Multivariate statistical assessment of heavy metal pollution sources of groundwater around a lead and zinc plant

Assessment of potentially toxic elements in groundwater through interpolation, pollution indices, and chemometric techniques in Dehradun in Uttarakhand State

Providing safe drinking water for the entire world's population is essential for ensuring sustainable development. The presence of harmful compounds in aquifers, majorly toxic elements, is a serious environmental concern around the globe. This research aimed to quantify for the initial period the amounts of toxic elements in freshwater in the Dehradun Industrial Region of Uttrakhand, India, as well as the associated health risks. The PTEs (potentially toxic elements) Fe, Cd, Mn, Cu, Cr and Pb, Zn, Ni is measured by AAS and compared to BIS and WHO requirements for drinking safety. The order of mean trace element values in all groundwater samples were determined as Fe > Zn > Cu > Ni > Co > Cd > Pb. HPI was discovered to be higher than high class during the research period (HPI > 30), but under the severe contamination criterion of 100. Iron's MI and PI values were consistently over the threshold limit during the research period, and certain toxic elements were discovered exceptionally near the threshold limit, indicating a severe future influence on groundwater quality. According to PCA (principal component analysis), CM (correlation matrix), and potential health hazard, maximum levels of toxic elements in groundwater in the Dehradun region are attributed to land use patterns, anthropogenic activity, industrial activity, fertilizer and pesticide leaching, and residential waste into the aquifer system. The findings of this study could aid local planners and policymakers in preventing health risks from contaminated aquifers through the deployment of suitable monitoring and mitigation measures.

Groundwater quality and human health risk assessment in selected coastal and floodplain areas of Bangladesh

Groundwater aquifers are a common source of drinking water in Bangladesh. However, groundwater contamination is a major public health concern across the country. This research aims to examine the groundwater quality and health concerns using a random sampling process. Multivariate statistical and health risk analyses of elements were performed to determine the source of contaminants and their effects on human health. A total of 24 parameters were analyzed, where Na⁺, NH₄⁺, K⁺, Mg²⁺, F^-, NO₃^-, Mn, Fe, Se, U, and As concentrations were found to be high in different sampling points compared to the Department of Environment of Bangladesh (DoE), and the World Health Organization (WHO) groundwater quality standards. Principal Component Analysis (PCA) and Cluster Analysis (CA) identified the dominant and potential sources of contaminants in the groundwater aquifer, including geogenic, salinity intrusion, industrial, and agricultural. The results of the degree of contamination level (C_d) and the heavy metal pollution index (HPI) showed that 28% and 12% of the sampling points had high levels of heavy metal contamination, indicating a high risk for human health issues. Cr concentrations were found to have a higher carcinogenic (cancer) risk than As and Cd concentrations. Hazard quotient (HQ) and hazard index (HI) scores expressed the hazardous status and possible chronic effects in the context of individual sampling points. For both child and adults, 44% and 36% of the sampling points had a high HI score, indicating the possibility of long-term health risks for local populations.

In Situ Measurements of Domestic Water Quality and Health Risks by Elevated Concentration of Heavy Metals and Metalloids Using Monte Carlo and MLGI Methods

The domestic water (DW) quality of an island province in the Philippines that experienced two major mining disasters in the 1990s was assessed and evaluated in 2021 utilizing the heavy metals pollution index (MPI), Nemerow’s pollution index (NPI), and the total carcinogenic risk (TCR) index. The island province sources its DW supply from groundwater (GW), surface water (SW), tap water (TP), and water refilling stations (WRS). This DW supply is used for drinking and cooking by the population. In situ analyses were carried out using an Olympus Vanta X-ray fluorescence spectrometer (XRF) and Accusensing Metals Analysis System (MAS) G1 and the target heavy metals and metalloids (HMM) were arsenic (As), barium (Ba), copper (Cu), iron (Fe), lead (Pb), manganese (Mn), nickel (Ni), and zinc (Zn). The carcinogenic risk was evaluated using the Monte Carlo (MC) method while a machine learning geostatistical interpolation (MLGI) technique was employed to create spatial maps of the metal concentrations and health risk indices. The MPI values calculated at all sampling locations for all water samples indicated a high pollution. Additionally, the NPI values computed at all sampling locations for all DW samples were categorized as “highly polluted”. The results showed that the health quotient indices (HQI) for As and Pb were significantly greater than 1 in all water sources, indicating a probable significant health risk (HR) to the population of the island province. Additionally, As exhibited the highest carcinogenic risk (CR), which was observed in TW samples. This accounted for 89.7% of the total CR observed in TW. Furthermore, all sampling locations exceeded the recommended maximum threshold level of 1.0 × 10⁻⁴ by the USEPA. Spatial distribution maps of the contaminant concentrations and health risks provide valuable information to households and guide local government units as well as regional and national agencies in developing strategic interventions to improve DW quality in the island province.

Various Natural and Anthropogenic Factors Responsible for Water Quality Degradation: A Review

Recognition of sustainability issues around water resource consumption is gaining traction under global warming and land utilization complexities. These concerns increase the challenge of gaining an appropriate comprehension of the anthropogenic activities and natural processes, as well as how they influence the quality of surface water and groundwater systems. The characteristics of water resources cause difficulties in the comprehensive assessment regarding the source types, pathways, and pollutants behaviors. As the behavior and prediction of widely known contaminants in the water resources remain challenging, some new issues have developed regarding heavy metal pollutants. The main aim of this review is to focus on certain essential pollutants’ discharge from anthropogenic activities categorized based on land-use sectors such as industrial applications (solid/liquid wastes, chemical compounds, mining activities, spills, and leaks), urban development (municipal wastes, land use practices, and others), and agricultural practices (pesticides and fertilizers). Further, important pollutants released from natural processes classified based on climate change, natural disasters, geological factors, soil/matrix, and hyporheic exchange in the aquatic environment, are also discussed. Moreover, this study addresses the major inorganic substances (nitrogen, fluoride, and heavy metals concentrations). This study also emphasizes the necessity of transdisciplinary research and cross-border communication to achieve sustainable water quality using sound science, adaptable legislation, and management systems.

Heavy metals pollution indexing, geospatial and statistical approaches of groundwater within Challawa and Sharada industrial areas, Kano City, North-Western Nigeria

Abstract

The present study focused on pollution status of groundwater in the industrial areas of Challawa and Sharada in Kano city based on pollution indices, statistical and spatial analyses. Twenty groundwater samples representing groundwater of the studied areas (Ten from each area) were analyzed for the presence of Cd, Cr, Ni, Fe, Mn and Zn using atomic absorption spectrophotometer. The result showed 95%, 5%, 60%, 15% and 25% of the analyzed water samples had detectable Cd, Cr, Ni, Fe, and Mn above the drinking water limits of both Nigerian standards for drinking water quality NSDWQ and World Health Organization (WHO) with Cd dominating other analyzed heavy metals in the groundwater. Evaluation of heavy metal pollution revealed a low polluted status based on the contaminant index (Cd), synthetic pollution index, heavy metals evaluation index, and heavy metal pollution index. Metal index categorized the groundwater as seriously polluted. The statistical evaluation gave strong and positive correlations between indices and a moderate one between the metallic ions. Component analysis revealed a strongly positive loading of Fe, Ni and Zn while Cd had a strong negative loading. Cr and Mn were positive and moderately loaded. Statistical analyses suggested both anthropogenic and geogenic sources for the heavy metals mainly from the industrial and agricultural practices and rock weathering processes, respectively. This study is expected to be a useful tool in the planning, monitoring and mitigation of pollution activities in the area.

Article Highlights

Nanostructured micro particles as a low-cost and sustainable catalyst in the recycling of PET fiber waste by the glycolysis method

Magnetic Mg-Al-O@Fe₃O₄ micro particles were synthesized by coating nanosized Mg-Al double oxides onto Fe₃O₄ micro particles. The formed hierarchical structure gave Mg-Al-O@Fe₃O₄ micro particles a high active surface area, which enabled these micro particles to work efficiently as a catalyst in the glycolysis of poly(ethylene terephthalate) (PET). The bis(hydroxyethyl) terephthalate (BHET) yield reached above 80 mol% in the presence of 0.5 wt% of Mg-Al-O@Fe₃O₄ micro catalyst in the reaction system within 90 min at 240 °C. After the reaction, Mg-Al-O@Fe₃O₄ micro catalyst was easily retrieved by a magnetic decantation and can be repetitively used for two times with a high catalytic efficiency. After that, the deactivated Mg-Al-O@Fe₃O₄ micro catalyst can be regenerated by heat treatment. The regenerated Mg-Al-O@Fe₃O₄ micro catalyst displays a comparable catalytic performance as that of the virgin catalyst. In addition, the Mg-Al double oxides and Fe₃O₄ micro particles are low-cost and environmentally benign. Therefore, the Mg-Al-O@Fe₃O₄ micro catalyst may contribute to an economically and environmentally improved large-scale circular recycling of PET fiber waste.

Irrigation water quality and its impact on the physicochemical and microbiological contamination of vegetables produced from market gardening: a case of the Vea Irrigation Dam, U.E.R., Ghana

The rationale for this study was to assess the physicochemical and bacteriological qualities of the Vea irrigation water and resultant effects on the quality of fresh vegetables produced in the area and associated implications for consumers' health. A total of 45 water samples were collected from the reservoir and canals. Also, 16 vegetable samples comprising four samples each of tomatoes, carrots, spring onions, and cabbages were collected from four farms with installed irrigation systems fed by the Vea Dam. The irrigation water samples were analyzed for total coliform (TC) and fecal coliform (FC), Escherichia coli, pH, and turbidity, while the samples of vegetables were analyzed for TC and FC, and E. coli. The results showed that except for pH, the bacterial loads and turbidity of the sampled vegetables and irrigation water were above the standards of the WHO and the International Commission on Microbiological Specifications for Food. Comparatively, the samples of cabbage recorded the highest levels of microbial contamination. The study suggests that the water should be treated before being used for irrigation; consumers should ensure that vegetables are properly washed and cooked/treated before consumption; and periodic monitoring and assessment should be done to ensure that the adverse effects of these activities are forestalled.

Heavy metals and arsenic content in water along the southern Caspian coasts in Iran

Due to the importance of pollution monitoring in marine ecosystems and lack of a coherent and systematic investigation of heavy metal ions along the southern shores of the Caspian Sea, in the present study, the amount of these metals and As ions in coastal waters along its 780-km-long coast in Iran have been studied. Heavy metals (cobalt, nickel, copper, zinc, cadmium, mercury, lead) and a poisonous metalloid (arsenic) were selected in 59 sampling stations and determined using differential pulse polarography method. The multivariate statistical tools were applied to describe and interpret the experimental data. The overall mean concentrations of studied metals (in microgram per liter; μg L^-1) in the samples were found in the order Zn (10.9) > Ni (7.4) > Cu (5.5) > Pb (1.9) > Hg (1.4) > As (1.3) > Co (1.1) > Cd (0.2). The results when compared with reported international standards confirmed that the sampled waters do contain some of these elements above the suggested maximum permissible limits. Hg and Cu were detected in 54.2 and 72.9% of the samples, almost all above the permissible limits. Ni, Zn, Pb, and Co were detected in 100, 96.6, 93.2, and 88.1%, respectively, while 8.5, 22.0, 3.4, and 1.7% were above the permissible limits. Cd and As were present in 61 and 93% of the samples, and their concentrations were higher than the rate presented by Russian System of Management Chemicals (RSMC). In addition, spatial distribution of heavy metal concentrations showed that Gorgan Bay is an ecosystem serving as a filter, trapping natural and anthropogenic materials that are brought from industrial, commercial, and urbanized areas. The multivariate data analysis reveals that Caspian Sea is contaminated by both anthropogenic as well as pedo-geochemical sources.

Potential of polyaniline modified clay nanocomposite as a selective decontamination adsorbent for Pb(II) ions from contaminated waters; kinetics and thermodynamic study

BACKGROUND

Nowadays significant attention is to nanocomposite compounds in water cleaning. In this article the synthesis and characterization of conductive polyaniline/clay (PANI/clay) as a hybrid nanocomposite with extended chain conformation and its application for water purification are presented.

METHODS

Clay samples were obtained from the central plain of Abhar region, Abhar, Zanjan Province, Iran. Clay was dried and sieved before used as adsorbent. The conductive polyaniline was inflicted into the layers of clay to fabricate a hybrid material. The structural properties of the fabricated nanocomposite are studied by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR) and scanning electron microscope (SEM). The elimination process of Pb(II) and Cd(II) ions from synthetics aqueous phase on the surface of PANI/clay as adsorbent were evaluated in batch experiments. Flame atomic absorption instrument spectrophotometer was used for determination of the studied ions concentration. Consequence change of the pH and initial metal amount in aqueous solution, the procedure time and the used adsorbent dose as the effective parameters on the removal efficiency was investigated.

RESULTS

Surface characterization was exhibited that the clay layers were flaked in the hybrid nanocomposite. The results show that what happen when a nanocomposite polyaniline chain is inserted between the clay layers. The adsorption of ions confirmed a pH dependency procedure and a maximum removal value was seen at pH 5.0. The adsorption isotherm and the kinetics of the adsorption processes were described by Temkin model and pseudo-second-order equation. Time of procedure, pH and initial ion amount have a severe effect on adsorption efficiency of PANI/clay.

CONCLUSIONS

By using suggested synthesise method, nano-composite as the adsorbent simply will be prepared. The prepared PANI/clay showed excellent adsorption capability for decontamination of Pb ions from contaminated water. Both of suggested synthesise and removal methods are affordable techniques.

Human nail usage as a Bio-indicator in contamination monitoring of heavy metals in Dizajabaad, Zanjan province-Iran

BACKGROUND

Due to pedogeochemical background and anthropogenic sources, heavy metal contamination of soil is a widespread problem in some parts of Zanjan province located in North West Iran. In this study an affected area located near National Iranian Lead and Zinc Company (NILZ) was selected for detailed study.

METHODOLOGY

Thirty soil samples and eighteen leaf samples were collected and analyzed for heavy metal contamination by Inductively Coupled Plasma-Optical Emission Spectroscopy (ICP-OES). Both soil and plant samples were found to be basically polluted by Pb (72.60 and 97.11), Zn (546.47 and 166.61), and Cd (1.80 and 1.55) mg. kg(-1) respectively. High concentrations of these elements in soil and plant species signifies possible health risks to humans. The distribution maps drawn using Arc GIS (10) show high concentrations of these toxic metals around Dizajabaad village. To assess vulnerability and health risks of metal concentrations in human bodies' twenty nine fingernail samples were also collected from people living in this village.

RESULTS AND DISCUSSION

Analysis for different heavy metal contents of nail samples reveals very high levels of the same toxic elements (Pb = 15.15, Cd = 1.18, As = 15.47, Zn = 68.46 and Ni = 18.22 mg. kg(-1)) compared with samples collected from an unaffected area and available values indicated in the literature. Further, high concentration of heavy metals in the nail samples suggests long term exposure of inhabitants to these toxic metals.

Spatial distribution, temporal variation, and sources of heavy metal pollution in groundwater of a century-old nonferrous metal mining and smelting area in China

This study first presents the spatial distribution, temporal variation, and sources of heavy metal pollution in groundwater of a nonferrous metal mine area in China. Unconfined groundwater was polluted by Pb, Zn, As, and Cu, in order, while confined karst water in the mines showed pollution in the following sequence: Zn, Cd, Cu, Pb, and As. Pollution by Pb was widespread, while Zn, As, Cu, and Cd were found to be high in the north-central industrial region and to decrease gradually with distance from smelters and tailings. Vertically, more Pb, Zn, Cu, and Cd have accumulated in shallow Quaternary groundwater, while more As have migrated into the deeper fracture groundwater in the local discharge area. Zn, Cd, and Cu concentrations in groundwater along the riverside diminished owing to reduced wastewater drainage since 1977, while samples in the confluence area were found to have increasing contents of Pb, Zn, As, Cu, and Cd since industrialization began in the 1990s. Sources of heavy metals in groundwater were of anthropogenic origin except for Cr. Pb originated primarily from airborne volatile particulates, wastewater, and waste residues and deposited continuously, while Zn, Cd, and Cu were derived from the wastewater of smelters and leakage of tailings, which corresponded to the related soil and surface residue researches. Elevated As values around factories might be the result of chemical reactions. Flow patterns in different hydrogeological units and adsorption capability of from Quaternary sediments restricted their cross-border diffusion.

Real and simulated bioavailability of lead in contaminated and uncontaminated soils

BACKGROUND

Lead (Pb) is a toxic element that occurs in elevated concentrations in soils, mostly as a result of anthropogenic activities. This study assess the Pb bioavailability in soils from two areas with different contamination level using Diffusive Gradients in Thin-Films (DGT) technique, single extractions and metal contents of vegetables grown on contaminated soils.

RESULTS

In the area situated far from mining and smelting activities, the pseudo total Pb concentration (12 - 51 mg kg(-1) dw) was found to be comparable to that normally found in unpolluted areas. In the area from the vicinity of the Pb smelter very high concentrations of pseudo-total Pb (850 - 9300 mg kg(-1) dw) were found. The average concentrations of Pb accumulated in onion, garlic, carrot, and parsley grown on this contaminated soils were 18, 48, 38 and 91 mg kg(-1) dw, respectively, and represent a risk factor for the consumers.

CONCLUSIONS

The present study demonstrates the utility of DGT technique for the assessment of Pb bioavailability, since, generally, better correlations are obtained between the effective Pb concentration and Pb concentration in vegetables than for bioavailable Pb determined by chemical extractions and Pb concentration in vegetables.