Arsenic Concentrations Research Articles

Arsenic contamination in rice consumption in Bandung city - West Java

Abstract Arsenic contamination in rice is of concern due to the potential health risks associated with various health problems, including certain types of bladder and lung cancers and skin lesions. Arsenic is a naturally occurring element that can be found in soil and water and its contamination in rice is possible. Meanwhile, rice is a staple food in Indonesia and its consumption is widespread across the country. According to the US Department of Agriculture, Indonesia is the world’s fifteenth-largest rice consumption with 128.6 kg per capita per year thus arsenic in rice is a concern. This study was conducted to measure the arsenic contamination in rice consumed by people in Bandung. Bandung was preferably selected due to its high population. As the capital city of West Java, its population hits more than 2.5 million and places it as the 5th most populated area in Indonesia. Ten rice samples were collected from a traditional market in Bandung, West Java. The sample was prepared using the Indonesian Regulation Standard (SNI) method and measured by ICP-MS. The arsenic concentration in rice was found varies between 0.0775-0.2550 mg/kg. The maximum allowable arsenic content for consumption based on the Indonesian National Standard (SNI) is 0.4 mg/kg, according to the World Health Organization (WHO) is 0.3 mg/kg, and according to the European Commission Standard for parboiled milled rice, the maximum level is 0.15 mg/kg. The HQAs value was higher than 1 (HQAs > 1), the rice in Bandung Market have potential for non-carcinogenic risk in long-term. ILCRAs result in this study between ILCR > 10−3 and >10−4 indicates threshold cancer risk for rice consumption. By calculating the ILCR, scientists and policymakers can prioritize interventions, implement regulatory measures, and develop strategies to reduce exposure levels, ultimately mitigating the potential cancer risks within a given population. It is important to note that the study should be continued over the next few years, to monitor the potential health risks associated with consuming contaminated rice.

Impact of Droughts on Served Drinking Water Disparities in California, 2007-2020.

Objectives. To quantify the impact of droughts on drinking water arsenic and nitrate levels provided by community water systems (CWSs) in California and to assess whether this effect varies across sociodemographic subgroups. Methods. I integrated CWS characteristics, drought records, sociodemographic data, and regulatory drinking water samples (n = 83 317) from 2378 water systems serving 34.8 million residents from 2007 to 2020. I analyzed differential drought effects using fixed-effect regression analyses that cumulatively accounted for CWS-level trends, income, and agricultural measures. Results. CWSs serving majority Latino/a communities show persistently higher and more variable drinking water nitrate levels. Drought increased nitrate concentrations in majority Latino/a communities, with the effect doubling for CWSs with more than 75% Latino/a populations served. Arsenic concentrations in surface sources also increased during drought for all groups. Differential effects are driven by very small (< 500) and privately owned systems. Conclusions. Impending droughts driven by climate change may further increase drinking water disparities and arsenic threats. This underscores the critical need to address existing inequities in climate resilience planning and grant making. (Am J Public Health. 2024;114(9):935-945. https://doi.org/10.2105/AJPH.2024.307758).

Seasonal and spatial variations of arsenic and its species in particulate matter in an urban environment of Brno, Czech Republic

The present paper deals with an analysis of total arsenic concentration using ICP-MS/MS and an analysis of concentration of several arsenic species, arsenite (AsIII), arsenate (AsV), monomethylarsonate (MMA), dimethylarsenite (DMA), and trimethylarsine oxide (TMAO), using HPLC-ICP-MS/MS in the PM10 fraction of airborne urban aerosol. The samples were collected during two campaigns, in the autumn of 2022 and in the winter of 2023, at three locations within the central European city of Brno, with the aim to evaluate the seasonal and spatial variations in the PM10 composition. The results confirmed only the seasonal variability in the content of the methylated arsenic species in PM10 influenced by biomethylation processes. To gain better understanding of the possible arsenic origin, a supplementary analysis of the total arsenic concentrations was performed in samples of different size fractions of particulate matter collected using ELPI + . Local emissions, including industrial activities and heating during the winter season, were suggested as the most likely predominant source contributing to the total As content in PM10.Graphical abstract

Development of cost-effective inorganic arsenic extraction method for resource-limited regions: Analysis of efficiency and regulatory implications

This study evaluated the effectiveness of coke and lemonade extraction methods compared to the standard 1 % v/v HNO3 method for determining inorganic arsenic (iAs) concentrations in rice bran samples using a field-deployable method (Arsenator field kit). The limit of detection (LOD) for the methods was 45 μg kg−1, comparable to existing literature. The extraction efficiencies were assessed by comparing iAs recovery rates, with coke extraction yielding the highest recovery of 127.4 %, followed by lemonade at 116.2 %, and HNO3 at 100 %. Statistical analysis indicated strong correlations between the extraction methods, particularly between HNO3 and coke (Pearson correlation coefficient, 0.990), suggesting that coke extraction is a reliable alternative to the traditional HNO3 method. However, lemonade extraction showed a lower correlation (0.940) and higher false negative rates, indicating potential limitations for regulatory compliance. Notably, at the maximum contaminant limit (MCL) of 0.100 mg kg−1, coke extraction produced an 8 % false positive rate with no false negatives, while lemonade extraction had an 8 % false positive rate and a 17 % false negative rate. This study underscores the potential of coke extraction as a cost-effective and efficient alternative for assessing iAs levels in rice products, especially in resource-limited settings. Recommendations include the standardization of coke extraction protocols and the development of robust monitoring programs to ensure food safety and public health protection against arsenic contamination. Overall, the findings contribute valuable insights for improving arsenic detection methods and regulatory compliance in food safety practices.

P19-81 Arsenic, lead and essential elements content in tea samples from Turkey: a risk assessment study

P19-81 Arsenic, lead and essential elements content in tea samples from Turkey: a risk assessment study

Potential of Heavy Metals and Microplastics Contamination in River Mpanga, Fort Portal, Kabarole District, Uganda

Anthropogenic environmental pollution is a major development challenge in Ugandan rivers and lakes, the key drivers being industrialization, agriculture, and urbanization. The aim of the study was to assess the potential of heavy metal and microplastic contamination in River Mpanga, Fort Portal, Uganda. Triplicate water and sediment samples were collected from three sampling sites, preserved, and analyzed at the Chemistry Department, Makerere University for heavy metals, while microplastics analysis was conducted at NaFIRRI, Jinja. Sediment heavy metal contamination was assessed from the geoaccumulation index, while microplastic characterization and quantification were determined from stereomicroscopy and morphological features. Arsenic was the most prevalent metal with a mean concentration of 13.2 ppm thus higher than permissible maximum limits of WHO. The mean concentrations (ppm) of copper, lead, and cadmium were 0.01, 0.01, and 0.001 respectively, and below the permissible maximum. Sediment samples revealed very strong arsenic contamination, strong contamination for copper, moderate to strong contamination for lead, and a potential lack of contamination for cadmium. The higher concentrations of the heavy metals in the sediments compared to water could be attributed to bioaccumulation, as evidenced by the high geoaccumulation values. Microplastics occurred throughout the river and included fragments, filaments, film, pellets, form, and fibers. The presence of heavy metals and microplastics was attributed to anthropogenic activities within the river vicinity, which discharged heavy metal-laden waste into River Mpanga. High arsenic concentrations and sediment accumulation of contaminants pose serious potential public health threats to the local communities.

Nectopsyche sp (Trichoptera: Leptoceridae) sublethal effects caused by different concentrations of arsenic (As): a biochemical markers approach.

Environmental impacts related to arsenic (As) contamination are a persistent issue of particular interest in Latin American countries with increasing mining activities. In Ecuador, the redefinition of public policies to promote the increase in mining since 2008 has led to a significant rise in the presence of this heavy metal in rivers and effluents, sometimes exceeding the 0.1 mg L-1, limit recommended by Ecuadorian Environmental Regulations. This study aimed to evaluate the sublethal effects through the detection of biochemical biomarker changes (Catalase, Antioxidant capacity by FRAP, and Glutathione S-transferase) generated in larvae of Nectopsyche sp following prolonged exposure to different concentrations of As (C1 = 0.05 mg L-1, C2 = 0.1 mg L-1, C3 = 0.8 mg L-1) in a controlled environment, emulating the maximum limits allowed by current Ecuadorian legislation. While As concentration levels in water increased, so did levels in the tissue of Nectopsyche sp specimens. On the other hand, behavioral parameters (mortality and mobility) did not show differences in either time or As concentrations. However, both Catalase and Antioxidant capacity by FRAP levels tended to decrease with increasing As concentration, and in both cases, the differences were significant. Additionally, Glutathione S-transferase activity did not increase significantly. These results preliminarily demonstrate that biochemical responses change with varying As concentrations in Nectopsyche sp and are affected at behavioral and biochemical levels produced by the As at chronic levels.

New evidence of the timing of arsenic accumulation and expression of arsenic-response genes in field-grown Pteris vittata plants under different arsenic concentrations

The timing and efficiency of arsenic (As) accumulation is crucial for using the hyperaccumulator P. vittata in remediation of As-contaminated soils. In this study, through an innovative microXRF-based approach, using a new “pinna powder” sampling method, we monitored As accumulation over time in fronds of individual P. vittata plants grown in the greenhouse and in the field on two natural soils, with high (750 mg/kg) and moderate (58.4 mg/kg) As concentrations. Results, validated by multivariant statistical analysis show that the peak of As occurs on both soils at 45/60 days and at 100/120 days in greenhouse and field grown plants, respectively. Furthermore, in field trials, the timing of As accumulation in both soils was similar during the first autumn-winter and the second spring-summer phytoextraction cycle. After the two cycles, soil As content was reduced by 70.4% in the high-As soil and 26.4% in the moderate one. Moreover, candidate genes involved in As hyperaccumulation -the arsenite antiporter PvACR3, the As (V)-reductases Pv2.5-8 and the organic cation transporter PvOCT4- are expressed in response to As in field-grown plants with similar kinetics in both soils. In conclusion, we established by this innovative technique, the timing of maximum As accumulation that is linked to the intrinsic hyperaccumulation mechanism and represents a highly powerful tool to set up the duration of phytoextraction cycles.

Predicting the risk of arsenic accumulation in soil-rice system in Asian monsoon region

Rice is a staple food for a significant portion of the global population. Arsenic (As) accumulated in rice grains influences rice quality which threatens human health. In this study, we used three machine learning models to predict arsenic accumulation in rice based on over 300 surveys. The prediction results of soil arsenic indicate that high-arsenic soil areas are mainly distributed in South and Southeast Asia such as India, China, and Thailand. In addition, higher bioaccumulation factors (BAF), associated with higher temperature, are predominantly observed in eastern India and southern Myanmar. However, arsenic content in soil is relatively lower in these areas. About 5.5 billion population may be threatened by the consumption of high-arsenic rice. It can be concluded that temperatures may influence the BAF except for soil arsenic, and soil physicochemical properties. Further research on the relationship between climate parameters and BAF should be conducted to address and adapt to future climate change. Additionally, understanding the mechanism of arsenic accumulation under different climatic conditions is crucial for developing agricultural technologies to reduce arsenic accumulation in rice.

Analysis of Heavy Metals in Water and Wastewater

The primary focus of the study is to assess the presence and concentration of heavy metals in the water and evaluate its suitability for drinking purposes. Given that a significant portion of the local population depends on groundwater for their daily needs, the study is critical in understanding the potential health risks associated with consuming contaminated water. The study begins with a comprehensive survey to gauge the extent of water usage among the local population and their perceptions of water quality. Results from the survey reveal that nearly half of the households in the region are not connected to a formal drinking water network, relying instead on wells and springs. While the majority of respondents perceive the water quality as good, the analytical findings suggest otherwise. Groundwater samples were collected from twelve wells and three springs across the region. These samples were subjected to rigorous analysis using inductively coupled plasma-atomic emission spectrometry (ICP-AES) to detect the concentration of various heavy metals, including aluminum, silver, iron, cadmium, arsenic, chromium, cobalt, zinc, lead, and copper. The results indicate that many of these metals are present in concentrations that exceed the World Health Organization's recommended limits for safe drinking water. Iron, in particular, was found at high levels in all sampled locations, raising significant concerns. The study also employs the Heavy Metal Pollution Index (HPI) to provide a more comprehensive assessment of water quality. The HPI values calculated for the sampled water sources reveal that a majority of the wells and all of the springs have levels of heavy metal contamination that render the water non-potable. This finding is particularly alarming given the region's dependence on water, especially during periods of drought when alternative water sources are scarce.

Metals and other trace elements in plasma and feathers of seabirds breeding in Svalbard

We assessed the concentrations of metals and other trace elements in two of the most common seabird species breeding on Svalbard, the black-legged kittiwake (Rissa tridactyla) and the Brünnich's guillemot (Uria lomvia). Both of these species feed mostly on fish and crustaceans but have different foraging strategies, kittiwakes being surface feeders while guillemots are divers. We investigated the concentrations of arsenic (As), cadmium (Cd), chromium (Cr), copper (Cu), mercury (Hg), lead (Pb), selenium (Se) and zinc (Zn) in the plasma and body feathers of black-legged kittiwakes (n = 17), as well as in the body feathers of Brünnich's guillemots (n = 13). Samples were collected from adult birds at two time points, one week apart during July 2017 in Kongsfjorden, Svalbard. Of the non-essential trace elements, As was found at the highest median concentration at both the first (56.23 ng/g ww) and second (39.99 ng/g ww) sampling timepoints in the kittiwake plasma. When separating for the sexes, as well as sampling time, males sampled at the first sampling time point had significantly higher concentrations of As (median at 0.087 ng/g versus 0.039 ng/g) and Se (median 0.26 ng/g versus 0.16 ng/g) compared to males sampled at the second time point. There was no significant difference in plasma concentrations between females at first and second sampling time points. Kittiwake feathers contained significantly higher concentrations of As, Cd and Hg than guillemot feathers, while guillemot feathers had significantly higher concentrations of Cu, Pb and Zn. However, of the non-essential elements in both kittiwake and guillemot feathers Hg was found with the highest median concentrations at 5160 and 1080 ng/g, respectively, thus in kittiwakes exceeding the level of 5000 ng/g associated with adverse effect (e.g., impaired reproduction). Levels of Hg and Se found in the kittiwake feathers were higher than previous studies on seabirds in the Arctic.

Efficient Pb(II) removal from contaminated soils by recyclable, robust lignosulfonate/polyacrylamide double-network hydrogels embedded with Fe2O3 via one-pot synthesis

Soil heavy metal removal strategies are increasingly valued for effectively reducing contamination and preventing secondary pollution. In this work, a double network hydrogel (Fe2O3@LH), consisting of lignosulfonate (LS) and polyacrylamide with embedded Fe2O3 nanoparticles, was synthesized successfully via a one-pot method and subsequently applied to adsorb lead (Pb) from contaminated soil. Incorporating Fe2O3 into the hydrogel enhances the adsorption capacity of Fe2O3@LH for Pb(II). The Fe2O3@LH hydrogel demonstrates a maximum Pb(II) adsorption capacity of 143.11 mg g–1, with Pb(II) removal mechanisms involving electrostatic adsorption, cation exchange, precipitation reactions, and the formation of coordination complexes, achieving a 22.3 % maximum removal efficiency in soil cultivation experiments. Additionally, the application of Fe2O3@LH markedly reduces the concentrations of cadmium (Cd) and arsenic (As) in the soil, meanwhile enhances the levels of total nitrogen (TN), soil organic matter (SOM), and cation exchange capacity (CEC) by 23.1 %, 10.6 %, and 16.9 %, respectively. Following 90 days of continuous application in the soil, the recovery rate of Fe2O3@LH remains above 75 %. The toxicity assay using zebrafish larvae indicates that Fe2O3@LH demonstrates good biosafety. This study demonstrates the considerable potential of Fe2O3@LH hydrogel for practical application in reducing Pb(II) levels in contaminated soil.

Utilization of rice husk ash as a potential catalyst for diatom growth and adsorbent for heavy metals in aquaculture systems

Many aquaculture environments suffer from significant silicon deficiencies and severe heavy metal contamination, posing substantial risks to both production and safety in aquaculture. This study aimed to assess the release of silicate from rice husk ash (RHA) and its impact on phytoplankton abundance and community composition, which are key factors affecting shellfish growth and survival. Additionally, the capacity of RHA to adsorb mercury (Hg2+) was examined using different modification methods. The results demonstrated that the concentration of dissolved silicate in seawater increased with higher RHA doses, reaching a maximum of 189.77 ± 45.61 μmol L−1 in the high RHA treatment (HR) with 1.0 g L−1 of RHA. Notably, the HR treatment group exhibited a significant increase in chlorophyll-a concentration for nano-phytoplankton (2–20 μm), with an up to eightfold rise in abundance compared to the control group. Moreover, the HR treatment resulted in a maximum diatom abundance of 4217 ± 741.98 cells L−1, benefiting diatom species such as Coscinodiscus sp., Nitzschia sp., and Cyclotella sp. These findings underscore the potential of RHA as a catalyst for diatom growth, which in turn supports the growth of shellfish. Furthermore, no concentrations of mercury (Hg), lead (Pb), cadmium (Cd), arsenic (As), copper (Cu), zinc (Zn), and chromium (Cr) were detected in any of the silicate enrichment treatments, confirming the safety of the RHA. The treatment of RHA with NaOH achieved an impressive removal efficiency of Hg2+, reaching up to 97.41 ± 0.33 %. This study highlights the promising application of agricultural waste RHA as a catalyst for diatom growth and an adsorbent for heavy metals in water systems relevant to aquaculture practices.

The sulfurization precipitation and competition mechanisms of Cu(II) and As(V) in electrolyte towards efficient recovery of copper

The sulfide precipitation has been widely used to recover Cu(II) and remove As(V) in copper smelting electrolyte based on the Cu(II)-As(V) separation. However, the recovery efficiency was undesirable due to the inaccurate control of process parameters. It was necessary to investigate the process and mechanisms of sulfurization precipitation for accurate adjustment. Herein, under the single and mixed solutions of Cu(II) and As(V), the process parameters were investigated and the precipitation mechanisms were explored. And when using actual electrolytes, the corresponding sulfurization process and mechanisms were also revealed. The sulfurization results of single component solutions suggested that Cu(II) was rapidly precipitated in one step, but As(V) firstly generated intermediate, then it was gradually reduced to As(III) for a longer time and quickly precipitated in the form of amorphous. This phenomenon caused the significantly faster removal speed of Cu(II) than that of As(V). For their mixed solutions, only a small amount of As(V) were removed by adsorbing the precipitate at the low S/Cu molar ratios (RS/Cu), and Cu(II) and As(V) could achieve a good separation. Simultaneously, it revealed that the sulfidation competitive mechanisms were related to the solubility product constant (Ksp) and initial As(V) concentrations. In addition, the similar rules were also observed in actual electrolytes. Moreover, under RS/Cu = 1.2 and reaction time of 10 min, the arsenic content of sulfide precipitates in the actual electrolyte was less than 2.5%, which showed a great separation also could be obtained for the actual electrolyte. This result met the requirement of Cu(II) recovery. It can provide a good reference for adjusting sulfidation parameters in the actual process to achieve efficient copper recovery, reduce the production of hazardous waste containing arsenic at the source and realize the cleaner production of copper smelting system.

Application of biohybrid membranes for arsenic and chromium removal and their impact on pollutant accumulation in soybean (Glycine max L.) seedlings.

Chromium and arsenic are among the priority pollutants to be controlled by regulatory and health agencies due to their ability to accumulate in food chains and the harmful effects on health resulting from the ingestion of food contaminated with metals and metalloids. In the present work, four biohybrid membrane systems were developed as alternatives for the removal of these pollutants, three based on polyvinyl alcohol polymeric mesh (PVA, PVA-magnetite, PVA L-cysteine) and one based on polybutylene adipate terephthalate (PBAT), all associated with bioremediation agents. The efficiency of the bioassociation process was assessed through count methods and microscopy. The removal capacity of these systems was evaluated in synthetic liquid medium, both in the absence and in the presence of soybean (Glycine max L.) seedlings. The content of chromium and arsenic was also analyzed in aerial and hypogeous tissues of seedlings grown on contaminated solid substrate. PVA and PVA-magnetite biohybrid membranes showed the highest removal rates, between 57 and 75% of the initial arsenic content and more than 80% of the initial chromium content after 48h of treatment, when evaluated in synthetic liquid media with initial concentrations of 2.5ppm of pentavalent arsenic and 5ppm of hexavalent chromium, both in presence and absence of seedlings. PVA and PBAT promoted a significant reduction of arsenic translocation to the aerial parts, generally edible, of this crop of agronomic interest. The systems tested showed a high potential for biotechnological applications in matrices affected by the presence of arsenic and chromium.

Identification of key factors and mechanism determining arsenic mobilization in paddy soil-porewater-rice system

Arsenic (As) mobilization in paddy fields poses significant health risks, necessitating a thorough understanding of the controlling factors and mechanisms to safeguard human health. We conducted a comprehensive investigation of the soil-porewater-rice system throughout the rice life cycle, focusing on monitoring arsenic distribution and porewater characteristics in typical paddy field plots. Soil pH ranged from 4.79 to 7.98, while porewater pH was weakly alkaline, varying from 7.2 to 7.47. Total arsenic content in paddy soils ranged from 6.8 to 17.2 mg/kg, with arsenic concentrations in porewater during rice growth ranging from 2.97 to 14.85 μg/L. Specifically, arsenite concentrations in porewater ranged from 0.48 to 7.91 μg/L, and arsenate concentrations ranged from 0.73 to 5.83 μg/L. Through principal component analysis (PCA) and analysis of redox factors, we identified that arsenic concentration in porewater is predominantly influenced by the interplay of reduction and desorption processes, contributing 43.5 % collectively. Specifically, the reductive dissolution of iron oxides associated with organic carbon accounted for 23.3 % of arsenic concentration dynamics in porewater. Additionally, arsenic release from the soil followed a sequence starting with nitrate reduction, followed by ferric ion reduction, and subsequently sulfate reduction. Our findings provide valuable insights into the mechanisms governing arsenic mobilization within the paddy soil-porewater-rice system. These insights could inform strategies for irrigation management aimed at mitigating arsenic toxicity and associated health risks.

Performance and mechanism of arsenic-metal separation in copper smelting flue gas regulated by chalcopyrite

To reduce the release of arsenic from non-ferrous metal (especially copper) smelting flue gases as well as to recover arsenic, the dry quenching process has been successfully applied to remove arsenic. However, the formation of arsenate hindered the separation of arsenic, thus reducing the collection efficiency. To tackle the bottleneck, the strategy of mineral phase regulation was proposed by the conversion from arsenate to sulfate, metal sulfate and gaseous arsenic were formed and separated each other. Chalcopyrite served as a potential sulfation regulator due to the gradual production of active sulfur (S2 dimer and S monomers) at high temperatures. At a chalcopyrite dosage of 60 %, the separation efficiency of arsenic from the metals reached 93.78 % and the residual arsenic content in the arsenic-copper particulate matter was decreased from 40.38 % to 3.12 % at 700 °C. The separation of arsenic and metal was attributed to the release of active sulfur from chalcopyrite, which enhanced the conversion of arsenate to sulfate. The separated arsenic enters the following section in the form of gaseous As2O3, which is beneficial to the dry quenching collection of arsenic. This provides theoretical and technical support for the clean production of nonferrous metal smelting and the control of arsenic pollution in flue gas.

The environmental and agronomic benefits and trade-offs linked with the adoption alternate wetting and drying in temperate rice paddies

ContextAlternating wetting and drying (AWD) is an irrigation practice, alternative to continuous flooding, to improve the agro-environmental sustainability of rice cultivation. Benefits include reduction in water consumption, methane (CH4) emissions and arsenic (As) concentrations in grain. However, drainage periods during AWD can negatively affect nitrogen (N) use efficiency by the crop and grain yields, while increasing nitrous oxide (N2O) emissions and cadmium (Cd) contents in grain. ObjectiveThe objective of this study was to provide a holistic evaluation of AWD adoption in temperate rice cropping systems, including associated trade-offs. We hypothesized that the adoption of AWD in water seeded rice paddies can reduce the global warming potential (GWP) without affecting plant N uptake or introducing yield gaps, and also maintain a high quality of rice grain by limiting the uptake of metal(loid)s present in the soil, thereby resulting in an overall positive agro-environmental performance. MethodsIn a two-year field experiment in NW Italy two alternative irrigation practices involving water seeding followed by AWD management of different severity (AWDsafe and AWDstrong) were evaluated relative to the conventional water seeding and continuous flooding (WFL), comparing three different rice varieties. Yields and yield components, plant N uptake, apparent N recovery (ANR), metal(loid) concentrations in grain, and CH4 and N2O emissions were evaluated. ResultsAWDsafe and AWDstrong maintained or increased yields compared to WFL depending on varieties, despite an increase in sterility. There were no consistent differences in N uptake and ANR. Both AWDsafe and AWDstrong significantly reduce As concentration in grain, but significantly increase Cd and nickel (Ni). AWDsafe and AWDstrong reduced CH4 emissions by 45–55 % and 40–73 %, respectively, compared toWFL, while no increase in N2O emissions was observed. This resulted in a reduction in the GWP of 46 and 54 % with AWDsafe and AWDstrong, respectively. Conclusions and ImplicationsAWD was shown to be effective for mitigating GHG emissions from temperate rice cropping systems while maintaining high yield performance comparable or higher than WFL. AWD may represent a viable alternative to continuous flooding to improve agro-environmental sustainability of temperate rice cropping systems, but the trade-off between decreasing As and increasing Cd and Ni contents in the grain may represent an important concern for food safety with the adoption of this alternative water management practice.

Source to Receptor: Assessing Health Risks from Heavy Metal Exposure in Mining Soils

This research quantifies the health risks associated with exposure to heavy metals in the Matjhabeng Local Municipality, a gold mining region in South Africa, utilising a deterministic source–pathway–receptor approach. This study uniquely integrates both non-carcinogenic and carcinogenic risk assessments across multiple heavy metals, providing a comprehensive perspective on health impacts in mining-impacted communities. The study measured concentrations of arsenic (As), cadmium (Cd), lead (Pb), cobalt (Co), chromium (Cr), copper (Cu), iron (Fe), nickel (Ni), selenium (Se), and zinc (Zn) in soil samples, with mean values found to be 3.2 mg/kg, 2.5 mg/kg, 45 mg/kg, 17 mg/kg, and 25 mg/kg for As, Cd, Pb, Co, and Cr, respectively. The deterministic assessment revealed minimal non-carcinogenic risks for ingestion across all demographics (HQ &lt; 1), while significant dermal risks were identified for Cd, Pb, Co, and Cr (HQ &gt; 1), particularly for the adult group. The inhalation pathway emerged as a critical exposure route, with HQ values ranging from 5 to 15 and chronic hazard index values significantly exceeding safe limits (CHI &gt; 5). The carcinogenic risk through inhalation notably surpassed the acceptable thresholds set by the United States Environmental Protection Agency (1 × 10−4 to 1 × 10−6), with a calculated lifetime cancer risk far exceeding the limit for As, Cd, Cr, Co, and Ni for both adults and juveniles. These findings underscore the urgent need for targeted risk mitigation strategies in the community to address the significant health risks posed by airborne heavy metal exposure.

Trusted artificial intelligence for environmental assessments: An explainable high-precision model with multi-source big data

Environmental assessments are critical for ensuring the sustainable development of human civilization. The integration of artificial intelligence (AI) in these assessments has shown great promise, yet the "black box" nature of AI models often undermines trust due to the lack of transparency in their decision-making processes, even when these models demonstrate high accuracy. To address this challenge, we evaluated the performance of a transformer model against other AI approaches, utilizing extensive multivariate and spatiotemporal environmental datasets encompassing both natural and anthropogenic indicators. We further explored the application of saliency maps as a novel explainability tool in multi-source AI-driven environmental assessments, enabling the identification of individual indicators' contributions to the model's predictions. We find that the transformer model outperforms others, achieving an accuracy of about 98% and an area under the receiver operating characteristic curve (AUC) of 0.891. Regionally, the environmental assessment values are predominantly classified as level II or III in the central and southwestern study areas, level IV in the northern region, and level V in the western region. Through explainability analysis, we identify that water hardness, total dissolved solids, and arsenic concentrations are the most influential indicators in the model. Our AI-driven environmental assessment model is accurate and explainable, offering actionable insights for targeted environmental management. Furthermore, this study advances the application of AI in environmental science by presenting a robust, explainable model that bridges the gap between machine learning and environmental governance, enhancing both understanding and trust in AI-assisted environmental assessments.