An Evaluation of CO2, Measurements as an Indicator of Air Pollution

Measurements of ambient carbon dioxide (CO₂), made at the Continuous Air Monitoring Program station in downtown Cincinnati, Ohio, and at a rural location near Cincinnati are presented and evaluated to determine the significance of CO₂ data in urban air quality monitoring programs. Through analysis of rural CO₂ data and evaluation of combustion-sources by means of a diffusion model, it is demonstrated that the variation of urban CO₂ concentrations around the prevailing atmosphere background level results from combustion-and noncombustion {natural) sources. The concentration from natural sources can be substantial and in fact override the combustion sources. Because it is not yet practical to predict the contribution of natural sources to urban CO₂ concentrations, data obtained for-this gas have only limited utility as an index of air quality. Significant statistical relationships between CO₂ data and air quality measurements for summer months are shown to result from similar meteorological effects rather than similar sources. A seasonal and spatial variation of ih-ese relationships is postulated and subsequently demonstrated by analysis of CO₂ and air quality measurements from New Orleans, Louisiana, and SU Louis, Missouri.     

Engineered containment systems: Identification of dominant ecological processes for long‐term performance assessment and monitoring

The infiltration of rainfall into contaminated soils and wastes provides the mechanism whereby hazardous chemical and radionuclide constituents of concern are leached and transported to underlying groundwater and potential human and ecological receptors. The application of engineered covers to reduce rainfall infiltration is an approach that is often selected for the remediation of contaminated sites. Evapotranspiration, or water‐balance, cover designs have been shown to be effective ways of preventing infiltration in arid and semiarid climates. This particular design relies on evaporation and vegetative transpiration to reduce potential infiltration to acceptable levels. In this article, we identify and examine the dominant ecological processes that affect the performance of evapotranspiration cover designs. © 2012 Wiley Periodicals, Inc.     

Human exposure to PCBs, PBDEs and HBCDs in Ghana: Temporal variation, sources of exposure and estimation of daily intakes by infants

Human exposure to polychlorinated biphenyls (PCBs) and brominated flame retardants (BFRs) such as polybrominated diphenyl ethers (PBDEs) and hexabromocyclododecanes (HBCDs) was evaluated in Ghana using breast milk samples collected in 2004 and 2009. Mean levels and ranges of PBDEs (4.5; 0.86-18 ng/g lw) and PCBs (62; 15-160 ng/g lw) observed in the present study were unexpectedly high, in spite of the fact that Ghana is a non-industrialized country when compared with many of the Asian and European countries. Significant increases were found in the concentrations of PCBs and PBDEs over the years, while no significant increase was observed for HBCDs. Estimated hazard quotient (HQ) showed that all the mothers had HQ values exceeding the threshold of 1 for PCBs, indicating potential health risk for their children. PCBs in dirty oils and obsolete equipment should be of concern as potential sources in Ghana, and e-waste recycling with little or no experience in safe handling could be a threat to this sub-region noted for unregulated disposal of e-waste. The results may point towards an increase in trends in human milk in Ghana, especially in the larger cities but further analysis would be required to confirm this upward trend in levels. This is the first study to report BFRs in human breast milk from Africa, and undoubtedly from Ghana.     

Kinetics and dynamic modelling of batch anaerobic digestion of municipal solid waste in a stirred reactor

A series of batch, slurry anaerobic digestion experiments were performed where the soluble and insoluble fractions, and unwashed MSW were separately digested in a 200l stirred stainless steel vessel at a pH of 7.2 and a temperature of 38 degrees C. It was found that 7% of the total MSW COD was readily soluble, of which 80% was converted to biogas; 50% of the insoluble fraction was solubilised, of this only 80% was converted to biogas. The rate of digesting the insoluble fraction was about four times slower than the rate of digesting the soluble fraction; 48% of the total COD was converted to biogas and 40% of the total nitrogen was converted to ammonia. Soluble and insoluble fractions were broken down simultaneously. The minimum time to convert 95% of the degradable fraction to biogas was 20 days. The lag phase for the degradation of insoluble fraction of MSW can be overcome by acclimatising the culture with the soluble fraction. The rate of digestion and the methane yield was not affected by particle size (within the range of 2-50mm). A dynamic model was developed to describe batch digestion of MSW. The parameters of the model were estimated using data from the separate digestion of soluble and insoluble fractions and validated against data from the digestion of unwashed MSW. Trends in the specific aceticlastic and formate-utilising methanogenic activity were used to estimate initial methanogenic biomass concentration and bacterial death rate coefficient. The kinetics of hydrolysis of insoluble fraction could be adequately described by a Contois equation and the kinetics of acidogenesis, and aceticlastic and hydrogen utilising methanogenesis by Monod equations.     

Seasonality of reproduction in the cushion star Odontaster validus at Signy Island, Antarctica

The reproductive and larval biology of the common Antarctic cushion-star Odontaster validus Koehler (Echinodermata: Asteroidea) were studied in a shallow-water population at Signy Island in the maritime Antarctic. The gonad index peaked in April/May, and injection with 1-methyladenine indicated that competence to spawn peaked in May/June. Gastrulae were first detected in May, and maximal water-column larval densities were measured in July. Reproduction was therefore highly seasonal, although not all individuals appeared to spawn each year. The pyloric caeca index increased in summer (typically November to March, but variable between years) and decreased during winter (June to October), suggesting that feeding activity was seasonal. All aspects of biology investigated showed significant interannual variability. Comparison with previous studies in the high Antarctic at McMurdo Sound indicated a similar if more pronounced seasonality at Signy, but the warmer seawater temperatures in the maritime Antarctic (particularly in late winter/early spring from September onwards) resulted in faster larval development at Signy. Received: 21 April 1997 / Accepted: 28 January 1998     

Modelling small groundwater systems: experiences from the Braunton Burrows and Ainsdale coastal dune systems,UK

Coastal dunes are delicate systems that are under threat from a variety of human and natural influences. Groundwater modelling can provide a better understanding of how these systems operate and can be a useful tool towards the effective management of a coastal dune system, e.g. by identifying strategically important locations for flora and fauna and guiding the planning of management operations through predicting impacts from climatic change, sea level rise and land use management. Most dune systems are small, typically of the size 10–100 km², compared with inland groundwater systems. Applying conventional groundwater modelling approaches to these small systems presents a number of challenges due to the local scale of the system and the fact that the system boundaries (sea, drains, ponds etc.) are close to the main body of the aquifer. In this paper, two case studies will be presented using different modelling approaches to understand the groundwater balance in two dune systems in the UK. The studies demonstrate that, although conventional hydraulic models can describe the general system behaviour, a fuller understanding of the recharge mechanisms and system boundaries is needed to represent adequately system dynamics of small groundwater systems.     

An Ecological Multidisciplinary Approach to Protecting Society,Human Health,and the Environment at Nuclear Facilities

As the United States and other countries move toward a greater reliance on nuclear energy, it becomes increasingly important to characterize the environment around such facilities to protect society, human health, and the environment. This article presents an ecological, multidisciplinary approach to gathering the information needed to establish baselines, site new nuclear facilities, protect existing nuclear facilities and nuclear wastes, improve the basis for emergency planning, devise suitable monitoring schemes to ensure continued protection, provide data to track local and regional response changes, and provide for mitigation, remediation, and decommissioning planning. We suggest that there are five categories of information or data needs: (1) geophysical, sources, fate and transport; (2) biological systems; (3) human health; (4) stakeholder and environmental justice; and (5) societal, economic, and political. All of these categories are influenced by temporal and spatial patterns, vulnerabilities, and global changes. These informational needs are more expansive than the traditional site characterization but encompass a suite of physical, biological, and societal needs to protect all aspects of human health and the environment, not just physical health. We suggest that technical teams be established for each of the major informational categories, with appropriate representation among teams and with a broad involvement of a range of governmental personnel, natural and social scientists, Native Americans, environmental justice communities, and other stakeholders. Although designed for nuclear facilities, the templates and information teams can be adapted for other hazardous facilities. © 2013 Wiley Periodicals, Inc.     

Digestion of waste bananas to generate energy in Australia

This paper presents results from laboratory studies to measure the methane yield and rate of digestion of reject bananas. These parameters were determined in experiments that took into account the likely configuration of a full-scale plant in the banana growing region of north Queensland. The digestion was conducted in a 200-l reactor using fed-batch operation, relying entirely on the natural microbial consortia on the reject bananas to avoid reliance on external inocula such as sludge, an undesirable material around food packaging facilities. An enrichment culture was first established in a highly buffered 200-l batch digestion unit. The fed-batch digester was then started by exchanging leachate with the mature batch reactor. Under loading conditions of 0.6 kg VS m(-3)d(-1) over 70 days where the average working volume was 160 l, the digester produced 398+/-20 l CH4 kg VS(-1). Increasing the loading rate to 1.6 kg VS m(-3)d(-1) resulted in a reduced methane yield of 210 l CH4 kg VS(-1) over 23 days of operation, with a concomitant accumulation of banana waste in the digester. The leachate at the end of digestion contained over 4000 mg l(-1)K, 200 mg l(-1) N and 75 mg l(-1), levels that exceed acceptable limits for general agricultural irrigation.