Surfactant-enhanced solubilization and subsequent biodegradation of phenanthrene and pyrene from aqueous solutions by Arthrobacter strain Sphe3 was investigated. The results show that growth of Arthrobacter strain Sphe3 was increased upon increase in concentration of Tween 20 and Tween 80. Inhibition of bacterial growth was observed with increasing Triton X-100 concentrations, whereas sodium dodecyl sulfate (SDS) totally inhibited this bacterial growth. Phenanthrene and pyrene solubilization was enhanced in the presence of surfactants and found to be linearly proportional to their concentrations, above the critical micelle concentration (CMC). In addition, Tween 20 and Tween 80 enhanced the biodegradation of phenanthrene and pyrene. The high correlation coefficient (R ²) values obtained at all the concentrations studied, suggest that biodegradation kinetics of both phenanthrene and pyrene in the presence of Tween 20 and Tween 80 follow first-order kinetic equation model. Experimental results suggest that Tween 20 and Tween 80 may have great potential for applications in bioremediation of these polycyclic aromatic hydrocarbon (PAH) compounds using Arthrobacter strain Sphe3.

Arrival of tar balls to the Goa coast during pre- and southwest monsoon seasons has been a regular phenomenon in the past few years. In one such event, we observed tar ball deposits along the Goa coast during August 2010, April 2011 and May 2011 when no oil spill was reported in the Arabian Sea (AS). The only source for the formation of tar balls could be the spill/tanker-wash from the tankers passing through the international tanker routes across the AS. Assuming this, an attempt has been made to simulate surface winds, currents and tar ball trajectories for August 2010 using hydrodynamics and particle tracking models. Tar ball particles were released numerically at eight locations in the AS, and five of them reached the Goa coast, matching reasonably well with the observations. The present study confirms our view that the source of these tar balls is the accidental spills or tanker-wash along the international oil tanker route in the AS. A review of the global scenario of tar ball study is also presented in the Introduction.

Pollution by heavy metals (Co, Cu, Ni, Pb, Sb and Zn), Ra-226 and U was studied in eight profiles (1.0-1.8 m deep) in the floodplain sediments of the Ploucnice River, the Czech Republic. The element concentrations were processed by establishing local geochemical background functions from non-polluted overbank fines yet not affected by reductimorphic processes and a subsequent calculation of enrichment factors in the polluted strata. In the case of Cu and Ni, the geogenic variability of the watershed (Cretaceous marine sediments and Cenozoic volcanics and their weathering products) was successfully handled using different background functions in two parts of the studied area, which allowed us to decipher the anthropogenic and natural portions of the heavy metals and hence evaluate the history of pollution. The upper course of the river drains an extensive area of so-called chemical mining (underground acid leaching of low-grade U-bearing sediments) and hydrometallurgical processing in Straz pod Ralskem that started in the late 1960s and operated without waste-processing plants up to 1989. The river system has consequently been impacted by U and gamma-emitting Ra-226 and obviously also by divalent heavy metals (Co, Ni, Zn). In the entire study area, that pollution was preceded by increasing levels of Cu, Pb and Sb and by the Pb-206/Pb-207 ratio decreasing from 1.20 towards 1.17, which had started earlier in the twentieth century before the U mining. That pre-mining pollution can be attributed to diffuse anthropogenic activities of regional or continental importance. The most recent Pb-206/Pb-207 ratio in the Ploucnice alluvium coincides with that of peatbog profiles on the borders of the Czech Republic, showing the usefulness of floodplains as pollution archives of widespread regional to continental pollution signals.

High mercury concentrations in freshwater fish from the Nordic region have been of concern for a long time. Ongoing monitoring of key ecological species occurs in these countries to follow the situation. Here, we investigated spatial and temporal trends in mercury concentrations in European perch (Perca fluviatilis) within the Swedish and Finnish aquatic environments, collated from national monitoring programmes collected between 1974 and 2005 (n = 5,172). Data were length and weight adjusted to remove perch size as a confounding factor. Temporal trend analyses and t tests comparing pre- and post-1996 mercury concentrations for each country (1974-1995; 1996-2005; perch adjusted to 200 g/25 cm), showed a significant decrease in mercury concentration in perch from Sweden (p < 0.001) and a possible increase in mercury concentration in perch from Finland (p < 0.001). No statistically significant geographical trends were seen. Average mercury concentrations exceeded both the current environmental quality standard (EQS) of 20 ng/g wet weight (ww) and a discussed EQS for the Nordic region of 200-250 ng/g ww. Despite large reductions in mercury use and production in these countries, concentrations in perch continue to be higher here than in other European areas, posing a continued environmental risk. © 2013 Springer Science+Business Media Dordrecht.

In recent years, much attention has been devoted in developing inexpensive or alternative systems for treating acid mine drainage (AMD). Manganese is a common component of AMD, and it is traditionally removed by precipitation. However, in order to meet the standard limits for discharging, usually <1 mg L, it is necessary to raise the pH above 10 which implies in high consumption of reagents and a final pH that does not meet the required value for discharging. This study investigated the removal of manganese from an acid mine effluent and laboratory solutions by using an industrial residue consisted of manganese dioxide (MnO). The pH of the acid effluent is around 2.7, and the manganese concentration is approximately 140 mg L. Batch experiments assessed the influence of pH and the efficiency of manganese dioxide (MnO) in the Mn removal. In the presence of MnO, the metal concentration meets the discharging limit at pH range of 6.8 to 7.2. Experiments carried out with columns packed with MnO assessed the influence of the flow rate on the process. Best results were obtained for columns fed with mine water neutralized with limestone at pH 7.0 and a residence time of 3.3 h. The maximum manganese loading capacity for MnO was around 14 mg g. RAMAN spectroscopy showed that the MnO is essentially constituted of pyrolusite. In addition, the solid hausmannite (MnO) was observed on the surface of the MnO residue after its contact with the Mn solution.

Approximately 1.1 million deer–vehicle collisions occur in the United States each year. The predominant methods of disposing of these carcasses (landfill and burial) have several costly disadvantages, including long travel distances to landfills, increasing landfill restrictions, and lack of viable burial areas. Some states have found static compost windrows to be an easy and cost-effective carcass management technique. This type of composting involves the construction of passively aerated static piles, which do not require the materials turning needed with more traditional composting methods. In this study, deer mortality static compost windrows were monitored for 1 year. Windrows were analyzed for pathogen destruction and the degree to which underlying soil filtered leachate contaminants. In response to high windrow temperatures, indicator pathogens Escherichia coli and Salmonella were reduced by 99.99 % the first sampling day (day 7) and ascarids were deemed non-viable by day 77. Soil filtration of leachate was effective in reducing concentrations of ammonia, chloride, and total organic carbon. Nitrate, a contaminant of particular regulatory concern, had an estimated mass contaminant loss of 2.1 kg/ha, compared to the estimated 9 to 50 kg/ha loss from fertilizer application of common agronomic crops. Results of this study indicate that with properly constructed static compost windrows, (1) high temperatures effectively destroy indicator pathogens; (2) the natural filtration of leachate through soil reduces deer mortality contaminant concentrations; and (3) the low volume of leachate (i.e., two percent of the precipitation that fell on windrows) results in nominal losses of nitrate and other contaminants.

The photooxidation degradation of tri (2-chloroethyl) phosphate (TCEP) by combining UV with hydrogen peroxide as oxidant was primarily studied in the present study by evaluating various treatment parameters. The results suggested that light intensity, initial pH and concentration of TCEP and H₂O₂, and reaction time affected the degradation efficiency of TCEP. The total organic carbon (TOC) removal rates, and the yield rates of Cl⁻and PO₄ ³⁻reached up to 86 %, 94 % and 97 %, respectively, under the optimized conditions in the present study. The degradation process obeyed the pseudo-first-order kinetic reaction expressed as ln (C ₜ/C ₀) =−0.0275 t with a R ² of 0.9962. The addition of t-butanol indicated that hydroxyl radicals played an important role in the degradation of TCEP. The primary investigation of the degradation mechanism of TCEP suggested that TCEP molecules were attacked by hydroxyl radicals produced from H₂O₂ with the irradiation of UV light, PO₄ ³⁻, Cl⁻and chlorinated alcohol/aldehyde, and/or non-chlorinated aldehyde with small molecular weight were produced, these produced small organic molecules were furthered oxidized to acids, most of them were finally mineralized to CO₂ and H₂O. The present technology was successfully applied for degrading TCEP in simulated real wastewater, which shows a promising potential for treating similar contaminants using corresponding advanced oxidation technology.

We investigated the influence of immobilization of bacterial cells and photocatalytic material TiO2 on the degradation of phenol by conducting batch microcosm studies consisting of suspended, immobilized cells and immobilized TiO2 at various initial phenol concentrations (50-1,000 mg L-1). Results showed that both suspended and immobilized cells were concentration-dependent, exhibiting the increasing degradation rate with the concentration of up to 500 mg L-1 above which it declined. The degradation rate of 0.39-3.47 mg L-1 h-1 by suspended cells was comparable with those of the literature. Comparison of the degradation rates between suspended, immobilized cells and immobilized TiO2 revealed that immobilized cells achieved the highest degradation rate followed by immobilized TiO2 and suspended cells due to the toxicity of phenol at the high concentration of 1,000 mg L-1. This indicates that immobilization of bacterial cells or photocatalytic materials can serve a better alternative to offer the higher degradation efficiency at high phenol concentrations. © 2013 Springer Science+Business Media Dordrecht.

Two Co oxide catalysts supported on natural zeolites from Indonesia (INZ) and Australia (ANZ) were prepared and used to activate peroxymonosulphate for degradation of aqueous phenol. The two catalysts were characterized by several techniques such as X-ray diffraction, scanning electron microscopy, energy dispersive X-ray spectroscopy (EDS) and N2 adsorption. It was found that Co/INZ and Co/ANZ are effective in activation of peroxymonosulphate to produce sulphate radicals for phenol degradation. Co/INZ and Co/ANZ could remove phenol up to 100 and 70 %, respectively, at the conditions of 25 ppm phenol (500 mL), 0.2 g catalyst, 1 g oxone and 25 C. Several parameters such as amount of catalyst loading, phenol concentration, oxidant concentration and temperature were found to be the key factors influencing phenol degradation. A pseudo first order would fit to phenol degradation kinetics, and the activation energies on Co/INZ and Co/ANZ were obtained as 52.4 and 61.3 kJ/mol, respectively. © 2013 Springer Science+Business Media Dordrecht.

Photoreactivation is considered to be one of the principal disadvantages of the application of ultraviolet disinfection, but knowledge about the photoreactivation potential is limited since few studies to model photoreactivation have been carried out. In order to develop a model for the prediction of the photoreactivation potential, the photoreactivation of Escherichia coli, fecal coliforms, and total coliforms in the tertiary effluent of a wastewater treatment plant was investigated using traditional plate count methods in this study. The tested bacteria were exposed to various UV doses (5-80 mJ/cm2) with a low-pressure UV-collimated beam apparatus and then put under sunlight lamp to experience photoreactivation for up to 72 h. All tested bacteria underwent photoreactivation with a similar trend. When the UV dose increased from 5 to 20 mJ/cm2, the maximum reactivation value of E. coli decreased from 105 to 10 CFU/mL over 8 h, and the reactivation rate decreased from 3.6 to 3.0 × 10-4/h. Based on the photoreactivation results, an exponential model was developed to predict the possible maximum photoreactivation level (N m = αD - β N 0). This simple photoreactivation potential prediction model contains only two variables (UV dose and initial bacterial count), with two constants related to the microorganism species. This model can be easily generalized and is helpful for the optimum design of UV disinfection systems. © 2013 Springer Science+Business Media Dordrecht.