Metal Pollution Research Articles

Chemical characteristics and health risk evaluation of natural waters in the Du River Source National Nature Reserve: A case study in Zhushan County, Hubei Province, China

To study the distribution of trace elements in natural water of the Du River Source National Nature Reserve and to assess the water quality and health risks, Zhushan County in Hubei Province was selected as the study area. Element content in 361 natural water samples collected from Zhushan County were measured by ICP-MS, ICP-OES, and HG-AFS. The main anions and cations present in water samples from Zhushan County are Ca2+ and HCO3−. The water chemistry is predominantly influenced by the weathering of carbonate rocks. The water samples with high content of selenium (Se) (0∼82.9 μg/L, mean 4.6 μg/L) in natural water in Zhushan County are mainly distributed in the northern part of Zhushan. The strontium (Sr) content of 49.6% of the water samples (0.001–2.177 mg/L, mean 0.234 mg/L) reached the criteria of natural mineral water for drinking in China (Sr ≥ 0.2 mg/L), which is distributed throughout the county. The high content of metasilicic acid (H2SiO3) (0.026–35.910 mg/L, mean 12.598 mg/L) and zinc (Zn) (0∼407.218 μg/L, mean 12.406 μg/L) are concentrated in northern Zhushan County. 99.7% water samples were freshwater and 98.9% meet the criteria of “good” water quality. All of the natural water samples have low health risk and low heavy metal pollution. 6.1% water samples meet the criteria of Se-type mineral water, while 45.4% meet the criteria of Sr-type mineral water, and 4.4% water samples meet the criteria of “low sodium, high Se, and high Sr” mineral water. Zhushan County has the potential for Se-type mineral water and Sr-type mineral water development. The findings of this study hold immense significance for the public health implications of drinking water in Du River Source, thereby offering valuable insights for effective water resources management.

Chronic lead poisoning–induced budgerigar liver damage, gut microbiota dysbiosis, and metabolic disorder

Birds are sensitive to heavy metal pollution, and lead (Pb) contamination can negatively affect their liver and gut. Therefore, we used budgerigars to examine liver and gut toxicosis caused by Pb exposure in bird, and the possible toxic mechanisms. The findings showed Pb exposure increased liver weight and decreased body weight. Moreover, histopathological and immunofluorescence assay results demonstrated obvious liver damage and cell apoptosis increased in Pb- treated budgerigars. Quantitative polymerase chain reaction (qPCR) results also showed Pb caused an increase in apoptosis by inhibiting the PPAR-γ/PI3K/Akt pathway. The gut microbe analyses indicated Firmicutes, Proteobacteria, and Bacteroidetes were dominant microbial phyla, and Network analysis results shown Arthrobacter, Bradyrhizobium and Alloprevotella as the hubs of Modules I, II, and III, respectively. Phenylpropanoids and polyketides, Organoheterocyclic compounds, Organic oxygen compounds, and Organic nitrogen compounds were dominant metabolite superclasses. Tauroursodeoxycholic acid, taurochenodeoxycholic acid (sodium salt), and 2-[2-(5-bromo-2-pyridyl)diaz-1-enyl]-5-(diethylamino)phenol were significantly enriched in the Pb-treated group. It showed that 41 Kyoto Encyclopedia of Genes and Genomes (KEGG) orthologues and 183 pathways differed between the Pb-treated and control budgerigars using microbial and metabolomic data. Moreover, orthogonal partial least-squares discrimination analysis (OPLS-DA) based on microbial and metabolite indicated distinct clusters in the Pb-treated and control groups. Additionally, the correlation analysis results indicated that a positive correlation for the Pb-treated and control groups between gut microbiota and metabolomic data, respectively. Furthermore, the microenvironment of the gut and liver were found to affect each other, and this study demonstrated heavy metal especially Pb may pose serious health risks to birds through the “gut–liver axis” too.

Distribution, toxicity load and risk assessment of heavy metals in the groundwater of Dhemaji, Assam, India

Metal contamination in drinking water has drawn attention since it gravely jeopardizes human health. This study was conducted in pre- and post-monsoon season in 2021 at Dhemaji, Assam, India. It characterized metal pollutants in groundwater, their distribution, possible sources, and evaluated the potential toxicity and associated health risk assessment. The seasonal mean concentration of Fe in both seasons is observed highest followed by Mn, Zn, Cu, As, and Ni. Furthermore, the metal concentrations during pre-monsoon are comparatively higher. The geogenic processes and agricultural practices are the major sources of groundwater metal contamination as evident from the statistical analysis. The different pollution indices viz. Heavy-metal Pollution Index (HPI), Heavy-metal Evaluation Index (HEI) and Degree of Contamination (Cd) suggested that groundwater is not suitable for drinking uses. The Heavy Metal Toxicity Load (HMTL) suggesting As, Co, Mn and Hg should be removed from the groundwater to ensure safety. Water pollution indices (WPI) suggest that Fe, Mn, As and Ni are the main pollution-causing metals in the study area which may be restored under the BIS and WHO limit by diluting the water. The human health risk has been calculated by carcinogenic and non-carcinogenic risk assessment. The non-carcinogenic risk for adults and children is within the threshold limit. The carcinogenic risk shows that continuous exposure of As and Ni may give rise to cancer among adults and children in the region. Therefore, comprehensive groundwater quality monitoring with well-planned treatment should be needed to provide safe and clean drinking water in the studied area.

Dealing with elemental toxicities in crops: hot topics and likely solutions

Abstract Background The widespread presence of arsenic (As) and cadmium (Cd) in agricultural soils coupled with a problem of Al phytotoxicity threatens sustainability of agricultural production system as well as natural ecosystems. Scope Understanding the role of membrane transporters responsible for uptake, translocation, and sequestration of above metal(oid)s and the modes of their regulation may be critical to tackle the above issue. In this review, we summarize the current knowledge of membrane transporters mediating As, Cd and Al homeostasis in plants, highlighting unanswered questions and offering potential solutions. Amongst these, the following topics may deserve a special attention in future studies: (1) uncoupling transport of As and inorganic phosphorous in plant roots focusing on PHT1;1 transporters; (2) revealing the modes of their post-translational regulation, especially under hypoxic conditions; (3) better understanding of structure–function relations of various transporters isoforms for Cd, to uncouple transport of toxic Cd metals from that for essential micronutrients such as Fe, Zn or Mn; (4) revealing the role of non-selective cation channels (NSCC) in Cd uptake and revealing mechanisms of their regulation; (5) elucidate the role of various aquaporins in Al3+ uptake in plant roots; (6) understanding the role of slow vacuolar (SV) channels in Al sequestration in plant vacuoles; and (7) revealing the mechanistic basis of long-distant transport of toxic ions, with specific emphasis of phloem transport. Conclusion These multidisciplinary efforts strive to ensure global food safety by mitigating the impact of heavy metal pollution on agriculture and human well-being.

Application and mechanism of carbonate material in the treatment of heavy metal pollution: a review.

Among the many heavy metal pollution treatment agents, carbonate materials show strong flexibility and versatility by virtue of their high adsorption capacity for heavy metals and the characteristics of multiple and simple modification methods. It shows good potential for development. This review summarizes the application of carbonate materials in the treatment of heavy metal pollution according to the research of other scholars. It mainly relates to the application of surface-modified, activated, and nano-sized carbonate materials in the treatment of heavy metal pollution in water. Natural carbonate minerals and composite carbonate minerals solidify and stabilize heavy metals in soil. Solidification of heavy metals in hazardous waste solids is by MICP. There are four aspects of calcium carbonate oligomers curing heavy metals in fly ash from waste incineration. The mechanism of treating heavy metals by carbonate in different media was discussed. However, in the complex environment where multiple types of pollutants coexist, questions on how to maintain the efficient processing capacity of carbonate materials and how to use MICP to integrate heavy metal fixation and seepage prevention in solid waste base under complex and changeable natural environment deserve our further consideration. In addition, the use of carbonate materials for the purification of trace radioactive wastewater and the safe treatment of trace radioactive solid waste are also worthy of further exploration.

Time-Domain Transfer Learning for Accurate Heavy Metal Concentration Retrieval Using Remote Sensing and TrAdaBoost Algorithm: A Case Study of Daxigou, China

Traditionally, the assessment of heavy metal concentrations using remote sensing technology is sample-intensive, with expensive model development. Using a mining area case study of Daxigou, China, we propose a cross-time-domain transfer learning model to monitor heavy metal pollution using samples collected from different time domains. Specifically, spectral indices derived from Landsat 8 multispectral images, terrain, and other auxiliary data correlative to soil heavy metals were prepared. A cross time-domain sample transfer learning model proposed in the paper based on the TrAdaBoost algorithm was used for the Cu content mapping in the topsoil by selective use of soil samples acquired in 2017 and 2019. We found that the proposed model accurately estimated the concentration of Cu in the topsoil of the mining area in 2019 and performed better than the traditional TrAdaBoost algorithms. The goodness of fit (R2) of the test set increased from 0.55 to 0.66; the relative prediction deviation (RPD) increased from 1.37 to 1.76; and finally, the root-mean-square deviation (RMSE), decreased from 8.33 to 7.24 mg·kg−1. The proposed model is potentially applicable to more accurate and inexpensive monitoring of heavy metals, facilitating remediation-related efforts.

Removal of Heavy Metal Ions(Fe2+, Mn2+, Cu2+ and Zn2+) on to Activated Carbon Prepared from Kashmiri Walnut Shell (Juglans regia)

Heavy metal pollution poses significant threats to the environment and human health, even at trace concentrations. In this study, activated carbon derived from Kashmiri walnut shell (Juglans regia) was investigated for its potential to adsorb heavy metal ions (Fe2+, Mn2+, Cu2+, and Zn2+). Standard solutions containing heavy metal ions at concentrations ranging from 10 to 50 ppm were prepared for adsorption experiments, i.e., at temperature 25 °C, and adsorbent dosage 1 g using a column mechanism. The activated carbon was first treated with 0.1M HCl and 0.5M ammonia solutions, and then washed with demineralised water. Subsequently, the metal ion solutions were passed through the column individually, and the filtrates were analyzed for heavy metal ion presence. The experimental results demonstrated that walnut shell-derived activated carbon exhibited promising adsorption capacity spanning from 0.36 mg/g for Zn2+, 0.5 mg/g for both Mn2+ and Cu2+ and 0.54 mg/g for Fe2+ thus showing the adsorption trend as Fe2+ > Mn2+ = Cu2+ > Zn2+. This study highlights the potential of using walnut shell-derived activated carbon as an effective and cost-efficient method for mitigating heavy metal pollution in contaminated water sources.

Assessment of benthic ecological status and heavy metal contamination in an estuarine intertidal mudflat in the Northern Bohai Sea

Evaluating the ecological quality and pollution status of coastal mudflats is crucial for environmental protection and management, particularly when these areas serve as major shellfish production hotspots. In this study, we assessed the benthic ecological quality and heavy metals pollution in Geligang, located in the Northern Bohai Sea using the macrobenthos diversity index and the heavy metal pollution index. The Shannon-Wiener index (H′), AZTI marine biotic index (AMBI), multivariate AMBI (M-AMBI) showed that the benthic ecological quality in Geligang is either good or high. The potential ecological risk index and geoaccumulation index highlighted that cadmium (Cd) and mercury (Hg) as the primary heavy metal pollutants in Geligang. Surprisingly, the biomass of the two dominant species other than these indices serve as reliable indicators of heavy metal pollution. This suggests that the biomass of Mactra veneriformis and Potamocorbula laevis could be used to assess heavy metal pollution levels in Geligang.

Source Governance-Oriented Zoning for Heavy Metal Pollution in Farmland Soil: a Case Study of an Industrial Park in Mid-Western Shaanxi Province, China

Source Governance-Oriented Zoning for Heavy Metal Pollution in Farmland Soil: a Case Study of an Industrial Park in Mid-Western Shaanxi Province, China

Effects of exogenous chloride ions on the migration and transformation of Cd in a soil-rice system

Soil cadmium (Cd) contamination has emerged as a significant global environmental concern, posing numerous risks to individual organisms and entire ecosystems. Concurrently, the global increase in pesticide usage has elevated the influx of chloride ions (Cl−) into the soil. Given Cl−’s robust ability to coordinate and complex with various heavy metal ions, understanding its influence on the migration and transformation of Cd in soil-rice systems is essential for the rational application of pesticides and the effective mitigation of soil heavy metal pollution. In this paper, we explained the effect of Cl− on the environmental behavior of Cd in the soil-rice system in terms of growth traits, Cd uptake and accumulation by rice, and Cd solid-solution phase interface behavior through pot experiments and sand culture experiments. The results showed that Cd concentrations in all parts of the rice treated with CaCl2 during the filling period were lower than those in the Ca(NO3)2-treated group, with Cd accumulation diminishing as Cl− concentration increased. This suggests that the filling period is critical for Cd uptake and accumulation in rice. Unlike the accompanying anion NO3−, exogenous Cl− reduced Cd concentrations in the soil solution but increased them in rice. Notably, when the Cd/Cl ratio ranged from 0.625 to 2.5, Cl− formed predominantly CdCl+-complexes with free Cd2+ in the soil solution, enhancing the mobilization of Cd bound to soil particles and its subsequent absorption by rice. This study aims to assess Cl−’s effect on Cd migration and transformation in soil-rice systems, providing insights for safe rice production on Cd-contaminated soils and rational use of chlorine-containing pesticides.

An Assessment of Soil Metal Contamination in Oil Fields Utilizing Petroleum Contamination Indices and GIS Methods

In recent decades, there has been a growing focus on soil quality due to the significant industrialization and urbanization observed in many places worldwide. The primary hazards to soil are recognized as a reduction in organic material, heightened soil erosion. The metal content of samples collected from March to August at ten different stations in the Al-Garraf Oil Field was analysed (Cd, Cr, Cu, Fe, Mn, Ni, Pb, and Zn). The correlation analysis revealed that organic matter from petroleum waste affected the metal content of the Al-Garraf Oil Field. The values found in the literature have been compared to the results. Using the geoaccumulation index (Igeo) to calculate the metal pollution status in the oil field The results of the Igeo index reveal that the soil of Al-Garraf Oil Field was moderately contaminated with heavy metals (Cd, extremely contaminated by Mn, and heavily to heavily extremely contaminated by Pb metal. The correlation matrix reveals a significant positive association between Cr-Mn, Cu-Pb, Cu-Ni, Zn-Cu, and Zn-Pb, indicating that these heavy metals have a same origin. An inverted distance weighted (IDW) technique in GIS was utilised to generate and analyse a map of heavy metal concentrations for the purpose of illustrating the pollutant distribution in a lucid fashion. The map visually represented the stations most significantly impacted by these elements.

The adsorption effect of aquaculture residual feed on heavy metals and its impact on microbial metabolism of feed

BackgroundIntensive and large-scale aquaculture has a high biological density, and a large amount of artificial feed must be provided. As a result, residual feed would be discharged into natural water bodies with water exchange. Due to heavy metal pollution in surface water, residual feed may adsorb heavy metals in the water, affecting the subsequent microbial degradation of feed and the restoration of the water environment. The combined ecological impacts of these two types of pollution urgently need to be explored.ResultsThis study explored the adsorption effect of residual feed on heavy metals and its impact on microbial degradation of residual feed. The results showed that both the insoluble component (mainly fiber, ash, and ether extract, abbreviated as FAE) and soluble component (soluble protein and starch) of the feed had adsorption effects on heavy metals. As the salinity increased, the adsorption capacity of Cu2+ and Cd2+ decreased, while the adsorption effect on Pb2+ was not changed significantly. The adsorption of heavy metals by residual feed could affect the biological degradation of residual feed. The residual feed could adsorb heavy metals and bacterial cells simultaneously, forming FAE-B(bacteria)-S(starch)-Pr(protein)-metal adsorption complex. This adsorption effect could reduce the negative impact of heavy metals on microbial degradation of residual feed. The simulated degradation experiments in actual water bodies also confirmed this. However, the accumulation of heavy metals in residual feed may bring negative effects, such as being consumed by aquatic organisms and entering the food chain.ConclusionsThe results of this study provide a basis for the collection and centralized treatment of residual feed in aquaculture, as well as the control and remediation of residual feed pollution in natural water bodies.Graphical

Cerium‐based metal–organic frameworks (MOFs) as a sustainable approach to mitigating environmental stress‐induced intestinal ulcers in earthworms

Exposure to environmental stresses such as heavy metal pollution, herbicides, and climate change may cause adverse effects on biological animals such as earthworms, leading to conditions including intestinal ulcers. This study outlines the potential of a cerium‐based metal–organic framework (Ce‐MOF) in healing alcohol‐induced ulcers in earthworms. The Ce‐MOF was synthesized via a solvothermal technique and analyzed using X‐ray diffraction, Fourier transform infrared spectroscopy, and scanning electron microscopy. Ce‐MOF exhibited a one‐dimensional channel and demonstrated multi‐enzyme‐like activity. It was examined on earthworms suffering from ulcers caused by alcohol use. Examinations at a macroscopic level, histological analysis, and transmission electron microscopy images showed significant harm to the intestinal lining in ulcerated worms. The ulcer treatment with Ce‐MOF substantially enhanced intestinal morphology, repaired the epithelial lining, and facilitated ulcer healing. Furthermore, Ce‐MOF decreased the death rate and enhanced the weight of earthworms in comparison to untreated groups. This study emphasizes the potential of Ce‐MOF as an innovative therapeutic agent for alcohol‐induced ulcers, emphasizing its prospective uses in regenerative medicine and tissue regeneration.

Physiological and transcriptomic analyses reveal the cadmium tolerance mechanism of Miscanthus lutarioriparia.

Miscanthus lutarioriparia is a promising energy crop that is used for abandoned mine soil phytoremediation because of its high biomass yield and strong tolerance to heavy metals. However, the biological mechanism of heavy metal resistance is limited, especially for applications in the soil restoration of mining areas. Here, through the investigation of soil cadmium(Cd) in different mining areas and soil potted under Cd stress, the adsorption capacity of Miscanthus lutarioriparia was analyzed. The physiological and transcriptional effects of Cd stress on M. lutarioriparia leaves and roots under hydroponic conditions were analyzed. The results showed that M. lutarioriparia could reduce the Cd content in mining soil by 29.82%. Moreover, different Cd varieties have different Cd adsorption capacities in soils with higher Cd concentration. The highest cadmium concentrations in the aboveground and belowground parts of the plants were 185.65 mg/kg and 186.8 mg/kg, respectively. The total chlorophyll content, superoxide dismutase and catalase activities all showed a trend of increasing first and then decreasing. In total, 24,372 differentially expressed genes were obtained, including 7735 unique to leaves, 7725 unique to roots, and 8912 unique to leaves and roots, which showed differences in gene expression between leaves and roots. These genes were predominantly involved in plant hormone signal transduction, glutathione metabolism, flavonoid biosynthesis, ABC transporters, photosynthesis and the metal ion transport pathway. In addition, the number of upregulated genes was greater than the number of downregulated genes at different stress intervals, which indicated that M. lutarioriparia adapted to Cd stress mainly through positive regulation. These results lay a solid foundation for breeding excellent Cd resistant M. lutarioriparia and other plants. The results also have an important theoretical significance for further understanding the detoxification mechanism of Cd stress and the remediation of heavy metal pollution in mining soil.

Spatial and temporal distribution of nitrogen, phosphorus, and heavy metals loads in Guanshan River Basin based on SWAT modeling

ABSTRACT This study takes Guanshan River Basin, a typical inflow river of the Danjiangkou Reservoir, as the research area, and the nonpoint source (NPS) pollution characteristics of nitrogen and phosphorus from 2013 to 2018 were evaluated by establishing a Soil and Water Assessment Tool (SWAT) model. The pollution characteristics of heavy metals were also evaluated by combining the SWAT and simple output coefficient method. The results show that the pollutant load in Guanshan River Basin contributes significantly to the Danjiangkou Reservoir. Temporally, pollutant loads were primarily concentrated in the flood season, which had a significant positive correlation with precipitation, water yield, and sediments in the abundant period. Among them, sediments were the most important driving factor, followed by water yield. Spatially, pollutant loads were mainly concentrated downstream of the basin, where cultivated land is widespread. In this regard, it is suggested that the input of chemical fertilizers, pesticides, and livestock manure in cultivated land should be controlled and soil erosion downstream of the basin should be prevented to mitigate nitrogen, phosphorus, and heavy metal pollution. This research offers a basis for the formulation and implementation of watershed management for the Danjiangkou Reservoir.

Antioxidant vitamins in Benin bronze casters and their environmental cohorts: A preliminary nutritional assessment

The process of bronze casting often leads to prolonged exposure to air pollutants, heavy metals, and potentially hazardous working conditions. Understanding the levels of antioxidant vitamins among the Benin bronze casters is vital because their exposure to environmental pollutants and potential occupational hazards may increase their oxidative stress levels. Therefore, this study aimed to evaluate the levels of antioxidant vitamins; A, C, and E in Benin bronze casters. A total of ninety (90) consenting participants were recruited for this study; They included foundry workers (bronze casters), randomly selected individuals around the foundry site (environmental), and healthy unexposed individuals (control). Vitamins A, C, and E levels were determined using pectrophotometry. Data obtained was analyzed using Statistical Package for Social Science (SPSS) software. The findings revealed that vitamin A levels were significantly lower in bronze casters (36.06±9.15) when compared to environmental (58.57±41.05) and control groups (62.61±51.12) (p<0.05). Vitamin C levels were significantly lower in bronze casters (0.53±0.14) when compared to the environmental group (1.02±0.53) and the control group (1.55±0.37) (p<0.05). Also, there was a significant reduction in vitamin C levels in the environmental group when compared to the control group (p<0.05). Vitamin E levels were significantly lower in bronze casters (5.14±1.92) and environmental (6.28±3.32) groups when compared to the control group (11.49±3.75) (p<0.05). There was a strong positive correlation between vitamin A and vitamin C (r=-0.589, p=0.001). Vitamin C showed a strong positive correlation with vitamin E levels (r=0.562, p=0.001). In conclusion, the lower vitamin levels suggest an increased vulnerability to oxidative stress, which occupational hazards and environmental factors, such as exposure to metal toxins and pollutants may exacerbate.

Spatial health risk assessments of nickel in the groundwater sources of a mining-impacted area

Mining activities have increased the potential risks of metal pollution to the groundwater resources in arid areas across the globe. Therefore, this study aimed to examine the health risk associated with nickel (Ni) in the groundwater sources of a mining-impacted area, South Khorasan, Eastern Iran. A total of 110 stations were included in the study, comprising 62 wells, 40 qanats, and 8 springs in summer, 2020. Initially, the collected samples were tested for temperature, pH, and electrical conductivity (EC). Subsequently, the samples were filtered and treated with nitric acid (HNO3) to measure the concentration of Ni using Inductively Coupled Plasma Mass Spectrometry (ICP-MS). Hazard quotient (HQ) and non-carcinogenic risk assessments were employed to evaluate the potential risks of Ni to the inhabitants. The findings revealed that the concentration of Ni ranged from 0.02 to 132.39 μg l−1, and only two stations exhibited Ni concentrations above the WHO standards (20 μg l−1). The results demonstrated that 98.21% of the sampled locations had HQ values below one, indicating negligible risk, while 1.78% of the stations exhibited HQ values of one or higher, representing a high non-carcinogenic risk for water consumers. Overall, the concentration of nickel in the groundwater of South Khorasan exceeded the World Health Organization (WHO) limit solely in the Halvan station, posing a non-carcinogenic risk for the residents in that area, and therefore, additional efforts should be made to provide healthier groundwater to consumers in this region.

Determination of threshold values and heavy metal pollution assessment of soils in an industrial area in Ghana.

Industrial activities have the potential to pollute soils with a wide variety of heavy metals (HMs). In Ghana, however, assessment of HM pollution of soils in industrial areas remains limited. Accordingly, HM soil pollution in one of the industrial areas in Accra, Ghana was assessed. Soil samples were taken and analysed forHMs, including Fe, Zr, Zn, Ti, Sr, Rb, Mn, Pb, Cu, and Co, using X-Ray Fluorescence (XRF). HM geochemical threshold values (GTVs) were determined to establish soil HM pollution levels and identify areas needing remediation. Furthermore, risk assessments wereconducted to evaluate the potentialecological and human health risks associated with these metals.The mean concentrations of Fe, Zn, Rb, Sr, Zr, Ti, Mn, Co, Cu, and Pb in the soils were: 27133.83, 147.72, 16.30, 95.95, 307.11, 4663.66, 289.85, 418.54, 44.97, and 112.88 mg/kg, respectively. Generally, the concentrations of HMsdecreased with depth, although some lower layers exhibited elevated HM levels. Soil pollution levels were categorized as low for Fe, Rb, Zr, Ti, Mn, Co, and Cu; moderate for Sr and Zn; and considerable for Pb. Notably, the northwestern part of the study area displayed a considerable to very high degree of HM contamination. While HMs in the soils posed low ecological risk, the human health risk assessment indicated potential health effects from Co, particularly in children. The presence of HMs in the soils was noted to originate from both natural geological phenomena and human activities, including industrial operations, agricultural practices, landfill activities, and vehicular emissions.

Assessment of Soil Heavy Metal Pollution and the Ecological Risk in an Agricultural Area from Sánchez Ramírez Province, Dominican Republic

Assessment of Soil Heavy Metal Pollution and the Ecological Risk in an Agricultural Area from Sánchez Ramírez Province, Dominican Republic

In Situ Construction of CuTCPP/Bi4O5Br2 Hybrids for Improved Photocatalytic CO2 and Cr(VI) Reduction.

Global warming and heavy metal pollution pose tremendous challenges to human development, and photocatalysis is considered to be an effective strategy to solve these problems. Herein, copper(II) tetra (4-carboxyphenyl) porphyrin (CuTCPP) molecules were successfully in situ loaded onto Bi4O5Br2 by a hydrothermal approach. A series of experimental results show that the light absorption capacity and photogenerated carrier separation efficiency were synchronously enhanced after the construction of CuTCPP/Bi4O5Br2 composites. Hence, the as-prepared composites possess significantly improved photocatalytic ability for both CO2 and Cr(VI) reduction. Specifically, CuTCPP/Bi4O5Br2-2 achieves a CO generation rate of 17.14 μmol g-1 under 5 h irradiation, which is twice as high as that of Bi4O5Br2 (8.57 μmol g-1). Besides, the optimized CuTCPP/Bi4O5Br2-2 also exhibits a removal rate of 61.87% for Cr(VI) within 100 min under irradiation. Furthermore, the mechanism of CO2 and Cr(VI) photoreduction was explored by in situ Fourier transform infrared spectroscopy and capture experiments, respectively. This work can be a reference toward the construction of photocatalysts with high activity for solar energy conversion.