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Excessive use of chemical fertilizers and pesticides cause severe hazards to human health and becomes a part of the food web. A comprehensive analysis of wastewater-treated crops and soil was carried out to determination of polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), and organochlorine pesticides (OCPs) via GC/MS, and their health risk potential was calculated. Results showed that the mean concentrations of Ʃ10PAHs and Ʃ11OCP in crops, soil, and sewage sludge samples ranged from 10.68 ± 0.32 to 19.42 ± 0.58, 8.28 ± 0.25 to 11.65 ± 0.34, and 6.73 ± 0.2 to 14.93 ± 0.45 and 581.09 ± 17.4 to 6219.07 ± 186.5, 229.6 ± 6.8 to 547.4 ± 16.4, and 131.5 ± 3.9 to 1107.4 ± 33.2 ng g−1 respectively. Concentrations of Ʃ7PCB in crops and Ʃ2PCB in sludge sample ranged from 6.03 ± 0.18 to 480.39 ± 14.4 and 49.42 ± 1.48 to 386.06 ± 11.5 ng g−1. In soil samples, only PCB 18 was detected and ranged from below the detected limit to 180.02 ± 5.4 ng g−1. The maximum total health risk (ingestion, dermal, and inhalation) for PAHs was found in adults (1.5E − 07) as compared to children (9.92E − 08). Incremental lifetime cancer risk (ILCR) was slightly higher in children (2.39E − 08) as compared to adults (4.96E − 08). The total health risk of OCP was at the threshold level in children (3.05E − 07 to 6.39E − 07) and adults (1.21E − 07 to 2.60E − 07). The total risk of PCB 8 in children ranged from 3.43E − 07 to 3.23E − 09 and in adults was 2.20E − 07 to 6.98E − 09. All the ranges were under the safe limits of USEPA. There has been much previous research, but unfortunately, no serious implementation or proper monitoring was in practice. This study generates the basic data about contamination of organic pollutants in wastewater irrigated soil and crops. [ABSTRACT FROM AUTHOR]

Understanding the extent of contamination, sources and various carcinogenic and non-carcinogenic risks associated with different heavy metals in soil-crop systems is crucial for the prevention of heavy metal pollution. A survey was undertaken to determine heavy metal concentrations and degree of pollution in soil-crop systems (rice, wheat, and corn) using various indices such as pollution factor ( CF ), geo-accumulation index ( I geo ), enrichment coefficients and transfer coefficient, and to determine the source of heavy metals pollution in the Wanjiang Economic Zone, Anhui Province, China. A total of 308 pairs of soil-crop samples were collected in this study, comprising 245 pairs of soil-rice samples, 53 pairs of soil-wheat samples, and 10 pairs of soil-corn samples. The concentrations of cadmium (Cd) and nickel (Ni) in the soil of the study area exceeded the national limitation of heavy metals in the soil of China (GB 15618-2018, Soil Environmental Quality: Risk Control Standard for Soil Contamination of Agricultural Land. Ministry of Environmental Protection of China. Beijing. China ). The concentrations of copper (Cu), zinc (Zn) and lead (Pb) were also above the national limits to a lesser extent. All eight heavy metals (Cd, Cu, Ni, Pb Zn, arsenic (As), chromium (Cr), and mercury (Hg)) exceeded the background values in the study area. The enrichment coefficients of rice, wheat and maize to Cd, Cu and Zn were higher than those to other elements. On the basis of I geo , it can be indicated that the rhizosphere soil of rice was slightly polluted by Cd and Hg, while the concentrations of the other heavy metals were below the safety limits. The CF and pollution load index ( PLI ) indicated that the soil in the study area was heavily contaminated with heavy metals. A principal component analysis identified different sources of soil heavy metal pollution, that is, Cu, Pb, Zn and Cd from industrial sources, Cr and Ni from natural sources, and As and Hg from agricultural sources. The carcinogenic risk of heavy metals was related to the intake of crops. Residents in the study area ingest rice, wheat, and corn on a daily basis. On the basis this study, it is suggested that local governments should pay attention to the carcinogenic risk of heavy metals in rice.

In order to study the characteristics and factors influencing Cd accumulation in surface soils and crops in karst areas, and to provide a theoretical basis for safe land use, 360 surface soil samples, 7 deep soil samples, and 85 rice samples were collected from central Qianjiang District, Chongqing. The samples and 73 corn samples (corresponding to root-zone soil samples), were analysed to determine the content of Cd, TFe 2 O 3 , Mn, organic matter (C org ), Se, and pH. Based on geostatistical analyses, the spatial distribution and Cd enrichment of the surface soils were determined and a safety evaluation for the soil and crops was carried out. The results showed that the spatial distribution of Cd in the surface soil was uneven, with the surface layer showing significant enrichment. This pattern was controlled by the soil parent material and human activities. The enrichment of surface layer was mainly affected by iron manganese oxides and organic matter (C org ). Soil Cd was mainly found at 'non-polluted' and 'lightly polluted' levels, although some areas present strong ecological risks. The main contaminated area occurs in association with Permian strata, demonstrating a geological control on soil Cd pollution. Slight-to-severe Cd pollution was identified in bulk crops; the recommended daily consumption limit for rice is 0.87 kg·d -1 and corn is 1.53 kg·d -1 . The bioavailability of Cd is affected by soil pH and Se content. Under acidic conditions, Cd bioavailability is high, and crops in areas with high soil Se are safer. It is recommended that crops with low Cd accumulation are planted in the Permian outcrop area of Shuitian Township, or alternatively, soil pH should be adjusted to control the risk of Cd pollution and ensure safe land use. In addition, planting crops in areas with high soil Se content is preferable.