Assessment of anthropogenic sources of water pollution using multivariate statistical techniques: a case study of the Alqueva’s reservoir, Portugal

Multivariate statistical techniques were applied to evaluate spatial/temporal variations, and to interpret water quality data set obtained at Alqueva reservoir (south of Portugal). The water quality was monitored at nine different sites, along the water line, over a period of 18 months (from January 2006 to May 2007) using 26 water quality parameters. The cluster analysis allowed the formation of five different similarity groups between sampling sites, reflecting differences on the water quality at different locations of the Alqueva reservoir system. The PCA/FA identified six varifactors, which were responsible for 64% of total variance in water quality data set. The principal parameters, which explained the variability of quality water, were total phosphorus, oxidability, iron, parameters that at high concentrations indicate pollution from anthropogenic sources, and herbicides indicative of an intensive agricultural activity. The spatial analysis showed that the water quality was worse in the north of the reservoir.     

A field trial to assess the performance of CO2-supersaturated water injection for residual volatile LNAPL recovery

A pilot scale field trial was conducted to evaluate the recovery of volatile, light non-aqueous phase liquids (LNAPLs) using a novel remediation method termed supersaturated water injection (SWI). SWI uses a patented technology to efficiently dissolve high concentrations of CO₂ into water at elevated pressures. This water is injected into the subsurface resulting in the nucleation of CO₂ bubbles at and away from the injection point. The nucleating bubbles coalesce, rise and volatilize residual LNAPL ganglia. In this study, an LNAPL composed of 103 kg of volatile pentane and hexane, and 30 kg of non-volatile Soltrol was emplaced below the water table at residual saturation. The SWI technology removed 78% of the pentane and 50% of the less volatile hexane. Contaminant mass was still being removed when the system was shut down for practical reasons. The mass removed is comparable to that expected for air sparging but a much smaller volume of gas was injected using the SWI system.     

Spatial econometric model of natural disaster impacts on human migration in vulnerable regions of Mexico

Mexico's vast human and environmental diversity offers an initial framework for comprehending some of the prevailing great disparities between rich and poor. Its socio-economic constructed vulnerability to climatic events serves to expand this understanding. Based on a spatial econometric model, this paper tests the contribution of natural disasters to stimulating the emigration process in vulnerable regions of Mexico. Besides coping and adaptive capacity, it assesses the effects of economic losses due to disasters as well as the adverse production and trade conditions of the 1990s on emigration rates in 2000 at the municipality level. Weather-related disasters were responsible for approximately 80 per cent of economic losses in Mexico between 1980 and 2005, mostly in the agricultural sector, which continues to dominate many parts of the country. It is dramatic that this sector generates around only four per cent of gross domestic product but provides a livelihood to about one-quarter of the national population. It is no wonder, therefore, that most emigration from this country arises in vulnerable rural areas.     

Perceptions of climate change,multiple stressors and livelihoods on marginal African coasts

Studies of multiple stressors in Africa often focus on vulnerable inland communities. Rising concentrations of the world’s poor live in coastal rural–urban areas with direct dependencies on marine as well as terrestrial ecosystem goods and services. Using participatory methods we elicited perceptions of stressors and their sources, impacts and consequences held by coastal communities in eastern Africa (Mtwara in Tanzania and Maputo in Mozambique). Respondent-informed timelines suggest wars, economic policies and natural increase have led to natural resource-dependent populations in marginal, previously little-inhabited lowland coastal areas. Respondents (n = 91) in interviews and focus groups rank climate stressors (temperature rise/erratic rain) highest amongst human/natural stressors having negative impacts on livelihoods and wellbeing (e.g., cross-scale cost of living increases including food and fuel prices). Sources of stress and impacts were mixed in time and space, complicating objective identification of causal chains. Some appeared to be specific to coastal areas. Respondents reported farms failing and rising dependence on stressed marine resources, food and fuel prices and related dependence on traders and credit shrunk by negative global market trends. Development in the guise of tourism and conservation projects limited access to land–sea livelihoods and resources in rural–urban areas (coastal squeeze). Mental modelling clarified resource user perceptions of complex linkages from local to international levels. We underline risks of the poor in marginal coastal areas facing double or multiple exposures to multiple stressors, with climate variability suggesting the risks of climate change.     

Design of a new monitoring network and first testing of new biological assessment methods according to water framework directive

In most European member states, more or less completely new monitoring networks and assessment methods had to be developed as basic technical tools for the implementation of the EU Water Framework Directive (WFD). In the river basin of the Stever, the largest tributary to the river Lippe (River Rhine, Northrhine-Westphalia, Germany), a WFD-monitoring network was developed, and new German biological methods for rivers, developed for the purposes of the WFD, have been applied. Like most rivers in the German lowland areas, nearly all the river courses of the Stever system are altered by hydro-morphological degradation (straightening, bank fixation, lack of canopy etc.). In 2005 and 2006, the biological quality components of macroinvertebrates, fish and macrophytes were investigated and evaluated for the assessment of the ecological status of about 50 surface water bodies within the whole Stever system. Basic physical and chemical parameters, as well as priority substances, have been analysed in the same period. In this contribution, the design of the new monitoring network, the core principles of the German biological methods, and the most important results of the pilot monitoring will be presented. As main impacts with severe effects on the faunal and floral communities, the many migration barriers and the bad quality of the river morphology could be stated. Organic pollution is no more a severe problem in the Stever. The pilot project was successfully conducted in close collaboration with the water authorities (District Government Münster) and the water association Lippeverband.     

Water Consumption and Long-run Socio-economic Development: an Intervention and a Principal Component Analysis for the City of Milan

This paper analyses the evolution of water consumption in Milan during the twentieth century. However, dealing with a century time series raises some complicated statistic and econometric issues. To study the main research questions outlined by the literature, as the presence of consumption habits and the link between consumption and price, we use a quite original approach – based on intervention analysis and principal component analysis (PCA) – which seems to be more adequate than “regression-type” approaches to study a so long time series. Results indicate (1) how some events have modified the normal evolution of per-capita water consumption; (2) that per-capita water consumption is a very persistent series, namely, that water users should have well-developed consumption habits; (3) that per-capita consumption and water price present a strong negative correlation.

Analysis of mobile source air toxics (MSATs)—Near-road VOC and carbonyl concentrations

Exposures to mobile source air toxics (MSATs) have been associated with numerous adverse health effects. While thousands of air toxic compounds are emitted from mobile sources, members of a subset of compounds are considered high priority due to their significant contribution to cancer and noncancer health risks and the contribution of mobile sources to total exposure as evaluated by the U.S. Environmental Protection Agency (EPA) National-Scale Air Toxics Assessments (NATA). These pollutants include benzene, 1,3-butadiene, ethylbenzene, acrolein, acetaldehyde, formaldehyde, naphthalene, polycyclic organic matter, and diesel particulate matter/organic gases. This study provided year-long trends of benzene, 1,3-butadiene, acrolein, acetaldehyde, and formaldehyde in Las Vegas, NV. Results indicated that MSAT concentrations often did not exhibit trends typical of other primary emitted pollutants in this study. Instead, other mobile sources beyond the highway of interest contributed to the measured values, including a major arterial road, a large commercial airport, and a nearby parking lot. The data were compared with relevant census-tract NATA estimates, with estimated ambient 1,3-butadiene concentrations similar to the measured values. Measured benzene values were much lower relative to the NATA total ambient benzene concentrations. Measured acrolein values were much higher relative to the NATA total acrolein concentrations. Measured acetaldehyde and formaldehyde values were also higher relative to the NATA total acetaldehyde and formaldehyde concentrations for all wind conditions and downwind conditions. Some possible explanations for these differences include nearby sources influencing the measured values; meteorological influences that may not be well captured by the NATA modeling regime; chemical reactivity of measured compounds; and additional explanatory variables may be needed for certain urban areas in order to accurately disaggregate anthropogenic air toxics emissions.

Implications: Comparison of air toxics concentrations measured at four long-term near-road sites in Las Vegas, NV, show generally good agreement with the EPA 2005 U.S. Environmental Protection Agency. 2005. National Air Toxics Assessments (NATA)(accessed December 7, 2012) http://www.epa.gov/ttn/atw/natamain/index.html (http://www.epa.gov/ttn/atw/natamain/index.html)  [Google Scholar] NATA total ambient concentrations. Measured concentrations did not compare as well with EPA 2005 U.S. Environmental Protection Agency. 2005. National Air Toxics Assessments (NATA)(accessed December 7, 2012) http://www.epa.gov/ttn/atw/natamain/index.html (http://www.epa.gov/ttn/atw/natamain/index.html)  [Google Scholar] NATA for the on-road mobile portion of the ambient concentrations. This highlights the complexity of air toxic emission sources and impacts in urban areas, especially around large highway facilities; NATA's inability to capture local-scale meteorology and fine-scale ambient gradients; and that additional explanatory variables may be needed for certain urban areas in order to accurately disaggregate anthropogenic air toxics emissions.     

Evolutionary algorithm for vehicle driving cycle generation

Modeling transit bus emissions and fuel economy requires a large amount of experimental data over wide ranges of operational conditions. Chassis dynamometer tests are typically performed using representative driving cycles defined based on vehicle instantaneous speed as sequences of "microtrips", which are intervals between consecutive vehicle stops. Overall significant parameters of the driving cycle, such as average speed, stops per mile, kinetic intensity, and others, are used as independent variables in the modeling process. Performing tests at all the necessary combinations of parameters is expensive and time consuming. In this paper, a methodology is proposed for building driving cycles at prescribed independent variable values using experimental data through the concatenation of "microtrips" isolated from a limited number of standard chassis dynamometer test cycles. The selection of the adequate "microtrips" is achieved through a customized evolutionary algorithm. The genetic representation uses microtrip definitions as genes. Specific mutation, crossover, and karyotype alteration operators have been defined. The Roulette-Wheel selection technique with elitist strategy drives the optimization process, which consists of minimizing the errors to desired overall cycle parameters. This utility is part of the Integrated Bus Information System developed at West Virginia University.