Preliminary assessment of surface soil lead concentrations in Melbourne,Australia

Urban soils in many cities have been found to be contaminated with lead from past usage of leaded petrol, deteriorating lead-based exterior paints and industrial sources. Currently, the spatial distribution of soil lead concentrations in the Melbourne metropolitan area is unknown. The objective of this study was to perform a preliminary assessment of the spatial distributions of the surface soil lead (Pb) concentrations in the Melbourne metropolitan area, Australia. Fifty-eight surface soil samples were collected at a depth of 0–2 cm along three linear transects oriented across the Melbourne metropolitan area. Surface soil samples were also collected at a higher density in five Melbourne suburbs. Soil cores (0–50 cm) were collected in four locations, soil transects were collected at intervals with distance away from the roadway (0–50 m) in two inner city parks, and one control soil sample was collected in a rural setting. The median soil Pb concentration of the soil transect samples was 173 mg/kg (range 32–710 mg/kg), and the median soil Pb concentration of the five suburbs was 69 mg/kg (range 9–1750 mg/kg). The suburb of Footscray had the highest soil Pb concentration with a median soil Pb concentration of 192 mg/kg (range 40–1750 mg/kg). Soil Pb concentrations were generally higher nearest the centre of the Melbourne metropolitan area and in the west of Melbourne and lower in the outer suburbs to the east and north of the city centre. Soil Pb concentrations decreased with distance from roadways in the two transects taken from urban parks, and soil lead decreased with depth in the four soil cores. The soil Pb concentrations in the Melbourne metropolitan area appear to be lower than soil lead concentrations observed in inner city areas of Sydney New South Wales (NSW) and Newcastle NSW. The spatial extent of the soil Pb hazard remains undefined in portions of the Melbourne metropolitan area.     

Using the paired comparison methodology to assess environmental values in the coastal zone of Ghana

Like many developing countries, Ghana is grappling with environmental issues, such as the degradation of coastal natural resources. In an attempt to ameliorate the current state of affairs, broad institutional arrangements and policy interventions have been put in place. However coastal natural resources are still being overexploited and the effects of this are felt more strongly by certain groups (such as women and the rural poor) than others. This has led to the argument pointing to an urgent need to include local resource users as active participants in environmental decision making and to incorporate their environmental values in the management of coastal natural resources. Using empirical data from women in two Ghanaian coastal communities, this paper highlights the importance of exploring how the environmental attitudes and values of women might be considered in the management of local coastal natural resources. It assesses effectiveness of the paired comparison methodology in this respects and how this method can be also used to prioritise their environmental concerns. The results show that in both areas respondents place the greatest importance on the coastal natural resources as sources of wealth creation and of food, values which are often described as being “anthropocentric”. The paper thus argues that having discovered that the ecological value placed on natural resources is low, initiatives that could win the support of people would be those that link the livelihood and wellbeing to coastal NRM. It emphasizes the fact that conservation cannot exist outside of people and social systems; nor will it succeed unless they are linked to the welfare of resource users.     

Preliminary Studies on the Population Genetics of the Central Stoneroller (Campostoma anomalum) from the Great Miami River Basin, Ohio

Molecular approaches are particularly useful for measuring genetic diversity and were applied to samples of central stonerollers obtained from sites along tributaries to the Great Miami River in Ohio. We used Random Amplified Polymorphic DNA (RAPD) analysis to assess the level of genetic diversity within and among these populations. RAPD analysis generates genetic profiles that were used to develop indices of genetic similarity. The RAPD method provides a cost effective means of generating an arbitrary sample of anonymous loci across the genome and generate a virtually unlimited set of loci for use in genetic analysis in the absence of specific sequence information. These attributes make RAPDs well suited for use in evaluating the diversity and assessing the potential vulnerability to exposure of populations across multiple spatial scales. The results demonstrate that a significant amount of structuring exists among populations analyzed to date and that a trend exists towards genetic diversity being an inverse function of site distance from the main stem as well as a being directly related to stream order. This indicates that populations farthest from main conduits or in lower order streams, and thereby most isolated, may be the most vulnerable populations to stressor exposure. It is hoped that information pertaining to genetic diversity, when integrated with other metrics of resource condition, will aid in making scientifically grounded decisions on resource management that enhance the probability of population survival and preserve natural evolutionary processes.     

Legalizing markets and the consequences for poaching of wildlife species: the vicuña as a case study

Vicuña provide an excellent case study for examining the sustainable use of wildlife outside protected areas: the community-based conservation approach. Vicuña populations in the high Andes of Argentina, Bolivia, Chile, Ecuador and Perú fell to a critically low level, but a Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) ban on trade in their fiber has seen numbers recover dramatically, and now live shearing of vicuña for a high-value international market is being promoted as a mechanism to secure both sustainable vicuña populations and local livelihoods. We used a dynamic optimization model to explore the consequences of legalizing markets, including the consequences for poaching which is critical in vicuña dynamics. Using parameters obtained from the literature and expert knowledge, we explored different scenarios for the Argentine region of Cieneguillas. Our results showed that the role of the international market is ambiguous; live shearing for an international market can provide the very best of outcomes for both vicuña and local people, with large herds generating high revenues. But an international market also creates a market for poached vicuña fiber; as a result, vicuña numbers risk once again falling to critically low levels, resulting also in minimal revenues from sale of fiber. The message for the international community is that if community-based conservation is not implemented carefully then its impact can easily be perverse.     

Discussion: “Meadow Restoration Increases Baseflow and Groundwater Storage in the Sierra Nevada Mountains of California” by Luke J.H. Hunt,Julie Fair,and Maxwell Odland

We discuss a recent paper which evaluated the hydrologic changes resulting from a pond‐and‐plug meadow restoration project in the Sierra Nevada Mountains of California. In the study, measurements of streamflow into and out of the meadow suggested late‐summer baseflow increased as much as five‐fold when compared with prerestoration conditions. However, the volume of streamflow attributed to the restored meadow (49,000–96,000 m³ over four months) would require that 2.5–4.8 m of saturated meadow soils drain during summer months. The groundwater data from this meadow record only 0.45 m of change over this timeframe, which is less than might be expected from plant use alone (0.75 m), suggesting this restored meadow may be acting as a water sink throughout summer rather than a source.     

The Anthropocene: From Global Change to Planetary Stewardship

Over the past century, the total material wealth of humanity has been enhanced. However, in the twenty-first century, we face scarcity in critical resources, the degradation of ecosystem services, and the erosion of the planet's capability to absorb our wastes. Equity issues remain stubbornly difficult to solve. This situation is novel in its speed, its global scale and its threat to the resilience of the Earth System. The advent of the Anthropence, the time interval in which human activities now rival global geophysical processes, suggests that we need to fundamentally alter our relationship with the planet we inhabit. Many approaches could be adopted, ranging from geoengineering solutions that purposefully manipulate parts of the Earth System to becoming active stewards of our own life support system. The Anthropocene is a reminder that the Holocene, during which complex human societies have developed, has been a stable, accommodating environment and is the only state of the Earth System that we know for sure can support contemporary society. The need to achieve effective planetary stewardship is urgent. As we go further into the Anthropocene, we risk driving the Earth System onto a trajectory toward more hostile states from which we cannot easily return.     

Relationships between dairy slurry total solids, gas emissions, and surface crusts

Livestock slurry storages are sources of methane (CH?), nitrous oxide (NO?), and ammonia (NH?) emissions. Total solids (TS) content is an indicator of substrate availability for CH? and N?O production and NH? emissions and is related to crust formation, which can affect these gas emissions. The effect of TS on these emissions from pilot-scale slurry storages was quantified from 20 May through 16 Nov. 2010 in Nova Scotia, Canada. Emissions from six dairy slurries with TS ranging from 0.3 to 9.5% were continuously measured using flow-through steady-state chambers. Methane emissions modeled using the USEPA methodology were compared with measured data focusing on emissions when empty storages were filled, and retention times were >30 d with undegraded volatile solids (VS) remaining in the system considered available for CH? production (VS carry-over). Surface crusts formed on all the slurries. Only the slurries with TS of 3.2 and 5.8% were covered completely for ～3 mo. Nitrous oxide contributed <5% of total greenhouse gas emissions for all TS levels. Ammonia and CH? emissions increased linearly with TS despite variable crusting, suggesting substrate availability for gas production was more important than crust formation in regulating emissions over long-term storage. Modeled CH? emissions were substantially higher than measured data in the first month, and accounting for this could improve overall model performance. Carried-over VS were a CH? source in months 2 through 6. The results of this study suggest that substrate availability regulates emissions over long-term storage and that modifying the USEPA model to better describe carbon cycling is warranted.     

The effect of digestion and dewatering on sudden increases and regrowth of indicator bacteria after dewatering

Several investigators have reported higher densities of indicator bacteria after dewatering of anaerobically digested biosolids. The increases appear to occur at two points in the biosolids process: the first, referred to as "sudden increase", occurs immediately after dewatering; the second, "regrowth", occurs during storage over longer periods. The objectives of this study were to examine the effect of digestion and dewatering processes on sudden increase and regrowth of fecal coliform and E. coli. Samples were collected from five thermophilic and five mesophilic digestion processes, with either centrifuge or belt filter press dewatering. Sudden increase typically was observed in the thermophilic processes with centrifuge dewatering and was not observed in the mesophilic processes with either centrifuge or belt filter press dewatering. Regrowth was observed in both thermophilic and mesophilic processes with centrifuge dewatering but not belt filter press dewatering.     

Estimation of Smog Effects in the Hydrocarbon-Nitric Oxide System

Hydrocarbon components (propylene, simulated auto exhaust, or authentic auto exhaust) were irradiated in the presence of nitric oxide in large chambers instrumented for measurements of numerous variables. Eye irritation was measured using a selected panel of human subjects. The various dependent variables are presented as functions of the reactant concentrations by means of contour diagrams derived by computer treatment. The effect of “hydrocarbon” and nitric oxide levels on smog effects are discussed; the observed relationships between end effects and reaction rates are considered. The study simulated the effects of varying degrees of vehicular emissions control over one or both reactants and has a bearing on the establishment of vehicle emission standards in California.     

Sorption and degradation of neonicotinoid insecticides in tropical soils

ABSTRACT

Neonicotinoids are the most widely applied class of insecticides in cocoa farming in Ghana. Despite the intensive application of these insecticides, knowledge of their fate in the Ghanaian and sub-Saharan African environment remains low. This study examined the behavior of neonicotinoids in soils from cocoa plantations in Ghana by estimating their sorption and degradation using established kinetic models and isotherms. Studies of sorption were conducted using the batch equilibrium method on imidacloprid, thiamethoxam, clothianidin, acetamiprid and thiacloprid, while degradation of imidacloprid, thiamethoxam and their respective deuterated counterparts was studied using models proposed by the European forum for coordination of pesticide fate and their use (FOCUS). Analytes were extracted using the quick, easy, cheap, effective, rugged and safe (QuEChERS) procedure and quantified by liquid chromatography-tandem mass spectrometry (LC–MS/MS). Average recoveries were high (≥ 85%) for all analytes. The findings from the study suggest that neonicotinoid insecticides may be persistent in the soils studied based on estimated half-lives > 150 days. The study also revealed generally low-sorption coefficients for neonicotinoids in soils, largely influenced by soil organic carbon.