Metals In Water Resources Research Articles

Cellulose-based homogeneous method for suppressing coffee ring effect of cadmium detection in water using laser-induced breakdown spectroscopy

Heavy metal pollution has a negative impact on water resources and poses a threat to crop safety and human health through biogeochemical cycles. To detect heavy metals in water, the dried droplet method (DDM) combined with laser-induced breakdown spectroscopy (LIBS) is commonly used. However, the uneven distribution of heavy metals caused by the coffee ring effect (CRE) can adversely affect the intensity and stability of the detection signal. In this study, the cellulose-based homogeneous method (CHM) was proposed to suppress CRE, ensure a uniform distribution of heavy metal (represented by Cadmium (Cd) in experiments) on the liquid-solid conversion deposition layer, and enhance the detection signal. A rapidly evaluated approach was developed using LIBS to visualize the homogeneity of Cd distribution on the deposition layer, which could also determine the type and concentration of cellulose. Furthermore, a comprehensive investigation of the mechanism was conducted from the perspective of fluid dynamics. The use of CHM resulted in a 94.81 % increase in signal average intensity and reduced the relative standard deviation (RSD) to 0.13 times. The R2 value achieved 0.997, and the limit of detection (LOD) reached 0.029 mg/L. CHM was validated using natural lake water samples spiked with a standard Cd solution resulting in a recovery rate ranging from 105.3 % to 109.06 %. The proposed method exhibits great potential to detect heavy metals in water resources, industrial wastewater, and agricultural water to assess water quality and water security.

Performances Study of Polyvinylidene Fluoride (PVDF)/Waste Eggshell (WES) Mixed-Matrix Membrane for Copper Removal

The presence of heavy metals in water resources brings hazard to health and the environment considering that most of these cannot be degraded and may result in bioaccumulation in the food chain. This study investigated the applicability and efficiency of waste eggshells for the removal of Copper (Cu) heavy metal in aqueous solution. The mixed-matrix membrane with polyvinylidene fluoride (PVDF) as membrane material, N-Methyl-2-pyrrolidone (NMP) as solvent and waste eggshell as additive with ratio of (a) 15:85:0, (b) 14.9:85:0.1, (c) 14.7:85:0.3, (d) 14.5:85:0.5 and (e) 14:85:1 is fabricated using phase inversion method. Phase inversion is a well-studied immersion precipitation technique for membrane synthesis. Using this common method, polymer is dissolved in an organic solvent and the solution cast upon a glass surface with 0.40 knife gap. The resulting membrane morphologies were analysed by using Scanning Electron Microscopy (SEM) and the significant functional group of the resulting membranes were identified using Fourier Transform Infrared Spectroscopy (FTIR). The addition of waste eggshell to the casting solution improved the morphology and structure of the membrane significantly. The appearance of waste eggshell on membrane surface demonstrated in SEM and FTIR analysis. Furthermore, the result of the study showed that the waste eggshells as an adsorbent could remove Cu in an aqueous solution up to 99% with water permeability of 56.52 Lm-2h-1bar-1. Overall, the study demonstrated that the waste eggshell that is generally considered as wastes in large quantities could become an economically advantageous for Cu removal.

Evaluation of phthalic acid tri-ethylene diamine (TED) and folic acid-based carbon quantum dots for the detection of heavy metals in water resources using fibre-optic instrumentation

ABSTRACT Heavy metal pollution and toxicity from water resources have remained a great concern for the entire population. This research demonstrates the capability of carbon quantum dots (CQDs) for fluorescence-based heavy metal detection in different water resources using a fibre-optic spectrometer device. Two different types of CQDs phthalic acid and triethylenediamine (PT CQDs) and Folic acid (FCQDs) were synthesized using microwave irradiation and hydrothermal method, respectively. CQDs were characterized using several techniques such as TEM, EDX, XPS and FTIR. PTCQD and FCQDs both were tested for sensing capability in water reservoirs like household and river water. The results indicate that both CQDs were able to detect all six heavy metal ions (Pb2+, Co2+, Mn3+, Hg2+, Ni2+, Cr3+) tested in the study in the range of 0–100 µM. It was found that FCQDs show a three-fold higher sensitivity and greater resolution than PTCQDs for all the heavy metals samples. The CQDs’ sensing capability shows that they can achieve a limit of detection in the range of 0.15–3 µM along with 100% accuracy in terms of recovery with minimal error, these results indicate that both CQDs have a tremendous potential to be used as a sensor for the detection of heavy metals even in complex water matrices. FCQDs show more sensitivity for all metals compared to PTCQDs and used in future as a sensing tool for heavy metal detection with better sensitivity and accuracy with less response time.

Heavy metal pollution in groundwater of urban Delhi environs: Pollution indices and health risk assessment

The excess presence of heavy metals in water resources deteriorates the quality and has a high potential for bioaccumulation and environmental contamination. The study of heavy metals in water is essential because of their integration in the food chain and the potential for sublethal effects on aquatic and human life. To understand the extent of heavy metal pollution, a total of 64 groundwater samples (32 in each pre-and post-monsoon season) were collected around the Yamuna River's flood plains in the Delhi region. In this study, pollution indices and health risk assessment methodologies were used to estimate the significant threat to humans. In examined seasons, the sequence of heavy metal content in groundwater is Fe > Mn > Zn > B > As>Ni > Pb. The heavy metal pollution index (HPI) revealed that in the pre-and post-monsoon seasons, 53% and 44% (HPI >100), of groundwater samples are at high-risk zone respectively. 53% of pre-monsoon and 56% of post-monsoon samples were found highly polluted, according to the degree of contamination (Cd). Moreover, health risk assessment shows that hazard index (HI) values for heavy metals were found significantly high (HI >1) in groundwater samples inferring increased non-cancerous risk to the local community. The results imply that continuous exposure can lead to chronic diseases in the population residing in the study region. In both carcinogenic and non-carcinogenic assessments, children's hazard index and carcinogenic risk assessment (CR) scores were found higher. As a result, compared to adults in the study region, children are more vulnerable to potential health threats. The principal component analysis (PCA) method was used to figure out the origin of heavy metals, and it was found that As, Fe, Mn, and Zn come from non-anthropogenic sources, whereas mixed sources (natural and anthropogenic) may be responsible for B, Ni, and Pb presence. The results of the study will help to develop an effective strategy for environmental assessment and monitoring to control groundwater pollution of the Delhi urban environs.

Carcinogenic and Non-Carcinogenic Risk Assessment of Heavy Metals in Water Resources of North East of Iran in 2018

Introduction: Contamination of water with heavy metals has turned into a health concern, particularly in the developing countries. In this study, concentration of heavy metals and associated carcinogenic and non- carcinogenic risk was investigated in water samples collected from Gonbad-e Kavus, a high-risk area for cancer. Materials and Methods: Samples were collected from Gorgan River, Golestan reservoir and wells around villages with high prevalence in 2018. Samples were analysed through inductively coupled plasma mass spectrometry. After determining the concentration of heavy metals in water samples from different sources, health risk assessment was carried out according to the Environmental Protection Agency. Results: Arsenic in samples 6-9 was higher than 10 µg/L, calcium and magnesium in sample 5 was higher than 200 mg/L and 150 mg/L respectively, and sodium in all samples was higher than 50 mg/L. According to the findings, these concentrations were higher than the maximum allowed limit in most water samples. Hazard quotient (HQ) in samples 8 and 9 were associated with arsenic and health risk in sample 1 was related to antimony. Furthermore, since all samples contained high amounts of lithium, water from this area better should not be consumed by children older than one year. Conclusion: Given the high rate of arsenic contamination, consumption of water in the study area could be health threatening for all individuals and is not recommended for children. This highlights the need for taking immediate actions to review the water treatment process and ensure safety of the drinking water in this area.

A review on cleaner strategies for extraction of chitosan and its application in toxic pollutant removal

Existence of human beings in this world require a cleaner environment, in which, water is the main requirement for living. Owing to the considerable development in civilisation and considerable population explosion, an increase in the contamination of natural water resources by means of non-biodegradable contaminants like heavy metals is observed thereby increasing the need for treatment of water before usage. Despite the existence of specific limits for disposal of heavy metals in water resources, studies still show high contamination of heavy metals in all these water resources. This review provides a brief note on sources and toxicity of different heavy metals in various oxidation states, their effects as well as highlights the numerous available and advanced techniques for heavy metals removal. Of all techniques adsorption is found to be beneficial as it doesn't inculcate any secondary pollutants to the environment. Additionally, this article has investigated the advantages of polymer nanocomposites in adsorption and mainly focused on biopolymer chitosan owing to its abundance in natural environment. The cleaner techniques for the extraction of chitosan and its functionalisation using different types of nanofillers are comprehensively discussed in this review. This article suggests a better alternative for conventional adsorbents as well as aids in remediation of wastes.

Design of prescriptive model using nano-enabled sensors for water treatment and precise drip irrigation

Agriculture is one of the major sources of Indian economy where 60% of the population depend on it for survival. Due to increase in population size, water scarcity problem and pollutant water from industries directly affects economic growth in agriculture field. Over the past decade, many researchers have addressed this problem and provided solutions for water treatment and methodologies to effectively use water resources based on crop need. Most studies have only focused on effective water management practice and failed to remove water toxicants. Hence this paper seeks to address the removal of heavy metals in water resources using nano-sensors and proposed a prescriptive model to estimate the amount of resources like nutrients, fertilizers and water based on crop requirements. The proposed model is designed with the objective of implementation in irrigation areas to effectively remove toxicants from water resources and efficiently manage resources like nutrients, soil, fertilizers and water based on drip irrigation.

Assessment of water resources pollution associated with mining activity in a semi-arid region

Mining, although relevant and indispensable for human socioeconomic development, is considered one of the most polluting anthropogenic activities. Water resources are the most vulnerable environmental compartment to the direct impacts of mining, especially in the semi-arid regions. In these regions, mining activity constitutes an important challenge in the management of water resources; since its impacts can be maximized by the adverse meteorological conditions. This study aimed to assess the level of contamination in water resources of three important mining areas in a semi-arid region, where approximately 70,000 people live. The concentrations of eleven heavy metals in sediment, surface and groundwater samples were determined by ICP OES. The results obtained for water samples indicated significant contamination by Cd, Pb, and U, based on the limits established by Brazilian and international regulatory legislation. In the case of sediment samples, higher concentrations of Cr, Cu, Ni, and V were observed. Pollution indices (PLI, CF and Igeo) revealed moderate to extreme contamination mainly along the Jacaré and Contas rivers. The Pearson correlation, Principal Component, and Hierarchical Cluster analyses were performed to identify patterns in the distribution of elements and common sources of pollution. The results suggested that the concentrations of Co, Cr, Cu, Fe, Mn, Ni, and V were mainly related to mining activities and, to a lesser extent, natural sources. In the case of Cd and Pb, contamination may have an important contribution from fertilizers use, whereas Zn has a mixed source of both lithogenic and anthropogenic origin. On the other hand, the high concentrations of U, specifically in groundwater samples, were associated with geogenic causes. Although the potential ecological risk values indicated a low ecological risk; other sediment quality indices (TEL, PEL, ΣTU, and PEL-Q) revealed that there is 25% of the probability that the content of heavy metals in water resources near the mining areas induces adverse toxic effects on aquatic organisms.

Potential health risk and levels of heavy metals in water resources of lead\u2013zinc mining communities of Abakaliki, southeast Nigeria

Heavy metals are potential health risk, especially in mining sites where they deteriorate from sulfide-rich ore bodies. Lead, cadmium, arsenic and mercury are very carcinogenic, while others are toxic. The assessment of the levels of these metals in water resources of the lead–zinc mining communities of Enyigba, Mkpuma Akpatakpa, Ameka, Amorie, Amanchara and Alibaruhu was carried out, and the potential health risk has been investigated. These areas make up the main mining communities of Abakaliki, where active and abandoned mines are located. One hundred and six water samples were analyzed in two seasons using atomic absorption spectrophotometric and ultra-violet/visible spectroscopy. Result indicates levels of Pb2+ > Hg2+ > As2+ > Cd2+ > Mn2+ > Ag2+ > Se2+ > Ni2+ > Cr2+ > Cu2+ in water sources. High levels of Mn2+(63.45 mg/L), Pb2+(11.42 mg/L), Cr3+(14.60 mg/L), Ni2+(1.260), Cd2+(15.67 mg/L), Ag+(6.06 mg/L), Hg2+(2.60 mg/L), As(4.13 mg/L), Se2+(2.68 mg/L), Zn2+(10.53 mg/L) and Co2+(0.9 mg/L) above the WHO recommended standard for drinking water were observed. Only Cu2+ recorded safe concentrations in 100% samples analyzed. Levels of associated metals including Pb2+, As, Hg2+, Se2+ and Cd2+ are higher in groundwater especially in areas close to the active mines; this is due to mineralization in the area. Seasonal analysis shows a decreased concentration of chemical constituents in the rainy season relative to the dry season. Potential health risk is associated with accumulation of toxic heavy metals in tissues including Parkinson disease, arsenicosis, acrodynia, selenoises, Alzheimer’s disease, hair loss, mental imbalance and abortion in women abound in the areas. Alternative water supply sources and sensitization on the potential health risk are highly advocated in these communities.

Heavy metals occurrence, assessment and distribution in water resources of the lead–zinc mining areas of Abakaliki, Southeastern Nigeria

The assessment, occurrence and distribution of heavy metals in water resources of the lead–zinc mining areas of Abakaliki, Southeastern Nigeria, were carried out. Major communities including Enyigba, Mkpuma Akpatakpa, Ameka, Amorie, Amanchara and Alibaruhu where active and abandoned mines are located were assessed. This study compared the prevalence of these metals in the different mining communities. One hundred and six water samples were analyzed in two seasons using Atomic Absorption Spectrophotometer and Ultra-Violet/Visible Spectroscopy. Results were compared with World Health Organization Standard (WHO) for drinking water. Result indicates high concentrations with ranges: Mn2+ (63.45 mg/L), Pb2+ (11.42 mg/L), Cr3+ (14.60 mg/L), Ni2+ (1.260), Cd2+ (15.67 mg/L), Ag+ (6.06 mg/L), Hg2+ (2.60 mg/L), As (4.13 mg/L), Se2+ (2.68 mg/L), Zn2+ (10.53 mg/L), Co2+ (0.9 mg/L). These are above the WHO recommended standard for drinking water. Only Cu2+ and Se2+ recorded safe concentrations in 100% samples analyzed in both surface and groundwater in the rainy season. Percentage contamination shows Pb2+ > Hg2+ > As2+ > Cd2+ > Mn2+ > Ag2+ > Se2+ > Ni2+ > Cr2+>Cu2+especially in areas close to the active mines. Surface water resources recorded higher contamination. However, Pb2+, As, Hg2+, Se2+ and Cd2+ showed high percentage of contamination in groundwater samples. The Ameka and Mkpuma Akpatakpa mining areas recorded higher concentrations of the hydrogeochemical constituents than the Enyigba, Ameka and Amorie mining regions. Seasonal analysis shows a decreased concentration of chemical constituents in the rainy season relative to the dry season.

Comparison of the effectiveness of natural dolomite and modified dolomite in the removal of heavy metals from aqueous solutions

Presence of heavy metals in water resources is a critical environmental challenge in various communities. To date, various methods have been applied to remove heavy metals, such as the use of cost-efficient materials. The present study aimed to evaluate the adsorption of heavy metals (iron, zinc, nickel, lead, and cadmium) on dolomite and thermally-modified dolomite. We assessed the potentials of natural and thermally-modified dolomite in terms of the adsorption of heavy metals from aqueous solutions. The samples were analyzed to determine the concentrations of metal ions using Spectra 200 Varian. For the optimization and evaluation of the influential factors in the adsorption amount, factors such as the initial concentration of the solution, pH, contact time, and adsorbent dosage were considered. Comparison of the final removal results indicated that lead and cadmium had the shortest contact time (15 minutes), while the longest contact time belonged to iron and nickel (60 minutes). In addition, the highest and lowest removal efficiency within the optimum time was 99% and 93%for cadmium and iron, respectively, while the minimum dosage of the optimum adsorbent belonged to iron and zinc. The minimum removal efficiency belonged to nickel (3 mg/l), while the maximum removal efficiency was obtained for cadmium, iron, and zinc (10, 5, and 5 mg/l) with the concentrations of 99%. According to the results, modified dolomite has great potential to remove metals and heavy metals.

Efficiency of calcium carbonate from eggshells as an adsorbent for cadmium removal in aqueous solution

Abstract The presence of heavy metals in water resources brings hazard to health and the environment considering that most of these cannot be degraded and may result in bioaccumulation in the food chain. Its removal from aqueous solution can relatively be done through adsorption, a known technique that efficiently reduces heavy metal concentration. This study investigated the applicability and efficiency of waste chicken eggshells as an adsorbent for the removal of Cadmium (Cd) heavy metal in aqueous solution. The adsorbent dose, contact time and initial concentration were the chosen variables of the study that were optimized through the Central Composite Design of the Response Surface Methodology using Design Expert 7.0 software. The result of the study showed that the chicken eggshells as an adsorbent could remove Cd in an aqueous solution up to 73%. The optimum adsorption capacity was 146 mg g−1 obtained at 150 mg L−1 initial concentration, 75 min contact time, 0.75 g adsorbent dose, and pH 6 at room temperature. Heterogeneous adsorption occurred during the process as revealed by isotherm studies with Freundlich model emerged having a higher coefficient of determination (R2 = 0.91) than the Langmuir model (R2 = 0.86). Overall, the study demonstrated that the chicken eggshell that is generally considered as wastes in large quantities could become an economically advantageous raw material for the removal of carcinogenic Cd from the water body.

Survey of Heavy Metal Contamination in Water Sources in the Municipality of Torola, El Salvador, through In Situ Sorbent Extraction

The presence of heavy metals in water resources directly affects consumer health. The quality of surface water resources in Central America is usually low due to the presence of metals and other pollutants. The lack of analytical instrumentation to perform routine monitoring of water has encouraged the development of easy tools to facilitate the determination of heavy metals in waters in remote sites. In this study, we evaluated the use of different sorbents, such as Adsorbsia As600 (titanium dioxide), Iontosorb Oxin, 8-hydroxyquinoline bearing functional groups, and Duolite GT-73, with thiol functionality, for Cd, Ni, Cu, Zn, and Al extraction. It was found that both Adsorbsia As600 and Iontosorb Oxin allowed the adsorption of all metals, and the recovery was achieved using either HCl or ethylenediaminetetraacetic sodium salt (EDTA) solutions. Hence, Adsorbsia As600 was employed for in situ sampling in the metal contamination evaluation of water samples (from 15 wells and nine storage tanks) from the municipality of Torola, Mozarán, El Salvador. The developed procedure allowed all the metals in the samples to be detected, and Ni and Al were found to be above Salvadoran guidelines for drinking water quality.

Evaluation the concentration of mercury, zinc, arsenic, lead and cobalt in the Ilam city water supply network and resources

Background: The presence of heavy metals in water resources above threshold levels can be toxic and carcinogenic for consumers. This study determined the concentrations of heavy metals in the drinking water distribution network and resources of the city of Ilam in Iran. Methods: In this cross-sectional study from 6 sources of water supply and also, different parts of the water supply system of Ilam city, samples were collected based on standard sampling methods. The samples were tested with a BRAIC atomic absorption spectrophotometer. The data was analyzed using nonparametric Mann-Whitney test. Results: The concentration of zinc in all water sources of the city of Ilam was higher than WHO guidelines and Iranian standard 1053. Contamination by cobalt, arsenic and lead from Ilam dam, Pich-e Ashoori well and Haft Cheshmeh well was higher than national and international standards. The amount of cobalt and mercury at Ilam dam was significantly different from the levels at other sources (P < 0.05). Conclusion: The use of pesticides in the agricultural sector, contamination of water by human waste and aged and worn water pipes are the likely sources of the increased concentrations of heavy metals, especially lead and arsenic. Because there is a cumulative effect from these metals, appropriate measures are necessary by the relevant agencies to address this problem.

Copper oxide nanoblades as novel adsorbent material for cadmium removal

A wide variety of new materials and their hybrids have emerged as novel adsorbents to help resolve contamination of heavy metals in water resources. In this research, copper oxide (CuO) nanoblades were synthesized in high yield using a facile chemical method. These synthesized CuO nanoblades were characterized for their topological, morphological, structural, optical, and chemical behavior using a variety of techniques including scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infra red (FTIR) spectrometry, Raman spectroscopy, and UV–Visible spectroscopy. The in-depth investigation confirmed that the blade-shaped synthesized nanomaterial was in pure CuO form. The synthesized nanoblades were 3–4nm thick and 70–200nm in length with consistent dots of 3nm at one side on every blade. The performance of these nanoblades was further evaluated and optimized for cadmium (Cd) removal in relation to the parameters solution pH, contact time, and adsorbent/adsorbate dose. Their cytotoxicity was also assessed for probable utilization at the industrial/commercial level. CuO nanoblades showed a maximum adsorption capacity of 192.30mg/g for Cd (adsorbent dose: 0.5mg/ml) and exhibited a best fit for Langmuir isotherm with R2 value of 0.99 and b =0.007. This is the first report for chemical synthesis of copper oxide nanoblades followed by their utilization for removal of cadmium ions with such high adsorption capacity.

CONTAMINACIÓN POR METALES PESADOS: IMPLICACIONES EN SALUD, AMBIENTE Y SEGURIDAD ALIMENTARIA

La contaminación por metales pesados y metaloides en recursos hídricos, suelos y aire plantea una de las más severas problemáticas que comprometen la seguridad alimentaria y salud pública a nivel global y local. En esta revisión, se aborda el problema específico de contaminación por mercurio (Hg), Arsénico (As), Cadmio (Cd) y Plomo (Pb) en ambiente y alimentos. Se presenta una descripción sobre las fuentes de contaminación y exposición en seres vivos así como la incorporación y retención en alimentos y productos de consumo humano. Se abordan casos de estudio y resultados obtenidos en algunos países del mundo incluido Colombia.

New biosensor for detection of copper ions in water based on immobilized genetically modified yeast cells.

Contamination of water by heavy metals represents a potential risk for both aquatic and terrestrial organisms, including humans. Heavy metals in water resources can come from various industrial activities, and drinking water can be ex-post contaminated by heavy metals such as Cu(2+) from house fittings (e.g., water reservoirs) and pipes. Here, we present a new copper biosensor capable of detecting copper ions at concentrations of 1-100 μM. This biosensor is based on cells of a specifically modified Saccharomyces cerevisiae strain immobilized in alginate beads. Depending on the concentration of copper, the biosensor beads change color from white, when copper is present in concentrations below the detection limit, to pink or red based on the increase in copper concentration. The biosensor was successfully tested in the determination of copper concentrations in real samples of water contaminated with copper ions. In contrast to analytical methods or other biosensors based on fluorescent proteins, the newly designed biosensor does not require specific equipment and allows the quick detection of copper in many parallel samples.

Cadmium removal from aqueous solution using nano/milli-sized particles of cedar leaf ash

Heavy metals in water resources are one of the important environmental problems. These metals have hazardous effects on human health. This study was conducted to investigate the comparison between adsorption of cadmium from aqueous solution using nano/milli-sized adsorbents of cedar leaf ash by batch experiments and with variation of impressive parameters such as pH, contact time, and adsorbent amount. The results showed, the optimum pH of adsorption was 5. Adsorption equilibrium times for nano/milli-sized adsorbents were obtained in 30 and 45 min, respectively. With increasing the amount of milli-sized adsorbent, adsorption efficiency increased but increasing of nanosized adsorbent at first, caused the increase in adsorption efficiency and then adsorption efficiency decreased because of clogging phenomenon of adsorbent in aqueous solution. The experimental data were analyzed using two isotherm models (Langmuir and Freundlich) and two kinetic models (pseudo-first-order and pseudo-second-order). Based on the results, adsorption of cadmium followed from the models of pseudo-second-order kinetic and Langmuir isotherm well. Adsorption capacity of nanosized adsorbent was about two times more than adsorption capacity of milli-sized adsorbent. This case indicated the high ability of nanoparticles in adsorption of cadmium from aqueous solution.

Geochemical mobilization of some heavy metals in water resources and their impact on human health in Sohag Governorate, Egypt

Geochemical mobilization of heavy metals in water has been cited as an important factor in many diseases of Sohag Governorate, Egypt. Forty-two groundwater samples were collected from the Quaternary aquifer and eight samples from surface water of Sohag governorate. The results recorded high contamination with cadmium and lead. Besides, about 50 % of samples are contaminated with iron and manganese at an alert level. All the metals under study exhibited an asymmetric statistical distribution in the investigated area. The study identified positive relationship between contaminated water (surface and groundwater) of Sohag with Cd (r s = 0.43) as well as Pb (r s = 0.21) and renal failure rate (R.F.R. = 26 patients/105 capita). The spatial distribution of these two metals (Cd and Pb) showed that they accumulated in the southern part of Sohag Governorate around Albalina District and in the northwestern part at Gehina District, which have the highest R.F.R. This study highlighted the need for more detailed research to assess the different pollutants and their relation to chronic diseases.

Groundwater Contamination by Heavy Metals in Water Resources of Shiraz Area

Lack of sewage collection systems, percolation of surface waters, and seepage of wells have raised the groundwater table in Shiraz area in the south of Iran. The growing population generates environmental pollution resulting in the degradation of the quality of surface and groundwaters used for agriculture. Inorganic and organic pollutants have been traced in Shiraz water resources. Heavy metals, As+2, Cd2+, Cr2+, Fe2+, Hg2+, and Pb2+ have been reported as potential pollutants of both surface and groundwaters. The safety of groundwater supplies in Shiraz was studied with respect to heavy metal concentrations. From 50 semi deep wells, which supply water for agricultural production, three water samples per well were examined to determin the physical and chemical characteristics of the water. The results of the study indicated that the concentration of Cd2+, Cr2+, Fe2+, Mn2+, and Pb2+ exceed permissible values for crop production. A network of gallery systems was proposed for wastewater collection and the disposal of Shiraz groundwater, to increase the water table depth in urban areas. It is estimated that about 100M m3 wastewater could be drained annually through the proposed gallery system which could be used for agricultural production. It is believed that mixing the drained waters from the proposed network of galleries with the agricultural water supplies will help control concentrations of heavy metals so they do not have serious acute impacts on agricultural production. The chronic effects of the impacts of water quality on agricultural production should be monitored temporarilly.