Soil & Environmental Health最新文献

Diet intake accounts for >90% of selenium (Se) exposure in humans, with rice being the main source of Se intake for >60% of the Chinese population. In this study, 48 rice grain samples labeled Se-enriched were obtained from 22 major rice producing areas in China through online sources. Their total Se contents, Se speciation, and Se bioaccessibility were evaluated to provide a holistic view of Se-enriched rice in the market. The total Se contents were 0.006–0.951 ​μg ​g⁻¹ (average 0.249 ​μg ​g⁻¹), which showed great regional variations, with 73% of the samples satisfying the Se-enriched standard based on GB/T22499-2008 (0.04–0.30 ​mg ​kg⁻¹). Over 80% of Se in the rice samples was organic Se species including selenomethionine, selenocysteine and methylselenocysteine, with selenomethionine being the main Se species, accounting for 61–98%. Based on a modified physiologically-based extraction test (MPBET), the Se bioaccessibility in 33 selected samples was 8.05–49.6% (28.6%) in the gastric phase and 18.1–117% (82.5%) in the intestinal phase. Further, Se bioaccessibility was positively correlated with organic Se (r ​= ​0.89–0.93), but not with inorganic Se (selenite and selenate), suggesting that Se bioaccessibility depended on organic Se in these rice grains. The data call for re-evaluation of Se-enriched rice in the market. Further, the potential risk of long-term consumption of Se-enriched rice in the market towards human health should be studied.

In response to declineing natural water sources, treated wastewater has been introduced into the water cycle as a new water source for irrigation. However, this practice exposes the agricultural environment to various contaminants of emerging concern. To better understand their fate in the soil and to effectively predict their bioavailability for plant uptake, there is a need to quantify their concentrations in soil solutions. In this study, we examined the concentrations of treated wastewater-derived ​contaminants of emerging concern in soil solutions under three scenarios: (1) shifting from irrigation with freshwater to treated wastewater (FW→TWW scenario), (2) long-term continuous irrigation with treated wastewater (TWW→TWW scenario), and (3) prolonged irrigation with treated wastewater followed by freshwater (TWW→FW scenario). Contaminants of emerging concern including carbamazepine, 1H-benzotriazole, lamotrigine, venlafaxine, and thiabendazole were ubiquitous in the treated wastewater (mean concentrations of 125, 945, 180, 3630, and 90 ​ng/L, respectively) and irrigated soils. Interestingly, their concentrations in the soil solutions were different (higher or lower) from the corresponding concentrations in the irrigation water. In both the freshwater to wastewater (FW→TWW) and treated wastewater to freshwater (TWW→FW) irrigation scenarios, lower contaminant concentrations were observed in soil solutions compared to the prolong treated wastewater irrigation scenario (TWW→TWW), indicating that a steady state condition was not achieved after a single irrigation season. For example, the concentrations of 1H-benzotriazole in Nir Oz soil solutions were 638, 310, and 1577 ​ng/L for the three irrigation scenarios, respectively. Moreover, the ​contaminants concentrations in soil solutions were slightly lower in the TWW→FW irrigation scenario compared to the TWW→TWW scenario. Our data suggest that rain-fed crops are also exposed to treated wastewater-derived contaminants of emerging concern released from the adsorbed phase into the soil solution. The readily-available contaminants concentration in soil solution depends on the physicochemical properties of the molecule, the water type used for irrigation and the irrigation history, the contaminant concentration in the irrigation water, and soil characteristics.

Salt-affected soil has become one of the major threats to soil health. However, the evaluation of biochar amendment effects and the underlying mechanisms on the physical, chemical, and biological indicators used for assessing the health of salt-affected soils is lacking. This review summarized biochar performance and mechanisms in improving the health of salt-affected soils. Biochar addition significantly improved soil physico-chemical properties by enhancing aggregate stability (15.0–34.9%), porosity (8.9%), and water retention capacity (7.8–18.2%), increasing cation exchange capacity (21.1%), soil organic carbon (63.1%), and nutrient availability (31.3–39.9%), as well as decreasing bulk density (6.0%) and alleviating salt stress (4.1–40.0%). Following biochar incorporation, soil biological health can also be improved, particularly enhancing microbial biomass (7.1–25.8%), facilitating enzyme activity (20.2–68.9%), and ultimately increasing plant growth. To properly assess the health of salt-affected soils, it is important to select indicators related to ecological service functions including plant production, water quality, climate change, and human health. This will improve the evaluation of soil multifunctionality and enhance current soil health assessment methods. Finally, limitations and future needs of biochar research and biochar-based technologies for soil health assessment in salt-affected soils are discussed. Based on a global meta-analysis to illustrate biochar effects on salt-affected soil health indicators, this review offers valuable insights for developing sustainable biochar-based tools for remediating salt-affected soil.

The on-site use of greywater is increasingly popular for alleviating water stress in various parts of the world, particularly as a water source for irrigation. However, greywater can contain a range of pathogenic bacteria that may compromise public health as well as substances with the potential to induce environmental consequences, such as soil hydrophobicity, accumulation of salts, and damage to plants. While the health issues are being addressed by greywater legislation, its environmental risks are largely ignored. Therefore, the main objective of the current study was to quantify the impacts of greywater irrigation on soils by developing a soil quality index (SQI) using a 14-month planter experiment. The sum of the absolute value of all indicator scores represents the final score of the integrated SQI, which ranges from 0 to 100. Three threshold values were used: <30 represents deteriorated soil quality, 50–70 indicates intermediate quality, and >70 represents optimal quality. The results based on the planter experiment revealed that, after 14 months, the SQI of all raw greywater-irrigated soils was lower than 70, indicating soil functions and plant health might be compromised. The use of scoring functions was a useful tool for quantifying and comparing the effects of greywater irrigation on different soil quality indicators. Integration of all indicator scores into a single SQI quantifies and summarizes the overall beneficial and detrimental effects of greywater irrigation. However, for better understanding and management decisions, SQI scores should be used and interpreted in conjunction with the scores of the single indicators constituting the index. In our experiment, treated ​greywater ​did ​not compromise ​soil quality even after 14 months of irrigation. As such, based on the fact that irrigation with raw greywater might compromise soil quality, treatinggreywater prior to its use is recommended.

Soil quality standards for pesticides play a crucial role in protecting plants and preventing potential health hazards to humans. Here we discuss modeling approaches to define pesticide soil quality standards from two effect endpoints, which ensures consistency throughout the entire pesticide life cycle from application to human exposure assessment. Given that pesticides are applied in a pulse-like emission pattern and their soil concentrations change over time, both a ceiling legal limit and an average legal limit for pesticide soil quality standards should apply to the initial pesticide application practice and the potential human health effect. The timing intervals for pesticide application and the dissipation half-life in the soil can be used to quantify the relationship between the ceiling and average legal limits. By analyzing primary exposure pathways related to soil contamination, the average legal limit can be linked to theoretical human health risks, which requires a comprehensive evaluation for an adequate safety margin, including human interactions with soil, exposure assessment of soil pesticides, and allocation exposure assessment. To establish acceptable human health risks, the average legal limit can be determined, and the ceiling legal limit can be estimated based on the quantitative relationship between the ceiling and average legal limits. Additionally, we discuss situation-specific factors, including climate-pattern and behavior-pattern factors, to define pesticide soil quality standards to further complete the modeling framework. We hope insights presented in this paper will assist regulatory agencies worldwide in defining pesticide soil quality standards that meet their specific regulatory needs throughout the entire pesticide life cycle.

Heavy metal (loid) pollution poses a serious threat to the health and habitability of ecosystems worldwide. This study aims to investigate the concentration, pollution degree, pollution sources, and health risks of heavy metal (loid)s (HMs) in soil of Shanxi Province, China. The concentrations of Cu, Ni, Cd, Pb, Hg and As were measured by ICP-MS in 146 soil samples collected from agricultural land. The pollution degree and ecological risks of HMs were analyzed by variety of indexes, and the human health risks were assessed using the USEPA model. Results showed the average concentrations of Cu, Cd, Pb, Hg and As were 1.08, 1.15, 1.44, 1.50 and 1.25 times higher than the background values in the soil of investigated areas, respectively. The contamination factors revealed moderate pollution of Hg, Pb, As, Cd and Cu in the investigated areas, and the pollution load index indicated considerable contamination. The Nemerow index revealed low to severe contamination with HMs. The potential ecological risk of HMs indicates that Hg and Cd pose a moderate risk threat to the soil ecology. Coal mining was the primary sources of soil HMs identified by ACPS-MLR. Soil As (75.1%) and Ni (62.3%) were mainly derived from coal mining, Pb (73.1%) was from traffic emissions, and Hg (38.6%) originated from coal combustion. The health risks associated with these HMs due to soil exposure were within the acceptable levels for adults. The As concentration imposes the strongest effect based on the non-carcinogenic risk analysis in different exposed populations. In conclusion, the higher concentration of soil HMs moderately threatens soil ecology, but there was no significant human health risk found in the study. Furthermore, this study reveals the potential risk and sources of HMs in Shanxi Province, which is helpful for managing contaminated soil in the region.

Municipal solid waste (MSW) compost is being prioritised as a sustainable solution for urban waste management and is increasingly being used by agriculture as a soil enhancer, quasi-fertiliser and carbon mitigation tool. Here, we examine these changes and the growing global use of MSW compost and discuss its expanding adoption and application across different world regions. Factors influencing the composition of MSW compost, including processing technologies as well as feedstock characteristics such as seasonality, source variation, and maturation regimes, are discussed. An analysis of advantages and disadvantages of MSW compost is presented. The benefits are considered from the perspective of interplays within carbon, nitrogen and phosphorus cycles, and emerging roles in pollutant remediation. Conversely, the potential risks such as the presence of toxic elements, microplastics, and persistent organic pollutants, and impacts on greenhouse gas emissions are also examined. The production of high-quality MSW compost is underpinned by the selection and screening of appropriate feedstock. However, there are increasing opportunities for production technologies, which improve physical, chemical, and biological traits of the composts to the point that they can also provide phyto-stimulant/protection services. However, there is little information on the use of MSW compost in forestry. Overall, this review provides a comprehensive overview of the global trends, composition factors, advantages and disadvantages, strategies for efficient use, and future perspectives of MSW compost utilisation. It highlights the importance of balanced decision-making that considers both environmental and economic factors to maximise the potential benefits of MSW compost for sustainable waste management and soil improvement.

The use of nanoparticles in agrichemical formula and food products as additives has increased their chances of accumulation in humans via oral intake. Due to their potential toxicity, it is critical to understand their fate and distribution following oral intake. Cerium oxide nanoparticle (CeO₂NP) is commonly used in agriculture and is highly stable in the environment. As such, it has been used as a model chemical to investigate nanoparticle's distribution and clearance. Based on their estimated human exposure levels, 0.15–0.75 ​mg/kg body weight/day of CeO₂NPs with different sizes and surface charges (30–50 ​nm with negative charge and <25 ​nm with positive charge) were gavaged into C57BL/6 female mice daily. After 10-d, 50% of mice in each treatment were terminated, with the remaining being gavaged with 0.2 ​mL of deionized water daily for 7-d. Mouse organ tissues, blood, feces, and urine were collected at termination. At the tested levels, CeO₂NPs displayed minimal overt toxicity to the mice, with their accumulation in various organs being negligible. Fecal discharge as the predominant clearance pathway took less than 7-d regardless of charges. Single particle inductively coupled plasma mass spectrometry analysis demonstrated minimal aggregation of CeO₂NPs in the gastrointestinal tract. These findings suggest that nanoparticle additives >25 ​nm are unlikely to accumulate in mouse organ after oral intake, indicating limited impacts on human health.

Phytostabilization of metal-contaminated soils is effective to reduce their solubility and availability in soils and reduce their toxicity to plants. However, the evaluation of appropriate treatments and efficient plant species needs to consider the effects not only of soil characteristics, but also of microbial population. In this work, the effects of seven different plants, including crops and locally adapted species, in two metal-contaminated soils based on a field phytoremediation experiment were evaluated. The two soils (agricultural and mining) contained 6.1, 2322 and 1422, and 13.5, 2071 and 13,971 ​mg ​kg⁻¹ Cd, Pb and Zn concentrations, respectively. In the agricultural soil, combination of crop species Cynara cardunculus and Brassica juncea Czern. was the most effective in reducing metal extractability and in stimulating microbial activity. In the mining soil, compost-assisted phytostabilization decreased CaCl₂-extractable Cd and Zn (12–50% for Cd and 71–76% for Zn). The reduced metal toxicity enhanced microbial biomass activity and diversity, particularly under B. juncea. Thus, phytostabilization using selected species was effective in reducing metal toxicity in contaminated soils.