Multi-Elements in Source Water (Drinking and Surface Water) within Five Cities from the Semi-Arid and Arid Region, NW China: Occurrence, Spatial Distribution and Risk Assessment

Heavy metal stabilization remediation in polluted soils with stabilizing materials: a review

The remediation of soil contaminated by heavy metals has long been a concern of academics. This is due to the fact that heavy metals discharged into the environment as a result of natural and anthropogenic activities may have detrimental consequences for human health, the ecological environment, the economy, and society. Metal stabilization has received considerable attention and has shown to be a promising soil remediation option among the several techniques for the remediation of heavy metal-contaminated soils. This review discusses various stabilizing materials, including inorganic materials like clay minerals, phosphorus-containing materials, calcium silicon materials, metals, and metal oxides, as well as organic materials like manure, municipal solid waste, and biochar, for the remediation of heavy metal-contaminated soils. Through diverse remediation processes such as adsorption, complexation, precipitation, and redox reactions, these additives efficiently limit the biological effectiveness of heavy metals in soils. It should also be emphasized that the effectiveness of metal stabilization is influenced by soil pH, organic matter content, amendment type and dosage, heavy metal species and contamination level, and plant variety. Furthermore, a comprehensive overview of the methods for evaluating the effectiveness of heavy metal stabilization based on soil physicochemical properties, heavy metal morphology, and bioactivity has also been provided. At the same time, it is critical to assess the stability and timeliness of the heavy metals' long-term remedial effect. Finally, the priority should be on developing novel, efficient, environmentally friendly, and economically feasible stabilizing agents, as well as establishing a systematic assessment method and criteria for analyzing their long-term effects.

Comprehensive ecological risk assessment for semi-arid basin based on conceptual model of risk response and improved TOPSIS model-a case study of Wei River Basin, China

Comprehensive ecological risk assessment is of great significance for the restoration of watershed ecosystem health, and the appropriate and effective assessment method is the premise of ecological risk assessment. In this study, the conceptual model of risk response was developed by identification of ecological risk sources, stressors, endpoints and the corresponding response mechanism as well as the improved TOPSIS model based on Canberra distance and the combinatorial weighting method based on AHP and Critic were combined for the assessment. According to the three aspects of agriculture, industrial and urbanization, the occurrence mechanism of comprehensive ecological risk of rivers in semi-arid areas was analyzed. Furthermore, twenty-four indexes were selected to establish the index system and the Wei River Basin was taken as an example to verify the model. The results of comprehensive ecological risk assessment and stressor analysis showed that the deterioration of water quality (enrichment of heavy metals) and the decrease of benthos integrity were the two main risk factors for the increase of comprehensive ecological risk in Wei River Basin. And the regulation of ecological risk for the Wei River Basin is improvement of water quality and biotic integrity.

Cadmium in Groundwater Consumed in the Rural Areas of Gonabad and Bajestan, Iran: Occurrence and Health Risk Assessment

Evidences show that high levels of cadmium intake may be contributing to a wide range of deleterious health effects. This study was performed to estimate the concentration of cadmium and the health risk to human by cadmium through the ingestion of groundwater in 39 rural areas of Gonabad and Bajestan, eastern Iran. The mean cadmium concentrations in groundwater in the studied rural areas of Gonabad and Bajestan ranged from 0.087 to 14.32 μg/L and from 0.417 to 18.36 μg/L, respectively. Health risk quotient for cadmium contamination for 16 and 38% of children and infants in rural areas of Gonabad and Bajestan, respectively, was more than 1 which causes non-carcinogenic risk to the local population. The carcinogenic risk of cadmium in drinking water for adults, children, and infants in 16, 33, and 33% of studied rural areas of Gonabad and Bajestan, respectively, was higher than the safe limit of 1.0 × 10^-4. For rural areas of Bajestan, the cancer risk in 42, 52, and 52% of adults, children, and infants was above the safe limit. It was strongly suggested that the accessible procedures of treatment should be taken for a portion of contaminated rural areas before the distribution of the groundwater for the local population.

Use of a Survey to Assess the Environmental Exposure and Family Perception to Lead in Children (<6 Years) in Four Valley Cities, Northwestern China

With the growth of industry, the extensive use of lead, and urban expansion in Northwestern Valley Cities (NVC) China, there is probable reason for presuming an increasing risk of lead exposure. However, little is known about the lead exposure of children less than 6 years old in NVC. As a first investigation, this study uses a survey to systematically determine the influences of various risk factors within the family environment, parents' background, children's behavior, mother's behavior during pregnancy, and parental perception about children's blood lead (CBL). A total of 596 families were recruited from the general population in Urumqi, Lanzhou, Xining and Yan'an. Parents, and their children (<6 years old), were asked about the environment and behaviors which could possibly relate with lead exposure. The results indicated that in the typical NVC of China, children's environment and behavior, parents' education level, and mother's pregnancy behavior, were associated with potential CBL. It was noted that not all parents in NVC China recognized the importance of children's lead exposure. Therefore, children's health care and medical screening campaigns need to be designed to improve family's fundamental knowledge of lead hazards, associated health effects, and prevention in the NVC of China.