Health risk of heavy metals from vegetables irrigated with sewage water in peri-urban of Dera Ismail Khan,Pakistan     

H. Ullah  N. U. Khan  F. Ali  Z. A. Shah  Q. Ullah 《International Journal of Environmental Science and Technology》2018,15(2):309-322

Health risks of heavy metals in vegetables irrigated with sewage water were investigated in the present study. The findings indicated a massive accumulation of heavy metals in soil and vegetables collected from Dera Ismail khan, Pakistan. The concentration levels of heavy metal in vegetables grown on soil irrigated with untreated sewage water were significantly higher at (P ≤ 0.001) than in vegetables grown on fresh-water-irrigated soil and proceeded the recommended limits of World health organization. Moreover, the findings also indicated that the adults and children consuming such vegetables ingested a large proportion of the selected toxic metals. Health risk index was greater than one for Pb and Cd in all the selected vegetables and was greater than one for Ni in three vegetables like Spinacia oleracea, Benincasa fistulosa and Lactuca sativa. Health risk assessment would be a useful tool for information regarding any threats of heavy metals contamination in vegetables.  相似文献   

Effectiveness of Mg–Al-layered double hydroxide for heavy metal removal from mine wastewater and sludge volume reduction     

M. Tamzid Rahman  T. Kameda  S. Kumagai  T. Yoshioka 《International Journal of Environmental Science and Technology》2018,15(2):263-272

Health hazards from heavy metal pollution in water systems are a global environmental problem. Of similar concern is sludge that results from wastewater treatment due to unsatisfactory sludge management technology. Therefore, the effectiveness of using Mg–Al-layered double hydroxide in the removal of heavy metals from mine wastewater was tested and compared with that of calcium hydroxide [Ca(OH)₂], which is a common treatment method for heavy metal removal. Initially, the mine wastewater contained cations of the heavy metals iron (Fe), zinc (Zn), copper (Cu), and lead (Pb). The Mg–Al-layered double hydroxides were able to remove 371, 7.2, 121, and 0.4 mg/L of these pollutants, respectively, using the co-precipitation method. The removal of these metals is most effective using 0.5 g Mg–Al-layered double hydroxide (Mg/Al molar ratio 4) and 20 min of shaking. Zn was removed by the formation of Zn(NO₃)(OH)·H₂O and Zn₅(NO₃)₂(OH)₈ when LDH, Mg/Al molar ratios of 4 and 2, respectively, were used. Similarly, Fe, Cu, and Pb were removed by the formation of Fe–Al-layered double hydroxide, Cu₂(OH)₃·NO₃ and Pb₄(OH)₄(NO₃)₄, respectively. While Ca(OH)₂ is also capable of reducing the heavy metal concentrations below the Japanese recommended values, this analysis shows that using 0.5 g Mg–Al-layered double hydroxide is a better treatment condition for mine wastewater, because it generates lower sludge volumes than 0.1 g of Ca(OH)₂. The measured sludge volume was 1.5 mL for Mg–Al-layered double hydroxide and 2.5 mL for Ca(OH)₂, a nearly twofold further reduction.  相似文献   

High-performing antifouling bacterial consortium for submerged membrane bioreactor treating synthetic wastewater     

H. Waheed  S. Pervez  I. Hashmi  S. J. Khan  S.-R. Kim 《International Journal of Environmental Science and Technology》2018,15(2):395-404

Biofouling, associated with membranes, is considered as a major operational challenge in membrane bioreactor (MBR) technology. Interrupting the process for the formation of biofilm by the action of interspecies quorum quenching (QQ) has received a significant attention since recent years. An antifouling bacterial consortium was identified to improve biofouling inhibition performance during MBR operation. For this purpose, various QQ bacteria were isolated from laboratory-scale MBR using enrichment culture method and identified via 16S rRNA. Potential quenching strains including Enterobacter cloaca, Delftia sp., and Pseudomonas sp. were utilized to control biofouling in the MBR operated in the continuous mode for 38 days. Three laboratory-scale MBRs, including two MBRs with different anti fouling consortium and a control, were operated in parallel under similar operating conditions. Biofouling control by QQ bacteria was compared based on the membrane permeability and EPS secretion from biofilm on the membrane. Both MBRs with antifouling consortium (AC-MBRs) experienced around three times less biofouling as compared to conventional MBR leading to significant decrease in acyl homoserine lactones (AHLs) concentration in the biocake. More than 90, 45, and 49% of COD, NH₄–N, and PO₄ ^3?–P removal efficiencies elucidate that QQ bacterial consortium could effectively reduce membrane biofouling without compromising the MBR efficiency. Comparatively lower concentration of bound EPS in AC-MBRs restricted the bacterial adhesion to membrane resulting in enhanced membrane permeability depicting that a broader range of signal molecules could be hydrolyzed using antifouling consortium than single or no QQ strain in the submerged MBR.  相似文献   

Synthesis of rare earth-doped yttrium vanadate polyscale crystals and their enhanced photocatalytic degradation of aqueous dye solution     

C. K. Chandrashekar  P. Madhusudan  H. P. Shivaraju  C. P. Sajan  B. Basavalingu  S. Ananda  K. Byrappa 《International Journal of Environmental Science and Technology》2018,15(2):427-440

In this study, a series of RE³⁺:YVO₄ catalysts were successful synthesized by environmentally friendly mild hydrothermal and supercritical hydrothermal techniques. The rare earth-doped YVO₄ photocatalysts were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, Fourier transform infrared spectroscopy, photoluminescence spectroscopy. The X-ray diffraction analysis reveals that the as-prepared YVO₄ crystals are of tetragonal phase. Further, the Fourier transform infrared spectroscopy result shows the absence of OH– molecules. The photoluminescence spectroscopy curves and UV–Vis spectra suggest that the band gap energy of YVO₄ is shifted to lower energy level due to doping of Nd³⁺ and Er³⁺ ions. The catalytic activities of the as-prepared RE³⁺:YVO₄ samples were tested for the photodegradation of amaranth aqueous dye solution under sunlight irradiation. Remarkably, the rare earth-doped YVO₄ nanocrystal sample showed outstanding photocatalytic degradation activities than undoped YVO₄ nanocrystal sample with good reusability. Under full spectrum irradiation, the as-prepared Nd³⁺-doped YVO₄ nanocrystals exhibited about 83% degradation efficiency. The apparent rate constant k for as-prepared Nd³⁺-doped YVO₄ nanocrystals with 50 mg of photocatalyst exhibits highest k value (0.32 min^?1), which is 2.9% higher than pure YVO₄ nanocrystals (0.11 min^?1).  相似文献   

<Emphasis Type="Italic">Trichoderma viride</Emphasis> (MTCC 800): a potential candidate for agri-horti waste utilization by solid state fermentation     

V. Ahuja  A. K. Bhatt 《International Journal of Environmental Science and Technology》2018,15(12):2679-2684

Waste management is one of the major environmental concerns globally. Meaningful utilization of various types of wastes for the production of useful products not only provides added economic benefits through variety of products but is also helpful in minimizing the environmental pollution. Trichoderma viride, a well-known fungus, has been used in the past for production of enzymes like proteases, cellulases and chitinase besides various beneficial biological activities, i.e., mycoremediation, mycoparasitism and for increasing soil fertility. In the present investigation, biodegradation potential of T. viride (MTCC-800) was evaluated by solid state fermentation using wastes like pomace, floral waste, plant litter, vegetable refuse, sawdust and sugarcane bagasse. The fungus degraded all the waste materials including sawdust that contain toxic compounds. Among all agri-horti wastes used, maximum growth of T. viride was recorded in vegetable refuse (58.16%) followed by sugarcane bagasse (48.76%) and others. The results of the present investigation, indicate that T. viride can be a potential candidate for meaningful utilization of industrial and other wastes and if. Successful at large scale it can not only help in reduction of environmental pollution but can also be a better substitute for chemical fertilizers and pesticides besides economic gains.  相似文献   

TiO<Subscript>2</Subscript>-based shaped catalyst for the recovery of elemental sulfur from H<Subscript>2</Subscript>S and SO<Subscript>2</Subscript> gas streams     

V. Nourozi Rad  M. Anbia  M. Hossaini Sadr 《International Journal of Environmental Science and Technology》2018,15(3):631-636

The Claus process has been used for the conversion of H₂S and SO₂ to elemental sulfur. These two sulfur compounds need special attention because they are very poisonous with negative impact on both the environment and human health. Here, highly active Fe–Ni/TiO₂ catalyst has been prepared and shaped by three different binders (bentonite, polyethylene glycol and carboxymethyl cellulose) into extrudes. Comparing the mechanical strength and surface area of prepared extrudes, the optimal shaped catalyst was selected with 20% of bentonite, 2% of PEG and 2% of CMC. The optimal catalyst was characterized by X-ray powder diffraction, temperature-programmed reduction, Brunauer–Emmett–Teller specific surface area, Barrett–Joyner–Halenda, scanning electron microscopy and energy-dispersive X-ray techniques and used for sulfur recovery process. The performance of this product for sulfur recovery via Claus process was excellent with the conversion of hydrogen sulfide of 76.77% and sulfur dioxide of 97.83%. The catalyst also provides high hydrolysis activity of CS₂ (83.06%). Therefore, a highly active TiO₂-supported shaped catalyst with 85.62% of conversion efficiency has been prepared successfully to convert the small amounts of H₂S, SO₂ and CS₂ to elemental sulfur.  相似文献   

Interactive effect of cadmium and zinc on chromium uptake in spinach grown in Vertisol of Central India     

M. L. Dotaniya  S. Rajendiran  M. Vassanda Coumar  V. D. Meena  J. K. Saha  S. Kundu  A. Kumar  A. K. Patra 《International Journal of Environmental Science and Technology》2018,15(2):441-448

A pot culture experiment was conducted to study impact and interaction of multi-metals on growth, yield and metals uptake by spinach (variety All Green). Three levels of each chromium (0, 50 and 100 mg/kg), cadmium (0, 1 and 2 mg/kg) and zinc (0, 10 and 20 mg/kg) in combinations (total treatments 3 × 3 × 3 = 27) were applied in a Vertisol (5 kg). The results showed that increasing the concentration of chromium, cadmium and zinc in soil enhanced the respective metal concentrations in spinach root and shoot. When cadmium at 2 mg/kg along with chromium at 100 mg/kg soil was applied, chromium concentration and uptake were decreased in root and shoot. Meanwhile, zinc application had no significant effect on chromium uptake and concentration in spinach biomass. From the results, it was concluded that cadmium at higher dose had an antagonistic effect over chromium. On the other hand, in chromium, cadmium and zinc combinations particularly at their higher levels, a competition among each other was found. Therefore, the findings could be used as guidelines for controlling and management of heavy metals pollution in farmland.  相似文献   

Eco-friendly smart hydrogels for soil conditioning and sustain release fertilizer     

J. Pushpamalar  S. J. Langford  M. B. Ahmad  Y. Y. Lim  K. Hashim 《International Journal of Environmental Science and Technology》2018,15(10):2059-2074

In the agricultural industry, biomass waste generated along with the production of food, is transformed into value-added products. Also, the demand for the slow or control release fertilizer is increasing to reduce the cost of maintaining the agricultural land. These issues are tackled by converting biomass waste to a slow fertilizer release vehicle and biodegradable water retention material that could reduce the cost for fertilizer application and simultaneously preserved the soil from dryness. A series of carboxymethyl sago pulp (CMSP) hydrogels were prepared by electron beam irradiation. Slow release systems were evaluated by loading potassium nitrate (KNO₃) and ammonium nitrate (NH₄NO₃) into the CMSP hydrogels. These CMSP hydrogels endow slow release property, biodegradability and a soil moisture preservation property that could find greener application in agricultural industries. The results indicate that CMSP hydrogels have a great potential as an agent for slow release of fertilizers.  相似文献   

Investigation of metal pollution in Moryayla (Erzurum) and surrounding stream sediments,Turkey     

G. Kirat  N. Aydin 《International Journal of Environmental Science and Technology》2018,15(10):2229-2240

The enrichment factor (EF), geochemical index (Igeo), pollution factor (Cf), and pollutant load index (PLI) were calculated using average shale metal concentration values to determine metal pollution in Moryayla and surrounding stream sediments. It was determined that the average concentration values are above the world average shale values. According to the results obtained, the mean accumulation levels of heavy metals in the study area were Mn > Zn > Cu > Pb > As > Cr > Ni > Sb. Considerable degree of enrichment was observed because the elements As, Cu, and Pb are at EF > 5 at locations 47, 53, 70, and 71. The values obtained from the Igeo, Cf, and PLI are a wide range of pollutants (from unpolluted to moderately polluted to extremely polluted to) for the various elements studied.  相似文献   

Surface modification of <Emphasis Type="Italic">Nizimuddinia zanardini</Emphasis> and <Emphasis Type="Italic">Stoechospermum marginatum</Emphasis> using 4-phenyl-3-thiosemicarbazide to improve heavy metals biosorption from water     

S. A. Alavi  H. Zilouei  K. Zargoosh  A. Asadinezhad  A. Yousefi Abdolmaleki 《International Journal of Environmental Science and Technology》2018,15(5):993-1000

Surface modification of two algal biomasses, Nizimuddinia zanardini and Stoechospermum marginatum, using 4-phenyl-3-thiosemicarbazide ligand was performed to investigate the consequences on the adsorption of heavy metals from aqueous solution. Stabilization of amino group of 4-phenyl-3-thiosemicarbazide on the surface of biomasses was confirmed using Fourier transform infrared spectroscopy. Chemical modification was found to exert significant positive effects on biosorption. Adsorption capacities for Pb(II), Cd(II) and Cr(VI) using modified N. zanardini were observed to be 19.3, 16.75 and 15.75 mg/g, respectively, compared to 17.48, 14.18 and 11.85 mg/g for raw N. zanardini biomass. Also, adsorption of Pb(II), Cd(II) and Cr(VI) by the modified S. Marginatum was found to be 17.54, 15.62 and 14.77 mg/g, respectively, in comparison with that of the raw biomass which were 16.86, 12.9 and 11.2 mg/g. The obtained results of the equilibrium adsorption were studied through different isotherm models of Langmuir, Freundlich and Temkin, where the Langmuir model was observed to agree well with the results. Prevalent kinetic models including pseudo-second order and intra-particle diffusion were applied, and the pseudo-second order was found to describe the adsorption kinetics data adequately. Intra-particle model was also utilized in order to show penetration of metal ions, where it was realized that the biosorption took place in two or three steps including film diffusion, molecular diffusion and chemical reaction.  相似文献