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.     

Flow injection online spectrophotometric determination of uranium after preconcentration on XAD-4 resin impregnated with nalidixic acid

In this work, spectrophotometer was used as a detector for the determination of uranium from water, biological, and ore samples with a flow injection system coupled with solid phase extraction. In order to promote the online preconcentration of uranium, a minicolumn packed with XAD-4 resin impregnated with nalidixic acid was utilized. The system operation was based on U(VI) ion retention at pH 6 in the minicolumn at flow rate of 15.2 mL min^?1. The uranium complex was removed from the resin by 0.1 mol dm^?3 HCl at flow rate of 3.2 mL min^?1 and was mixed with arsenazo III solution (0.05 % solution in 0.1 mol dm^?3 HCl, 3.2 mL min^?1) and driven to flow through cell of spectrophotometer where its absorbance was measured at 651 nm. The influence of chemical (pH and HCl (as eluent and reagent medium) concentration) and flow (sample and eluent flow rate and preconcentration time) parameters that could affect the performance of the system as well as the possible interferents was investigated. At the optimum conditions for 60 s preconcentration time (15.2 mL of sample volume), the method presented a detection limit of 1.1 μg L^?1, a relative standard deviation (RSD) of 0.8 % at 100 μg L^?1, enrichment factor of 30, and a sample throughput of 42 h^?1, whereas for 300 s of the preconcentration time (76 mL of sample volume), a detection limit of 0.22 μg L^?1, a RSD of 1.32 % at 10 μg L^?1, enrichment factor of 150, and a sampling frequency of 11 h^?1 were reported.     

Comparative distribution of the scalp hair trace metal contents in the benign tumour patients and normal donors

The scalp hair samples of benign tumour patients (n = 77) and normal donors (n = 86) were analysed for selected trace metal contents using atomic absorption spectrophotometry. In the scalp hair of benign tumour patients, highest average levels were found for Ca (1,401 microg/g), followed by Na (476.9 microg/g), Mg (441.6 microg/g), Zn (438.3 microg/g), K (119.2 microg/g) and Fe (96.38 microg/g) while in comparison, the maximum mean levels in the scalp hair of normal donors were shown by Ca (556.5 microg/g), followed by Zn (154.2 microg/g), Mg (153.4 microg/g), Na (97.45 microg/g) and Fe (81.68 microg/g). Almost all metal levels revealed higher dispersion and asymmetry in the scalp hair of benign tumour patients compared with the normal donors. The average concentrations of Ca, Cd, Co, K, Mg, Mn, Na, Ni, Pb, Sb, Sr and Zn were significantly higher in the hair of benign tumour patients compared with the normal donors. Significant gender-based differences were also observed in the scalp hair metal contents of benign tumour patients. Strong positive correlations were found between Cd-Cr (0.547) and Cd-Co (0.507) in the hair of benign tumour patients whereas Ca-Mg, Mg-Sr, Co-Cd, Cr-Cd, Li-Cr, Li-Co, Li-Cd, Na-Cd, Na-Co and Na-Li exhibited strong relationships (r > 0.50) in the hair of normal donors. Cluster analysis (CA) and principal component analysis (PCA) were used for the source identification and apportionment of scalp hair trace metals in the two donor groups. The scalp hair of benign tumour patients and normal donors revealed six and five main clusters of trace metals, respectively. PCA extracted seven principal components of trace metals in the scalp hair of benign tumour patients while six principal components were observed in the case of normal donors. The study evidenced significantly different patterns of metal distribution in the hair of benign tumour patients in comparison with normal donors.     

Efficient removal of heavy metals from electroplating wastewater using polymer ligands

Poly(hydroxamic acid)-poly(amidoxime) chelating ligands were synthesized from poly(methyl acrylate-co-acrylonitrile) grafted acacia cellulose for removing toxic metal ions from industrial wastewaters. These ligands showed higher adsorption capacity to copper (2.80 mmol?g⁻¹) at pH 6. In addition, sorption capacities to other metal ions such as iron, zinc, chromium, and nickel were also found high at pH 6. The metal ions sorption rate (t_1/2) was very fast. The rate of adsorption of copper, iron, zinc, chromium, nickel, cobalt, cadmium and lead were 4, 5, 7, 5, 5, 8, 9 and 11 min, respectively. Therefore, these ligands have an advantage to the metal ions removal using the column technique. We have successfully investigated the known concentration of metal ions using various parameters, which is essential for designing a fixed bed column with ligands. The wastewater from electroplating plants used in this study, having chromium, zinc, nickel, copper and iron, etc. For chromium wastewater, ICP analysis showed that the Cr removal was 99.8% and other metal ions such as Cu, Ni, Fe, Zn, Cd, Pb, Co and Mn removal were 94.7%, 99.2%, 99.9%, 99.9%, 99.5%, 99.9%, 95.6% and 97.6%, respectively. In case of cyanide wastewater, the metal removal, especially Ni and Zn removal were 96.5 and 95.2% at higher initial concentration. For acid/alkali wastewater, metal ions removing for Cd, Cr and Fe were 99.2%, 99.5% and 99.9%, respectively. Overall, these ligands are useful for metal removal by column method from industrial wastewater especially plating wastewater.     

Female CEO succession and corporate social disclosure in China: unveiling the significance of ownership status and firm performance

Environmental Science and Pollution Research - This study intends to examine the effect of CEO succession with gender change from male to female (i.e., female CEO succession) on corporate social...     

Investigation on the role of graphene-based composites for in photocatalytic degradation of phenol-based compounds in wastewater: a review

Environmental Science and Pollution Research - The ineptitude of conventional water management systems to eradicate noxious compounds leads to the development of advanced treatment systems. The...     

Detection of Norovirus and Hepatitis A Virus in Strawberry and Green Leafy Vegetables by Using RT-qPCR in Egypt

Food and Environmental Virology - There is an upward trend of consumption of organic fresh vegetables due to consumer demand for healthy foods without chemical additives. On the other hand, the...