Presence and fate of priority substances in domestic greywater treatment and reuse systems.

A wide range of household sources may potentially contribute to contaminant loads in domestic greywater. The ability of greywater treatment systems to act as emission control barriers for household micropollutants, thereby providing environmental benefits in addition to potable water savings, have not been fully explored. This paper investigates the sources, presence and potential fate of a selection of xenobiotic micropollutants in on-site greywater treatment systems. All of the investigated compounds are listed under the European Water Framework Directive as either "Priority Substances" (PS) or "Priority Hazardous Substances" (PHS). Significant knowledge gaps are identified. A wide range of potential treatment trains are available for greywater treatment and reuse but treatment efficiency data for priority substances and other micropollutants is very limited. Geochemical modelling indicates that PS/PHS removal during treatment is likely to be predominantly due to sludge/solid phase adsorption, with only minor contributions to the water phase. Many PS/PHS are resistant to biodegradation and as the majority of automated greywater treatment plants periodically discharge sludge to the municipal sewerage system, greywater treatment is unlikely to act as a comprehensive PS/PHS emission barrier. Hence, it is important to ensure that other source control options (e.g. eco-labeling, substance substitution, and regulatory controls) for household items continue to be pursued, in order that PS/PHS emissions from these sources are effectively reduced and/or phased out as required under the demands of the European Water Framework Directive.

Effects of temperature on metal tolerance and the accumulation of Zn and Pb by metal-tolerant fungi isolated from urban runoff treatment wetlands.

AIMS: To investigate the ability of two fungi to accumulate Zn and Pb, the effect of temperature on their metal tolerance and possible mechanisms involved in metal accumulation. METHODS AND RESULTS: Beauveria bassiana and Rhodotorula mucilaginosa isolated from constructed wetlands receiving urban runoff were grown in modified glycerol asparagine medium containing elevated levels of Zn and Pb at 30 degrees C. Beauveria bassiana accumulated up to 0.64% of available Zn and 8.44% of Pb. The corresponding values for R. mucilaginosa were up to 2.05% for Zn and 16.55% for Pb. Radial growth of colonies grown at 4 degrees and 30 degrees C on agar containing Zn or Pb indicated that metal tolerance was not seriously affected by a decrease in temperature. Transmission electron microscopy and emission dispersion x-ray spectrophotometry suggested that the mechanism of resistance in B. bassiana may be associated with the precipitation of Pb (possibly in the form of oxalates). CONCLUSION: The processes of biosorption could potentially occur throughout the year with both living and dead cells able to accumulate metals. SIGNIFICANCE AND IMPACT OF THE STUDY: Identified precipitation processes could be an important mechanism in metal removal in wetland substrates serving as long-term storage sinks.

Selected stormwater priority pollutants: a European perspective.

The chemical characteristics of stormwater are dependent on the nature of surfaces (roads, roofs etc.) with which it comes into contact during the runoff process as well as natural processes and anthropogenic activities in the catchments. The different types of pollutants may cause problems during utilisation, detention or discharge of stormwater to the environment and may pose specific demands to decentralised treatment. This paper proposes a scientifically justifiable list of selected stormwater priority pollutants (SSPP) to be used, e.g., for evaluation of the chemical risks occurring in different handling strategies. The SSPP-list consists of 25 pollutant parameters including eight of the priority pollutants currently identified in the European Water Framework Directive. It contains general water quality parameters (organic and suspended matter, nutrients and pH); metals (Cd, Cr, Cu, Ni, Pb, Pt and Zn); PAH (naphthalene, pyrene and benzo[a]pyrene); herbicides (pendimethalin, phenmedipham, glyphosate and terbutylazine); and other representative industrially derived compounds (nonylphenol ethoxylates, pentachlorophenol, di(2-ethylhexyl)phthalate, PCB-28 and methyl tert-butyl ether). Tools for flux modelling, enabling calculation of predicted environmental concentrations (PECs), and for ranking the susceptibility of a pollutant to removal within a range of structural stormwater treatment systems or best management practices (BMPs) have been developed, but further work is required to allow all SSPPs to be addressed in the development of future stormwater pollution control measures. In addition, the identified SSPPs should be considered for inclusion in stormwater related monitoring campaigns.

Constructed wetlands in UK urban surface drainage systems.

This paper presents the outcome of an inventory of planted wetland systems in the UK which are classified according to land use type and are all examples of sustainable drainage systems. The introduction of constructed wetlands to treat surface runoff essentially followed a 1997 Environment Agency for England and Wales report advocating the use of "soft engineered" facilities including wetlands in the context of sustainable development and Agenda 21. Subsequently published reports by the UK Construction Industry Research and Information Association (CIRIA) have promoted the potential benefits to both developer and the community of adopting constructed wetlands and other vegetated systems as a sustainable drainage approach. In addition, the UK Environment Agency and Highways Agency (HA) have recently published their own design criteria and requirements for vegetative control and treatment of road runoff. A case study of the design and performance of a constructed wetland system for the treatment of road runoff is discussed. The performance of these systems will be assessed in terms of their design criteria, runoff loadings as well as vegetation and structure maintenance procedures. The differing design approaches in guidance documents published in the UK by the Environment Agency, CIRIA and HA will also be evaluated.

Prophylactic Diclectin reduces the incidence of postoperative vomiting.

BACKGROUND: Diclectin(R) (DCL) is an effective antiemetic used for relief of nausea and vomiting in pregnancy. It is unknown whether DCL is effective in the prevention of postoperative nausea and vomiting (PONV). METHODS: We conducted a randomized, stratified, double-blind placebo-controlled trial to examine the incidence of PONV in women undergoing elective laparoscopic tubal ligation in the day surgery setting. DCL (doxylamine succinate 10 mg and pyridoxine hydrochloride 10 mg) was administered orally the night before surgery, the morning of surgery, and upon hospital discharge. RESULTS: We enrolled 146 women in the trial, 127 of whom were included in the effectiveness analysis and 102 of whom were included in the efficacy analysis. We did not detect a difference in the incidence of nausea and vomiting in the first six hours postoperatively after adjusting for additional antiemetics administered. Patients receiving DCL as compared with placebo were significantly less likely to experience vomiting six to 24 hr postoperatively [5/59 (8.5%) vs 14/55 (25.4%), P < 0.017]. Treated patients tended to return to work earlier than those who received placebo (1.74 vs 3.7 days P = NS). CONCLUSION: Perioperative oral DCL reduces the incidence of postoperative vomiting in women undergoing elective laparoscopic tubal ligation, and may accelerate return to work.

Multicriteria decision approaches to support sustainable drainage options for the treatment of highway and urban runoff.

The control and treatment of urban and highway runoff involves a variety of stakeholders in the selection of sustainable drainage systems (SUDS) as the design process needs to consider not only water quantity but also water quality and amenity. Thus, technical, environmental/ecological, social/community and economic cost factors become prime potential sustainability criteria in terms of assessing long-term, cost-effective drainage options. The paper develops a multicriteria analysis methodology for the evaluation and accreditation of SUDS structures within the context of an overall decision-support framework. Approaches independently developed in the UK and France are outlined with the common multicriteria structures defining generic performance criteria together with supporting benchmark standards and exclusion thresholds. A French case study is presented to illustrate the approach and to highlight the inherent constraints and subjectivity embedded in the decision-making process.

An experimental constructed wetland system for the treatment of highway runoff in the UK.

This paper compares the performance of an experimental highway runoff treatment system, incorporating a subsurface flow constructed wetland, with that of a vegetated balancing pond. Both systems are located on the same major road in the UK which opened in November 1998. Copper, chromium and nickel total aqueous metal concentrations, although low, have been consistently removed (maximum efficiencies of 67.3, 69.8 and 87.0% respectively in the constructed wetland), particularly in the summer. Zinc showed the highest aqueous metal concentrations and the generally positive removal by the constructed wetland system (maximum efficiency of 60.6%) correlates with the expected metal uptake by Typha latifolia and Phragmites australis. Sediment levels for these metals and for lead progressively decreased over the one year monitoring period. For the two storm events monitored in the constructed wetland system, all metals showed evidence of removal (removal efficiencies of 24.2 to 99.4%) except for copper. Lead and cadmium demonstrated the highest removal efficiencies followed by nickel and zinc. For both storms, the wetland acted as a source of copper (removal efficiencies of -88.4 to -97.1%), which may be explained by the die-back of aquatic plants and consequent release of organically bound copper.

Histamine-2-receptor antagonists and antacids in the critically ill population: stress ulceration versus nosocomial pneumonia.

We performed a meta-analysis to evaluate whether stress ulcer prophylaxis with histamine-2-receptor antagonists or antacids reduces mortality in critically ill patients. It appears that sucralfate results in a lower incidence of nosocomial pneumonia than either antacids or histamine-2-receptor antagonists. With respect to mortality, strong trends favored sucralfate over both antacids and histamine-receptor antagonists.