Publisher(s): China Academic Journals (CD Edition) Electronic Publishing House Co., Ltd.
ISBN: ISBN 978-7-499-00965-3 pdf
First Published: 2020.11.23
Discipline(s): Chemistry/ Metallurgy/ Environment/ Mine Industry
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Soil Pollution and Control, as part of China’s S&T Progress Series, has 60 excellent articles on soil contamination research in China. The book includes two chapters. Chapter 1 provides systematic analysis of the migration patterns, residue characteristics, sources, and health/ecological risks of soil pollutants such as heavy metals, pharmaceuticals and personal care products, organochlorine pesticides, polycyclic aromatic hydrocarbons, polychlorinated biphenyls, and fluorides in key regions of China like Beijing-Tianjin-Hebei region, Yangtze River Delta, and Pearl River Delta. Chapter 2 highlights the measures used to effectively address soil contamination in China. This book demonstrates a full spectrum of outcomes in the prevention and control of soil contamination in China, and provides a scientific basis and theoretical guidance for soil remediation worldwide. The original articles were published in Chinese and this book is a compilation of English versions of selected articles.
CHEN Shibao, researcher at the Institute of Agricultural Resources and Regional Planning, CAAS, and doctoral supervisor, is currently a director of Chinese Society for Environmental Sciences, a member of Specialized Committee on Heavy Metal Pollution Prev
1. Residue Characteristics, Sources and Risk Assessment of Organochlorine Pesticides in Riparian Soils of the Yangtze River Basin
China Environmental Science,Part 1: Types of Soil Pollution,Vol 39,No. 01
The soils around the mainstream and the tributaries of the Yangtze River Basin were selected as the research media, and the content of 13 organochlorine pesticides (OCPs) in the topsoil was analyzed. The sources were analyzed by the isomer ratio method and principal component analysis, and the health risk assessment was discussed. The results showed that the concentration of ∑ 13 OCPs in the topsoil of the Yangtze River Basin ranged from 8.94 to 77.79 ng/g, with an average content of 24.55 ng/g. HCHs and DDTs were the dominant components. The concentration level of OCPs was similar between the upstream and downstream, but the level in the midstream was higher than that in the upstream and downstream. However, the level of OCPs concentration in the Yangtze River Basin was at a medium level in the world. The HCHs in the soil were mainly from the historical residues of Lindane, while DDTs were mainly derived from the recent import of dicofol and the illegal use of industrial DDTs. The health risk assessment showed the risk in the midstream was higher than that in the upstream and downstream of the Yangtze River Basin. The Risk integral value of carcinogenic risks ranged from 10 ?6 to 10 ?4 in Chenglingji, Nanzui, and Xiangyin, which indicated that there were carcinogenic risks to children in these three areas.
China Environmental Science,Part 1: Types of Soil Pollution,Vol 38,No. 02
The concentrations, distributions and compositions of DDTs in surrounding soils collected for four times from a closed pesticide plant were studied, respectively, before and after the demolition of the plant. The results showed that the concentrations of DDTs (average 334 ng/g) in soils collected one month after the plant was demolished were higher than those (average 97.0 ng/g) obtained two months before the demolition. After that, a significant decrease was seen for the concentration of DDTs in surrounding soils. Before demolition, p, p'-DDE (average 35.6 ng/g) and p, p'-DDD (average 31.0 ng/g) were the main congeners in surrounding soils, while p, p'-DDT (average 289 ng/g) was the predominant congener in the soils after demolition, which was about 28.9 times that detected in surrounding soils before the plant demolition. The historical production of technical DDT and usage of dicofol in surrounding agricultural soils were the main reasons for the concentrations of DDTs in surrounding soils before the plant demolition, while the volatilization of technical DDTs was the main contribution for the concentration of DDTs in surrounding soils during the plant demolishing. The spatial distribution of DDT concentrations in surrounding soil is usually dominated by the wind, and the east wind is the prevailing wind direction in this area, which resulted in higher concentrations of DDTs in the western area than those in the eastern area both before and after the plant was demolished.
3. ?Distribution and Source Analysis of Polycyclic Aromatic Hydrocarbons (PAHs) and Organochlorine Pesticides (OCPs) in Soils from Shergyla Mountain, Southeast Tibetan Plateau
Environmental Science,Part 1: Types of Soil Pollution,Vol 37,No. 03
Soils were collected from Shergyla Mountain shade slope and south-facing slope in southeast Tibetan Plateau (TP) in August 2012 and they were measured for polycyclic aromatic hydrocarbons (PAHs) and organochlorine pesticides (OCPs) (including HCHs and DDTs). The concentrations of Σ16PAHs ranged from 99.3 to 1 984 ng·g ?1 dw, with a mean value of 1 017 ng·g ?1 dw. HCHs and DDTs in soils samples were in the range of 0.37–2.07 ng·g ?1 dw (mean 1.15 ng·g ?1 dw) and 0.70–43.9 ng·g ?1 dw (mean 9.87 ng·g ?1 dw), respectively. The concentrations of all measured compounds were much higher than those in central or western TP, and the PAHs concentration was even up to two orders of magnitude. The concentrations of α-HCH and DDTs in south-facing slope increased with altitude, but HCHs and DDTs in shade slope had no significant correlation with altitude. There was no consistent increasing or decreasing trend of PAHs in shade slope with altitude, and the concentrations of PAHs in south-facing slope showed a higher value in lower altitude, indicating the existence of local pollution emissions. The PAHs profile was dominated by lighter constituents (2 & 3-ring accounted for higher than 85 %), inferring that the PAHs in the study area were largely influenced by long range atmospheric transport (LRAT) of pollutants. The special diagnostic ratios of PAHs suggested that PAHs were mainly produced by low temperature combustion of biomass and fossil fuels, except that two sampling sites of shade slope had been possibly influenced by oil residue. The relatively low ratios of α/ γ-HCH inferred HCHs in the research area was the result of the combined contribution of the historical technical HCHs and Lindan. The ratios of p, p'-DDE/ p, p'-DDT and o, p'-DDT/ p, p'-DDT indicated DDTs were from the combined contribution of the historical technical DDTs and dicofol. According to the profile of PAHs, HCHs and DDTs and the meteorological conditions of Shergyla Mountain, the transport of PAHs and OCPs in the study area was mainly influenced by the Indian Monsoon.
China Environmental Science,Part 1: Types of Soil Pollution,Vol 39,No. 04
The contamination status of polycyclic aromatic hydrocarbons (PAHs) and the spatial distribution of ∑ 25PAHs and ∑ 7carcPAHs were investigated based on 39 surface soil samples collected in May 2015 from the Yellow River Basin. The sources of PAHs were obtained by the isomer ratio method and principal component analysis method, and the health risk assessment of PAHs was evaluated by the BaP toxic equivalent and the excess lifetime cancer risk (ELCR) model. The results showed that the concentrations of mesenteric twenty-five PAHs in the surface soil ranged from 18.23 to 6 805.49 ng/g with an average value of 343.764 ng/g; and the concentration of ∑ 7carcPAHs ranged from 2.23 to 2 796.34 ng/g with an average value of 126.6 ng/g. In general, the concentration of PAHs was higher in the middle and upper stream areas than in the downstream areas. In the majority of samples, we found that Ant/(Ant + Phe) < 0.1, 0.2 < Inp/(Inp + BghiP) < 0.5, Flu/(Flu + Pyr) < 0.4 which indicated that the main sources of pollution were coal combustion, oil emissions, and petroleum combustion used for transportation. In all sampling sites, except Xiangtang, the ELCR values ranged from 10 ?6–10 ?4, a level having potential health risks, while the value of ELCR in Xiangtang was at 10 ?3, a level posing relatively high health risks.
5. Vertical Distribution Characteristics of PAHs in Soils with Different Land Use Types during Rapid Urbanization
Environmental Science,Part 1: Types of Soil Pollution,Vol 40,No. 05
To study the vertical distribution characteristics of polycyclic aromatic hydrocarbons (PAHs) in the soils with different land use types during urbanization, three land use types (urban land, cultivated land, and woodland) were selected in the eastern part of Shenyang, where urbanization was occurring rapidly. In each case, five soil samples were obtained from different depths (0–1 m). Change in the concentrations of PAHs, vertical migration factors, and the distribution and sources of PAHs were analyzed in the vertical soil profiles. Total concentrations of PAHs in the different soil types were ordered as follows: city 1 (513.19–12 689.04 μg·kg ?1); dry field (36.18–7 196.10 μg·kg ?1); paddy field (70.92–747.53 μg·kg ?1); city 2 (19.39–636.47 μg·kg ?1); woodland (4.79–349.24 μg·kg ?1). PAHs were mainly trapped in shallow soils in urban and woodland, but can migrate deeper into the soil profile in cultivated land. High-ring PAHs were abundant at the depth of 0–30 cm, while low-ring PAHs were abundant in deeper soil profiles. SOM had a significant effect on the vertical distribution of PAHs, and the physical and chemical properties of PAHs had a significant influence on their migration ability. However, combustion sources from industrial activities and transportation in the region are still considered the main sources of PAHs despite the fact that some low-ring PAHs derive from petroleum product inputs.
6. Residual characteristics of polychlorinated biphenyls in surface soil of the Middle and Lower Reaches of the Yellow River
China Environmental Science,Part 1: Types of Soil Pollution,Vol 36,No. 06
The residual characteristics of polychlorinated biphenyls (PCBs) in 18 surface soil (0–15 cm) samples collected from the middle and lower reaches of the Yellow River were analyzed by GC-MS. The results showed that the concentrations of total PCBs in surface soil ranged from 0.43 to 39.83 ng/g dry weight (ng/g dw), with an average value of 3.72 ng/g dw, and the average PCBs level in this study was in a comparatively low level when compared with those in others regions. The toxic equivalency quantities of dioxin-like PCBs (DL-TEQ) in surface soil ranged from 1.85 to 27.22 pg/g dw, with an average value of 15.24 pg/g dw. The DL-TEQ values were much lower than the corresponding limit values in other countries and rarely posed potential ecological risk. PCB18, PCB33, PCB49, and PCB44 were identified as the prevalent contaminants of the surface soil. The PCBs homologues analysis revealed that the PCBs in the study area were dominated by di-, tri-, tetra- and penta-chlorinated biphenyls, indicating a relatively high proportion of lower PCBs. The PCBs in surface soil might come from the Aroclor 1242, 1248, 1254 and 1260 mixtures and the transformer oil produced in China based on the principal component analysis (PCA).
7. Distribution characteristics of pharmaceuticals and personal care products in water and soil environment in reclaimed water irrigation area of a city
China Environmental Science,Part 1: Types of Soil Pollution,Vol 36,No. 07
In order to preliminarily understand the distribution characteristics of pharmaceuticals and personal care products (PPCPs) in soil environment, and to identify the main source of PPCPs in groundwater of a farming area in southeast suburban of City B, drilled profiles in natural water irrigation area, reclaimed water irrigation area and wetland were investigated in detail. In each profile, samples of surface water, groundwater and soil samples from different depths were collected. The routine indexes and 15 target PPCPs of all samples were analyzed. The analytical results indicated that there was an obvious difference in concentration levels of PPCPs in different areas. Generally, the concentrations of PPCPs in the soil profiles in reclaimed water irrigation area were the highest, and those in the wetlands were the lowest. The average total concentration of soil PPCPs was 15.6 μg/kg. The detected PPCPs mainly include carbamazepine (CBZ), bezafibrate (BF), gemifibrozil (GF), chloramghenicol (CP) and indomethacin (IM). In the irrigation area, the average total concentrations of PPCPs in surface water and in groundwater were 272.5 ng/L and 63.5 ng/L, respectively. In surface water, there was a trend that the concentration of PPCPs decreased downwards. By using the mixing Multi-cell principle and concept of Push flow, vertical transport process of PPCPs from soil surface to ground water was depicted. The calculated results of 9 selected PPCPs (not including CBZ, mefenamic acid (MA) and nalidixic acid (NA)) in groundwater accorded well with the measured values. This preliminarily indicated that the reclaimed water is the main source of PPCPs in groundwater in the irrigation area.
Environmental Science,Part 1: Types of Soil Pollution,Vol 40,No. 08
Exploring the composition and accumulation of antibiotics in agricultural land soil for quality management of agricultural land and control of antibiotic pollution is of great significance. A total of 95 soil samples were collected from farmland soil in a typical agricultural and sideline production base of northern China. In this study, the concentrations of 10 antibiotics, including tetracycline antibiotics (TCs), macrolide antibiotics (MLs), and sulfonamide antibiotics (SAs), were determined in soil samples from different land use types using HPLC-MS/MS. In addition, the composition and spatial distribution of the antibiotics were compared. The relationships between the concentration distributions and the distance from livestock farms, highways, and rivers were analyzed. Moreover, the composition and accumulation of antibiotics in the soil with different planting patterns and soil properties were preliminarily discussed. The results showed that the concentrations of antibiotics in the soil were in low level, while the detection rate was high; in particular, the detection rate of the total amount of antibiotics was as high as 100%. In the study area, TCs were the dominant antibiotic type, accounting for 94% of the total. The coefficient of variation (CV) was high, which reflected a significant difference in the spatial variation of these antibiotics. The spatial distribution and accumulation of antibiotics in the soil in this area were affected by the intensity of human activity. The detection rate and concentrations of the various antibiotics decreased with increasing distance of the soil sample from livestock farms, highways, and rivers. Among these, there was a significant negative correlation between the concentration of antibiotics and the distance between livestock farms and the soil samples ( P < 0.05). The detection rate of three types of antibiotics in soil samples from the site within 50 m of a river reached 100%. The total concentration of the 10 antibiotics was the highest in orchards, followed by vegetable plots, and mixed fruit and vegetable areas. Furthermore, the sources and concentrations of antibiotics in a peach orchard and open-air vegetable field were significantly different from those in a walnut orchard, greenhouse vegetable field, and mixed field. Moreover, the soil pH, soil organic matter (SOM), cation exchange capacity (CEC), total nitrogen (TN), available phosphorus (AP), and available potassium (AK) were selected to characterize soil properties. Redundancy analysis showed that soil properties such as pH, SOM, CEC, AP, AK have great impacts on the distribution of antibiotics. The distribution of antibiotics was most closely related to AK, and the effect of TN was relatively weak. The results of this study suggested that the composition and accumulation of soil antibiotics in the area were affected by human activities and soil properties.
China Environmental Science,Part 1: Types of Soil Pollution,Vol 38,No. 09
Soil is considered as one of the primary receivers of antibiotic resistance genes (ARGs). Hence, clarifying the distribution and transfer of ARGs in soil is very important to evaluate the potential ecological risks of ARGs. In this paper, the origin, distribution and transfer of ARGs in soil were examined systematically. The major environmental factors that influenced the transmission of ARGs were summarized, and the necessity of the ARGs research in soil was also emphasized. Results showed that the previous studies mostly focus on the abundance and variety of exogenous ARGs in soil, while spatial distribution, propagation and behavior mechanism of ARGs are still found to be insufficient. Based on current research, prospective ARGs research in soil should master the distribution, source and rule of transformation, as well as the key restriction factors. Furthermore, a corresponding quantitative relationship should be established to provide a scientific basis data for the assessment of ARGs pollution and ecological risk.
10. Composition and Distribution of Antibiotics in Soils with Different Land Use Types in a Typical Peri-urban Area of the Yangtze River Delta
Environmental Science,Part 1: Types of Soil Pollution,Vol 38,No. 10
Antibiotics have been widely used for agriculture, aquaculture and livestock, as well as for human disease treatment in recent decades. However, antibiotics cannot be completely absorbed, most of them are excreted through urine and feces. A substantial part of the antibiotics enter soils through fertilization and irrigation. Antibiotics persist in the soil environment and threaten human and ecological security. Identifying the composition, distribution and influencing factors of antibiotics in soils with different land use types can help in understanding the spatial distribution and migration processes of antibiotics. In this study, a typical peri-urban catchment located in the Yangtze River Delta was selected as the study area, and 82 sampling sites were selected based on land use and topographical features. Soil samples were collected at depths of 0–40 cm at each sampling site. The types and quantity of antibiotics in each soil sample were identified and analyzed by using HPLC-MS/MS in the laboratory. The composition and concentration of antibiotics in different soil layers and the land use types were compared, and the factors affecting the spatial distribution of soil antibiotics were analyzed. Results from this study showed that the total concentration of antibiotic compounds (Σtotal) ranged from 0.05 μg·kg ?1 to 395.55 μg·kg ?1 in the study area, and a significant spatial distribution of antibiotics was found between different land use types. The Σtotal in cropland ranged from 0.35 μg·kg ?1 to 395.55 μg·kg ?1, and tetracyclines (TCs) were the dominant antibiotics (81.45%). The Σtotal in forest land ranged from 0.07 μg·kg ?1 to 3.65 μg·kg ?1, with values significantly lower than those in cropland ( P < 0.05). The Σtotal in orchard soil were significantly lower than that in cropland ( P < 0.05), and no significant difference in antibiotics was found between orchard land and forest land ( P > 0.05). The analysis of the composition and quantity of antibiotics in the soils showed that tetracyclines (TCs) and quinolones (QNs) were the dominant antibiotic types in orchard land (TCs: 67.63%, QNs: 29.55%) and forest land (TCs: 13.25%, QNs: 70.04%). The indices, including distance to town, distance to road, elevation, and C/N value in soils, were selected to explore the influence of human activity on soil antibiotic concentration. Results of the correlation analysis showed that the concentration of soil antibiotics decreased with increasing values of the four indices. This indicated that the concentrations of soil antibiotics in peri-urban areas were dominantly affected by land use and its spatial distribution, and the concentrations increased with the intensity of human activities. Results of this study can provide scientific guidance for soil management and soil security.
11. Abundance of the tetracycline resistance genes in a paddy soil after continuous application of composted swine manure for 6 years
China Environmental Science,Part 1: Types of Soil Pollution,Vol 35,No. 11
In the present study, the occurrence and abundance of tetracycline resistance genes (TRGs) were investigated in a paddy soil after continuous application of composted swine manure (9.0 t/hm 2 and 4.5 t/hm 2) for 6 years. Nine classes of TRGs (tetW, tetB(P), tetO, tetS, tetC, tetG, tetZ, tetL, and tetX) was detected in the soil applied with composted swine manure, among which the absolute abundance of tetG, tetL, tetB(P), tetO, tetW were significantly increased, and there were significantly more copies of tetB(P), tetW, tetO in the soil treated with 9.0 t/hm 2 composted swine manure than with 4.5 t/hm 2, while the absolute abundance of tetZ, tetC and tetS was not influenced. There was no significant difference in the relative abundance of detected TRGs distributed with a depth of 0–5 cm, 5–10 cm, and 10–20 cm in the same treatment. The relative abundance of tetG, tetL, tetB(P) and tetO was significantly increased in the soils treated with composted swine manure, but only tetO was influenced by the application weight of the manure. The results suggested that the residual TRGs in the composted swine manure shed further influence on the TRGs pool in soils with rice-wheat crop rotation, absolute and relative abundance of tetG, tetL, tetB(P) and tetO being significantly increased after continuous application of composted swine manure. Therefore, optimization of composting strategies is urgently needed to efficiently reduce the content of antibiotic resistance genes in the composted swine manure.
China Environmental Science,Part 1: Types of Soil Pollution,Vol 38,No. 12
This study used the large existing database on 137Cs reference inventories, according to the radioactivity ratio of 137Cs/ 239+240Pu (32.5, 137Cs radioactivity is corrected to 2005) in the northern hemisphere, and converted 137Cs reference inventories to the corresponding values for 239+240Pu. The 137Cs Reference Inventory Model for China’s mainland ( 137Cs-RI MCM) has been used to establish an analogous, by using Kriging/Cokriging interpolation to simulate the spatial distribution of the Pu-RI in the soils across China. At present, the measured deposition inventories for 239+240Pu range from 7.3 to 546 Bq/m 2and Pu-RI simulated values range from 3 to 812 Bq/m 2. Maxima in the deposition inventory correlated well with those of the Pu-RI simulation, which suggested the 137Cs-RI MCM has potential for the simulation of the Pu-RI in the soils of China’s mainland. In-homogeneity in the atmospheric deposition of 137Cs and 239+240Pu however lead to deviations between the local Pu-RI simulation values and the measured 137Cs/ 239+240Pu radioactivity ratios present in Chinese soil cores. In order to better illustrate the feasibility of the 137Cs-RI MCM, this study compared theoretical wet deposition inventories of 239+240Pu with the corresponding Pu-RIs in 62 cities of China between latitudes 30–40°N, and found that the theoretical calculations of Pu-RI or total deposition inventories and wet deposition inventories were reasonable.
13. Occurrence and source identification of heavy metals in the alluvial soils of Pearl River Delta region, south China
China Environmental Science,Part 1: Types of Soil Pollution,Vol 38,No. 13
Forty-four alluvial samples were collected at 22 sites in the Pearl River Delta to study the distribution and sources of eight heavy metals with factor analysis, enrichment factor and lead isotopic tracing methods. The study showed that the concentrations of all heavy metals were enriched relative to the background value of soil of China and Guangdong Province. The concentrations of Cr and Ni were similar in top soil and deep soil, while the concentrations of As, Cu, Zn, Cd, and Pb in top soils were slightly elevated to deep soils. And the concentration of Hg was significantly enriched in the top soils. Factor analysis indicated that the concentrations of Cu, Cr, Ni were mainly controlled by the natural conditions, and the anomalies of As, Pb, Hg were caused by anthropogenic contamination. In some cases, the high concentrations of Cd and Zn were controlled by both geological background and anthropogenic contamination. The results of enrichment factor analysis indicated that the pollution levels of eight heavy metals were Hg > As > Cd > Cu > Pb > Zn > Cr > Ni. The enrichment factor values would be low if the elements were enriched in deep soils. The scatter plot showed there was significantly negative correlation between Pb concentration and 206Pb/ 207Pb ratio. A binary comprehensive model showed that at least 30% Pb in the top soils were derived from anthropogenic contamination. In conclusion, the study found that the enhanced levels of Hg, Cd, As, Pb were due to contamination.
14. Spatiotemporal Variability and Source Apportionment of Soil Heavy Metals in an Industrially Developed City
Environmental Science,Part 1: Types of Soil Pollution,Vol 40,No. 14
In the present study, a total of 1 130 soil samples were collected in 2003 and 2013 in Ningbo City, and the content of eight typical heavy metals was measured. The degree of heavy metal pollution in the soil in the study area was evaluated using the pollution index evaluation method. The spatiotemporal variation in the pollution were analyzed by the geostatistical method, and the principal component analysis (PCA) and the UNMIX model were adopted to analyze the heavy metal pollution sources. The results showed that (1) apart from As, the mean values of the other seven heavy metals in both periods exceeded the soil background values in Zhejiang Province and national background values of China, which indicated that heavy metal pollution was common in the soil from the study area. From 2003 to 2013, the mean content of all elements increased to some degree, indicating that the heavy metals pollution was generally aggravated in ten years; the increase in the mean Hg content was the greatest; (2) the evaluation results based on the single-factor pollution index showed that the pollution degree was high for Hg, moderate for Cd, Cu, and Pb, slight for Zn, Cr, and Ni, and unpolluted for As. The evaluation results based on NCPI showed that the pollution index for all samples exceeded the warning value, and the number of soil samples that were characterized as heavily polluted with a comprehensive pollution index over 3 had increased significantly; (3) the spatial distribution of the same heavy metal in different periods presented similar characteristics. Generally speaking, the spatial distribution of Pb was similar to that of Hg, and the spatial distributions of Cr, As, Cu, Zn, and Ni were similar to each other; high value areas were mainly concentrated in the four areas of Haishu, Jiangbei, Jiangdong, and Zhenhai districts, where the polluted enterprises were densely distributed and human activities were frequent; (4) based on PCA and the UNMIX receptor model, the source analysis results of soil heavy metals in 2013 were essentially the same, i.e., the source of heavy metal pollution in the study area included the industrial sources and living sources. Industrial sources of heavy metal pollution had the highest contribution rate and derived from industrial wastewater, waste gas, and waste residue discharged by plasticizing, mining, and metallurgical enterprises, chemical and mechanical manufacturing enterprises, etc., causing the accumulation of Cr, As, Cu, Zn, and Ni in the soil. The living sources had the second highest contribution rate originated from the pollution of particulates and dust caused by domestic waste, automobile exhaust, and road friction. Additionally, natural factors had small contribution rates, mainly due to the spread of pollutants by prevailing winds and atmospheric settlement.
15. The forms, bioavailability of Cd in soils of typical sewage irrigation fields in northern China and its control factors
China Environmental Science,Part 1: Types of Soil Pollution,Vol 36,No. 15
Soils of five typical sewage irrigated fields in Beijing, Shandong, Tianjin, Hebei and Liaoning, respectively, were collected. The soils were added with 1.20 mg/kg Cd with Cd, and conducted aging for 30 days. A pot experiment was conducted to study the bioconcentration factors (BCF), root-stem & leaf translocation coefficient (TF) of Cd by wheat in different sewage irrigation field soils. The soil solution properties of sewage irrigated soil and the forms of Cd in solution (free Cd 2+) were determined using ion chromatography and WHAM6.0 model. The results showed that significant differences ( P < 0.05) were observed between BCF and root-stem & leaf TF of Cd by wheat in different sewage irrigated soils, the BCFs of Cd in plant stems and leaves ranged from 0.064–0.465, with a maximum variation of 626.5%. Among the tested sewage irrigated soils, the largest BCF of Cd was observed with the brown soil from Liaoning site and the smallest with the brown soil from Shandong site; the variation of root-stem & leaf TF of Cd followed the order of cinnamon soil from Hebei > brown soil from Liaoning ~ alluvial soil from Beijing > alluvial soil from Tianjin > brown soil from Shandong. Significant ( P < 0.05) positive correlation was observed between the free Cd 2+in soil solutions and the phyto-availability of Cd in different sewage irrigated soils, a significant negative correlation ( P < 0.001) was observed between the Cd concentrations of plant roots/stems and leaves and the negative logarithm of free Cd 2+[ p(Cd 2+)] in soil solutions, with the equations of y = ?3.310 6 x + 17.681 ( R 2 = 0.929) and y = ?0.338 9 x + 1.774 3 ( R 2 = 0.916) for roots, as well as stems and leaves, respectively. The change values of free Cd 2+ [ △p(Cd 2+)] speciation in soil solutions were positively correlated with pH and EC values, while they were negatively correlated with the contents of Cl ?, Na + and Ca 2+. It can be inferred that the increase of the contents of Cl ?, Na + and Ca 2+ in soils caused by sewage irrigation may lead to higher Cd environmental risk in the soil than before.
China Environmental Science,Part 1: Types of Soil Pollution,Vol 35,No. 16
A paddy field is typical constructed wetland, where mercury (Hg) is easily methylated to methylmercury (MeHg). Due to long-term wastewater irrigation, a large area of farmlands, including paddy fields in Tianjin City, has been seriously contaminated with Hg. There is therefore an important question to be answered in our understanding as to the characteristics of total Hg (THg) and/or MeHg accumulations in rice from wastewater-irrigated areas and risk assessment for evaluation Hg exposure for the population by rice consumption. In this study, a field survey of mercury pollution in 29 paddy fields (soil and rice) from wastewater-irrigated areas around north discharged river in Tianjin City was conducted to evaluate the health risks of mercury to residents by rice consumption. The results showed that: 1. THg and MeHg concentrations in surveyed paddy fields were (367.04 ± 129.36) μg/kg and (0.87 ± 0.77) μg/kg, respectively, and the background value of total mercury content in soil was 73 μg/kg. Analyses of the distribution of Hg species in different parts of rice plants from selected sampling locations shown that grain contained the lowest THg concentrations (12.80 ± 5.14) μg/kg, followed by stem < root < leaf. Contrary to THg, the highest concentration of MeHg was in grain (2.09 ± 1.20 μg/kg, %MeHg > 10%), followed by root > stem > leaf. This suggests that rice grain may preferentially accumulate MeHg compared to other parts of the plant. Observations clearly show that MeHg in the paddy soil could be more easily taken up and transferred to rice grain compared to THg. The probable weekly intake (PWI) of THg and MeHg for an adult population based on 60 kg body weight (bw) in studied wastewater-irrigated area was 0.068–1.25 μg/(kg·bw) and 0.0095–0.49 μg/(kg·bw), respectively, which were all well below reference dose established by WHO (FAO) or U.S. EPA. However, it was clearly manifested that there was a great concern of MeHg exposure risk for rice consumption around some highly Hg-contaminated areas. There were positive and significant correlations between soil MeHg concentrations and soil THg concentration, or clay content in the collected soil samples. Similarly, significant positive correlations were also found between MeHg concentrations in brown rice and soil THg concentrations, or soil MeHg concentrations and soil clay content. This study highlights the potential health risks of MeHg associated with cultivation and consumption of rice on the wastewater-irrigated areas.
17. Source Analysis, Spatial Distribution and Pollution Assessment of Heavy Metals in Sewage Irrigation Area Farmland Soils of Longkou City
Environmental Science,Part 1: Types of Soil Pollution,Vol 38,No. 17
Farmland soil samples in sewage irrigation area of Longkou City were collected, soil pH and the heavy metal content were tested. Taking the soil sample from 70 soil sampling sites as the study object, the source of heavy metals in this area was investigated in the study based on the correlation analysis and principal component analysis (PCA) of multivariate statistical analysis theory. The research group studied the spatial variation and distribution characteristics of heavy metal elements using both the theory of geostatistics and GIS spatial interpolation method. At last, the heavy metal pollution was evaluated by using Nemerow Index and improved fuzzy evaluation method. The results showed that all of the 9 kinds of heavy metal elements enriched in the soil of research area to different degrees, among which the average content 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 comprehensive pollution index of Cu, Cd and Pb was 7.06, 6.10 and 5.54 respectively, and these three elements all presented as heavy pollution. According to the results of correlation analysis and PCA, Cu, Zn, Pb and Cd were mainly affected by anthropogenic factors, and sewage irrigation was their common pollution factor. the pollution sources of the first two heavy metals included excessive use of fertilizers and pesticides in agricultural production and long-term accumulation, whereas pollution brought by coal mining and coal gangue piled up in the northern mining area as well as electroplating, 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 materials. Comprehensive evaluation results showed that, among the 70 sampling sites, 13 sites presented moderate pollution, 23 sites belonged to light pollution, 28 sites were at an 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 Zhuyouguan and Xufu Townships, which indicated that sewage irrigation caused a certain degree of heavy metal pollution to local soil.
18. Analysis of Characteristics and Sources of Heavy Metals in Farmland Soils in the Xijiang River Draining of Guangxi
Environmental Science,Part 1: Types of Soil Pollution,Vol 39,No. 18
In order to determine the distribution characteristics of heavy metal pollution in farmland soils and related influencing factors in the Xijiang River basin, 2 187 farmland soil samples were collected and their heavy metal content was tested. The spatial structure and distribution characteristics of heavy metal elements were studied using a combination of geostatistical theory and GIS spatial interpolation. The potential ecological risk index was employed for risk assessment. Multivariate statistical methods, such as correlation analysis and principal component analysis, were used to analyze heavy metal sources. Results showed that farmland soils in the basin were enriched with seven kinds of heavy metal to some extent, with Cd accumulation being the most evident. The independent sample t-test results showed significant differences in heavy metal content between dry and field paddy soils ( P < 0.05). Cd content in paddy soils was significantly higher than in corresponding dry land soils. Cd in farmland soils in Xijiang River exhibited higher potential ecological risk. Correlation analysis and principal component analysis showed that enrichment of Pb, Zn, As, Cd, and Cu in soil was due to anthropogenic factors such as mining activities, traffic, and sewage irrigation, while Ni and Cr were influenced by natural factors, such as soil parent material. High-content areas of As, Cd, Pb, Zn, and Cu in the upper reaches of the basin are all distributed in the Diaojiang River basin and the Dahuan River basin. Cd was most widely distributed. The most intensive sampling sites indicated that mining activities have caused some degree of heavy metal pollution in local farmland soils.
Environmental Science,Part 1: Types of Soil Pollution,Vol 39,No. 19
In this study, 2 585 soil samples were collected in the Xijiang River Basin in Guangxi Zhuang Autonomous Region and the spatial variability and contamination of Arsenic in soils were evaluated using geostatistical and GIS tools. The results showed that the concentrations of As in surface soils (23.82 mg·kg ?1) were higher than the background values of the Guangxi and Xijiang Rivers in natural soils; the upstream values (Diaojiang River and Huanjiang River) (30.22 mg·kg ?1) were significantly higher than those in other regions. Concentrations of As in soil samples were in the order of soil in mining areas > soil in dryland > natural soil > paddy soil. As concentrations in mining areas were significantly higher than in other areas; high As concentrations were measured in the upstream Diaojiang River Basin and the downstream Huanjiang River Basin. Low concentration clusters were in the six villages of Nandan, which are far from the mine, and in the upper reaches of the Dahuanjiang River and Xiaohuanjiang River Basin. Spatial autocorrelations of As in the watershed soil were evident and the structural variability was dominant. The concentration of As in the upper reaches decreased from the northwest to the southeast. High As concentrations were distributed naturally along the river basin; concentrations in the middle and lower reaches of the basin were between 0.44 mg·kg ?1and 40 mg·kg ?1. The concentration levels of As in total soil samples ranged from no-pollution to slight pollution, and the pollution was mainly distributed in the administrative areas of the city and the intensive areas of mining activities, among which the soil pollution in Jinchengjiang River and Nandan counties was more prominent. Effective measures should be taken to strengthen the safety level of tailings reservoirs during the rainy season, so as to maintain the production levels while protecting living standards of local residents.
20. Risk Assessment of Heavy Metal Contamination in Farmland Soil in Du'an Autonomous County of Guangxi Zhuang Autonomous Region, China
Environmental Science,Part 1: Types of Soil Pollution,Vol 36,No. 20
For a comprehensive understanding of the pollution characteristics and ecological risk of heavy metals of farmland soil in Du’an Autonomous County of Guangxi Zhuang Autonomous Region, China, this study evaluated the cadmium (Cd), arsenic (As), nickel (Ni), zinc (Zn), chromium (Cr), antimony (Sb), copper (Cu) and lead (Pb) pollution situation using the single factor index, the Nemerow pollution index and the Hakanson ecological risk index. The results showed that heavy metal pollution of farmland soil in Du’an County was serious. 74.6% of the soil samples had heavy metals concentrations higher than the Grade II of Environmental quality standard for soils (GB 15618-1995). The standard-exceeding rates of Cd, As, Ni, Zn, Cr, Sb, Cu, Pb were 70.6%, 42.9%, 34.9%, 19.8%, 19.6%, 2.94%, 1.59%, 0.79%, respectively. Cd and As were the main contaminants in Du’an County, the pollution was far more serious than those of the national and Guangxi Zhuang Autonomous Region. In terms of the ecological risk, heavy metals of farmland soil in Du’an County showed a “moderate”ecological risk, with Cd accounting for 88% of the total ecological risk. The north-east of Jiudu Town and the zone between Bao’an Town and Dongmiao Town were two areas with high ecological risk in Du’an County. The contamination of farmland soils in Du’an County was caused by two main sources. The As and Sb pollution in the farmland soil irrigated with polluted water near Diaojiang River may be caused mainly by the mining activities in the upper reaches of Diaojiang River.
21. Contents and spatio-temporal variability of soil heavy metals in the coastal mud-flat area of north Jiangsu Province
China Environmental Science,Part 1: Types of Soil Pollution,Vol 36,No. 21
The study was carried out in a representative coastal mudflat area in northern Jiangsu Province, China. Classical statistical and geostatistical methods were employed to summarize the concentrations of the four types of elements (Pb, Cr, Cd, As) in surface soil in 2009 and 2014, to analyze the effect of land use types on heavy metal content, and to determine spatial patterns and spatio-temporal variability of soil heavy metals in these two periods. Results indicated that the content was generally below the widely accepted environmental quality standard (first class) for the four types of soil elements. During the five years from 2009 to 2014, soil Cd accumulated significantly across the study area, soil Pb content in the residential area also increased remarkably, and significant accumulation of soil Pb and Cd was also observed in the industrial area, whereas the change of soil Cr and As contents was not significant in each type of land use. Under the control of large-scale tide deposits and small-range human activities, soil Pb and Cr contents exhibited similar spatial patterns during these two periods, whereas the spatial patterns of soil Cd and As showed great difference in the two periods. The enrichment of soil heavy metals across the different land use types in the study area exhibited spatial variability and directional trends. Atmospheric deposition was another important factor that influenced the spatio-temporal variability of soil heavy metals. The coastal mudflat area presently faces the problem of soil heavy metal enrichment. We should take preventive countermeasures, such as strengthening in situ monitoring and source reduction, optimizing industrial layout, and prompting process blocking and biological remediation, to prevent and minimize heavy metal hazards.
China Environmental Science,Part 1: Types of Soil Pollution,Vol 37,No. 22
In order to study the pollution characteristics and potential ecological risk of heavy metals in topsoil of Beijing, topsoil samples were collected in different functional areas of Beijing during November 2013 to December 2013. Totally 49 groups of topsoil samples with different particle sizes were obtained using precipitation method after the settlement and classification from the initial samples. Then the concentrations of 8 heavy metals (Cr, Ni, Cu, Zn, Mo, Cd, Ba and Pb) were measured by ICP-MS. The results showed that the average concentrations of Cd, Cu, Zn and Pb were1.4 mg/kg, 85 mg/kg, 333 mg/kg and 69 mg/kg in topsoil of Beijing, respectively, and the pollution of those heavy metals in traffic areas was significantly heavier than that in other functional areas. Geo-accumulation indexes ( I geo) of Cd, Cu, Mo, Ni, Pb and Zn were negatively correlated with the particle size. That is to say, the smaller the particle size was, the higher the corresponding value of I geo would be, and the higher the pollution level would be. The total potential ecological risks of heavy metals in traffic areas were much higher than those in other functional areas. And the total potential ecological risks of heavy metals in industrial zones and urban-rural fringe areas were the second highest. The smaller the particle size was, the higher the potential ecological risk indexes (RIs) would be. In addition, the potential ecological risk of Cd accounted for the major part of the total potential ecological risks.
23. Distribution of Urban Soil Heavy Metal and Pollution Evaluation in Different Functional Zones of Yinchuan City
Environmental Science,Part 1: Types of Soil Pollution,Vol 37,No. 23
Surface soil samples (0–20 cm) from eight different functional areas in Yinchuan city were collected. There were 10 samples respectively in each functional area. The urban soil heavy metals (Zn, Cd, Pb, Mn, Cu and Cr) pollution characteristics and sources in eight different functional areas were evaluated by mathematical statistics and geostatistical analysis method. Meanwhile, the spatial distributions of heavy metals based on the geography information system (GIS) were plotted. The average values of total Zn, Cd, Pb, Mn, Cu and Cr were 74.87, 0.15, 29.02, 553.55, 40.37 and 80.79 mg·kg ?1, respectively. The results showed that the average value of soil heavy metals was higher than the soil background value of Ningxia, which indicated accumulation of the heavy metals in urban soil. The single factor pollution index of soil heavy metals was in the sequence of Cu > Pb > Zn > Cr > Cd > Mn. The average values of total Zn, Cd, Pb and Cr were higher in northeastern, southwestern and central city, while the average values of Mn and Cu were higher in northeastern and central city. There was moderate pollution in road and industrial area of Yinchuan, while the other functional areas showed slight pollution according to Nemoro synthesis index. The pollution degree of different functional areas was as follows: road > industrial area > business district > medical treatment area > residential area > public park > development zone > science and education area. The results indicated that the soil heavy metal pollution condition in Yinchuan City has been affected by human activities with the development of economy.
24. Contamination Assessment and Sources Analysis of Soil Heavy Metals in Opencast Mine of East Junggar Basin in Xinjiang
Environmental Science,Part 1: Types of Soil Pollution,Vol 37,No. 24
The opencast mine of East Junggar Basin in Xinjiang is the largest self-contained coalfield in China, and the ecological environment of the opencast is very fragile because of its arid climate and poor soil. In this study, 50 soil samples (from 0 to 30 cm depth soil at intervals of 10 cm) in opencast Mine of East Junggar Basin in Xinjiang were collected in order to explore the heavy metals contamination of the coal mining. The contents of zinc (Zn), copper (Cu), cadmium (Cr), lead (Pb), mercury (Hg) and arsenic (As) were measured and the degree of pollution was assessed by Nemerow index, geo-accumulation ( I geo) index and potential ecological risk index. In addition, the layered comparison, dust fall and the distance between coal mine and samples location were used to analyze the source of heavy metals contamination. The results showed that value of As surpassed the Grade I of Environmental quality standard for soils (GB 15618-1995) mostly severely, followed by Cr, a relatively lower surpass was obtained by Hg and Cu, while Zn and Pb did not surpass the standard. According to the standard, the soil heavy metals content of research region was in light pollution status and the pollution index for each heavy metal followed the order of As (2.07) > Cr (0.95) > Cu (0.55) > Zn (0.48) > Hg (0.45) > Pb (0.38), which demonstrated a heavy pollution of As and clean status of others. Additionally, an I geo value of 1.14 for Hg reflected a moderated pollution. The major contribution factor was Hg with a risk index of 251.40. The source analysis showed that the content of Pb in the surface soil (10–20 cm) was different from that in the deep layer (20–30 cm), which may be caused by coal combustion and other human activities. The sources of Hg and As were similar and may come from coal combustion. The distance to the mining area was not the major factor affecting the diffusion of heavy metals, other candidate factors included terrain, aspect and wind direction, etc.
25. Spatial Characteristics and Environmental Risk of Heavy Metals in Typical Gold Mining Area of Shandong Province
Environmental Science,Part 1: Types of Soil Pollution,Vol 37,No. 25
In order to reveal the influence of anthropogenic factors on soil environment quality, a total of 77 samples in topsoils were collected from Jiaojia gold mining area in Shandong province and were determined for Cu, Pb, Zn, Cr contents. Spatial variation structure, spatial distributions of concentrations and potential contamination risk 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. Semi-variance analysis demonstrated that Pb could be fitted for exponential model, and Cu, Zn and Cr were fitted 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 four 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 the boundary zone of Jincheng town, Xinzhuang town and Canzhuang town, while the safe zone was situated in south part of the study area. Pb had the highest probability exceeding the threshold and distributed widely in middle or high environmental risk areas. The results of the study offered reference and foundation for the evaluation and control of soil pollution in the study area.
Environmental Science,Part 1: Types of Soil Pollution,Vol 41,No. 26
Spatial distribution and source apportionment of heavy metals in the surface soil of the Qinghai–Tibet Plateau was investigated to gain an understanding of the pollution characteristics. The surface soil (0–20 cm) samples were collected from the northeast to the southwest in the study area. The total amount of 13 heavy metals (Ba, Cd, Co, Cr, Cu, Fe, Mn, Mo, Ni, Pb, Sb, Sc, and Zn) was determined. The potential sources of heavy metals were preliminarily apportioned and identified by the principal component analysis–absolute principal component score–multiple linear regression (PCA–APCS–MLR) receptor model. Results show that the average contents of Cd and Sb significantly exceed the environment standard, and they were 2.13 and 1.52 the soil background values of the Qinghai–Tibet Plateau in the 1970 s, respectively. The enrichment factor (EF), geo-accumulation index ( I geo), and Nemero synthesis index (PN) were used to evaluate the surface soil heavy metal pollution, which indicated that Cd and Sb were also pollutants in the Qinghai–Tibet Plateau with a limited contamination grade. Various levels of contamination were presented at the central, southeastern, and northeastern areas of the Qinghai–Tibet Plateau, while the central and southeastern areas exhibited high contamination grades. The PCA–APCS–MLR levels revealed that three main sources of heavy metals in the soil of the Qinghai–Tibet Plateau were the natural, traffic, and mining factors. Co, Cr, Cu, Fe, Mn, Ni, and Sc were largely affected by natural sources, while Ba, Cd, Mo, and Pb were mainly affected by traffic factors. Specifically, Zn was influenced mainly by natural and traffic factors, and Sb was jointly affected by natural, traffic, and mining factors. Therefore, Sb and Cd contamination from traffic and mining factors should be noted in control plans for the heavy metal pollution in soil of the Qinghai–Tibet Plateau.
27. Migration and Source Analysis of Heavy Metals in Vertical Soil Profiles of the Drylands of Xiamen City
Environmental Science,Part 1: Types of Soil Pollution,Vol 40,No. 27
The concentrations of eight heavy metal elements (V, Cr, Co, Ni, Cu, Zn, Sr, and Pb) and the isotopic compositions of Pb and Sr were determined in vertical soil profiles of the drylands of Xiamen City using ICP-MS and TIMS. The vertical distributions and leaching migration patterns of the heavy metals were also analyzed. The results showed that most of the heavy metals (except for Sr) were not enriched relative to background values at most profile depths, which indicated that the heavy metal contents were less affected by exogenous sources. The migration coefficients of Sr were greater than 0 throughout the entire soil profile; Zn and Co were enriched in the surface soil; Cr, Ni, and Cu were depleted throughout the profile. V and Pb were less influenced by external activities. Sr and Pb showed clear vertical migration characteristics, and the migration depth of Sr was greater than that of Pb. The factor analysis showed that the heavy metals mainly originated from natural sources, followed by agricultural activities, transportation, and other complex anthropogenic activities. The enrichment factor analysis showed that Sr was affected by exogenous sources to varying extents. The isotopic composition analysis of Pb and Sr showed that Pb was mainly derived from the parent material, whereas Sr was interpreted as deriving from both the parent material and anthropogenic activities, and tended to migrate to the subsurface soil horizons (30–70 cm).
28. Source Apportionment of Heavy Metals in Agricultural Soils of the Jiulong River Basin Based on Positive Matrix Factorization
Environmental Science,Part 1: Types of Soil Pollution,Vol 41,No. 28
In order to study the source apportionment of heavy metals in agricultural soils of the Jiulong River Basin, Fujian Province, China, seventy-one agricultural soil samples were collected in July 2017. The concentrations of heavy metals in agricultural soils were determined by inductively coupled plasma mass spectrometry (ICP-MS) and atomic fluorescence spectrometry (AFS). Here, we use a positive matrix factorization (PMF) model for the source apportionment of heavy metals in the sampled soils. The results showed that most of the heavy metal concentrations in the sampled agricultural soils were higher than soil background concentrations for the Fujian Province. The concentrations of Cd, Zn, Pb, and Cu in some soil samples were greater than the screening value of the Chinese soil pollution risk levels for agricultural land (GB 15618-2018). The spatial distributions of heavy metals showed a moderate variation across three regions of the study area (i.e., the North River watershed, West River watershed, and the estuary area). The highest concentration of Cr, Ni, Cu, Zn, and Cd were found in Longyan City (North River watershed), the highest concentrations of Pb were found in the West River watershed, and the highest concentrations of Co, Hg, and As were found in the estuary area. The non-negative properties of the source component spectrum and source contribution rate (obtained by the PMF model), as well as the significant correlation between the measured and PMF predicted concentrations, indicated that the results of the PMF model were relatively reasonable and can meet research needs. The source apportionment results of the PMF model showed that natural sources, agricultural sources, coal combustion, and industrial sources were the four major potential sources for heavy metals in the sampled agricultural soils, contributing 37.0%, 26.7%, 17.6%, and 18.7%, respectively.
29. Comparative research on spatio-temporal variability of heavy metal pollution in cultivated soils—A case study of Huang-Huai-Hai Plain and middle reaches of the Yangtze River and Jianghuai Region
China Environmental Science,Part 1: Types of Soil Pollution,Vol 38,No. 29
Taking the Huang-Huai-Hai Plain (HHHP) and middle reaches of the Yangtze River and Jianghuai Region (MYJR) as the study area, the data of heavy metals in the cultivated soil were collected from published literatures. The single factor index method and Nemerow synthesis index method were used to evaluate the pollution degree of heavy metals. Combined with the soil survey data in the 1980s, the spatio-temporal variation characteristics during the period of the 1980s and 2000s were analyzed. Results showed that: (1) the heavy metals in cultivated soils in the study area were at a safe level, and more than 80% of the HHHP and more than 60% of the MYJR were at the clean level. (2) Heavy metal pollution in the MYJR was more serious than that of the HHHP. The single factor index evaluation results showed that the exceedance percentage of soil heavy metals pollution was 35.02% in MYJR, which is twice that of 15.97% in the HHHP. The Nemerow synthesis index method found that there were 20.29% and 13.17% in the pollution levels, where the proportion of light and serious pollution in the MYJR was larger than that in the HHHP, and the proportion of serious pollution in the MYJR was three times that in the HHHP. (3) The order of proportions of pollution at the different locations is as follows: the cultivated soils near the industrial and mining area, the cultivated soils in the sewage irrigation area, the cultivated soils in the main agricultural production area, and the suburban cultivated soils. (4) The heavy metal pollution proportion increased during the 1980s and 2000s. The increased exceedance percentages of Cd, Zn, Hg, and As in the HHHP were 6.34%, 1.98%, 12.78%, and 0.91%, respectively. And those of Cd, Ni, Zn, Cu, Hg, and As in the MYJR were 14.02%, 11.36%, 7.28%, 5.49%, 1.93%, and 0.72%, respectively. Areas of worsening pollution were mainly located in Tianjin, Cangzhou in Hebei, Ji’nan in Shandong and Yueyang in Hunan. In the process of urbanization, industrialization and agricultural development, the cultivated soils are threatened by the heavy metal pollution in the study area, which calls for the effective measures to prevent and remedy heavy metals pollution.
30. Effects of Continuous Application of Sewage Sludge Compost on Heavy Metals Accumulation and Migration Characteristics in Soil Profile and on Heavy Metals Uptake of Wheat
Environmental Science,Part 1: Types of Soil Pollution,Vol 38,No. 30
The use of sewage sludge compost (SSC) as fertilizer may cause increased leaching due to its high concentration of heavy metals and thus pose a threat to groundwater quality. The effect of SSC application on heavy metals leaching in calcareous soils has been studied in field trials, which provides basis for determining heavy metals environmental capacity and preventing metal pollution in farmland soil scientifically. The results indicated that the concentrations of Cu, Zn elevated obviously with the increase of the age and the dosage of SSC utilization in the surface soil (0–15 cm) under 4-year continuous application of SSC. Under higher levels of the compost treatment, the heavy metals Cu and Zn were found to migrate into the 15–30 cm soil and 60–90 cm soil under the experimental condition. Nevertheless, the majority of Cu and Zn from SSC accumulated in surface soil and the highest accumulation rates could reach 75.3% for Cu and 85.9% for Zn. The concentrations of Cd, Pb increased significantly in surface soil after 4-year continuous application of SSC, and their increases could reach 57.2%–165.2% for Cd and 13%–34% for Pb compared with CK. At 60–90 cm soil, the concentrations of Cr, As and Pb were also significantly higher than those in CK treatment. Application of SSC not only caused accumulation of some heavy metals in surface soil but also leached heavy metals located in the subsurface soil down in this experiment. Continuous utilization of SSC increased Zn concentration of wheat grain, and the increase could reach 13.3%–47.9%. For the concentrations of Cr and Pb in wheat grain, the values exceeded the limit refer to Food and Healthy Standards (GB2762-2012) in part of compost treatments. The cumulative ratio of heavy metals carried out by wheat was all below 10% after 4-year experiment, wheat grain carried much more Cu, Zn out than wheat straw, but it was opposite for Cr, As, Cd, Pb. The cumulative ratio of heavy metals carried by wheat decreased with the increasing level of SSC utilization. The amounts of heavy metals migrated to deeper soil should be considered when determining the environmental capacity of heavy metals in farmland soil.
31. Assessment of Heavy Metal Pollution and Tracing Sources by Pb & Sr Isotope in the Soil Profile of Woodland in Quanzhou
Environmental Science,Part 1: Types of Soil Pollution,Vol 38,No. 31
The contents of 8 heavy metal elements (Sr, Ni, Fe, Cr, Cu, Mn, Pb, Zn) and the lead & strontium isotope composition of soil profile of woodland in Quanzhou city were analyzed by AAS and ICP-MS, respectively. A modified BCR four-step sequential extraction procedure was carried out to obtain the speciation fractionation of heavy metals in the soil profile from 4 stations. The results of the heavy metal elements and the speciation fractionation of heavy metals in the soil profile showed that the heavy metal pollution in the woodland in Quanzhou was relatively light, and the main pollution factor was Sr. The non-residue state of Pb was the highest, leading to the highest activity. The result of Nemero comprehensive pollution index showed that Sr in the depth of 0–60 cm was at heavy pollution level. The results of the RSP showed that the activity of Pb was the highest. The results of EF showed that Pb, Sr, Mn and Zn had exogenous sources. Factor analysis showed that the main sources of heavy metals were the compound pollution of agricultural activities, natural resources, and the vehicle exhaust. Composition of Pb isotopic ratios showed that, Pb in soil profile of woodland in Quanzhou was from vehicle exhaust and parent material. The contribution rates of the two sources in the soil profile were calculated by using the two-mixed model. The contribution rates of parent material and vehicle exhaust were 85.14% (62.53%–98.36%) and 14.86% (1.640%–37.47%) on average, respectively. Strontium isotope tracing results showed that the main sources of strontium were also vehicle exhaust and parent material. Coupling both Pb and Sr isotope ratios agreed with the above mentioned results.
32. bTracing Sources of Heavy Metals in the Soil Profiles of Drylands by Multivariate Statistical Analysis and Lead Isotope
Environmental Science,Part 1: Types of Soil Pollution,Vol 37,No. 32
Contents of 26 heavy metals from two soil profiles in drylands in Xiamen City were determined by inductively coupled plasma source mass spectrometer (ICP-MS). The distribution characteristics, environmental risk and pollution sources of heavy metals in soil profiles were studied. Combining the assessment results of Nemero comprehensive pollution index method, the geological accumulation index method and potential ecological hazard index method, which indicated that Cd was the main pollution factor in soil of drylands in Xiamen City; the soil pollution was serious in the depth of 50–60 cm. Multivariate statistical analysis showed that the main sources of heavy metals were agricultural production activities and natural resources, and the main pollution factor Cd was from agricultural production. Composition of acid-extractable Pb isotope in soil profiles and potential pollution sources were compared and analyzed. The results showed that Pb in soil of drylands in Xiamen City was mainly from sludge and parent material. According to the distribution characteristics of soil profiles in the 206Pb/ 207Pb– 206 Pb/ 204 Pb diagram, applying Bivariate Mixture Model of Pb isotope, the contribution rate of parent material in P180 and P181 profiles was calculated, i.e., 54.36% and 42.88%, respectively, that of sludge was45.64% and 57.12%, respectively. The results show that the main sources of lead in soil of drylands in Xiamen City were parent material and sludge, which was consistent with the results of the multivariate statistical analysis.
33. Soil Pollution Characteristics and Ecological Risk Assessment of As at a Large-scale Arsenic Slag-contaminated Site
Environmental Science,Part 1: Types of Soil Pollution,Vol 39,No. 33
A large-scale arsenic slag-contaminated site was selected to determine soil pollution characteristics and the degree of ecological risk of a large-scale contaminated site. In this study, 184 site soil samples, 101 agricultural soil samples, and 14 arsenic slag samples were collected, and the pollution characteristics and ecological risk of As were evaluated by using multivariate statistics, geostatistics, and the geo-accumulation and potential ecological risk index methods. The results show that the average As contents in site soil, agricultural soil, and arsenic slag are 1 333.0, 358.1, and 17 316.1 mg·kg ?1, respectively. The degree of contamination of As exceeds the Grade III standard of environmental soil quality of China. The results of the vertical and three-dimensional distributions of contamination show that As is accumulated to different extents in different strata. The accumulation in the site surface soil is the most serious. The As concentrations in site soil samples are higher than that in agricultural soil samples. The potential ecological risk index method shows that all mean potential ecological risk indexes exceed 100 in different layers. Moreover, the percentage of samples in site and agricultural soils at medium pollution level is 58.21% and 61.39%, respectively, illustrating that the As pollution of soil samples from this contaminated site and surrounding farm areas is serious.