Analysis of BTEX and other substituted benzenes in water using headspace SPME-GC-FID: method validation

The analysis of BTEX and other substituted benzenes in water samples using solid phase microextraction (SPME) and quantification by gas chromatography with flame ionization detection (GC-FID) was validated. The best analytical conditions were obtained using PDMS/DVB/CAR fibre using headspace extraction (HS-SPME) at 50 [degree]C for 20 min without stirring. The linear range for each compound by HS-SPME with GC/FID was defined. The detection limits for these compounds obtained with PDMS/DVB/CAR fibre and GC/FID were: benzene (15 ng L(-1)), toluene (160 ng L(-1)), monochlorobenzene (54 ng L(-1)), ethylbenzene (32 ng L(-1)), m-xylene (56 ng L(-1)), p-xylene (69 ng L(-1)), styrene (35 ng L(-1)), o-xylene (42 ng L(-1)), m-dichlorobenzene (180 ng L(-1)), p-dichlorobenzene (230 ng L(-1)), o-dichlorobenzene (250 ng L(-1)) and trichlorobenzene (260 ng L(-1)). This headspace SPME-GC-FID method was compared with a previously validated method of analysis using closed-loop-stripping analysis (CLSA). The headspace SPME-GC-FID method is suitable for monitoring the production and distribution of potable water and was used, in field trials, for the analysis of samples from main intakes of water (surface or underground) and from the water supply system of a large area (Lisbon and neighbouring municipalities).     

A SIMPLE HYDRAULIC SIMULATOR1

ABSTRACT: A simple simulator was constructed, calibrated, programmed and used in management studies of a hydraulic system containing two pumping stations in series, connected by canals and reservoirs. The features of the model, its calibration and use are described, and comparisons between measured and computed hydraulic behavior are presented.     

Water-sensitive Urban Planning: Protecting Groundwater

Sustainable development requires the promulgation of guidelines for urban planning which consider the effects of the built environment on water resources. In this context, our paper focuses on the effects of urban development on the quantity and quality of rainwater which infiltrates into the soil on its way to recharge the aquifer. The paper includes: identification of the state of knowledge regarding the effect of urban development on runoff and infiltration; a case study-estimation of the effect of certain patterns of urban development in an Israeli neighbourhood,together with an option for mitigating them by relatively simple and inexpensive means; presentation of the components of urban planning which influence runoff and infiltration; and proposals for continuing research in this area which has been relatively neglected until recently.     

NITROGEN ACCUMULATION IN A CONSTRUCTED WETLAND FOR DAIRY WASTEWATER TREATMENT1

ABSTRACT: A free water surface (FWS) constructed wetland was installed at a dairy in Glendale, Arizona, to study the potential of such a wetland to remove nitrogen (N) from wastewater. The study objectives were: (1) to determine N removal from the wastewater, and (2) to evaluate N accumulation in soil and plant tissues. The system consisted of eight cells (70 × 9 × 1.5 m) planted with Typha domingensis, Scirpus validus, and Phragmites australis. The four cells in series were lined with plastic, and the four cells in a parallel series were lined with clay. Cells received approximately 180 m³/d of partially treated dairy effluent. Plant tissues and soil samples were collected above and below ground from 24 locations during one year. Total N removal from wastewater was about 17 percent. Clay‐lined cells accumulated more N in the soil and less N in plant biomass compared with plastic lined cells. Plant biomass accounted for approximately 60 percent of total N accumulated in cells with dense plant communities. Ninety percent of accumulated soil N was organic. Total N accumulated in soil reached a maximum (1,100 mg/kg) eight months after the introduction of wastewater.     

Impacts of Variable Climate and Effluent Flows on the Transboundary Santa Cruz Aquifer

Assessing groundwater resources in the arid and semiarid borderlands of the United States and Mexico represents a challenge for land and water managers, particularly in the Transboundary Santa Cruz Aquifer (TSCA). Population growth, residential construction, and industrial activities have increased groundwater demand in the TSCA, in addition to wastewater treatment and sanitation demands. These activities, coupled with climate variability, influence the hydrology of the TSCA and emphasize the need for groundwater assessment tools for decision‐making purposes. This study assesses the impacts of changes in groundwater demand, effluent discharge, and climate uncertainties within the TSCA from downstream of the Nogales International Wastewater Treatment Plant to the northern boundary of the Santa Cruz Active Management Area. We use a conceptual water budget model to analyze the long‐term impact of the different components of potential recharge and water losses within the aquifer. Modeling results project a future that ranges from severe long‐term drying to positive wetting. This research improves the understanding of the impact of natural and anthropogenic variables on water sustainability, with an accessible methodology that can be globally applied.     

Predictors of willingness to relocate for managerial and professional employees

This study explored possible determinants, both inside and outside the job sphere, of willingness to relocate. Data were collected from a large sample of managerial and professional employees in one organization. Unlike previous research, this study investigated willingness to relocate for three different purposes: (1) for a better job or career development; (2) to help the organization; or (3) to remain employed. However, only two factors of willingness to relocate emerged: willingness to relocate for career enhancement or company needs, and willingness to relocate to remain employed. Results showed that the strongest predictors of willingness to relocate to remain employed were job sphere variables such as satisfaction with career development opportunities and propensity to remain, while family and community variables were much more important in predicting willingness to relocate for career enhancement or company needs. The implications of these results for both the organization and individuals are discussed.     

Protestant work ethic,work involvement and the psychological impact of unemployment

This study is an attempt to replicate and extend recent findings concerning the moderating effect of employment commitment on the psychological impact of unemployment. It was carried out in a highly educated population and employed Protestant work ethic endorsement (PWE) and work involvement (WINV) as indicators of commitment to work. Evidence was collected by questionnaires from 432 individuals who had been unemployed and again, six months later, from most of the same individuals. Cross-sectional and longitudinal analysis shows that individuals with high WINV were likely to suffer more from unemployment and to gain more from finding employment than low work-involved individuals. PWE, on the other hand, did not moderate the relationship between employment status and psychological state.