[Health Risk Assessment of Heavy Metals in Soil and Wheat Grain in the Typical Sewage Irrigated Area of Shandong Province].

Sewage irrigation is a common alternative to make up for the shortage of agricultural irrigation in intensive agricultural areas. Abundant organic matter and nutrients in sewage can improve soil fertility and crop yield, but hazardous materials, such as heavy metals, will damage the soil environmental quality and threaten human health. To better understand the characteristics of heavy metal enrichment and potential health risk in a sewage irrigated soil-wheat system, a total of sixty-three pairs of topsoil and wheat grain samples were collected from the sewage irrigated area of Longkou City in Shandong Province. The contents of Cr, Cu, Ni, Pb, Zn, As, Cd, and Hg were determined to analyze heavy metal contamination and calculate bio-accumulation factor (BAF), estimated daily absorption (EDA), as well as hazard quotient (HQ). The results showed that the average contents of the eight heavy metals were 61.647, 30.439, 29.769, 36.538, 63.716, 8.058, 0.328, and 0.028 mg·kg-1, respectively, which all exceeded the background values of corresponding heavy metals in the eastern Shandong Province. Especially, the average content of Cd was higher than the current standard value of soil environmental quality of agricultural land soil pollution risk control, indicating the apparent soil contamination. However, the correlations between the heavy metal contents in soil and wheat grains were not significant, suggesting that it is difficult to conclude the enrichment degree of heavy metals in wheat grains merely by the heavy metal contents in soil. The results of BAF showed that the high enrichment capacity of wheat grain was primarily obtained with Zn, Hg, Cd, and Cu. According to the national food safety limit standard, the over-limit ratios of Ni (100%) and Pb (96.8%) in wheat grains were the most serious. As a result, under the current consumption of local wheat flour, the EDAs of Ni and Pb were high, accounting for 28.278% and 1.955% of the acceptable daily intakes (ADI) for adults and 131.980% and 9.124% of the ADIs for children. The results of the health risk assessment exhibited that As and Pb were the main sources causing health risks, accounting for approximately 80% of the total risk. Although the sums of the HQ of the eight heavy metals for adults and children were below 10, the total HQ of children was 1.245 times higher than that of adults. The food safety of children should receive more attention. When considering spatial characteristics, the health risk in the southern study area was higher than that in the northern part of the study area. The prevention and control of heavy metal contamination in the southern area should be strengthened in the future.

Source apportionment of nitrogen and phosphorus from non-point source pollution in Nansi Lake Basin, China.

Nitrogen (N) and phosphorus (P) from non-point source (NPS) pollution in Nansi Lake Basin greatly influenced the water quality of Nansi Lake, which is the determinant factor for the success of East Route of South-North Water Transfer Project in China. This research improved Johnes export coefficient model (ECM) by developing a method to determine the export coefficients of different land use types based on the hydrological and water quality data. Taking NPS total nitrogen (TN) and total phosphorus (TP) as the study objects, this study estimated the contributions of different pollution sources and analyzed their spatial distributions based on the improved ECM. The results underlined that the method for obtaining output coefficients of land use types using hydrology and water quality data is feasible and accurate, and is suitable for the study of NPS pollution at large-scale basins. The average output structure of NPS TN from land use, rural breeding and rural life is 33.6, 25.9, and 40.5%, and the NPS TP is 31.6, 43.7, and 24.7%, respectively. Especially, dry land was the main land use source for both NPS TN and TP pollution, with the contributed proportions of 81.3 and 81.8% respectively. The counties of Zaozhuang, Tengzhou, Caoxian, Yuncheng, and Shanxian had higher contribution rates and the counties of Dingtao, Juancheng, and Caoxian had the higher load intensities for both NPS TN and TP pollution. The results of this study allowed for an improvement in the understanding of the pollution source contribution and enabled researchers and planners to focus on the most important sources and regions of NPS pollution.

[Ecological Risk Assessment of Soil Heavy Metals for Different Types of Land Use and Evaluation of Human Health].

Surface soils were collected from five types of land use in the northern plain of Longkou City and the contents of five heavy metals (Cu, Pb, Zn, Cd, and As) were determined. Based on results from preliminary studies on heavy metal pollution of soil, the potential ecological risks caused by heavy metals in the soil and risks to human health were evaluated using the Hakanson potential ecological risk assessment model after adjusting the evaluation threshold and the health assessment model after modifying parameters. The results show that the contents of five heavy metals in the study area exceed the background value, the potential ecological risk of Cd is high and complex, in irrigated land, orchard land, and bare land it is mostly the second-class risk, and urban industrial land and mining land are dominated by severe risk. The element As is equivalent to the first two levels of each land class; the minor risk areas of the other three types of heavy metals are larger than 70%. The comprehensive ecological risk of the five elements is higher than the three-level risk in the field, except for the bare ground. The area of four-level risk of urban industrial land and mining land is relatively large. The five types of soil heavy metals in this area present noncarcinogenic and carcinogenic risks to human health. The element Pb and heavy metal As, both entering the body by oral intake, pose a noncarcinogenic and carcinogenic risk to adults and children, respectively.

[Source Analysis, Spatial Distribution and Pollution Assessment of Heavy Metals in Sewage Irrigation Area Farmland Soils of Longkou City].

Farmland soils in sewage irrigation area at Longkou City were collected, soil pH together with the heavy metal content were tested. Taking 70 soil points as the study object, this paper investigated the source of heavy metals in this area based on the correlation analysis and PCA of multivariate statistical analysis theory. We studied the spatial variation and distribution characteristics about heavy metals using both the theory of geostatistics and GIS spatial interpolation method. At last, the heavy metal pollution was evaluated in the way of Nemerow Index and improved fuzzy evaluation method. It turned out that, 9 kinds of heavy metal elements in the soil of research area had a certain degree of enrichment, among them the average of Cd was 3.06 times as high as the background value, and its enrichment was most severe. The result of Nemerow Index showed that, the values of comprehensive pollution index of Cu, Cd and Pb respectively were 7.06, 6.10 and 5.54, and they all belonged to high levels of pollution. According to the results of correlation analysis and principal component analysis, Cu, Zn together with Pb, Cd were mainly affected by human factors, sewage irrigation was their common pollution factor, the pollution sources for the first two heavy metals included excessive use of chemical fertilizers and pesticides in agricultural production and the accumulation of long time, whereas pollution from northern coal mining and coal gangue piled up as well as plating, machinery manufacturing and other industrial pollution were the pollution sources of the latter two elements. Other elements (Co, Cr, Mn, Ni and As) were mainly influenced by natural factors such as parent material. Comprehensive evaluation results showed that, among the 70 points, 13 points had moderate pollution,23 points belonged to light pollution, 28 points were at alert level, 6 points were in the safe range. From the perspective of spatial distribution,high value areas of heavy metal contents were mainly concentrated in towns of Zhuyouguan and Xufu. This showed that, sewage irrigation caused a certain degree of heavy metal pollution to local soil.

[Pollution Assessment and Spatial Distribution Characteristics of Heavy Metals in Soils of Coal Mining Area in Longkou City].

The present paper takes the coal mining area of Longkou City as the research area. Thirty-six topsoil (0-20 cm) samples were collected and the contents of 5 kinds of heavy metals were determined, including Cd, As, Ni, Ph, Cr. Geo-statistics analysis was used to analyze the spatial distribution of heavy metals. Principal component analysis (PCA) was used to explore the pollution sources of heavy metals and the degree of heavy metals pollution was evaluated by weighted average comprehensive pollution evaluation method. The results showed that enrichment phenomenon was significant for the 5 kinds of heavy metals. Taking secondary standard of National Environment Quality Standard for Soil as the background value, their exceed standard rates were 72.22%, 100%, 100%, 91.67%, 100%, respectively. Average contents of heavy metals in the soil samples were all over the national standard level two and were 1.53, 11.86, 2.40, 1.31, 4.09 times of the background value. In addition, the average contents were much higher than the background value of the topsoil in the eastern part of Shandong Province and were 9.85, 39.98, 8.85, 4.29, 12.71 times of the background value. According to the semivariogram model, we obtained the nugget-effects of 5 kinds of heavy metals and their values were in the order of As (0.644) > Cd (0.627) > Cr (0.538) > Ni (0.411) > Pb (0.294), all belonging to moderate spatial correlation. On the whole, the central part of the Sangyuan Coal Mine and its surrounding areas were the most seriously polluted, while the pollution of heavy metals in the east and west of the study area was relatively light. Principal component analysis suggested that the enrichment of Cd, As, Ni, Cr was due to irrigation of wastewater, the discharge of industry and enterprise, and the industrial activity. Automobile exhaust and coal combustion were the main pollution sources of Pb. The single-factor assessment of heavy metals pollution showed that the degree of different heavy metals pollution was in the order of As > Cr > Ni > Cd > Pb. Simultaneously, comprehensive pollution evaluation showed that the degree of heavy metals pollution in the study area was very serious, with comprehensive pollution index ranging from 2.17 to 4.66, among which, the numbers of moderate and heavy pollution samples were 10 and 26, respectively. Areas with heavy pollution were mainly distributed in the Sangyuan Coal Mine, Beizao Coal Mine, Liuhai Coal Mine; and the areas with moderate pollution covered Wali Coal Mine, Liangjia Coal Mine, and other regions. The results of this paper will provide data reference and theoretical support for the study of ecological risk assessment in the study area.

[Spatial Characteristics and Environmental Risk of Heavy Metals in Typical Gold Mining Area of Shandong Province].

In order to reveal the influence of anthropogenic factors on soil environment quality, a total of seventy-seven samples in topsoils were collected from Jiaojia gold mining area in Shandong province and were determined for Cu, Pb, Zn, Cr contents. Spatial structure, spatial distributions of concentrations and risk probability of heavy metals were analyzed using spatial statistic analysis. The average concentrations of Cu, Pb, Zn and Cr were 19.41 mg·kg-1, 27.32 mg·kg-1, 49.81 mg·kg-1 and 39.27 mg·kg-1, respectively. Pb, Zn and Cr were distributed normally and Cu was distributed normally after logarithm transformation. Semivariance analysis demostrated that Pb could be fitted to exponential model, and Cu, Zn and Cr were fit for spherical model. Nugget coefficents of Cu and Pb were between 0.25 and 0.75, which illustrated middle spatial autocorrelation; Zn and Cr showed the structural variation with nugget values below 0.25. Cu and Pb in the topsoils were distributed dispersedly due to effects of some human factors, whereas contents of Zn and Cr indicated relatively regular distributions and were mainly affected by natural factors. Spatial distributions of the 4 heavy metals were approximately consisitent and the high value areas appeared in the gold mines band. The result of hot spot analysis and indicator kriging interpolation revealed that the relatively high risk areas were located in Jincheng town, the boundary zone of Xinzhuang town and Canzhuang town, while the safe zone was situated in south part of the study area. Pb had higher probability exceeding the threshold and the middle or high environmental risk areas of Pb were distributed widely, which should be paid more attentions.