钙基膨润土辅助对堆肥及土壤Cu、Zn形态转化和白菜吸收的影响

通过好氧堆肥和盆栽试验,探究不同比例（0%、2.5%、5%、7.5%和10%）钙基膨润土（CB）辅助猪粪堆肥过程及盆栽土壤中Cu、Zn形态的变化,并分析CB对白菜生物量及吸收Cu、Zn的影响.结果表明,在所有处理的堆肥过程中,可交换态Cu、Zn的分布比例逐渐下降,而可氧化态和残渣态逐渐升高,与0% CB相比,2.5%~10% CB可使堆肥结束时生物可利用态（可交换态和可还原态）Cu、Zn的分布比例分别降低19.84%~48.90%和4.94%~16.39%,并以10% CB的效果最为显著.进而开展的盆栽试验显示,施用堆肥后,土壤有机质和EC显著升高,而pH有所下降;CB辅助堆肥能够促使土壤EC的降低及pH的升高,稳定土壤有机质.与纯土处理相比,施用堆肥可显著提升白菜的生物量,且10% CB处理中的生物量最大（6.51 g·盆^-1±0.34 g·盆^-1）.施用CB辅助堆肥后,种后土壤中生物可利用态Cu含量增加;但各处理中可交换态Zn含量分别降低38.91%、43.69%、46.02%、45.12%和54.65%.白菜在施用堆肥后Cu、Zn的吸收量显著降低,并且随着CB辅助比例的增加Zn的吸收量随之减少,而Cu的吸收量呈增加趋势.本研究表明,钙基膨润土能够降低堆肥过程中Cu、Zn活性,在堆肥施入土壤后仍对Zn有持续的固定作用,同时CB辅助堆肥可以提高白菜的生物量,减少重金属Zn在白菜中的累积,并以10% CB的效果最为显著.     

Elevated blood lead levels and cytogenetic markers in buccal epithelial cells of painters in India

Background, aim, and scope  

Lead, a major contaminant, is highly used in paint manufacturing due to its anticorrosive properties. Recent reports indicated high lead content among Indian paints used for commercial purposes. Painters are continuously exposed to these lead containing paints during painting of both commercial as well as residential buildings. Lead is well-known for its genotoxicty in occupational workers; however, in Indian painters the genotoxic effects of lead have not been reported to date. Therefore we aimed to study the genotoxic end points in painters due to their long-term exposure to these high lead-containing Indian paints.     

Perspectives of using fungi as bioresource for bioremediation of pesticides in the environment: a critical review

Pesticides are used for controlling the development of various pests in agricultural crops worldwide. Despite their agricultural benefits, pesticides are often considered a serious threat to the environment because of their persistent nature and the anomalies they create. Hence removal of such pesticides from the environment is a topic of interest for the researchers nowadays. During the recent years, use of biological resources to degrade or remove pesticides has emerged as a powerful tool for their in situ degradation and remediation. Fungi are among such bioresources that have been widely characterized and applied for biodegradation and bioremediation of pesticides. This review article presents the perspectives of using fungi for biodegradation and bioremediation of pesticides in liquid and soil media. This review clearly indicates that fungal isolates are an effective bioresource to degrade different pesticides including lindane, methamidophos, endosulfan, chlorpyrifos, atrazine, cypermethrin, dieldrin, methyl parathion, heptachlor, etc. However, rate of fungal degradation of pesticides depends on soil moisture content, nutrient availability, pH, temperature, oxygen level, etc. Fungal strains were found to harbor different processes including hydroxylation, demethylation, dechlorination, dioxygenation, esterification, dehydrochlorination, oxidation, etc during the biodegradation of different pesticides having varying functional groups. Moreover, the biodegradation of different pesticides was found to be mediated by involvement of different enzymes including laccase, hydrolase, peroxidase, esterase, dehydrogenase, manganese peroxidase, lignin peroxidase, etc. The recent advances in understanding the fungal biodegradation of pesticides focusing on the processes, pathways, genes/enzymes and factors affecting the biodegradation have also been presented in this review article.     

Visible light photocatalytic water disinfection and its kinetics using Ag-doped titania nanoparticles

The UN estimated about five million deaths every year due to water-borne diseases, accounting from four billion patients. Keeping in view, the ever increasing health issues and to undermine this statistics, a reliable and sustainable water-treatment method has been developed using visible light for water treatment. titania nanoparticles (NPs) have been synthesized successfully by a more applicable method Viz: liquid impregnation (LI) method. The bacterial death rate by photocatalysis under visible light was studied by employing a typical fluorescent source and was found to follow pseudo first-order reaction kinetics. The nanoparticles were characterized using X-ray diffraction (XRD), scanning electron microscopy, and energy-dispersive X-ray spectroscopy to deduce their size range, surface morphology, and elemental compositions, respectively. Among all the prepared grades, 1 % Ag–TiO₂ was found to be a very effective photocatalytic agent against Escherichia coli. The resulted photoinactivated data were also evaluated by different empirical kinetic models for bacterial inactivation. Hom, Hom-power, Rational, and Selleck models were not able to explain the disinfection kinetics but modified-Hom model fitted best with the experimentally obtained data by producing a shoulder, log-linear, and a tail region.     

Exposure of lead to mothers and their new born infants,residents of industrial and domestic areas of Pakistan

Prenatal and early-life exposure to lead (Pb) is hypothesized to have adverse effects on childhood health. The aim of this study was to evaluate the prenatal exposure to Pb and its adverse effects on mothers and their infants who are residents of industrial (exposed) and domestic areas (referents) in Karachi, Pakistan. The biological samples (scalp hair and blood) of mother–infants pairs were analyzed for Pb levels by atomic absorption spectrometry after microwave-assisted acid digestion method. The Pb levels in scalp hair and blood samples of exposed mothers were found in the range of 7.52–8.70 μg/g and 115–270 μg/L, respectively, which were significantly higher than those values obtained for referent mothers (p?<?0.001). The Pb levels in the blood (umbilical cord) and hair of neonates of exposed mother that were found in the range of 83–178 μg/L and 4.95–7.23 μg/g, respectively, were significantly higher than the obtained values of referent neonates (p?>?0.001). The correlation between maternal and cord blood of both groups was found in the range of 0.708–0.724 (p?<?0.01). It was observed that there were higher Pb burdens in exposed mothers and their infants as compared to referent mothers–neonates.     

Removal of arsenate from groundwater by electrocoagulation method

Purpose

Arsenic, a toxic metalloid in drinking water, has become a major threat for human beings and other organisms. In the present work, attempts have been made to remove arsenate from the synthetic as well as natural water of Ballia district, India by electrocoagulation method. Efforts have also been made to optimize the various parameters such as initial arsenate concentration, pH, applied voltage, processing time, and working temperature.

Method

Electrocoagulation is a fast, inexpensive, selective, accurate, reproducible, and eco-friendly method for arsenate removal from groundwater. The present paper describes an electrocoagulation method for arsenate removal from groundwater using iron and zinc as anode and cathode, respectively.

Results

The maximum removal of arsenate was 98.8% at 2.0?mg?L^?1, 7.0, 3.0?V, 10.0?min, and 30°C as arsenate concentration, pH, applied voltage, processing time, and working temperature, respectively. Relative standard deviation, coefficient of determination (r ²), and confidence limits were varied from 1.50% to 1.59%, 0.9996% to 0.9998%, and 96.0% to 99.0%, respectively. The treated water was clear, colorless, and odorless without any secondary contamination. The developed and validated method was applied for arsenate removal of two samples of groundwater of Ballia district, U.P., India, having 0.563 to 0.805?mg?L^?1, arsenate concentrations.

Conclusions

The reported method is capable for the removal of arsenate completely (100% removal) from groundwater of Ballia district. There was no change in the groundwater quality after the removal of arsenate. The treated water was safe for drinking, bathing, and recreation purposes. Therefore, this method may be the choice of arsenate removal from natural groundwater.     

Effect of progressive drought stress on growth,leaf gas exchange,and antioxidant production in two maize cultivars

Environmental Science and Pollution Research - Drought stress is one of the major environmental factors responsible for reduction in crop productivity. In the present study, responses of two maize...     

Surface runoff and nitrogen (N) loss in a bamboo (Phyllostachys pubescens) forest under different fertilization regimes

Nitrogen (N) losses from agricultural fields have been extensively studied. In contrast, surface runoff and N losses have rarely been considered for bamboo forests that are widespread in regions such as southern China. The thriving of bamboo industries has led to increasing fertilizer use in bamboo forests. In this study, we evaluated surface runoff and N losses in runoff following different fertilization treatments under field conditions in a bamboo (Phyllostachys pubescens) forest in the catchment of Lake Taihu in Jiangsu, China. Under three different fertilization regimes, i.e., control, site-specific nutrient management (SSNM), and farmer's fertilization practice (FFP), the water runoff rate amounted to 356, 361, and 342 m³?ha^?1 and accounted for 1.91, 1.98, and 1.85 % of the water input, respectively, from June 2009 to May 2010. The total N losses via surface runoff ranged from 1.2 to 1.8 kg?ha^?1. Compared with FFP, the SSNM treatment reduced total nitrogen (TN) and dissolved nitrogen (DN) losses by 31 and 34 %, respectively. The results also showed that variations in N losses depended mainly on runoff fluxes, not N concentrations. Runoff samples collected from all treatments throughout the year showed TN concentrations greater than 0.35 mg?L^?1, with the mean TN concentration in the runoff from the FFP treatment reaching 8.97 mg?L^?1. The loss of NO₃ ^?–N was greater than the loss of NH₄ ⁺–N. The total loss of dissolved organic nitrogen (DON) reached 23–41 % of the corresponding DN. Therefore, DON is likely the main N species in runoff from bamboo forests and should be emphasized in the assessment and management of N losses in bamboo forest.     

Biogeochemical transformation of greenhouse gas emissions from terrestrial to atmospheric environment and potential feedback to climate forcing

Environmental Science and Pollution Research - Carbon dioxide (CO2) is mainly universal greenhouse gas associated with climate change. However, beyond CO2, some other greenhouse gases (GHGs) like...     

Genotypic Variation in the Phytoremediation Potential of Indian Mustard for Chromium

The term “phytoremediation” is used to describe the cleanup of heavy metals from contaminated sites by plants. This study demonstrates phytoremediation potential of Indian mustard (Brasicca juncea (L.) Czern. & Coss.) genotypes for chromium (Cr). Seedlings of 10 genotypes were grown hydroponically in artificially contaminated water over a range of environmentally relevant concentrations of Cr (VI), and the responses of genotypes in the presence of Cr, with reference to Cr accumulation, its phytotoxity and anti-oxidative system were investigated. The Cr accumulation potential varied largely among Indian mustard genotypes. At 100 μM Cr treatment, Pusa Jai Kisan accumulated the maximum amount of Cr (1680 μg Cr g⁻¹ DW) whereas Vardhan accumulated the minimum (107 μg Cr g⁻¹ DW). As the tolerance of metals is a key plant characteristic required for phytoremediation purpose, effects of various levels of Cr on biomass were evaluated as the gross effect. The extent of oxidative stress caused by Cr stress was measured as rate of lipid peroxidation. The level of thiobarbituric acid reactive substances (TBARS) was enhanced at all Cr treatments when compared to the control. Inductions of enzymatic and nonenzymatic antioxidants were monitored as metal-detoxifying responses. All the genotypes responded to Cr-induced oxidative stress by modulating nonenzymatic antioxidants [glutathione (GSH) and ascorbate (Asc)] and enzymatic antioxidants [superoxide dismutase (SOD), ascorbate peroxidase (APX), and glutathione reductase (GR)]. The level of induction, however, differed among the genotypes, being at its maximum in Pusa Jai Kisan and its minimum in Vardhan. Pusa Jai Kisan was grown under natural field conditions with various Cr treatments, and Cr-accumulation capacity was studied. The results confirmed that Pusa Jai Kisan is a hyperaccumulator of Cr and hypertolerant to Cr-induced stress, which makes this genotype a viable candidate for use in the development of phytoremediation technology of Cr-contaminated sites.