Nitrogen saturation induced during winter by experimental NH4NO3 addition to a forested catchment

To investigate the potential risk of 'nitrogen saturation' in Scandinavian boreal forests, the authors are experimentally adding 30-50 kg N ha(-1) year(-1) as NH4NO3 in precipitation to an entire 0.52-ha 80-year-old spruce forested catchment at G?rdsj?n, near Gothenburg on the Swedish west coast. NO3 concentrations in runoff increased from 0 to about 7 microeq liter(-1) (maximum pulse of 43 microeq liter(-1)). The increase occurred in winter; during the April-October growing season, NO3 concentrations were very low. The speed of the response suggests that these forests are already close to saturation.     

Proximate mechanisms of contest competition among female Bwindi mountain gorillas (Gorilla beringei beringei)

Socioecological models provide a framework for predicting how animals respond competitively to the abundance and distribution of food resources. Testing predictions of socioecological models requires analysis of relationships among food resource characteristics, competitive behaviors, and measures of rank-related skew in energy balance or reproductive success. A positive relationship between dominance rank and energy balance has been observed among female mountain gorillas in Bwindi Impenetrable National Park, Uganda. This study examines the proximate mechanisms underlying feeding competition among those females. To assess the contestability of food resources, we measured the time a female spent feeding at a food site (food site residence time). We also examined the relationship between dominance rank and the access to resources, as well as the rate, context, and direction of aggression, and the number of neighbors in close proximity. As predicted, females had longer food site residence times and higher aggression rates with fruit and decaying wood than with herbaceous vegetation, suggesting that those resources may be contestable. Aggression was predominantly directed down the dominance hierarchy, although against expectation, rank was not significantly correlated with aggression rates or the time spent feeding on contestable foods. Higher-ranking females had significantly fewer neighbors, suggesting that lower-ranking females avoid higher-ranking ones. This study provides additional support for the claim that there is variability in how primates respond to the quality and distribution of food resources and that avoidance as a strategy to cope with feeding competition may result in similar skew in energy balance as rank-related aggression.     

Influences, practices and opportunities for environmental supply chain management in Nova Scotia SMEs

Executives are increasingly paying attention to the importance of supply chain management [Lambert DM, Cooper MC. Issues in supply chain management. Industrial Marketing Management 2000;29(1):65–83; Hagelaar GJLF, van der Vorst JGAJ. Environmental supply chain management: using life cycle assessment to structure supply chains. International Food and Agribusiness Management Review 2002;4:399–412]. The management of the supply chain can be a central aspect of a company's competitive advantage [Preuss L. Rhetoric and reality of corporate greening: a view from the supply chain management function. Business Strategy and the Environment 2005;14:123–139]. SCM also offers considerable opportunities to reduce a company's environmental impact. The supply chains of three small and medium enterprises (SMEs) operating in the Burnside Industrial Park in Nova Scotia, Canada were investigated to explore the opportunities to improve environmental performance of SMEs linked in supply chains. This study confirmed that time and, to a lesser degree, financial resources to address solid waste and energy issues are the greatest limiting factors. Small suppliers, and even to a certain degree medium-sized enterprises, have difficulties in allocating resources to initiatives that are not viewed as directly related to their core function, namely manufacturing the product or providing the service. This study clearly demonstrated that opportunities exist to reduce greenhouse gas emissions and solid waste. Although, the benefits that would be gained from the implementation of any of the individual actions in the supply chains explored in this study are individually small, the cumulative benefits that could be achieved among supply chains and within industrial parks are substantial, given the number of small- and medium-sized enterprises.     

A spatial analysis of pit latrine density and groundwater source contamination

This study aims to assess the relationship between chemical and microbial contamination of groundwater sources and a range of potential hazards in two peri-urban areas of Kisumu, Kenya where shallow wells and pit latrines are widely used. From 1998 to 2004, 263 samples were taken from 61 groundwater sources and tested for thermotolerant coliforms. Eighteen of these sources were also tested for chemical contaminants, including nitrate, chloride and fluoride. The locations of all water sources, buildings and pit latrines in the study area were surveyed. Local pit latrine densities were calculated using a geographic information system. Ten out 18 samples were above the World Health Organization guideline values for nitrate, 236 out of 263 were positive for thermotolerant coliforms, and all were above the guideline values for fluoride. There was neither a relationship between thermotolerant coliform levels and daily rainfall patterns nor with sanitary risk inspection scores for samples from shallow wells (r?=?0.01, p?=?0.91, n?=?191). The density of pit latrines within a 100-m radius was significantly correlated with nitrate and chloride levels (r?=?0.64, p?=?0.004 and r?=?0.46, p?=?0.05, respectively) but not with thermotolerant coliforms (r?=?0.22, p?=?0.11). These results illustrate both the public health risks associated with shallow groundwater sources, on-site sanitation and high population density. These findings have implications for current policies that promote latrine construction, especially in peri-urban areas of high population density. More comprehensive studies of larger communities should be commissioned to extend this analysis of the links between latrine density and groundwater contamination and so identify the contingent policy risks.     

Characterizing Rainwater Harvesting Performance and Demonstrating Stormwater Management Benefits in the Humid Southeast USA

Rainwater harvesting (RWH) has traditionally been implemented in areas with (semi) arid climates or limited access to potable water supplies; however, recent droughts in the humid southeastern United States have led to increased implementation of RWH systems. The objectives of this study were twofold: (1) present usage characteristics and performance results for four RWH systems installed in humid North Carolina (NC) as compared with systems located in arid/semiarid regions and (2) identify system benefits and modifications that could help improve the performance of RWH systems installed in humid regions of the world. For this study four RWH systems were installed in NC. Their usage was monitored for at least one year and compared with similar studies. Results revealed that dedicated water uses and usage characteristics for RWH systems in NC differed from those previously reported in the literature. Two of the systems studied met 100 and 61% of the potable water demand with designated uses of animal kennel flushing and greenhouse irrigation, respectively. The designated uses yielding the greatest potable water replacement were often seasonal or periodic, thus necessitating the need for identifying and implementing secondary objectives for these systems, namely, stormwater management. Otherwise, the expense and effort required to implement RWH systems in humid areas will most likely preclude their use.     

Sequential concentration of bacteria and viruses from marine waters using a dual membrane system

The ability to rapidly and effectively concentrate diverse microbes is an essential component for monitoring water quality at recreational beaches. The purpose of this study was to develop a 0.45 microm pore size dual membrane system, which can sequentially concentrate both viruses and bacteria. The top PVDF membrane was used to filter bacteria by physical straining while the bottom HA membrane retained viruses through adsorption. The recovery of this system was assessed using test organisms: enterococci and somatic coliphage. Volumes of 100 to 400 mL of unspiked and sewage-spiked beach water were filtered through both types of membranes. The PVDF membrane recovered statistically equivalent amounts of enterococci when compared to traditional membranes. All of the coliphage passed through the PVDF membrane, while 22% passed through the HA membrane. Increasing the volume from 100 to 400 mL did not significantly influence recoveries. Up to 35% of coliphage was eluted from the bottom membrane using beef extract solution. Rinsing bottom membranes with 0.5 mmol L(-1) H(2)S0(4) was found to deactivate somatic coliphage. This research demonstrates the potential of using a dual membrane adsorption system for the concentration of both bacteria and viruses from recreational beaches. A proposed bi-layer filtration system can be designed for simultaneous bacteria and virus filtration. Future experiments should focus on measurements utilizing additional bacteria and viruses.     

Water treatment control using the joint estimation outlier detection method

The loss of contaminated wastewater into the environment by leakage or other means is a serious problem. This problem is essentially the same as true of the loss of chemical reagents from a chemical production or purification process. The present article shows how the joint estimation method, an outlier detection method for time series analysis, can be used by a facility manager to deal with these problems.