Uncertainty assessment of mapping mercury contaminated soils of a rapidly industrializing city in the Yangtze River Delta of China using sequential indicator co-simulation

Accurate characterization of heavy-metal contaminated areas and quantification of the uncertainties inherent in spatial prediction are crucial for risk assessment, soil remediation, and effective management recommendations. Topsoil samples (0–15 cm) (n = 547) were collected from the Zhangjiagang suburbs of China. The sequential indicator co-simulation (SIcS) method was applied for incorporating the soft data derived from soil organic matter (SOM) to simulate Hg concentrations, map Hg contaminated areas, and evaluate the associated uncertainties. High variability of Hg concentrations was observed in the study area. Total Hg concentrations varied from 0.004 to 1.510 mg kg⁻¹ and the coefficient of variation (CV) accounts for 70%. Distribution patterns of Hg were identified as higher Hg concentrations occurred mainly at the southern part of the study area and relatively lower concentrations were found in north. The Hg contaminated areas, identified using the Chinese Environmental Quality Standard for Soils critical values through SIcS, were limited and distributed in the south where the SOM concentration is high, soil pH is low, and paddy soils are the dominant soil types. The spatial correlations between Hg and SOM can be preserved by co-simulation and the realizations generated by SIcS represent the possible spatial patterns of Hg concentrations without a smoothing effect. Once the Hg concentration critical limit is given, SIcS can be used to map Hg contaminated areas and quantitatively assess the uncertainties inherent in the spatial prediction by setting a given critical probability and calculating the joint probability of the obtained areas.     

The statistical investigation on airborne fungi and pollen grains of atmosphere in Izmir-Turkey

This study aims to investigate the differences in the concentrations of airborne fungi and pollens between the towns located in the province of Izmir and to determine the factors contributing to these differences. Five stations in each of four towns (Buca, Konak, Bornova, and Karsiyaka) were randomly selected as the research areas. Fungus (cfu/m³) and pollen counts (cm²/pollen count) in the air samples collected from each station between June 2003 and May 2004 were measured. The results revealed that whereas Karsiyaka had the highest fungus concentration (521.33 ± 777.1), Buca and Bornova had the lowest concentration (482.67 ± 308.44). The mean fungus concentration in the province of İzmir was 501.5 ± 486.7. Pollen concentration was the highest in Konak (486.67 ± 839.06) and the lowest in Bornova (369.83 ± 551.13). Fungus and pollen concentrations revealed no difference between the towns (p > 0.05). The relationship between pollen-fungus concentrations and temperature-dust-humidity-sulphurdioxide was investigated but it was found statistically insignificant (p > 0.05). As a result of regression analysis, it was determined that correlation of atmospheric parameters had no effects on pollen and fungus concentrations (p > 0.05).     

Effect of teeth amalgam on mercury levels in the colostrums human milk in Lenjan

Human milk is usually the only source of food for infants during the first 4 to 5 months of their life. Maternal environmental mercury exposure is directly related to fish consumption or amalgam filling. In this research, 38 human milk samples were collected from mothers of Lenjan area who were not occupationally exposed with mercury. Mercury concentration in human milk was determined by AMA254 Mercury Analyzer. A level of mercury was examined in relation to somatometric, demographic and dental amalgam parameters. Obtained results showed that only dental amalgam significantly increased the mercury level in human milk (p < 0.001). The mean mercury concentrations in milk of mothers without teeth fillings (n = 13), with one to three teeth fillings (n = 10), and four to eight teeth fillings (n = 15) were 2.87, 5.47, and 13.33 μg/l, respectively. The result of this study also showed a positive correlation of mercury milk levels with the number of teeth fillings of the mother (p < 0.05, r = 0.755). The estimated weekly intake of mercury of a breastfed infant in this study was, in some cases, higher than provisional tolerance weekly intake recommended by FAO/WHO, which pose a threat to their health.     

Assessment of river water quality during snowmelt and base flow periods in two catchment areas with different land use

River water quality was evaluated with respect to eutrophication and land use during spring snowmelt and summer base flow periods in Abashiri (mixed cropland-livestock farming) and Okoppe (grassland-based dairy cattle farming), eastern Hokkaido, Japan. Water from rivers and tributaries was sampled during snowmelt and summer base flow periods in 2005, and river flow was measured. Total N (TN), NO₃–N, and Si concentrations were determined using standard methods. Total catchment and upland areas for each sampling site were determined with ArcGIS hydrology modeling software and 1:25,000-scale digital topographic maps. Specific discharge was significantly higher during snowmelt than during base flow. In both areas, TN concentrations increased, whereas Si concentrations decreased, with increased specific discharge, and were significantly higher during snowmelt. The Si:TN mole ratio decreased to below or close to the threshold value for eutrophication (2.7) in one-third of sites during snowmelt. River NO₃–N concentrations during base flow were significantly and positively correlated with the proportion of upland fields in the catchment in both the Abashiri (r = 0.88, P < 0.001) and Okoppe (r = 0.43, P < 0.01) areas. However, the regression slope, defined as the impact factor (IF) of water quality, was much higher in Abashiri (0.025) than in Okoppe (0.0094). The correlations were also significantly positive during snowmelt in both areas, but IF was four to eight times higher during snowmelt than during base flow. Higher discharge of N from upland fields and grasslands during snowmelt and the resulting eutrophication in estuaries suggest that nutrient discharge during snowmelt should be taken into account when assessing and monitoring the annual loss of nutrients from agricultural fields.     

Overview and Forecast on Forestry Productions Worldwide

Our world is largely dependent upon the forestry productions. Through the exploitation of forest reserves, we manufacture various industrial products, furniture, and obtain fuel and energy. Forestry productions should be conducted without large-scale deforestation and environmental degradation. In present study we perform a review and forecast analysis on forestry productions worldwide, with the objectives of providing an insight into the trend for several types of forestry productions in the future, and providing referential data for sustainable forestry productions and environmental management. Polynomial functions are used to fit trajectories of forestry productions since 1961 and forecasts during the coming 20 years are given in detail. If the past pattern continues, world fibreboard production would dramatically grow and reach 224,300,000 ± 44,400,000 m³ by the year 2020, an increase up to 240.7 to 408.9% as compared to the present level. Roundwood production of the world would change by −55.5 to 70.4% and reach 3,526,600,000 ± 2,066,800,000 m³ by 2020. In 2020 world production of sawlogs and veneer logs would change by −100 to 164.6% and reach 1,212,900,000 ± 1,242,600,000 m³. Global wood fuel production would change by −68.9 to 1.4% and reach 1,130,900,000 ± 600,800,000 m³ by 2020. Forestry productions in developed countries would largely surpass productions in developing countries in the near future. World forestry production grew since 1961 excluding wood fuel. Roundwood and wood fuel account for the critical proportions in the forestry productions. Wood fuel production has being declined and rapid growing of roundwood production has slowed in recent years. Widespread use of regenerative wood substitutes and worldwide afforestation against deforestation will be among the most effective ways to reduce deforestation and environment degradation associated with forestry productions.     

Organophosphate pesticide environmental exposure: analysis of salivary cholinesterase and carboxilesterase activities in preschool children and their mothers

A pilot study was conducted to evaluate the usefulness of salivary cholinesterase and carboxylesterase as biomarkers of exposure to environmental organophosphate pesticides. Ninety samples were obtained from women and 62 samples from their preschool-aged children who live near an agricultural area of the Upper Valley of the Negro River (Patagonia, Argentina) where pesticides are applied 6 months a year. Each participant donated two samples under similar conditions: one in the pre-exposure period and another during the pulverization period. Demographic information, potential confounders, and risk behaviors were registered. Active or passive smoking had no effect on these enzyme activities in either group. During the pulverization period, cholinesterase activity was not detectable in 76% of the children's samples and 23% of the mothers' samples. Comparing samples collected during the pulverization period with respect to the pre-pulverization period, the average mother and child cholinesterase activity decreased by 65.7% (p < 0.001) and 85.8% (p < 0.001), respectively. Also, mother and child carboxylesterase activity decreased by 27.5% (p < 0.001) and 41.9% (p < 0.01), respectively. Child carboxylesterase activity in the pulverization period was associated to the habit of eating dust outdoors (p < 0.01). The most frequent inhibition levels observed for cholinesterase and carboxylesterase activity were between 70–100% and 0–29%, respectively, in both groups studied. This shows that at the same level of exposure, cholinesterase was more sensitive to inhibition than carboxylesterase. Therefore, carboxylesterase might more properly reflect the degree of environmental organophosphate exposure and may have potential as a novel tool for biomonitoring.     

Varying Stable Nitrogen Isotope Ratios of Different Coastal Marsh Plants and Their Relationships with Wastewater Nitrogen and Land Use in New England, USA

The stable nitrogen isotope ratios of some biota have been used as indicators of sources of anthropogenic nitrogen. In this study the relationships of the stable nitrogen isotope ratios of marsh plants, Iva frutescens (L.), Phragmites australis (Cav.) Trin ex Steud, Spartina patens (Ait.) Muhl, Spartina alterniflora Loisel, Ulva lactuca (L.), and Enteromorpha intestinalis (L.) with wastewater nitrogen and land development in New England are described. Five of the six plant species (all but U. lactuca) showed significant relationships of increasing δ ¹⁵N values with increasing wastewater nitrogen. There was a significant (P < 0.0001) downward shift in the δ ¹⁵N of S. patens (6.0 ± 0.48‰) which is mycorrhizal compared with S. alterniflora (8.5 ± 0.41‰). The downward shift in δ ¹⁵N may be caused by the assimilation of fixed nitrogen in the roots of S. patens. P. australis within sites had wide ranges of δ ¹⁵N values, evidently influenced by the type of shoreline development or buffer at the upland border. In residential areas, the presence of a vegetated buffer (n = 24 locations) significantly (P < 0.001) reduced the δ ¹⁵N (mean = 7.4 ± 0.43‰) of the P. australis compared to stands where there was no buffer (mean = 10.9 ± 1.0‰; n = 15). Among the plant species, I. frutescens located near the upland border showed the most significant (R ² = 0.64; P = 0.006) inverse relationship with the percent agricultural land in the watershed. The δ ¹⁵N of P. australis and I. frustescens is apparently an indicator of local inputs near the upland border, while the δ ¹⁵N of Spartina relates with the integrated, watershed-sea nitrogen inputs.     

Assessment of phenanthrene bioavailability in aged and unaged soils by mild extraction

It has become apparent that the threat of an organic pollutant in soil is directly related to its bioavailable fraction and that the use of total contaminant concentrations as a measure of potential contaminant exposure to plants or soil organisms is inappropriate. In light of this, non-exhaustive extraction techniques are being investigated to assess their appropriateness in determining bioavailability. To find a suitable and rapid extraction method to predict phenanthrene bioavailability, multiple extraction techniques (i.e., mild hydroxypropyl-β-cyclodextrin (HPCD) and organic solvents extraction) were investigated in soil spiked to a range of phenanthrene levels (i.e., 1.12, 8.52, 73, 136, and 335 μg g^− 1 dry soil). The bioaccumulation of phenanthrene in earthworm (Eisenia fetida) was used as the reference system for bioavailability. Correlation results for phenanthrene suggested that mild HPCD extraction was a better method to predict bioavailability of phenanthrene in soil compared with organic solvents extraction. Aged (i.e., 150 days) and fresh (i.e., 0 day) soil samples were used to evaluate the extraction efficiency and the effect of soil contact time on the availability of phenanthrene. The percentage of phenanthrene accumulated by earthworms and percent recoveries by mild extractants changed significantly with aging time. Thus, aging significantly reduced the earthworm uptake and chemical extractability of phenanthrene. In general, among organic extractants, methanol showed recoveries comparable to those of mild HPCD for both aged and unaged soil matrices. Hence, this extractant can be suitable after HPCD to evaluate risk of contaminated soils.     

Physicochemical and microbiological assessment of recreational and drinking waters

The present study was aimed to make an assessment of health risk due to pollution and human pathogenic bacteria associated with the recreational and drinking water sources in twin densely populated holy Indian cities Ayodhya and Faizabad. Though physicochemical studies revealed that the water available in the area is under recommended limits for human use, it is unsafe on account of poor microbiological quality of surface and ground water in the region. The most probable number (MPN) test results revealed the preponderance of ≥2,400 total coliforms (TC) (100 ml)^− 1 in river, pond, dug well and kund waters. Contrary to that, 94% tube wells, 32% hand pumps and 25% piped supply water were under safe limits having <3 TC (100 ml)^− 1. The shallow depth (~40 ft), water logging and presence of septic tanks in the near vicinity are the possible reasons of poor microbial quality of hand pump drinking water. The municipal supply water passes along sewage line where loose connections and/or cracks in pipe lead to mixing and contamination. The significant best quality of tube well water evident from the absence of TC could be attributed to the depth of well ≥150 ft and usually their location away from the habitation. A total of 263 bacteria from 186 water samples were isolated, and at least five genera of enteric bacteria from various water sources were identified morphologically and biochemically as Escherichia coli, Klebsiella sp., Enterobacter sp., Shigella sp. and Salmonella sp. The serotyping of 72 E. coli and 36 Salmonella sp. revealed 51 as E. coli O157 and 20 as Salmonella sp. The presence of enteric pathogens in water sources pose threat to human health and therefore call for immediate remedial measures.     

Determination of cobalt,nickel and iron at trace level in natural water samples by in-column chelation-reversed phase high-performance liquid chromatography

This paper reports the utilization of 4-(2-pyridylazo) resorcinol (PAR) as a chelating reagent for in-column derivatization and the determination of trace Co, Fe, and Ni ions by reversed-phase high-performance liquid chromatography with photodiode array detector. A good separation of Co, Fe, and Ni chelates were achieved by using an Inertsil ODS-3 column and a mobile phase, consisted of methanol–THF–water mixture (50:5:45) containing ammonium acetate buffer (pH 5.0) and PAR. After full optimization, good repeatability of retention times (relative standard deviation (RSD) < 0.05%) and peak areas (RSD < 1.7%) was achieved as well as a good linearity (r ² > 0.9991). The detection limits (S/N = 3), expressed as micrograms per liter, were 0.50 (Co), 9.07 (Fe), and 2.00 (Ni). The applicability and the accuracy of the developed method were estimated by the analysis of spiked water samples and certified reference material BCR 715 wastewater-SRM.     

Spatiotemporal distribution of arsineic species of oysters (Crassostrea gigas) in the coastal area of southwestern Taiwan

This study investigated total arsenic (As) and As species contents of oysters (Crassostrea gigas) in different production areas, seasons and sea locations on the southwestern coast of Taiwan. Analytical results indicate that contents of total As, arsenite, arsenate, dimethylarsinic acid, monomethylarsonic acid and arsenobetaine in oysters are 9.90 ± 3.68, 0.091 ± 0.104, 0.033 ± 0.038, 0.529 ± 0.284, 0.037 ± 0.046 and 3.94 ± 1.33 mg/g (dry wt), respectively. A ratio of inorganic As concentrations to total As concentrations is 1.26%. Total As contents of oysters cultured in the outer sea are statistically significantly lower than those of oysters cultured in the inner sea. The total As contents of oysters is the highest in Putai, where the blackfoot disease prevails. The low As contents in oysters is attributed to the low temperature in winter, which slows the metabolism of oysters. A maximum value is 33.37 μg/g (dry) in Putai in spring, because a considerable amount of aquacultural waste water with high As contents is discharged into adjacent drainage channels and rivers there during that season.     

Methyl mercury in fish—a case study on various samples collected from Ganges river at West Bengal

This study investigated the presence of total mercury (Hg) and organic mercury levels in the muscle of 19 common fresh water fish species captured from river Ganges, West Bengal, India. The total mercury level found in our study may not cause any toxic effect, but the methyl mercury (MeHg) level in some freshwater fish species was surprisingly very high and toxically unacceptable. The results of mercury analysis in various specimens indicated that some fish muscles tended to accumulate high levels of Hg, and approximately 50–84% of Hg was organic mercury. A strong positive correlation between mercury levels in muscle with food habit and fish length (age) was found. Wallago attu possessed the highest amount of organic mercury in their muscle tissues, and it was 0.93 ± 0.61 μg Hg/g of wet weight. Whereas in small-sized fishes Eutropiichthys murius, Puntius sarana, Cirrhinus mrigala, Mystus vittatus or Mystus gulio, and Tilapia mossambicus, it was below the detection limit. Contamination in Catla catla (0.32 ± 0.11), Anguilla bengalensis bengalensis (0.26 ± 0.07 μg Hg/g), Chitala chitala (0.25 ± 0.18), Rita rita (0.34 ± 0.14), and Ompok pabda (0.26 ± 0.04) was also above the 0.25 μg Hg/g of wet weight, the limit set by the PFA for the maximum level for consumption of fish exposed to MeHg. Though in Labeo rohita (0.12 ± 0.03), Mastacembelus armatus (0.17 ± 0.02), Pangasius pangasius (0.12 ± 0.16), Bagarius bagarius (0.12 ± 0.01), and Clupisoma garua (0.1 ± 0.01), concentration was below the recommended level, in Lates calcarifer (0.23 ± 0.0) and Mystus aor (0.23 ± 0.1), it was threatening. Interestingly, a low concentration of Hg was found in post-monsoon samples.     

Risk assessment due to intake of heavy metals through the ingestion of groundwater around two proposed uranium mining areas in Jharkhand,India

Heavy metal pollution of water resources can be apprehended in East Singhbhum region which is a highly mineralised zone with extensive mining of copper, uranium and other minerals. Ten groundwater samples were collected from each site and the heavy metal analysis was done by atomic absorption spectrophotometer. Analysis of the results of the study reveals that the concentration of iron, manganese, zinc, lead, copper and nickel in groundwater of Bagjata mining area ranged 0.06–5.3 mg l^− 1, 0.01–1.3 mg l^− 1, 0.02–8.2 mg l^− 1, 1.4–28.4 μg l^− 1, 0.78–20.0 μg l^− 1 and 1.05–20.1 μg l^− 1, respectively. In case of Banduhurang mining area, the range was 0.04–2.93 mg l^− 1, 0.02–1.1 mg l^− 1, 0.01–4.68 mg l^− 1, 1.04–33.21 μg l^− 1, 1.24–18.7 μg l^− 1 and 1.06–14.58 μg l^− 1, respectively. The heavy metals were found to be below the drinking water standards (IS:10500 1993) except iron (0.3 mg l^− 1) and manganese (0.1 mg l^− 1). The hazard quotients of the heavy metals for drinking water were below 1 posing no threat due to intake of water to the people for both the areas.     

Total mercury distribution in different tissues of six species of freshwater fish from the Kpong hydroelectric reservoir in Ghana

Total mercury concentrations were determined in seven tissues of 38 fish samples comprising six species from the Kpong hydroelectric reservoir in Ghana by cold vapour atomic absorption spectrometry technique using an automatic mercury analyzer. Mercury concentration in all the tissues ranged from 0.005 to 0.022 μg/g wet weight. In general, the concentration of mercury in all the tissues were decreasing in the order; liver > muscle > intestine > stomach > gonad > gill > swim bladder. Mercury concentration was generally greater in the tissues of high-trophic-level fish such as Clarotes laticeps, Mormyrops anguilloides and Chrysichthys aurutus whereas low-trophic-level fish such as Oreochromis niloticus recorded low mercury concentration in their tissues. The results obtained for total mercury concentration in the muscle tissues analysed in this study are below the WHO/FAO threshold limit of 0.5 μg/g. This suggests that the exposure of the general public to Hg through fish consumption can be considered negligible.     

Pasture composition in a trace element-contaminated area: the particular case of Fe and Cd for grazing horses

Pasture selection by livestock is an essential topic for rangeland management, especially in trace element-contaminated soils. We have studied the composition (nutrients and trace elements) of a grass-based diet from soils affected by a mine spill at different growth stages (October 2008 to May 2009). A diet based on other plants (mainly Compositae species) was also studied (May 2009) for comparison. Faeces and mane hair of horses feeding on these pastures were also analysed. Micronutrient (Cu, Fe, Mn and Zn) and potentially toxic trace element (As, Cd, Pb, Tl) concentrations were below the maximum tolerable levels (MTL) for horses, except for Fe (at early growth of pastures) and Cd (in the diet based on ‘other’ plants). Values of potential ingestion of Fe by horses were higher than 10 mg kg body weight^− 1 day^− 1. Cadmium concentrations in some pasture samples (those composed of Compositae species) were higher than 3 mg kg^− 1. Potential toxicity of such Cd levels in pastures is uncertain, since a high disparity of criteria about MTL by cattle exists (between 0.5 and 10 mg kg^− 1 diet). Nutrient concentrations were adequate for horses, which could counteract possible harmful effects derived from trace element ingestion. The analyses of excreta and mane hair point to the low risk of toxicity derived from the consumption of these contaminated pastures. However, the ingestion of regenerating pastures (autumnal samples) should be avoided due to the greater risk of ingestion of contaminated soil attached to the plant material. Management of these pastures by grazing requires periodic monitoring. Special attention should be given to Fe and particularly Cd (non-essential element) which accumulates in animal organs, where it could provoke uncertain long-term effects.     

Health risk assessment of heavy metals for edible parts of vegetables grown in sewage-irrigated soils in suburbs of Baoding City,China

With the long-term application of wastewater to vegetable production fields, there is concern about potential health risks of heavy metals contaminating the edible parts of vegetables grown in contaminated soils in the suburban areas of Baoding City, China. The average concentration of elemental Zn in sewage-irrigated soil was the highest (153.77 mg kg⁻¹), followed by Pb (38.35 mg kg⁻¹), Cu (35.06 mg kg⁻¹), Ni (29.81 mg kg⁻¹), and Cd (0.22 mg kg⁻¹) which were significantly higher (P < 0.05) than those in the reference soil. The results showed that long-term sewage irrigation had led to a growing accumulation of heavy metals in the soils, especially for Cd, Zn, and Pb. Furthermore, the concentrations of elemental Cd, Zn, and Ni in vegetables (e.g., Beassica pekinensis L., Allium fistulosum L., Spinacia oleracea L.) collected from the wastewater-irrigated soils exceeded the maximum permissible limits, and this also increased the daily intake of metals by food. However, compared with the health risk index of <1 for heavy metals, the ingestion of vegetables from the soils irrigated with sewage effluent posed a low health risk. Nevertheless, heavy metal concentrations should be periodically monitored in vegetables grown in these soils together with the implementation effective remediation technologies to minimize possible impacts on human health.     

Testing differences in methods of preparing moss samples

The main objective of this research was to estimate the total mass of nitrogen discharged from various sources in Korea using the mass balance approach. Three different nitrogen mass balances were presented: (1) agricultural activities including raising crops and animal husbandry; (2) domestic activities, and (3) activities in forest and urban areas. These nitrogen balances were combined to estimate riverine discharge of nitrogen to the ocean in national scale. Nitrogen inputs include atmospheric deposition, biological nitrogen fixation, application of inorganic fertilizers/manures, animal feed/imported foodstuffs, and meat/fish. Nitrogen outputs include ammonia volatilization, denitrification, human/animal waste generation, crop/meat production, and riverine discharge to the ocean. The estimated total nitrogen input in Korea was 1,194.5 × 10³ tons N/year. Nitrogen discharged into rivers was estimated as 408–422 × 10³ tons N/year, of which 66–71% was diffuse in origin. The estimated diffuse discharges for land uses were estimated as 82 × 10³ tons N/year from agricultural areas, 7 × 10³ tons N/year from forestry and 75 × 10³ tons N/year from urban and industrial areas.     

Rinodina sophodes (Ach.) Massal.: a bioaccumulator of polycyclic aromatic hydrocarbons (PAHs) in Kanpur City, India

The aim of this study is to determine the possibility of using Rinodina sophodes (Ach.) Massal., a crustose lichen as polycyclic aromatic hydrocarbons (PAHs) bioaccumulator for evaluation of atmospheric pollution in tropical areas of India, where few species of lichens are able to grow. PAHs were identified, quantified and compared to evaluate the potential utility of R. sophodes. The limit of detection for different PAHs was found to be 0.008–0.050 μg g^− 1. The total PAHs in different sites were ranged between 0.189 ± 0.029 and 0.494 ± 0.105 μg g^− 1. The major sources of PAHs were combustion of organic materials, traffic and vehicular exhaust (diesel and gasoline engine). Significantly higher concentration of acenaphthylene and phenanthrene indicates road traffic as major source of PAH pollution in the city. Two-way ANOVA also confirms that all PAHs content showed significant differences between all sampling sites (P 1%). This study establishes the utility of R. sophodes in monitoring the PAHs accumulation potentiality for development of effective tool and explores the most potential traits resistant to the hazardous environmental conditions in the tropical regions of north India, where no such other effective way of biomonitoring is known so far.     

Statistical source identification of metals in groundwater exposed to industrial contamination

Levels of selected metals Na, Ca, Mg, K, Fe, Mn, Cr, Co, Ni, Cd, Pb and Mn were estimated by flame atomic absorption spectrophotometry in groundwater samples from Kasur, a significant industrial city of Pakistan. Salient mean concentration levels were recorded for: Na (211 mg/l), Ca (187 mg/l), Mg (122 mg/l), K (87.7 mg/l), Fe (2.57 mg/l) and Cr (2.12 mg/l). Overall, the decreasing metal concentration order was: Na > Ca > Mg > K > Fe > Cr > Zn > Co > Pb > Mn > Ni > Cd. Significantly positive correlations were found between Na–Cr (r = 0.553), Na–Mn (r = 0.543), Mg–Fe (r = 0.519), Mg–Cr (r = 0.535), Pb–K (r = 0.506) and Pb–Ni (r = 0.611). Principal Component Analysis and Cluster Analysis identified tannery effluents as the main source of metal contamination of the groundwater. The present metal data showed that Cr, Pb and Fe levels were several times higher than those recommended for water quality by WHO, US-EPA, EU and Japan. The elevated levels of Cr, recorded as 21–42 fold higher compared with the recommended quality values, were believed to originate from the tanning industry of Kasur.     

Determination of total chromium by flame atomic absorption spectrometry after coprecipitation by cerium (IV) hydroxide

A method for the preconcentration of the total chromium based on coprecipitation with cerium (IV) hydroxide is proposed for determination of chromium by flame atomic absorption spectrometry. Different factors including carrier element amount, pH, sample volume and matrix ion effects for the precipitation were examined. The detection limit of the total chromium (k = 3, N = 15) was 0.18 μg l⁻¹. The presented method was applied for the determination of chromium in the wastewater samples from Kayseri and Nigde Organized Industrial Region-Turkey and in drinking water from our laboratory, Kayseri with satisfactory results (relative standard deviations below 8%, recoveries 95%). The analytical results obtained by the proposed method for certified copper sample was in good agreement with the certified value.