The Science of the total environment
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Sci. Total Environ. · Mar 2009
Identification of methyl triclosan and halogenated analogues in male common carp (Cyprinus carpio) from Las Vegas Bay and semipermeable membrane devices from Las Vegas Wash, Nevada.
Methyl triclosan and four halogenated analogues have been identified in extracts of individual whole-body male carp (Cyprinus carpio) tissue that were collected from Las Vegas Bay, Nevada, and Semipermeable Membrane Devices (SPMD) that were deployed in Las Vegas Wash, Nevada. Methyl triclosan is believed to be the microbially methylated product of the antibacterial agent triclosan (2, 4, 4'-trichloro-4-hydroxydiphenyl ether, Chemical Abstract Service Registry Number 3380-34-5, Irgasan DP300). The presence of methyl triclosan and four halogenated analogues was confirmed in SPMD extracts by comparing low- and high-resolution mass spectral data and Kovats retention indices of methyl triclosan with commercially obtained triclosan that was derivatized to the methyl ether with ethereal diazomethane. ⋯ Methyl triclosan was detected in all 29 male common carp from Las Vegas Bay with a mean concentration of 596 microg kg(-1) wet weight (ww) which is more than an order of magnitude higher than previously reported concentrations in the literature. The halogenated analogs were detected less frequently (21%-76%) and at much lower concentrations (<51 microg kg(-1) ww). None of these compounds were detected in common carp from a Lake Mead reference site in Overton Arm, Nevada.
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Medical waste has not received enough attention in recent decades in Iran, as is the case in most economically developing countries. Medical waste is still handled and disposed of together with domestic waste, creating great health risks to health-care stuff, municipal workers, the public, and the environment. A fundamental prerequisite for the successful implementation of any medical waste management plan is the availability of sufficient and accurate information about the quantities and composition of the waste generated. ⋯ The average bulk densities of total medical waste, hazardous-infectious waste, and general waste were determined to be 99.58, 96.16 and 101.26 kg/m3, respectively. Significant differences were observed between the medical waste characteristics of the hospitals studied here and those reported in other studies. In conclusion, the characteristics of generated medical waste, current environmental problems and strict budgets necessitate that the implementation of efficient management, training, and segregation program be top priorities if we are to minimize the treatment and disposal costs and reduce the risks of hazardous-infectious waste in Tabriz city.
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Sci. Total Environ. · Dec 2008
Ecological effects of diffuse mixed pollution are site-specific and require higher-tier risk assessment to improve site management decisions: a discussion paper.
Many Dutch ecosystems, whether terrestrial, aquatic or sediment-based, are diffusely polluted by mixtures of contaminants, whose concentrations often exceed regulatory Safe Values or other generic quality criteria. This situation has unclear consequences, especially when local authorities are confronted with such pollution. Water managers are frequently in doubt whether their water systems satisfy the criteria for 'Good Ecological Status' as defined in the EU's Water Framework Directive. ⋯ These issues are discussed against the background of current major policy shifts, in The Netherlands and elsewhere, from a pollutant-oriented assessment to an additional ecological and site-oriented assessment. The latter is most clearly represented in the Good Ecological Status aim of the EU-Water Framework Directive. The paper assesses, integrates and discusses the results of the Dutch research effort in this policy context.
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Sci. Total Environ. · Nov 2008
Methylmercury input to the Mississippi River from a large metropolitan wastewater treatment plant.
Methylmercury (MeHg) and total mercury (THg) inputs to the Mississippi River from a large metropolitan wastewater treatment plant were measured to characterize the relative contribution of the treatment plant to in-stream loads of these contaminants. Concentrations of MeHg and THg were determined in filtered and unfiltered whole water samples collected weekly from the treatment plant effluent stream and from the river upstream of the plant discharge. Unfiltered MeHg concentrations in the plant effluent ranged from 0.034 to 0.062 ng L(-1) and were always less than those in the river (range: 0.083-0.227 ng L(-1)). ⋯ The MeHg/THg ratio in unfiltered treatment plant effluent varied little (range: 1.6-1.9%), suggesting that THg concentration can serve as a relatively accurate proxy for MeHg concentration in this effluent stream. Supplemental sampling of the treatment plant influent stream showed that removals of MeHg and THg across the treatment process averaged 97% and 99%, respectively. These results show the treatment plant to be effective in removing MeHg and THg from wastewater and in minimizing its impact on Hg levels in the receiving water.