Regional assessment of marine and estuarine sediment toxicity in Southern California, USA

Sediment toxicity was investigated at 222 stations in the Southern California Bight (SCB) during 2008. This represented the first time that assessment methods established by California's new Sediment Quality Objectives program were employed in a survey of this scale. The goal was to determine the extent and magnitude of sediment toxicity in the SCB, how toxicity compared among specific environments, and whether toxicity has changed over the last decade. Two toxicity tests were used: the 10-day amphipod whole sediment survival test with Eohaustorius estuarius and a 48-h embryo development test with the mussel Mytilus galloprovincialis exposed at the sediment–water interface. Less than 1 % of the area of the SCB was found to be toxic to the amphipod test. No toxicity was found in offshore stations, but 14 % of embayment areas were toxic to the amphipods. The mussel test identified 13 % of the embayment areas to be toxic. Estuary and marina locations had the greatest areal extent of toxicity for both tests. The two toxicity methods agreed that sediments were not toxic at over half of the stations tested. The mussel test showed a greater magnitude of response than the amphipod. Sediment toxicity was shown to have declined in both extent and magnitude from levels measured in 1998 and 2003.     

Carbon--making the right choice for waste management in developing countries

Due to initiatives such as the clean development mechanism (CDM), reducing greenhouse gas emissions for a developing country can offer an important route to attracting investment in a variety of qualifying project areas, including waste management. To date CDM projects have been largely confined to schemes that control emission from landfill, but projects that avoid landfilling are beginning to be submitted. In considering the waste options which might be suitable for developing countries certain ones, such as energy from waste, have been discounted for a range of reasons related primarily to the lack of technical and other support services required for these more sophisticated process trains. The paper focuses on six options: the base case of open dumping; three options for landfill (passive venting, gas capture with flaring, and gas capture with energy production), composting and anaerobic digestion with electricity production and composting of the digestate. A range of assumptions were necessary for making the comparisons based on the effective carbon emissions, and these assumptions will change from project to project. The highest impact in terms of carbon emissions was from using a sanitary landfill without either gas flaring or electricity production; this was worse than the baseline case using open dumpsites. Landfills with either flaring or energy production from the collected gas both produced similar positive carbon emissions, but these were substantially lower than both open dumping and sanitary landfill without flaring or energy production. Composting or anaerobic digestion with energy production and composting of the digestate were the two best options with composting being neutral in terms of carbon emissions and anaerobic digestion being carbon negative. These generic conclusions were tested for sensitivity by modifying the input waste composition and were found to be robust, suggesting that subject to local study to confirm assumptions made, the opportunity for developing CDM projects to attract investment to improved waste management infrastructure is significant. Kyoto credits in excess of 1 tCO2e/t of waste could be realised.     

Environmental service payments: evaluating biodiversity conservation trade-offs and cost-efficiency in the Osa Conservation Area, Costa Rica

The cost-efficiency of payments for environmental services (PES) to private landowners in the Osa Conservation Area, Costa Rica, is evaluated in terms of the trade-off between biodiversity representation and opportunity costs of conservation to agricultural and forestry land-use. Using available GIS data and an 'off-the-shelf' software application called TARGET, we find that the PES allocation criteria applied by authorities in 2002-2003 were more than twice as cost-efficient as criteria applied during 1999-2001. Results show that a policy relevant assessment of the cost-effectiveness of PES relative to other conservation policies can be carried out at regional level using available studies and GIS data. However, there are a number of data and conceptual limitations to using heuristic optimisation algorithms in the analysis of the cost-efficiency of PES. Site specific data on probabilities of land-use change, and a detailed specification of opportunity costs of farm land, labour and capital are required to use algorithms such as TARGET for ranking individual sites based on cost-efficiency. Despite its conceptual soundness for regional conservation analysis, biodiversity complementarity presents a practical challenge as a criterion for PES eligibility at farm level because it varies depending on the set of areas under PES contracts at any one time.     

A Comparative Assessment of Runoff Nitrogen from Turf,Forest, Meadow,and Mixed Landuse Watersheds

Landscaping paradigms that encourage high‐input, intensively managed and mono‐culture turf/lawn landscapes have raised concerns about water quality. We conducted a watershed‐scale assessment of landscaping practices that included turf, urban, forest, native meadow, and mixed landuse watersheds with a professional golf course and a parking lot. The turf site was moderately managed and had lower fertilizer inputs than those typically used by homeowners and golf courses. Stream water sampling was performed during base flow and storm events. Highest nitrate and total nitrogen concentrations in runoff were observed for the mixed watershed draining the golf course. In contrast, concentrations in base flow from the turf watershed were lower than expected and were comparable to those measured in the surrounding meadow and forest sites. Total nitrogen concentrations from the turf site increased sharply during the first storms following fertilization, suggesting that despite optimal management there exists a risk for nutrient runoff following fertilization. Overall, this study suggests that turf or lawns, when managed properly, pose minimal water quality risk to surface waters. Rate, timing of application, and the type of fertilizer appear to be the key factors affecting water quality. Better education of homeowners and landscaping professionals with regard to these factors may be a cost‐effective strategy to reduce nonpoint source pollution.     

Exploring insideness in urban children’s sense of place

This study, informed by phenomenology and ethnography, explores urban children’s relationship with their urban environment: In what ways do urban children exhibit “insideness” in their sense of place? This study proposes “insideness” as a conceptual construct to understand urban children’s sense of place in its ecological and dynamic nature. Employing qualitative research methods, the study explores place stories of urban children who live in low-income, immigrant neighborhoods in New York City. The study finds that as children cultivate their sense of place, they construct “insideness” in their sense of place including 1) environmental understanding (i.e., contextualized, comprehensive, and critical understanding of a place), 2) environmental competence (i.e., knowing how to navigate and engage in a place), and 3) diverse, strong affective relationships with a place. Using “insideness” as a conceptual tool, this study discusses children’s emplaced understanding and active and dialogical positionality in the development of their sense of place.     

Treatment of waste containing EDTA by chemical oxidation

Ethylenediaminetetraacetic acid (EDTA) is a chelating agent that has been extensively used to enhance the solubilization of heavy metal cations and release of EDTA contributes to environmental problems. EDTA is recalcitrant to microbial metabolism and chemical oxidation is considered a possible method of remedial treatment. The use of the commercially available process of MIOX Corporation generates mixed oxidants on site and this solution is markedly effective in the destruction of the chelating characteristic and the decarboxylation of EDTA. When measuring the release of C-14 from carboxyl labeled EDTA, the mixed oxidant solution was comparable to the Fenton's reaction over a broad pH range. The presence of Mn²⁺, Cr³⁺, or Fe³⁺ at levels equal to that of EDTA stimulated the rate of EDTA decomposition; however, the rate of EDTA breakdown was inhibited when the concentration of Cr³⁺ or Mn²⁺ exceeded the concentration of EDTA. The treatment of Co²⁺–EDTA or Cu²⁺–EDTA with mixed oxidants in the presence of ultra violet light resulted in the loss of chelation ability of EDTA. In the absence of chelated metals, over 75% of the chelation property of a 70 mM EDTA solution was destroyed in 45 min. The reaction products resulting from the use of mixed oxidants added to EDTA were non-toxic to bacteria and should not contribute to additional environmental problems.     

Effects of past and present livestock grazing on herpetofauna in a landscape‐scale experiment

Livestock grazing is the most widespread land use on Earth and can have negative effects on biodiversity. Yet, many of the mechanisms by which grazing leads to changes in biodiversity remain unresolved. One reason is that conventional grazing studies often target broad treatments rather than specific parameters of grazing (e.g., intensity, duration, and frequency) or fail to account for historical grazing effects. We conducted a landscape‐scale replicated grazing experiment (15,000 km², 97 sites) to examine the impact of past grazing management and current grazing regimes (intensity, duration, and frequency) on a community of ground‐dwelling herpetofauna (39 species). We analyzed community variables (species richness and composition) for all species and built multiseason patch‐occupancy models to predict local colonization and extinction for the 7 most abundant species. Past grazing practices did not influence community richness but did affect community composition and patch colonization and extinction for 4 of 7 species. Present grazing parameters did not influence community richness or composition, but 6 of the 7 target species were affected by at least one grazing parameter. Grazing frequency had the most consistent influence, positively affecting 3 of 7 species (increased colonization or decreased extinction). Past grazing practice affected community composition and population dynamics in some species in different ways, which suggests that conservation planners should examine the different grazing histories of an area. Species responded differently to specific current grazing practices; thus, incentive programs that apply a diversity of approaches rather than focusing on a change such as reduced grazing intensity should be considered. Based on our findings, we suggest that determining fine‐scale grazing attributes is essential for advancing grazing as a conservation strategy.     

Ecology,feeding competition and social structure in baboons

Predictions of the model of van Schaik (1989) of female-bonding in primates are tested by systematically comparing the ecology, level of within-group contest competition for food (WGC), and patterns of social behaviour found in two contrasting baboon populations. Significant differences were found in food distribution (percentage of the diet from clumped sources), feeding supplant rates and grooming patterns. In accord with the model, the tendencies of females to affiliate and form coalitions with one another, and to be philopatric, were strongest where ecological conditions promoted WGC. Group fission in the population with strong WGC was “horizontal” with respect to female dominance rank, and associated with female-female aggression during a period of elevated feeding competition. In contrast, where WGC was low, females’ grooming was focused on adult males rather than other females. Recent evidence suggests that group fission here is initiated by males, tends to result in the formation of one-male groups, and is not related to feeding competition but to male-male competition for mates. An ecological model of baboon social structure is presented which incorporates the effects of female-female competition, male-male competition, and predation pressure. The model potentially accounts for wide variability in group size, group structure and social relationships within the genus Papio. Socio-ecological convergence between common baboons and hamadryas baboons, however, may be limited in some respects by phylogenetic inertia. Received: 22 April 1994/Accepted after revision: 9 December 1995     

Eco-neighbourhoods: A review of projects

The recent literature on sustainable urban form has stressed the need to move away from a system of land-use segregation and towards one which intersperses land uses and facilitates localisation. The strategy of dispersed concentration gives shape to this mixed-use principle, and has been equated with the need to plan more self-sufficient neighbourhoods. There are several problematic issues raised by such a strategy, particularly in relation to the propensity of local people to use local facilities when the friction of distance is low. The image of sustainable neighbourhoods purveyed by advocates is at odds with the reality of suburban development. A review of current eco-neighbourhood projects around the world points to the varying degrees to which they have successfully overcome the implementational and behavioural difficulties. Market-led projects — particularly in semi-rural areas — have achieved rather limited success across the range of sustainability criteria. Some large-scale municipally led plans have faired better. Projects led by community non-profit trusts have been able to be most radical and demonstrate the practicability of eco-neighbourhoods in specific situations. Overall, however, the paucity of successful projects highlights the need for a more proactive central and local government stance.