Removal of heavy metals through adsorption using sand

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Speciation of arsenic and chromium metal ions by reversed phase high performance liquid chromatography

The speciation of arsenic [As(III) and As(V)] and chromium [Cr(III) and Cr(VI)] was carried out by high performance liquid chromatography. The column used was Econosil C18 (250 x 4.6 mm i.d., particle size 10 microm). The mobile phases consisted of water-acetonitrile (80:20, v/v) for arsenic and 10 mM ammonium acetate buffer (6.0 pH)-acetonitrile (10:90, v/v) for chromium speciation separately and respectively. The detection was carried out by UV-Vis at 410 nm and atomic absorption spectrometer (AAS) respectively and separately. The values of alpha and Rs of As(III) and As(V) species were 1.4 and 1.5 respectively while the values of alpha and Rs for Cr(III) and Cr(VI) were 1.35 and 0.2 respectively. The effect of the acetonitrile percentages was also carried out on the speciation of arsenic only. The relative standard deviation and limit of detection were in the range of 0.01-0.02 and 0.4-1.0 microg/ml respectively.     

Hand-arm vibration disorder among grass-cutter workers in Malaysia

Introduction. Prolonged exposure to hand-transmitted vibration from grass-cutting machines has been associated with increasing occurrences of symptoms and signs of occupational diseases related to hand–arm vibration syndrome (HAVS). Methods. A cross-sectional study was carried out using an adopted HAVS questionnaire on hand–arm vibration exposure and symptoms distributed to 168 male workers from the grass and turf maintenance industry who use hand-held grass-cutting machines as part of their work. The prevalence ratio and symptom correlation to HAVS between high and low–moderate exposure risk groups were evaluated. Results. There were positive HAVS symptoms relationships between the low–moderate exposure group and the high exposure group among hand-held grass-cutting workers. The prevalence ratio was considered high because there were indicators that fingers turned white and felt numb, 3.63, 95% CI [1.41, 9.39] and 4.24, 95% CI [2.18, 8.27], respectively. Less than 14.3% of workers stated that they were aware of the occupational hand–arm vibration, and it seemed to be related to the finger blanching and numbness. Conclusion. The results suggest that HAVS is under-diagnosed in Malaysia, especially in the agricultural sectors. More information related to safety and health awareness programmes for HAVS exposure is required among hand-held grass-cutting workers.     

Multivariate analysis of accumulation and critical risk analysis of potentially hazardous elements in forage crops

Environmental Monitoring and Assessment - Few estuaries remain unaffected by water management and altered freshwater deliveries. The Caloosahatchee River Estuary is a perfect case study for...     

Urban noise assessment and its nonauditory health effects on the residents of Chiniot and Jhang,Punjab, Pakistan

Environmental Science and Pollution Research - Elevated noise level is an emerging global problem. Therefore, the present work is conducted that can improve, increase, and integrate the already...     

Evaluation of fresh and stored rainwater quality in fluoride and arsenic endemic area of Thar Desert,Pakistan

In the current study, the chemistry of fresh and stored rainwater of Thar Desert, Pakistan, was estimated during two consecutive monsoon periods. The present research deals with the variation in physicochemical parameters, total arsenic (As^t), inorganic arsenic species (Asⁱ, As^V, As^III), and fluoride (F^?) in stored rainwater (SRW) at different time intervals (1 week to 3 months). The pH of fresh rainwater (FRW) samples showed slightly acidic to neutral in nature (6.08–7.06) which were inconsistent with the reference pH value (5.6) of rainwater. The resulted data indicated that As^t and F^? levels in SRW were enhanced with time duration. The levels of As^t and F^? in SRW after different time intervals were found in the range of 194–683 μg/L and 10–35.4 mg/L, respectively. The values of As^t and F^? were 20–70 and 7–24 times higher than those of WHO permissible limits, 10 μg/L and 1.5 mg/L, respectively. The As^III was dominant species in SRW, which corresponds to >60 % of Asⁱ. The characteristics of the SRW revealed an unacceptable quality to consume for drinking and agricultural purposes in the studied area.     

Cytotoxic, phytotoxic, and mutagenic appraisal to ascertain toxicological potential of particulate matter emitted from automobiles

Vehicular air pollution is a mounting health issue of the modern age, particularly in urban populations of the developing nations. Auto-rickshaws are not considered eco-friendly as to their inefficient engines producing large amount of particulate matter (PM), thus posing significant environmental threat. The present study was conducted to ascertain the cytotoxic, phytotoxic, and mutagenic potential of PM from gasoline-powered two-stroke auto-rickshaws (TSA) and compressed natural gas-powered four-stroke auto-rickshaws (FSA). Based on the increased amount of aluminum quantified during proton-induced X-ray emission analysis of PM from TSA and FSA, different concentrations of aluminum sulfate were also tested to determine its eco-toxicological potential. The MTT assay demonstrated significant (p?<?0.001) dose-dependent cytotoxic effects of different concentrations of TSA, FSA, and aluminum sulfate on BHK-21 cell line. LC₅₀ of TSA, FSA, and aluminum sulfate was quantified at 16, 11, and 23.8 μg/ml, respectively, establishing PM from FSA, a highly cytotoxic material. In case of phytotoxicity screening using Zea mays, the results demonstrated that all three tested materials were equally phytotoxic at higher concentrations producing significant reduction (p?<?0.001) in seed germination. Aluminum sulfate proved to be a highly phytotoxic agent even at its lowest concentration. Mutagenicity was assessed by fluctuation Salmonella reverse mutation assay adopting TA100 and TA98 mutant strains with (+S9) and without (?S9) metabolic activation. Despite the fact that different concentrations of PM from both sources, i.e., TSA and FSA were highly mutagenic (p?<?0.001) even at lower concentrations, the mutagenic index was higher in TSA. Data advocate that all tested materials are equally ecotoxic, and if the existing trend of atmospheric pollution by auto-rickshaws is continued, airborne heavy metals will seriously affect the normal growth of local inhabitants and increased contamination of agricultural products, which will amplify the dietary intake of the toxic elements and could result in genetic mutation or long-term health implications.     

Characterization and adsorption capacity of modified 3D porous aerogel from grapefruit peels for removal of oils and organic solvents

With the rapid industrialization, especially offshore oil exploitation, frequent leakage incidents of oils/organic solvents have adversely affected ecological systems and environmental resources. Therefore, great interest has been shown in developing new materials to eliminate these organic pollutants, which have become worldwide problems. In this study, a cost-effective, environmentally friendly porous aerogel with three-dimensional (3D) structure was prepared from grapefruit peel by a facile hydrothermal method as the adsorbent of oils/organic solvents. The as-prepared modified grapefruit peel aerogel (M-GPA) showed mesoporous structure with high specific surface area of 36.42 m²/g and large pore volume of 0.0371 cm³/g. The excellent hydrophobicity of M-GPA with a water contact angle of 141.2° indicated a strong potential for adsorption of oils and organic solvents. The high adsorption capacity of M-GPA for a series of oils and organic solvents was 8 to 52 times as much as its own weight. Moreover, the M-GPA was easily regenerated and a high adsorption capacity recovery above 97% was maintained after five adsorption–regeneration cycles. Therefore, the M-GPA is a promising recyclable adsorbent for the removal of oils/organic solvents from polluted water.