Effects of physicochemical factors on PAH degradation by Planomicrobium alkanoclasticum

Polycyclic aromatic hydrocarbons (PAHs) are environmental pollutants that are mutagenic, carcinogenic, and toxic to living organisms. Here, the ability and effectiveness of selected bacteria isolated from an oil‐contaminated area in biodegrading PAHs were evaluated, and the optimal conditions conducive to bacterial PAH biodegradation were determined. Of six bacterial isolates identified based on their 16S rRNA sequences, Planomicrobium alkanoclasticum could subsist on and consume nearly all hydrocarbons according to the 2,6‐dichlorophenolindophenol assay. The efficacy of this isolate at PAH biodegradation was then empirically confirmed. After 30 days of incubation, P. alkanoclasticum degraded 90.8% of the 16 PAH compounds analyzed and fully degraded eight of them. The optimum P. alkanoclasticum growth conditions were 35°C, pH 7.5, and NaNO₃ as the nitrogen source. Under these biostimulant conditions, P. alkanoclasticum degraded 91.4% of the total PAH concentration and completely decomposed seven PAHs after 15 days incubation. Hence, P. alkanoclasticum is an apt candidate for the biodegradation of PAHs and the bioremediation of sites contaminated by them.     

Stakeholder coordination analysis in hazardous waste management: a case study in China

Journal of Material Cycles and Waste Management - Hazardous waste management (HWM) in chemical industrial parks is an important issue related to sustainable development. Previous researches...     

Ozonation of aqueous solution of alpha endosulfan

Ozonation of alpha endosulfan and the effects of some parameters such as pH, temperature and partial pressure on ozonation were investigated and the kinetic constants were calculated in this study. Alpha endosulfan solutions were ozonated in a lab-scale semi-batch reactor under variable experimental conditions. Increase in dissolved ozone concentration had a positive effect on oxidation rate. Alpha endosulfan could be removed up to 94% at pH 4 for an ozonation time of 60 minutes. The oxidation reaction was found to be of second order and of first order with respect to both ozone and alpha endosulfan. The temperature dependent reaction expression of alpha endosulfan was obtained as kd = (1.889 exp(- 2.21 x 10(-3)/T). It was concluded that, although the rate of reaction was lower than the rate of other pesticide oxidation reported in the literature. alpha endosulfan presented an obvious reaction to ozonation.     

A STOCHASTIC MODEL TO EVALUATE RIPARIAN IRRIGATION EXPANSION IN THE EASTERN UNITED STATES1

ABSTRACT: Irrigation has expanded in parts of the eastern United States. In some areas, the adjoining surface (riparian) water is the most economical source of irrigation water. Expanded demand for riparian water may lead to conflict among irrigators and other streamflow users. Accurate information on the potential for and impacts of riparian irrigation expansion is needed to decide if control of such expansion is necessary. In this study, a stochastic economic model to evaluate the impacts of potential irrigation expansion is presented. The model considers the soil, location, and land use characteristics of individual sites, as well as weather and streamflow patterns. The application of the model to an eastern Virginia watershed indicates that, with maximum potential expansion, water availability becomes limited and yields will be reduced in some years. As a result, the expected net returns from irrigation and the probability of breaking even on the investment are reduced substantially. The results suggest the need to consider regulation of surface water allocation for irrigation development in riparian watersheds.     

Synthesis of magnetite-based nanocomposites for effective removal of brilliant green dye from wastewater

Environmental Science and Pollution Research - The present study aims at evaluating the batch scale potential of cotton shell powder (CSP), Moringa oleifera leaves (ML), and magnetite-assisted...     

Accounting embodied economic potential of healthcare waste recycling—a case study from Pakistan

Proper management of healthcare wastes is a key concern across resource-constrained countries in South Asia. Existing scientific research on this topic usually involves epidemiological and behavioral studies. Similarly, environmental impact assessment of healthcare wastes is mainly conducted from an end-user or anthropocentric point of view. In this study, we took a novel approach by analyzing healthcare wastes using an ecocentric position. Here, we utilize a case study of a general public hospital in a major city of Pakistan to analyze the embodied energy of its waste fractions by category. We used Emergy analysis to assess the true economic potential of recycling these waste items. While doing so, we compared the economic potential of current waste recycling practices with the scenario of 100% recycling of useful waste fractions. We discovered that the latent embodied energy of different recyclable waste fractions made them far more valuable than their existing market prices indicate. This value increased further if the useful waste fractions were completely recycled. In conclusion, this study used empirical evidence to argue in favor of source-segregation and recycling of healthcare wastes so that the higher costs associated with natural resource extraction and processing can be avoided. Future studies considering hazardous healthcare wastes can use the approach taken in this paper to analyze the impact of other practical waste treatment procedures.     

Association of textile industry effluent with mutagenicity and its toxic health implications upon acute and sub-chronic exposure

Complex industrial discharges pose certain risks to the ecosystem. This study was aimed at identifying acute and sub-chronic toxicological effects of the textile industry wastewater. The textile wastewater was evaluated for the metals and organic pollutants by atomic absorption spectrophotometer and GC-MS respectively. In vitro genotoxicity and mutagenicity were assessed by Comet assay in peripheral lymphocytes isolated from Ovis aries and Ames test in Salmonella typhimurium strains TA-100 and 102 respectively. Physiological and behavioral changes along with systemic toxicity were determined in Rattus norvegicus albinus following acute and sub-chronic exposure. High amount of heavy metals such as Cr, Pb, Hg, As, and Cd were detected in textile wastewater. Organic pollutants such as 25-deacetoxy cucurbitacin-b, E-14-Hexadecenal, 11-Tricosene, and phthalates were also found. In vitro genotoxicity assessment in lymphocytes showed statistically significant DNA damaging potential of textile wastewater. Textile wastewater also showed significantly higher (p? 0.05) mutagenic potential in Salmonella TA-100 and TA-102 strains than sodium azide and 2-amino anthracycline. Acute exposure of textile wastewater to Rattus norvegicus was associated with several physiological changes and behavioral symptoms. Sub-chronic exposure of textile wastewater in Rattus norvegicus instigated the degeneration and necrosis of epithelial cells in renal tubules, hydropic degeneration and necrosis of hepatocytes, peri-bronchiolar infiltration and emphysema of the alveoli, and the degradation of myocardial cells. This study concludes that the textile wastewater may cause genotoxicity and mutagenicity, result in physiological and behavioral changes upon acute exposure, and inflict various pathological lesions upon sub-chronic exposure.     

Sago pith waste ash as a potential raw material for ceramic and geopolymer fabrication

Journal of Material Cycles and Waste Management - This study focuses on the potential usage of sago pith waste ash (SPWA) obtained from sago pith waste (SPW) calcined from 500 to...     

Determination of total and bioaccessible metals in airborne particulate matter from an urban and a rural area at Sarajevo

Airborne particulate matter of up to 10 µm collected at an urban and a rural area at Sarajevo in 2013 and 2014 was acid digested for determination of total concentrations or extracted with synthetic gastric juice for the bioaccessible fractions of Cd, Cr, Cu, Fe, Mn, Ni, Pb, V, and Zn and determined by graphite furnace and flame atomic absorption spectrometry. The total concentrations of Cr, Cu, Fe, Mn, Pb, and V were higher at the urban site, while those of Cd, Ni, and Zn were virtually equal at both sites. The average bioaccessible fractions exhibited the following trend at both sites: Fe > Zn > Cu > Mn > Pb > Cr > V > Ni > Cd. Enrichment factors and daily intake of metals by inhalation were calculated.