HIchildren＞HImales＞HIfemales＞1 (assumed that the health risk due to the four heavy metals is additive), suggesting that the heavy metals were producing adverse effect on population health, and were especially hazardous for children. According to the research results, the government is suggested to strictly control the quality of irrigation water and remove the heavy metals from agricultural soil in order to ensure the safety of foodcrop production and local inhabitants.

Density-dependent Accumulation of Heavy Metals in Spring Wheat (Triticum Aestivum ) and the Risk Assessment from Weak Alkaline Soils, Northwest of China

“…decreased about 78% and 75% for Pb and Cd , respectively, compared to previous work done in the same region [5]. Above all, the higher the planting density is, the lower the Pb and Cd concentrations in wheat grain are, which means elevating planting density has a significant effect on reduction of Pb and Cd and a weaker effect on Cu and Zn in wheat grain.…”

“…From Table 1, it can be seen that the soil is slightly alkaline, and the total concentrations of the four selected elements are lower than the environmental quality standard for soils of China (GB15618-1995), except for Cd, and the concentrations of metals are also lower than that from the previous work done in this region (60.05 mg/kg, 230.66 mg/kg, 100.7 mg/kg, 5.7 mg/kg for Cu, Zn, Pb and Cd, respectively) [5]. However, concentrations of all the four elements exceeded their background values, indicating that over the past few decades the environment-unfriendly development of industry and agriculture might cause the local soil polluted.…”

“…HQs of Cu, Zn Pb and Cd are above 1 at all five planting densities, indicating there are potential noncarcinogenic effects to the consumers. Pb has the highest HQ followed by Cd in all densities, while a significant decrease of HQPb is found with the increasing of planting density, and the integrative risk also significantly decreased from D3 to D5 respect to the previous work (21.98 of Pb and 6.72 of Cd in local planting density [5]. So planting density could be considered as an alternative cultivation way for safer production on slightly polluted soils.…”

“…As the second largest crop in the world, wheat as the main food resource for locals is widely grown in northern China [1]. However, wheat grain is no longer safe for consumption because of high soil heavy metals [5]. Although measures have been taken by governments at all levels for protecting the grain crop security, the responses from local farmers are not positive enough for the consideration of yield and economic benefits.…”

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“…The outer layers of whole grains can also be a source of heavy metals if they are present in the environment (55). Adequate intake of other minerals and nutrients is the best defense against absorption and the negative impacts of many of these toxic minerals (56).…”