Provincial and seasonal influences on heavy metals in the Noyyal River of South India and their human health hazards

Hydrochemical insights, water quality, and human health risk assessment of groundwater in a coastal area of southeastern China

Groundwater is a vital water supply worldwide, but its quality has gradually deteriorated with the development of society. In this study, a total of 40 groundwater samples were collected during the pre- and post-monsoon to analyze the hydrochemical process and assess the groundwater quality and human health risks in a coastal area of southeastern China. The results showed that the concentrations of major ions were in the order of Ca2+ > Mg2+ > Na+ > K+ and HCO3- > SO42- > Cl- > NO3- > F- during the pre- and post-monsoon periods. A slight increase was observed during the post-monsoon period. The Piper diagram suggested that the hydrochemical type of groundwater was predominantly HCO3-Ca. Principal component analysis (PCA), ionic ratios, and saturation index (SI) determined that the water-rock interactions involving silicate and carbonate minerals played a significant role in the hydrochemical process. The results of the entropy-weighted water quality index (EWQI) and irrigation water quality index (IWQI) evaluations revealed that the general qualities of groundwater were suitable for both drinking and irrigation purposes. However, the excesses of NO3- and SO42- were observed locally. Human health risk assessment concluded that groundwater posed a low risk to human health, and infants faced higher risk compared with adults. The study would provide valuable information for groundwater environmental protection.

Risk assessment and source analysis of trace elements in soils around county landfills in Tibet

The ecology of the Qinghai‒Tibet Plateau is fragile, and the ecosystems in the region are difficult to remediate once damaged. Currently, landfilling is the mainstay of domestic waste disposal in China, and numerous, widely distributed county landfills exist. trace elements (TEs) in waste are gradually released with waste degradation and cannot be degraded in nature, affecting environmental quality and human health. To reduce the chance bias that exists in studies of individual landfills, we selected 11 representative county landfills in Tibet, total of 76 soil samples were collected, eight TEs (arsenic (As), mercury (Hg), chromium (Cr), copper (Cu), lead (Pb), cadmium (Cd), nickel (Ni), and zinc (Zn)) were determined, and analysed for the current status of pollution, risk to human health, and sources of TEs to explore the impact of the landfills. The results showed that only a few landfills had individual TEs exceeding the risk screening value of the Soil Environmental Quality Risk Control Standard for Soil Contamination (GB 15618-2018) (pH > 7.5). Most of the soils around the landfills had moderate levels of pollution, but some individual landfills had higher levels, mainly due to Cd and Hg concentrations. Source analysis showed that Hg originated mainly from atmospheric transport; the other TEs came mainly from the weathering of soil parent material and bedrock. The potential risk from TEs to human health was low, and the risk to children was greater than the risk to adults. Among the three exposure routes, oral ingestion resulted in the highest carcinogenic risk and noncarcinogenic risk, with a contribution rate of more than 95%. Among the TEs, Ni had the highest carcinogenic risk, followed by Cr and As, and As had the highest noncarcinogenic risk.

Potential toxic element contamination and non-carcinogenic risk assessment of groundwater from rapidly growing urban areas in Telangana, India

Groundwater is a critical resource for drinking purposes that is under pressure and polluted with multiple inorganic contaminants. Among various contaminants, potentially toxic element contamination in groundwater has significant public health concerns due to their toxicity at a low level of exposure. This investigation aimed to assess the toxic element contamination and associated non-carcinogenic human health risk at rapidly growing urban centers in Telangana to ensure potable water and to generate baseline data in the study province. Thirteen potential toxic trace elements (Al, As, B, Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, Se, and Zn) were determined in 35 groundwater samples collected from the Karimnagar and Siddipet smart cities in lower Manair River basin using inductively coupled plasma mass spectrometry (ICP-MS). The trace element concentration is found in the range for Al (1-112 µg/L), As (2-8 µg/L), B (34-438 µg/L), Cd (bdl-2 µg/L), Co (bdl-17 µg/L), Cr (bdl-4 µg/L), Cu (bdl-216 µg/L), Fe (4-420 µg/L), Mn (bdl-3311 µg/L), Ni (5-31 µg/L), Pb (bdl-62 µg/L), Se (1-18 µg/L), and Zn (3-1858 µg/L). Analytical data of groundwater revealed the occurrence of toxic elements observed as above the acceptable limits of Bureau of Indian Standards for drinking purposes found in the order of Al > Ni ≥ Mn > Se ≥ Cu ≥ Pb > Fe with 26% > 14% ≥ 14% > 9% ≥ 9% ≥ 9% > 6% of samples, respectively. The non-carcinogenic health risk to humans upon groundwater ingestion has been evaluated and found to be non-hazardous for all the individual elements studied except for aresenic. However, cumulative hazard quotient observed as > 1 in the category of infants and children might be a major potential health concern. This study provided baseline data and suggested implementing preventive measures to protect human health around the urban areas of lower Manair river basin, Telangana, India.

Nanocellulose-stabilized nanocomposites for effective Hg(II) removal and detection: a comprehensive review

Mercury pollution, with India ranked as the world's second-largest emitter, poses a critical environmental and public health challenge and underscores the need for rigorous research and effective mitigation strategies. Nanocellulose is derived from cellulose, the most abundant natural polymer on earth, and stands out as an excellent choice for mercury ion remediation due to its remarkable adsorption capacity, which is attributed to its high specific surface area and abundant functional groups, enabling efficient Hg(II) ion removal from contaminated water sources. This review paper investigates the compelling potential of nanocellulose as a scavenging tool for Hg(II) ion contamination. The comprehensive examination encompasses the fundamental attributes of nanocellulose, its diverse fabrication techniques, and the innovative development methods of nanocellulose-based nanocomposites. The paper further delves into the mechanisms that underlie Hg removal using nanocellulose, as well as the integration of nanocellulose in Hg detection methodologies, and also acknowledges the substantial challenges that lie ahead. This review aims to pave the way for sustainable solutions in mitigating Hg contamination using nanocellulose-based nanocomposites to address the global context of this environmental concern.

Seasonal impact of acid mine drainage on water quality and potential ecological risk in an old sulfide exploitation

Sulfides are usually associated with deposits of metals and coal. The reactive wastes from their exploitation, typically stored in piles and tailings dams, are often the mining sector's primary source of environmental problems. The surrounding river waters can present signs of acid mine drainage, responsible for aquatic ecosystem degradation. So, the main target of the present study is to investigate the impact of this process on the water's environmental quality and potential ecological risk. The study area is located at the Iberian Pyrite Belt, in an old sulfide exploitation, closed without environmental rehabilitation measures. The results exhibit high sulfate concentrations (410,601 mg/L) and potentially toxic elements, with prominence of Fe (134,000 mg/L), overcoming many other extreme cases of AMD pollution. The Ficklin diagram exposes that most samples are classified as "high-acid, high-metal." Two of them have extreme classifications (high-acid, extreme-metal). The pH value is well below the acceptable range for the environmental quality of superficial waters (5-7), measuring at a minimum of 0.84. Regarding seasonal variability, the study showed a higher degree of contamination in dry conditions (e.g., 4,420 mg/L of Cu), while the rainy month had lower concentrations of PTE (186.8 mg/L of Cu for the same sampling point). In addition, the water does not accomplish the environmental objectives established by the EU Water Framework Directive. According to the new approach developed based on a scale adjustment, the potential ecological risk index studied indicates that most sampled sites present strong, very strong, and even extremely potential ecological risk. With a typical Mediterranean climate, the region suffers from water scarcity, predicting increasingly in the future more degrading scenarios for water environmental quality. Consequently, urgent mitigation and remediation measures are necessary to improve and preserve water quality and fulfill the objectives of the United Nations Sustainability Development Goals.

Assessing Heavy Metals in the Sele River Estuary: An Overview of Pollution Indices in Southern Italy

Rapid industrialization, coupled with a historical lack of understanding in toxicology, has led in an increase in estuary pollution, frequently resulting in unexpected environmental situations. Therefore, the occurrence of heavy metals (HMs) constitutes a major environmental issue, posing a serious risk both to aquatic ecosystems and public health. This study aimed to evaluate the levels of eight HMs (As, Hg, Cd, Cr, Cu, Ni, Pb, and Zn) in water, suspended particles, and sediment near the Sele River estuary (Italy) in order to assess their environmental impacts on the sea and health risks for humans. The results revealed an increasing order of HM concentration according to the scheme suspended particulate matter (SPM) > sediment (SED) > dissolved phase (DP) and a moderate contamination status in sediment. The health risk assessment indicated that the non-carcinogenic risk was negligible. Carcinogenic risk, expressed as the incremental lifetime cancer risk (ILCR), was negligible for Cd and Ni and within tolerable limits for As, Pb, and Cr. The findings suggested that, even if there are currently no specific limits for chemical parameters in the transitional waters of Italy, monitoring systems should be implemented to determine pollution levels and implement effective steps to improve river water quality and reduce human health risks.

Environmental health risk assessment and source apportion of heavy metals using chemometrics and pollution indices in the upper Yamuna river basin, India

River Yamuna is the largest tributary of the Ganges with great economic importance, and provides water for about 57 million people and accounts for more than 70% of Delhi's water supply. Various pollution indices and chemometric methods were used to investigate heavy metal pollution, associated risks, and probable sources in the upper Yamuna river water. A total of 56 river water samples, 28 each in pre and post-monsoon season were collected and analysed for 15 heavy metals. The findings reveal that Al (38.66 ± 21.14 μg/L), As (16.52 ± 15.81 μg/L), and Mn (41.06 ± 89.25 μg/L) in pre-monsoon and Al (45.77 ± 29.46 μg/L), As (10.30 ± 12.15 μg/L), Fe (48.03 ± 81.11 μg/L), and Mn (31.02 ± 70.13 μg/L) in post-monsoon exceeded the Bureau of Indian Standards (BIS) acceptable limits. The pollution indices (HPI, NPI, HEI, and Cd) indicate that most locations are low to moderately polluted, except for the lower catchment. Health indices, i.e., hazard Index (HI) and incremental lifetime cancer risk (ILCR), suggest that the prolonged consumption of river water may cause potential human health hazards. In contrast, the water is suitable for domestic and other uses as the dermal risk is less prominent. The ecological risk index (ERI) of pre (0.22-58.75) and post-monsoon (0.12-44.21) were in the low-risk category (<110), indicating no ecological risk associated with heavy metals. In pre and post-monsoon, four principal components (PCs) described 73.97% and 76.18% of the total variance respectively, suggesting the mixed impact of numerous geogenic and anthropogenic sources in the region's water chemistry. Cluster analysis demonstrates that the lower catchment samples (National Capital Region, Delhi) significantly vary from each other due to wastewater discharge, industrialisation, and rapid urbanization, while the upper and mid-catchment samples are less distinct. Hence, more than 90% of the Yamuna water is extracted from the upper region; present findings may aid in developing an effective catchment scale management strategy.

Urinary concentrations of heavy metals in pregnant women living near a petrochemical area according to the industrial activity

BACKGROUND

The progressive industrialization has resulted in an increase in heavy metal pollution in the environment, which has a dangerous impact on human health. Prenatal exposure to heavy metals, even at very low concentrations, may be especially harmful to pregnant women and their children. Different industrial activities can contribute to heavy metal pollution in a specific area.

OBJECTIVE

1) To explore the concentrations of heavy metals in urine samples of pregnant women, and 2) to evaluate the potential effect of different industrial activities in Tarragona (Spain).

METHODS

Urinary levels of four heavy metals (nickel (Ni), cadmium (Cd), mercury (Hg), and lead (Pb)) from 368 pregnant women recruited in the ECLIPSES study were analyzed. Home addresses and all the industries potentially releasing heavy metals were geo-referenced. Buffer zones were established within a 1.5, 3, and 5 km radius at the center of each industry. Subsequently, the number of participants living in and out of each buffer zone was recorded.

RESULTS

Urinary levels of Ni and Cd, but not those of Hg and Pb, were obviously increased in pregnant women living near most of the industrial sites. After adjustment for potential co-variates, only Cd showed notable differences according to the industrial activity. Compared to women living outside the buffer, Cd levels were increased in those living within 1.5 and 3 km of chemical industries, within 5 km of energy industries, within 1.5, 3, and 5 km of mineral industries, and within 3 and 5 km of metal processing industries.

CONCLUSION

Among the analyzed heavy metals, Cd showed an increasing trend in urinary concentrations in women living near chemical, energy, mineral, and metal processing industries. This study highlights the need to develop legislative measures to minimize Cd exposure, especially by sensitive populations. Moreover, additive or synergistic effects of co-exposure to other air pollutants should not be disregarded.

Seasonal influence on microplastics in the sediments of a non-perennial river - Noyyal, Tamil Nadu, India

Microplastic (MP) is a contaminant presently causing a significant environmental risk. The present study aims to extract, measure, and classify MP in sediment samples from two seasons (monsoon and summer) in Noyyal River, South India. Microplastic was separated from sediments using the Sediment Microplastic Isolation technique. Microplastics were detected in four forms: foams, films, fragments, and fibres. Dominant polymer types during monsoon are Polystyrene (29%), Polycarbonate (13%), Nylon (13%), and Ethylene Vinyl Acetate (13%). Throughout summer, Polystyrene (17%) was the prevalent polymer type, followed by Nylon (14%), Polycarbonate (11%), and Polyvinyl Chloride (9%). Scanning Electron Microscope (SEM) demonstrated that MPs exhibit diverse surface morphologies, including foamy, fibrous, and granular nature. It also shows tearing and fracturing of MPs and aging, indicating substantial summer degradation. Using Polymer Hazard Index (PHI) and Pollution Load Index (PLI), MP vulnerability in sediments indicates that despite lesser PLI, the MPs pose an extreme danger threat to the environment during the summer season compared to the monsoon. The study thus provides insight into the seasonal variation of MPs and their threat in Noyyal River sediments, which will aid in formulating guidelines for the minimization of MPs in river systems.

Application of Monte Carlo simulation for carcinogenic and non-carcinogenic risks assessment through multi-exposure pathways of heavy metals of river water and sediment, India

Heavy metal contamination has severe detrimental impacts on the entire river ecosystem's quality and causes potential risks to human health. An integrated approach comprising deterministic and probabilistic (Monte Carlo simulation) models with sensitivity analysis was adopted to determine heavy metals' chronic daily intake (CDI) and their associated health risks from the riverine ecosystem. Both carcinogenic and non-carcinogenic risks of water and sediment were estimated through multi-exposure pathways. The analytical results indicated that the concentration patterns of heavy metals in sediment (Fe > Mn > Sr > Zn > Cr > Cu > Cd) were slightly different and higher than in water (Fe > Zn > Cr > Sr > Mn > Cu > Cd). The potential carcinogenic risks of Cr and Cd in sediment (5.06E-02, 5.98E-04) were significantly (p < 0.05) higher than in water (9.08E-04, 8.97E-05). Moreover, 95th percentile values of total cancer risk (TCR) for sediment (1.80E-02, 3.37E-02) were about 22 and 143 times higher than those of water (8.10E-04, 2.36E-04) for adults and children, respectively. The analysis of non-carcinogenic risk revealed a significantly higher overall hazard index (OHI) for both sediment (adults: 1.26E+02, children: 1.11E+03) and water (adults: 3.26E+00, children: 9.85E+00) than the USEPA guidelines (OHI ≤ 1). The sensitivity analysis identified that the concentration of heavy metals was the most influencing input factor in health risk assessment. Based on the reasonable maximum exposure estimate (RME), the study will be advantageous for researchers, scientists, policymakers, and regulatory authorities to predict and manage human health risks.

Investigation and comparative analysis of ecological risk for heavy metals in sediment and surface water in east coast estuaries of India

The sediments and surface water from 8 stations each from Dhamara and Paradeep estuarine areas were sampled for investigation of heavy metals, Cd, Cu, Pb, Mn, Ni, Zn, Fe, and Cr contamination. The objective of the sediment and surface water characterization is to find the existing spatial and temporal intercorrelation. The sediment accumulation index (I_sed), enrichment index (I_En), ecological risk index (I_EcR) and probability heavy metals (p-HMI) reveal the contamination status with Mn, Ni, Zn, Cr, and Cu showing permissible (0 ≤ I_sed ≤ 1, I_En ˂ 2, I_EcR ≤ 150) to moderate (1 ≤ I_sed ≤ 2, 40 ≤ R_f ≤ 80) contamination. The p-HMI reflects the range from excellent (p-HMI = 14.89-14.54) to fair (p-HMI = 22.31-26.56) in off shore stations of the estuary. The spatial patterns of the heavy metals load index (I_HMc) along the coast lines indicate that the pollution hotspots are progressively divulged to trace metals pollution over time. Heavy metal source analysis coupled with correlation analysis and principal component analysis (PCA) was used as a data reduction technique, which reveals that the heavy metal pollution in marine coastline might originate from redox reactions (FeMn coupling) and anthropogenic sources.

Contamination and health risks of heavy metals in the soil of a historical landfill in northern China

Landfill-induced heavy metal (HM) contamination of soils is a widespread and complex problem. The levels and potential hazards of HM contamination in landfills must be evaluated before they can be reused for any purpose. In order to reuse a historical landfill in northern China, 376 sampling sites were selected in 2019 using the checkerboard layout method, and the levels of arsenic (As), mercury (Hg), antimony (Sb), copper (Cu), lead (Pb), cadmium (Cd), nickel (Ni), zinc (Zn), and thallium (Tl) in the soil were measured. Multiple evaluation methods established the HM pollution levels, agricultural suitability, and health risks associated with the sampling sites. In most parts of the study area, the concentrations of all nine HMs exceeded the screening levels and maximum allowable concentrations for agricultural soils. Only the soils in Zones 5 and 6 can be used for agricultural activity. Moreover, the deep soils were heavily contaminated with HMs in certain areas, possibly because of leaching and infiltration in the surface soil and the rise and diffusion of polluted groundwater. The soil HMs in the study area posed a higher carcinogenic risks to both adults and children. The average carcinogenic risk associated with As was 6.12 × 10^-4, which was the major contributor to carcinogenic risk at all HM-contaminated sites. The results of this work empirically demonstrated that soil HM pollution is severe and problematic in the study area and remedial measures are urgently required.

Preliminary investigation of saline water intrusion (SWI) and submarine groundwater discharge (SGD) along the south-eastern coast of Andhra Pradesh, India, using groundwater dynamics, sea surface temperature and field water quality anomalies

Intensive anthropogenic activities along the coastal plains of Andhra Pradesh (such as urbanisation, agriculture and aquaculture) rely extensively on coastal fresh groundwater resources that are pumped at unsustainable rates causing groundwater decline and water quality problems due to saline water intrusion. Hydrogeological studies are imperative to implement groundwater conservation strategies in coastal Andhra Pradesh, which is experiencing a severe freshwater shortage due to overexploitation and saline water intrusion as well as clean water loss through the aquifer system close to the coastal plains. An attempt is made in this study to demarcate the submarine groundwater discharge (SGD) and saline water intrusion (SWI) zones adopting a three-tier validation system, i.e. groundwater dynamic, LANDSAT resultant sea surface temperature (SST) variance and site-specific water characteristics along the southeast coast of Andhra Pradesh, India. A total of 234 water samples (139 porewater, 31 groundwater and 64 seawater samples) were evaluated along ~ 450 km southeast coastline of Andhra Pradesh. In situ porewater physio-chemical parameters, i.e. EC, TDS, pH, DO, temperature, and salinity, at every 1 km except non-accessible areas and groundwater for every 5 km were analysed and used for identification of SGD zones in the study area. The hydraulic gradient values vary from - 11 to 250 m in post-monsoon and - 14 to 250 m in pre-monsoon. And sea surface temperature anomaly for 2017, 2018 and 2019 varies between 21-39 °C, 15-34 °C and 20-39 °C. Three districts out of the four districts studied (Krishna, Guntur and Nellore) were shown to be prone to SWI, whereas Prakasam district was susceptible for SGD. For the first time, this kind of preliminary study was carried out in the coastal Andhra Pradesh region, and it will serve as a basis for the meticulous analysis of the fresh and saline water mixing zones/process as well as to develop and manage the groundwater resources along the water-stressed coastal plains of Andhra Pradesh, India.

Monsoon Effect on Heavy Metal and Chemical Composition in Parastromateus niger of the Oman Sea: Health Risk Assessment of Fish Consumption

This study aimed to evaluate the bioaccumulation of heavy metals (copper, zinc, and lead) and chemical compositions (fat, protein, moisture, and ash) in the Parastromateus niger muscle of the Oman Sea in pre-monsoon and post-monsoon. An atomic absorption spectrophotometer was used to determine heavy metal concentrations in fish muscle tissue. Chemical composition contents were measured using the Association of Official Analytical Chemists (AOAC) methods. Zinc was the most abundant heavy metal in two seasons (0.077 ± 0.005 μg/g), followed by copper (0.033 ± 0.005 μg/g) and lead (0.015 ± 0.005 μg/g). The mean concentrations of all heavy metals of muscle in pre-monsoon were higher than in post-monsoon. The concentrations of Cu, Zn, and Pb were lower than the maximum permissible limits (MPL) of international standards for human consumption established by FAO, FAO/WHO, WHO, and MAFF. The protein and fat content in fish muscle collected in pre-monsoon was higher than in post-monsoon. A significant difference between protein, fat, moisture, and ash values was recorded in two seasons (P < 0.05). The human health risk of heavy metals was evaluated according to the United States Environmental Protection Agency (USEPA) standards. The estimated daily intake (EDI) of each heavy metal in two seasons was lower than the tolerable daily intake (TDI). THQ (target hazard quotient) and TTHQ (total target hazard quotient) values were lower than the threshold limit of 1.0, indicating a non-carcinogenic risk for consumers. TR (target carcinogenic risk) value for Pb was much lower than the unacceptable risk level (10^-4); therefore, the consumption of muscles of Parastromateus niger did not significantly pose a human health risk.

Receptor model-oriented sources and risks evaluation of metals in sediments of an industrial affected riverine system in Bangladesh

Toxic metals in river sediments may represent significant ecological concerns, although there has been limited research on the source-oriented ecological hazards of metals in sediments. Surface sediments from an industrial affected Rupsa River were utilized in this study to conduct a complete investigation of toxic metals with source-specific ecological risk assessment. The findings indicated that the average concentration of Ni, Cr, Cd, Zn, As, Cu, Mn and Pb were 50.60 ± 10.97, 53.41 ± 7.76, 3.25 ± 1.73, 147.76 ± 36.78, 6.41 ± 1.85, 59.78 ± 17.77, 832.43 ± 71.56 and 25.64 ± 7.98 mg/kg, respectively and Cd, Ni, Cu, Pb and Zn concentration were higher than average shale value. Based on sediment quality guidelines, the mean effective range median (ERM) quotient (1.29) and Mean probable effect level (PEL) quotient (2.18) showed medium-high contamination in sediment. Ecological indexes like toxic risk index (20.73), Nemerow integrated risk index (427.59) and potential ecological risk index (610.66) posed very high sediment pollution. The absolute principle component score-multiple linear regression (APCS-MLR) and positive matrix factorization (PMF) model indicated that Zn (64.21%), Cd (51.58%), Cu (67.32%) and Ni (58.49%) in APCS-MLR model whereas Zn (49.5%), Cd (52.7%), Cu (57.4%) and Ni (44.6%) in PMF model were derived from traffic emission, agricultural activities, industrial source and mixed sources. PMF model-based Nemerow integrated risk index (NIRI) reported that industrial emission posed considerable and high risks for 87.27% and 12.72% of sediment samples. This work will provide a model-based guidelines for identifying and assessing metal sources which would be suitable for mitigating future pollution hazards in Riverine sediments in Bangladesh.

Assessment of U and As in groundwater of India: A meta-analysis

More than 2.5 billion people depend upon groundwater worldwide for drinking, and giving quality water has become one of the great apprehensions of human culture. The contamination of Uranium (U) and Arsenic (As) in the groundwater of India is gaining global attention. The current review provides state-of-the-art groundwater contamination with U and As in different zones of India based on geology and soil texture. The average concentration of U in different zones of India was in the order: West Zone (41.07 μg/L) > North Zone (37.7 μg/L) > South Zone (13.5 μg/L)> Central Zone (7.4 μg/L) > East Zone (5.7 μg/L) >Southeast Zone (2.4 μg/L). The average concentration of As in groundwater of India is in the order: South Zone (369.7 μg/L)>Central Zone (260.4 μg/L)>North Zone (67.7 μg/L)>East Zone (60.3 μg/L)>North-east zone (9.78 μg/L)>West zone (4.14 μg/L). The highest concentration of U and As were found in quaternary sediments, but U in clay skeletal and As in loamy skeletal. Results of health risk assessment showed that the average health quotient of U in groundwater for children and adults was less than unity. In contrast, it was greater than unity for As posing a harmful impact on human health. This review provides the baseline data regarding the U and As contamination status in groundwater of India, and appropriate, effective control measures need to be taken to control this problem.

β-Cyclodextrin/CMK-8-Based Electrochemical Sensor for Sensitive Detection of Cu2

In this work, β-cyclodextrin (β-CD)/mesoporous carbon (CMK-8) nanocomposite was synthesized and used as an electrochemical sensing platform for highly sensitive and selective detection of Cu2+. The morphology and structure of β-CD/CMK-8 were characterized by scanning electron microscope (SEM) and X-ray diffraction (XRD). In addition, the dates from electrochemical impedance spectroscopy (EIS) and Cyclic voltammetry (CV) demonstrated that the β-CD/CMK-8 possessed a fast electronic transfer rate and large effective surface area. Besides this, the β-CD/CMK-8 composite displayed high enrichment ability toward Cu2+. As a result of these impressive features, the β-CD/CMK-8 modified electrode provided a wide linear response ranging from 0.1 ng·L-1 to 1.0 mg·L-1 with a low detection limit of 0.3 ng·L-1. Furthermore, the repeatability, reproducibility and selectivity of β-CD/CMK-8 towards Cu2+ were commendable. The sensor could be used to detect Cu2+ in real samples. All in all, this work proposes a simple and sensitive method for Cu2+ detection, which provides a reference for the subsequent detection of HMIs.

Water quality evaluation and ecological-health risk assessment on trace elements in surface water of the northeastern Qinghai-Tibet Plateau

The Qinghai-Tibet Plateau is a unique area with water sources for approximately 40 % of the population in the world. Water resources and water quality are closely associated with ecological security and human health. Fifty-one trace elements in surface water samples (n = 40) were measured, and water quality, health and ecological risks were assessed. Trace elements showed significant variations in different surface water bodies in the study area. Concentrations of minor elements were relatively high in saline and salt lakes while those of REEs varied from 0.05 to 33.62 μg/L with an average value of 3.80 μg/L. The Nemerow pollution index (NP) values of trace elements ranged from 0.08 to 3.48, with an average value of 0.36 in rivers, fresh lakes and reservoir water samples; The heavy metal pollution index (HPI) values ranged from 3.70 to 21.18, indicating that most samples were within the critical limit; The heavy metal evaluation index (HEI) values and degree of contamination (DC) values indicated a free pollution status. The water quality index (WQI) values showed that 96 % of the samples belonged to excellent status in rivers, fresh lakes and reservoir water samples. More attention should be given to the Cr, Zn and Hg in the study area according to potential ecological risk assessment. Hazard quotients for residential children in 30 sites exceed 1.0 with maximal value of 10.97, suggesting the high non-carcinogenic risks for children in the study area. U, Zr and Cr for the ingestion pathway, Cr and U for the dermal pathway were primary contributors to the total health risk. Carcinogenic risk values of trace elements for residential and recreational receptors were in the range of 3.20 × 10^-5-7.38 × 10^-3 and 8.62 × 10^-6-3.63 × 10^-3, respectively. The carcinogenic risk values of Cr in surface water were higher than the target risk of 1 × 10^-4, while the carcinogenic risk values of As were below the target risk. The results of this study provided information on trace elements for human health protection and water management in the northeastern Qinghai-Tibet Plateau.

Pollution simulation and remediation strategy of a zinc smelting site based on multi-source information

Contaminated sites pose a significant risk to human health and the regional environment. A comprehensive study was dedicated to improving the understanding of the contamination condition of a smelting site by integrating multi-source information through 3D visualization techniques. The results showed that 3D visualization reveals excellent potential for application in the environmental studies to finely depict contamination in soils and establish relationships with geological features, hydrological conditions, and sources of contamination. The contamination plume model revealed that the soil environment at the site was seriously threatened by toxic metals, and dominated by multi-metal contamination, with contamination soil volume ranked as Cd > As > Pb> Zn > Hg. The stratigraphic model revealed the heterogeneous geological conditions of the site and identified the mixed fill layer as the primary remediation soil layer. The permeability model revealed that soil permeability significantly influenced contamination dispersion and contributed to delineate the contamination boundary accurately. The ecological hazard model targeted the high ecological hazard area and determined the high hazard contribution of Cd and Hg in the site soil. The outcomes can be directly applied to actual site remediation and provide a reference for the contaminated sites evaluation and restoration in the future.

Effect of elemental composition assigned to antrotopic pollution on the quality of the water and sediment of the Marrecas river (PR, Brazil) as highlighted by multivariate statistical analyses

In recent years, several environmental pollutants have been monitored in surface waters and sediments. However, few studies apply multivariate statistics to identify the main components and correlate them temporally and spatially. In this sense, the present study sought to monitor the quality of water and sediments in the Rio Marrecas/Brazil, through the analysis of physicochemical parameters and trace elements, as well as to identifying sources of contamination, using multivariate statistics. For this purpose, sampling was carried out in nine locations for a period of 12 months. The Total Reflection X-ray Fluorescence (TXRF) technique was used to quantify the 15 elements identified in water and sediment samples. Through multivariate statistical analyses, the most significant elements, their correlations and possible pollutant sources were defined, and the pollution index (HPI) and assessment index (HEI) of heavy metals were applied. The parameters pH and BOD₅ do not comply with Brazilian legislation. Based on PCA and Spearman correlation, there was strong evidence of contamination of the water naturally, composed of the elements Ti, V, Mn, Fe, and of anthropogenic origin composed of the elements Ca, Ni, Cu, Zn. These findings provide insights to determine the impacts of heavy metals on human health and the environment.