USE OF STAGE DATA TO CHARACTERIZE HYDROLOGIC CONDITIONS IN AN URBANIZING ENVIRONMENT1

ABSTRACT: This paper presents the results of a study on the use of continuous stage data to describe the relation between urban development and three aspects of hydrologic condition that are thought to influence stream ecosystems—overall stage variability, stream flashiness, and the duration of extreme‐stage conditions. This relation is examined using data from more than 70 watersheds in three contrasting environmental settings—the humid Northeast (the metropolitan Boston, Massachusetts, area); the very humid Southeast (the metropolitan Birmingham, Alabama, area); and the semiarid West (the metropolitan Salt Lake City, Utah, area). Results from the Birmingham and Boston studies provide evidence linking increased urbanization with stream flashiness. Fragmentation of developed land cover patches appears to ameliorate the effects of urbanization on overall variability and flashiness. There was less success in relating urbanization and streamflow conditions in the Salt Lake City study. A related investigation of six North Carolina sites with long term discharge and stage data indicated that hydrologic condition metrics developed using continuous stage data are comparable to flow based metrics, particularly for stream flashiness measures.     

Using polymer mats to biodegrade atrazine in groundwater: laboratory column experiments

Large-scale column experiments were undertaken to evaluate the potential of in situ polymer mats to deliver oxygen into groundwater to induce biodegradation of the pesticides atrazine, terbutryn and fenamiphos contaminating groundwater in Perth, Western Australia. The polymer mats, composed of woven silicone (dimethylsiloxane) tubes and purged with air, were installed in 2-m-long flow-through soil columns. The polymer mats proved efficient in delivering dissolved oxygen to anaerobic groundwater. Dissolved oxygen concentrations increased from <0.2 mg l(-1) to approximately 4 mg l(-1). Degradation rates of atrazine in oxygenated groundwater were relatively high with a zero-order rate of 240-380 microg l(-1) or a first-order half-life of 0.35 days. Amendment with an additional carbon source showed no significant improvement in biodegradation rates, suggesting that organic carbon was not limiting biodegradation. Atrazine degradation rates estimated in the column experiments were similar to rates determined in laboratory culture experiments, using pure cultures of atrazine-mineralising bacteria. No significant degradation of terbutryn or fenamiphos was observed under the experimental conditions within the time frames of the study. Results from these experiments indicate that remediation of atrazine in a contaminated aquifer may be achievable by delivery of oxygen using an in situ polymer mat system.     

Present forest biodiversity patterns in france related to former Roman agriculture

Combined archaeological and ecological investigations in a large ancient oak forest in Central France have revealed a dense network of ancient human settlements dating from the Roman period. We demonstrate a strong correlation between present-day forest plant diversity patterns and the location of Roman farm buildings. Plant species richness strongly increases toward the center of the settlements, and the frequency of neutrophilous and nitrogen-demanding species is higher. This pattern is paralleled by an increase in soil pH, available P, and delta(15)N, indicating the long-term impact of former agricultural practices on forest biogeochemical cycles. These extensive observations in a forested region on acid soils complement and confirm previous results from a single Roman settlement on limestone. Ancient Roman agricultural systems are increasingly being identified in contemporary French forests; the broad extent and long-lasting effects of previous cultivation shown in this study require that land-use history be considered as a primary control over biodiversity variations in many forest landscapes, even after millennia of abandonment.     

Life cycle assessment of spray dried soluble coffee and comparison with alternatives (drip filter and capsule espresso)

This paper aims to evaluate the environmental burdens associated with spray dried soluble coffee over its entire life cycle and compare it with drip filter coffee and capsule espresso coffee. It particularly aims to identify critical environmental issues and responsibilities along the whole life cycle chain of spray dried coffee. This life cycle assessment (LCA) specifically uses foreground data obtained directly from coffee manufacturers and suppliers. Aside from energy consumption and greenhouse gases emissions, water footprint is also studied in detail, including regionalization of water impacts based on the ecological scarcity method 2006. Other impact categories are screened using the IMPACT 2002+ impact assessment method.The overall LCA results for a 1 dl cup of spray dried soluble coffee amounts approximately to 1 MJ of primary non-renewable energy consumption, to emissions of 0.07 kg of CO_2-eq, and between 3 and 10 l of non-turbined water use, depending on whether or not the coffee cultivation is irrigated and wet treated. When considering turbined water, use can be up to 400 l of water per cup. Pouch – and to a lesser extent metal can packaging alternatives – show lower environmental burdens than glass or sticks.On average, about one half of the environmental footprint occurs at a life cycle stage under the control of the coffee producer or its suppliers (i.e., during cultivation, treatment, processing, packaging up to distribution, along with advertising) and the other half at a stage controlled by the user (shopping, appliances manufacturing, use and waste disposal). Key environmental parameters of spray dried soluble coffee are the amount of extra water boiled and the efficiency of cup cleaning during use phase, whether the coffee is irrigated or not, as well as the type and amount of fertilizer used in the coffee field. The packaging contributes to 10% of the overall life cycle impacts.Compared to other coffee alternatives, spray dried soluble coffee uses less energy and has a lower environmental footprint than capsule espresso coffee or drip filter coffee, the latter having the highest environmental impacts on a per cup basis. This study shows that a broad LCA approach is needed to help industry to minimize the environmental burdens directly related to their products. Including all processes of the entire system is necessary i) to get a comprehensive environmental footprint of the product system with respect to sustainable production and consumption, ii) to share stakeholders responsibility along the entire product life cycle, and iii) to avoid problem shifting between different life cycle stages.     

Microbial and physicochemical parameters associated with Legionella contamination in hot water recirculation systems

Hot water recirculation systems (HWRS) in hotels and nursing homes, which are common in countries such as Spain, have been related to outbreaks of legionellosis. To establish the relationships of microbial and physicochemical parameters, especially protozoa, with the occurrence of Legionella in HWRS, 231 samples from hotels and nursing homes were analysed for Legionella, protozoa, heterotrophic plate counts (HPC) at 22 and 37 °C, Pseudomonas, metals, temperature and others. Legionella pneumophila was the dominant species isolated, and 22 % were sg. 1. The sampling method became particularly important in order to define which factors were involved on the occurrence of Legionella. Results showed that the bacteria and the accompanying microbiota were more abundant in the first flush water whose temperature was lower. The bacteria occurred in those samples with high HPC and were inversely correlated with high temperatures. Multivariate regression showed that a concentration above 1?×?10⁵?CFU/100 mL of HPC at 37 °C, Fe above 0.095 ppm and the presence of protozoa increased significantly the risk of Legionella colonization, while univariant regression showed that the presence of Cu above 0.76 ppm and temperature above 55 °C diminished it. Therefore, to reduce the risk associated with Legionella occurrence in HWRS these parameters should be taken into consideration.     

Responding to climate variability: the opening of an artificial mouth on the Senegal River

The city of Saint-Louis is marked by recurrent floods, despite the decrease in rainfall. The town that grew downstream the vast plain where Senegalese-Mauritanian basin topography flattens considerably has experienced periodic flooding since its foundation. In 2003, the premature flooding of the Senegal River urged the Senegalese authorities to take the initiative to open a breach in the coastal sand strip of the “Langue de Barbarie,” in order to evacuate the water surplus from the river to the ocean and therefore resolve forever the problem of river flooding. But the disruption of estuarine dynamics has led to a rapid expansion of this gap: a few meters wide at its excavation, it reaches over 2,700 m in August 2009. Moreover, 10 months after the widening of the gap, the old river mouth was completely closed. If the natural movement of a mouth can be observed on some major deltas in the world (even on the Senegal River in the past), this is here a true man-made relocation. Based on the statistical analysis of series of hydrological data, this article demonstrates on the one hand that climatic conditions in 2003 which generated a major flood is an anomaly detected in the sequence of dry climate variability observed in the Sahel. On the other hand, it studies the rapid evolution of this new mouth of the Senegal River and discusses some of impacts on the regional social–ecological system, in this sensitive Sahelian environment.     

Effects of temperature on mineralisation of petroleum in contaminated Antarctic terrestrial sediments

Although petroleum contamination has been identified at many Antarctic research stations, and is recognized as posing a significant threat to the Antarctic environment, full-scale in situ remediation has not yet been used in Antarctica. This is partly because it has been assumed that temperatures are too low for effective biodegradation. To test this, the effects of temperature on the hydrocarbon mineralisation rate in Antarctic terrestrial sediments were quantified. 14C-labelled octadecane was added to nutrient amended microcosms that were incubated over a range of temperatures between -2 and 42 degrees C. We found a positive correlation between temperature and mineralisation rate, with the fastest rates occurring in samples incubated at the highest temperatures. At temperatures below or near the freezing point of water there was a virtual absence of mineralisation. High temperatures (37 and 42 degrees C) and the temperatures just above the freezing point of water (4 degrees C) showed an initial mineralisation lag period, then a sharp increase in the mineralisation rate before a protracted plateau phase. Mineralisation at temperatures between 10 and 28 degrees C had no initial lag phase. The high rate of mineralisation at 37 and 42 degrees C was surprising, as most continental Antarctic microorganisms described thus far have an optimal temperature for growth of between 20 and 30 degrees C and a maximal growth temperature <37 degrees C. The main implications for bioremediation in Antarctica from this study are that a high-temperature treatment would yield the most rapid biodegradation of the contaminant. However, in situ biodegradation using nutrients and other amendments is still possible at soil temperatures that occur naturally in summer at the Antarctic site we studies (Casey Station 66 degrees 17(') S, 110 degrees 32(') E), although treatment times could be excessively long.