Health risks of heavy metals in contaminated soils and food crops irrigated with wastewater in Beijing, China

TLDR: It is highlighted that both adults and children consuming food crops grown in wastewater-irrigated soils ingest significant amount of the metals studied, however, health risk index values of less than 1 indicate a relative absence of health risks associated with the ingestion of contaminated vegetables.

About: This article is published in Environmental Pollution.The article was published on 2008-04-01 and is currently open access. It has received 1951 citations till now. The article focuses on the topics: Soil contamination & Environmental pollution.

Figures

Table 4 DIM and HRI for individual heavy metals caused by the consumption of different selected vegetables grown in wastewater-irrigated soils

Table 2 Heavy metal transfer factors (on dry weight basis) for plants grown in wastewater-irrigated soils

Table 3 Pearson’s correlation coefficients (r) between the heavy metal concentrations in so

Table 1 Characteristics of wastewater-irrigated and reference soils collected from the study

Fig. 1. Heavy metal concentrations (dry weight basis) in the edible parts of plants grown in wastewater-contaminated soils: (a) Cd; (b) Cr; (c) Cu; (d) Ni; (e) Pb; and (f) Zn. The error bars indicate the standard deviation while the asterisks indicate significant differences in heavy metal concentrations between plants grown in wastewater-irrigated and reference soils, at P < 0.05 (*), P < 0.01 (**) and P < 0.001 (***), respectively.

Frequently asked questions

Q1. What are the contributions in "Health risks of heavy metals in contaminated soils and food crops irrigated with wastewater in beijing, china" ?

The authors studied the health risks of heavy metals in contaminated food crops irrigated with wastewater. Furthermore, this study highlights that both adults and children consuming food crops grown in wastewater-irrigated soils ingest significant amount of the metals studied. 

Q2. What is the cause of contamination of soils with metals?

In this study area, soil contamination with metals is mainly due to wastewater irrigation, application of sludge in the farmlands, and possible atmospheric deposition. 

Q3. What is the effect of heavy metals on the health of plants?

Heavy metal accumulation in plants depends upon plant species, and the efficiency of different plants in absorbing metals is evaluated by either plant uptake or soil-toplant transfer factors of the metals (Rattan et al., 2005). 

Q4. What is the effect of continuous wastewater irrigation on the soil?

their results showed that continuous wastewater irrigation led to elevated levels of heavy metals in the soils and in edible parts of food crops. 

Q5. What is the main reason for heavy metals in soils?

Excessive accumulation of heavy metals in agricultural soils through wastewater irrigation, may not only result in soil contamination, but also lead to elevated heavy metal uptake by crops, and thus affect food quality and safety (Muchuweti et al., 2006). 

Q6. How much water soluble organic carbon was increased in wastewater-irrigated soils?

The water soluble organic carbon was increased by 5.4%, while its humic acid fraction increased by 51.8%, in wastewater-irrigated soils. 

Q7. What was the method used to measure the organic carbon in soil?

Water soluble organic carbon and its fractions including humic acid carbon and fulvic acid carbon were measured as described by Chen et al. (2004). 

Q8. What is the cause of the contamination of vegetables?

Heavy metal accumulation by vegetables is a cause of serious concern due to the potential public health impacts (Bi et al., 2006; Cui et al., 2005). 

Q9. What are the main sources of metal exposure to humans?

The findings of this study regarding DIM and HRI suggest that the consumption of plants grown in wastewatercontaminated soils is nearly free of risks, but there are also other sources of metal exposures such as dust inhalation, dermal contact and ingestion (for children) of metal-contaminated soils, which were not included in this study. 

Q10. What was the conversion factor used to convert fresh green vegetable weight to dry weight?

The conversion factor 0.085 was used to convert fresh green vegetable weight to dry weight, as described by Rattan et al. (2005). 

Q11. What is the main reason why heavy metals are a problem in food crops?

As mentioned earlier, food crops were contaminated with heavymetals and the consumption of such foodstuffs can cause human health risks. 

Q12. What is the significance of the correlation between soil metal concentrations and plants?

The high transfer values for Cd, Cu, and Ni from soil to plants indicate a strong accumulation of the respective metals by food crops, particularly by leafy vegetables.