Co-exposure of heavy metals in rice and corn reveals a probabilistic health risk in Guizhou Province, China.

The adverse effects of heavy metals have arousing concern in the high geological background area, especially in southwestern Guizhou, China. However, the pollution status of heavy metals are still unclear when exposed to rice and corn in Guizhou province. Therefore, the concentration, pollution level, spatial distribution, and probabilistic health risks of Ni, Cr, Pb, Cu, and Zn are estimated in rice and corn. A total of 241 samples (117 for rice and 124 for corn) were collected from Guizhou province and measured by a method of inductively coupled plasma-mass spectrometry (ICP-MS). The results showed that rice and corn were contaminated with Ni and Cr. High concentrations of Ni were presented in the southeast of rice. It indicated that 22.0 % of rice samples were contaminated with Ni. HI values for children and adults exceeded 1.0 in rice and corn, suggesting that humans might be subject to probabilistic non-carcinogenic risks. FTCR demonstrated that rice and corn might cause probabilistic carcinogenic risks to children and adults, which were both greatly higher than 1.0 × 10-4. Moreover, the contributions of Ni to the HI and FTCR were the highest for adults and children. Therefore, more attention should be paid to the exposure of heavy metals in rice and corn, especially in Ni. The results would provide a novel prospective for pollution control and be helpful for environmental regulation.

Low dosage fluorine ameliorates the bioaccumulation, hepatorenal dysfunction and oxidative stress, and gut microbiota perturbation of cadmium in rats.

Many "hot spot" geographic areas around the world with soils and crops co-polluted with cadmium (Cd) and fluorine (F), two of the most representative pollutants in the environment. However, it still exists argumentative on the dose-effect relationship between F and Cd so far. To explore this, a rat model was established to evaluate the effects of F on Cd-mediated bioaccumulation, hepatorenal dysfunction and oxidative stress, and the disorder of intestinal microbiota as well. 30 healthy rats were randomly assigned to Control group (C group), Cd 1 mg/kg (Cd group), Cd 1 mg/kg and F 15 mg/kg (L group), Cd 1 mg/kg and F 45 mg/kg (M group), and Cd 1 mg/kg and F 75 mg/kg (H group) for 12 weeks by gavage. Our results showed that Cd exposure could accumulate in organs, cause hepatorenal function damage and oxidative stress, and disorder of gut microflora. However, different dosages of F showed various effects on Cd-induced damages in liver, kidney, and intestine, and only the low supplement of F showed a consistent trend. After low supplement of F, Cd levels were declined by 31.29% for liver, 18.31% for kidney, and 2.89% for colon, respectively. The serum aspartate aminotransferase (AST), blood urea nitrogen (BUN), creatinine (Cr), and N-acetyl-ß-glucosaminidase (NAG) were significantly reduced (p < 0.01); The activity of superoxide dismutase (SOD) was elevated and mRNA expression level of NAD(P)H quinone oxidoreductase 1 (NQO1) was decreased in the liver and kidney (p < 0.05). Moreover, low F dosage up-regulated the abundance of Lactobacillus from 15.56% to 28.73% and the 6.23% of F/B ratio was declined to 3.70%. Collectively, this highlights that low dosage of F might be a potential strategy to ameliorate the hazardous effects by Cd-exposed in the environment.

Co-exposure of potentially toxic elements in wheat grains reveals a probabilistic health risk in Southwestern Guizhou, China.

Bijie is located at a typical karst landform of Southwestern Guizhou, which presented high geological background values of potentially toxic elements (PTEs). Recently, whether PTE of wheat in Bijie is harmful to human health has aroused people's concern. To this end, the objectives of this study are to determine the concentrations of PTE [chromium (Cr), nickel (Ni), arsenic (As), lead (Pb), cadmium (Cd), and fluorine (F)] in wheat grains, identify contaminant sources, and evaluate the probabilistic risks to human beings. A total of 149 wheat grain samples collected from Bijie in Guizhou were determined using the inductively coupled plasma mass spectrometer (ICP-MS) and fluoride-ion electrode methods. The mean concentrations of Cr, Ni, As, Cd, Pb, and F were 3.250, 0.684, 0.055, 0.149, 0.039, and 4.539 mg/kg, respectively. All investigated PTEs met the standard limits established by the Food and Agriculture Organization except for Cr. For the source identification, Cr and Pb should be originated from industry activities, while Ni, As, and Cd might come from mixed sources, and F was possibly put down to the high geological background value. The non-carcinogenic and carcinogenic health risks were evaluated by the probabilistic approach (Monte Carlo simulation). The mean hazard quotient (HQ) values in the three populations were lower than the safety limit (1.0) with the exception of As (children: 1.03E+00). However, the mean hazard index (HI) values were all higher than 1.0 and followed the order: children (2.57E+00) > adult females (1.29E+00) > adult males (1.12E+00). In addition, the mean carcinogenic risk (CR) values for Cr, As, Pb, and Cd in three populations were all higher than 1E-06, which cannot be negligible. The mean threshold CR (TCR) values were decreased in the order of children (1.32E-02) > adult females (6.61E-03) > adult males (5.81E-03), respectively, all at unacceptable risk levels. Moreover, sensitivity analysis identified concentration factor (C W ) as the most crucial parameter that affects human health. These findings highlight that co-exposure of PTE in wheat grains revealed a probabilistic human health risk. Corresponding measures should be undertaken for controlling pollution sources and reducing the risks for the local populace.

Accumulation and risk assessment of heavy metals in rice: a case study for five areas of Guizhou Province, China.

In the present study, the concentration and accumulation abilities of five heavy metals (Cd, Hg, As, Pb, Cr) in rice were assessed and their human health risk to local citizens had been evaluated. Soil and rice samples (125 samples) were collected from Guiyang (GY), Qiannan (QN), Bijie (BJ), Tongren (TR), and Zunyi (ZY) in Guizhou Province. Heavy metals were measured by inductively coupled plasma-mass spectrometry (ICP-MS) after microwave digestion. The mean concentrations of Cd, Hg, As, Pb, and Cr were 0.58, 0.65, 12.31, 38.70, and 87.30 mg/kg in soil and were 0.05, 0.005, 0.11, 0.07, and 0.34 mg/kg in rice, respectively. The bioconcentration factors (BCF) decreased with the order Cd > Hg > As > Cr > Pb. Non-carcinogenic risk in this study was evaluated using the method of the hazard quotient (HQ) and hazard index (HI). The mean HQ values for Cd, Hg, Pb, and Cr were all lower than the standard limit (1.0) for children and adults, except As with the mean HQ for children of 2.79. The mean HI values for children and adults were 4.22 and 1.42, which exceeded 1.0. The mean carcinogenic risk (CR) values of As and Pb for children and adults were higher than the upper limit of the acceptable range (1 × 10-4) established by the United States Environmental Protection Agency (USEPA). In a conclusion, the non-carcinogenic and carcinogenic risks induced by heavy metals for children were higher than that for adults. This study revealed that consumption of rice in study areas may pose potential non-carcinogenic and carcinogenic risks to humans, and As was the largest contributor.