Validation of QuEChERS-based method for determination of flusilazole residues in grape by high-performance liquid chromatography with photodiode array detector

A high-performance liquid chromatography with photodiode array detector analytical method was developed to determine the residue levels of flusilazole in grape and investigate the dissipation pattern and safety. The results showed that the mean recoveries were in the range of 86%–90%. Limits of detection and quantification were 0.008 and 0.02 mg/kg, respectively. The residue levels of flusilazole were best described by first-order rate kinetics and with half-lives ranging from 4.2 days (recommended dose) to 4.6 days (double the recommended dose). In conclusion, flusilazole at the recommended or even at double the recommended doses does not pose any apparent hazards to consumers.     

Prevalence of Rotaviruses Groups A and C in Egyptian Children and Aquatic Environment

The objective of this study is to compare the prevalence of rotaviruses groups A and C in Egyptian children and aquatic environment. From 110 stool specimens of children with acute diarrhea and using RT-PCR, 35 samples (31.8 %) were positive for human rotavirus group A and 15 samples (13.6 %) were positive for human rotavirus group C. From 96 samples collected from Zenin wastewater treatment plant over a 2-year period (November 2009–October 2011) and using RT-PCR, rotavirus group A was detected in (4/24) 16.7 %, (5/24) 20.8 %, (4/24) 16.7 %, and (4/24) 16.7 %, while rotavirus group C was detected in (2/24) 8.3 %, (3/24) 12.5 %, (3/24) 12.5 %, and (0/24) 0 % in raw sewage, after primary sedimentation, after secondary sedimentation, and after final chlorination, respectively. Moreover, from 96 samples collected from El-Giza water treatment plant over a 2-year period (November 2009–October 2011), rotavirus group A was detected in (7/24) 29.2 %, (6/24) 25 %, (5/24) 20.8 %, and (3/24) 12.5 %, while rotavirus group C was detected in (3/24) 12.5 %, (1/24) 4.2 %, (1/24) 4.2 %, and (0/24) 0 % in raw Nile water, after sedimentation, after sand filtration, and after final chlorination, respectively. Using SYBR Green real-time RT-PCR, the number of human rotavirus group A genome or infectious units was higher than rotavirus group C. VP6 sequence analysis of the RT-PCR positive rotavirus group C samples revealed that four clinical specimens and three environmental samples showed similar sequences clustered with Moduganari/Human Nigerian strain AF 325806 with 98 % homology, and two clinical specimens and one environmental sample showed similar sequences clustered with Dhaka CB/Human Bangladesh strain AY 754826 with 97 % homology.     

Decision support methods for the environmental assessment of contamination at mining sites

Polluting mine accidents and widespread environmental contamination associated with historic mining in Europe and elsewhere has triggered the improvement of related environmental legislation and of the environmental assessment and management methods for the mining industry. Mining has some unique features such as natural background pollution associated with natural mineral deposits, industrial activities and contamination located in the three-dimensional sub-surface space, the problem of long-term remediation after mine closure, problem of secondary contaminated areas around mine sites and abandoned mines in historic regions like Europe. These mining-specific problems require special tools to address the complexity of the environmental problems of mining-related contamination. The objective of this paper is to review and evaluate some of the decision support methods that have been developed and applied to mining contamination. In this paper, only those methods that are both efficient decision support tools and provide a ‘holistic’ approach to the complex problem as well are considered. These tools are (1) landscape ecology, (2) industrial ecology, (3) landscape geochemistry, (4) geo-environmental models, (5) environmental impact assessment, (6) environmental risk assessment, (7) material flow analysis and (8) life cycle assessment. This unique inter-disciplinary study should enable both the researcher and the practitioner to obtain broad view on the state-of-the-art of decision support methods for the environmental assessment of contamination at mine sites. Documented examples and abundant references are also provided.     

Effects of long-term chlorpyrifos exposure on mortality and reproductive tissues of Banded Gourami (Trichogaster fasciata)

Abstract

This study assessed the long-term toxicity of chlorpyrifos on survival and reproduction of Banded Gourami by using mortality, gonado-somatic index (GSI) and histopathological observations as endpoints. Adult fish were exposed to five different concentrations of chlorpyrifos (0, 15, 50, 150, 500?µg/L) in 15 PVC tanks for 15, 30, 45, 60 and 75?days. Results showed that all male and female fish died after 15?days of 500?µg/L chlorpyrifos exposure. No consistent significant effect was observed for both male and female GSI. Furthermore, results showed dose- and time-dependent histopathological alterations for both ovary and testes. The 60-d No Observed Effect Concentration (NOEC) for most histopathological alterations of Banded Gourami ovary and testes was 50?μg/L, while 60-d NOEC for mortality of both male and female fish was < 15?μg/L. The results show that the long-term exposure to chlorpyrifos not only affect the reproductive tissues of Banded Gourami at exposure concentrations but also cause their mortality. Future studies should evaluate effects at lower concentrations.     

Systematic Development of an Artificial Neural Network Model for Real-Time Prediction of Ground-Level Ozone in Edmonton,Alberta, Canada

Abstract

Ground-level ozone is a secondary pollutant that has recently gained notoriety for its detrimental effects on human and vegetation health. In this paper, a systematic approach is applied to develop artificial neural network (ANN) models for ground-level ozone (O₃) prediction in Edmonton, Alberta, Canada, using ambient monitoring data for input. The intent of these models is to provide regulatory agencies with a tool for addressing data gaps in ambient monitoring information and predicting O₃ events. The models are used to determine the meteorological conditions and precursors that most affect O₃ concentrations. O₃ time-series effects and the efficacy of the systematic approach are also assessed. The developed models showed good predictive success, with coefficient of multiple determination values ranging from 0.75 to 0.94 for forecasts up to 2 hr in advance. The inputs most important for O₃ prediction were temperature and concentrations of nitric oxide, total hydrocarbons, sulfur dioxide, and nitrogen dioxide.     

Effects of sewage sludge amendments on pesticide sorption and leaching through undisturbed Mediterranean soils

The Gharb region in Morocco is an important agricultural zone where soils receive pesticide treatments and organic amendments to increase yields. The groundwater aquifer in the Gharb region is relatively shallow and thus vulnerable. The objective of this work was to study the influence of organic amendments on diuron, cyhalofop-butyl and procymidone leaching through undisturbed soil columns. Two soils were sampled from the Gharb region, a Dehs (sandy soil) and a R’mel (loamy clay soil). Following elution (124.5 mm), the amount of pesticide residues in the leachates of the sandy soil (0.06–0.21 %) was lower than in those of the loamy clay soil (0.20–0.36 %), which was probably due to preferential flow through the loamy clay soil. The amount of procymidone leached through the amended soil columns was greater than the control for the sandy soil only. The organic amendments did not significantly influence diuron and cyhalofop-butyl leaching in either of the soils. The application of organic amendments affected the amounts of dissolved organic matter (DOM) eluted and thus pesticide leaching as a function of soil-type. Nevertheless, in some case, the formation of pesticide-DOM complexes appeared to promote pesticide leaching, thus increasing groundwater contamination risks.     

Potential concerns related to using octadecyltrichlorosilane (OTS) in rendering soils and porous ceramics hydrophobic

The treatment of hydrophilic porous ceramics to render them hydrophobic and wetting to non-aqueous phase liquids (NAPLs) is frequently needed in multiphase flow experiments to control the flow or to measure the pressure of the NAPL. In addition, research dealing with soil wettability implies a need for hydrophobic or NAPL-wet soils. The traditional procedure, which has been widely used in literature, to render hydrophilic porous ceramics and soils hydrophobic is achieved by placing the hydrophilic solid in a 5% (by volume) octadecyltrichlorosilane (OTS) solution in ethanol followed by rinsing in ethanol. This research assesses the use of this procedure as it was found that this treatment procedure resulted in excess OTS on the surface of treated hydrophobic solids which can dissolve in an organic phase and in turn alter the wettability condition of adjacent hydrophilic soils. A modified procedure, which results in hydrophobic solids free of excess OTS, is presented.