Study of the Degradation Behaviour of Virgin and Biodegradable Plastic Films in Marine Environment Using ASTM D 6691

Journal of Polymers and the Environment - Biodegradable plastics have been introduced to the global market with a potential increase in their production and consumption rate, as a means to minimise...     

Simulating endosulfan transport in runoff from cotton fields in Australia with the GLEAMS model

Endosulfan (6,7,8,9,10,10-hexachloro-1,5,5a,6,9,9a-hexahydro-6,9methano-2,4,3-benzodioxathiepin 3-oxide), a pesticide that is highly toxic to aquatic organisms, is widely used in the cotton (Gossypium hirsutum L.) industry in Australia and is a risk to the downstream riverine environment. We used the GLEAMS model to evaluate the effectiveness of a range of management scenarios aimed at minimizing endosulfan transport in runoff at the field scale. The field management scenarios simulated were (i) Conventional, bare soil at the beginning of the cotton season and seven irrigations per season; (ii) Improved Irrigation, irrigation amounts reduced and frequency increased to reduce runoff from excess irrigation; (iii) Dryland, no irrigation; (iv) Stubble Retained, increased soil cover created by retaining residue from the previous crop or a specially planted winter cover crop; and (v) Reduced Sprays, a fewer number of sprays. Stubble Retained was the most effective scenario for minimizing endosulfan transport because infiltration was increased and erosion reduced, and the stubble intercepted and neutralized a proportion of the applied endosulfan. Reducing excess irrigation reduced annual export rates by 80 to 90%, but transport in larger storm events was still high. Reducing the number of pesticide applications only reduced transport when three or fewer sprays were applied. We conclude that endosulfan transport from cotton farms can be minimized with a combination of field management practices that reduce excess irrigation and concentration of pesticide on the soil at any point in time; however, discharges, probably with endosulfan concentrations exceeding guideline values, will still occur in storm events.     

Enhancing biomass energy use in Kenya

This paper argues that in Kenya, environmental and economic factors will favour the continued use of biomass as a primary fuel for household and institutional cooking for the next decade or longer. The paper describes several successful projects which have improved the efficiency of urban charcoal use and of rural woodfuel use. The Kenya Ceramic Jiko, a more efficient version of the traditional charcoal stove, is a model programme sustained by free market competition, artisans participation, and widespread public acceptance. The Maendeleo stove is the best example of a successful rural woodstove project. The performance attributes of the stove, and its promotion through Kenya's largest women's organization, have resulted in the distribution of an estimated 26 000 Maendeleo stoves. Rural stove efficiency will become important as the cash-based economy expands in those areas. Agroforestry will also be critical to an enhanced use of biomass energy in Kenya. Experience to date shows that successful agroforestry programmes will have to be appropriate to local conditions and crops .     

Urban waterfowl population: Ecological evaluation of management and planning

An urban population of ducks in Puyallup, Washington, USA was studied for 14 consecutive months beginning in November 1978. Observations were made weekly from four study sites where ducks would congregate at early morning hours. Factors contributing to the presence of waterfowl in Puyallyup included abundant food supplies and a creek corridor that connected fragmented habitats in the urban area to the larger rural populations of waterfowl. Mallards (Anas platyrhynchos) were the most abundant of the 13 species observed and were the only ducks remaining during the nesting season. Habitat size and complexity were important factors influencing the species diversity of a particular site. Nesting success of mallards was poor due to limited distribution of nesting habitat, intraspecific aggression, and human disturbance. Both site-specific and more broad-based strategies are suggested for managing and planning for duck populations in urban areas.     

Human impacts on the stream-groundwater exchange zone

Active exchanges of water and dissolved material between the stream and groundwater in many porous sand- and gravel-bed rivers create a dynamic ecotone called the hyporheic zone. Because it lies between two heavily exploited freshwater resources—rivers and groundwater—the hyporheic zone is vulnerable to impacts coming to it through both of these habitats. This review focuses on the direct and indirect effects of human activity on ecosystem functions of the hyporheic zone. River regulation, mining, agriculture, urban, and industrial activities all have the potential to impair interstitial bacterial and invertebrate biota and disrupt the hydrological connections between the hyporheic zone and stream, groundwater, riparian, and floodplain ecosystems. Until recently, our scientific ignorance of hyporheic processes has perhaps excused the inclusion of this ecotone in river management policy. However, this no longer is the case as we become increasingly aware of the central role that the hyporheic zone plays in the maintenance of water quality and as a habitat and refuge for fauna. To fully understand the impacts of human activity on the hyporheic zone, river managers need to work with scientists to conduct long-term studies over large stretches of river. River rehabilitation and protection strategies need to prevent the degradation of linkages between the hyporheic zone and surrounding habitats while ensuring that it remains isolated from toxicants. Strategies that prevent anthropogenic restriction of exchanges may include the periodic release of environmental flows to flush silt and reoxygenate sediments, maintenance of riparian buffers, effective land use practices, and suitable groundwater and surface water extraction policies.     

Effect of Phanerochaete chrysosporium inoculation during maturation of co-composted agricultural wastes mixed with olive mill wastewater

The co-composting of olive mill wastewater with a variety of agricultural wastes was investigated. To reduce the toxicity of the phenolic fraction and to improve the degree of maturity of the compost, inoculation with the white-rot fungus Phanerochaete chrysosporium was carried out during the maturation phase. The results showed that agricultural wastes that contain high levels of lignin-related compounds, such as the residue from trimmings, improved the microbial activity and thus reduced the soluble phenols residue. The inoculation of P. chrysosporium during compost maturation reduced and modified the phenolic fraction, allowing a reduction in the time to reach compost maturity with the improvement in the germination index of 100% after 36 days in two of three trials performed.     

Congruence Among Encounters,Norms, Crowding,and Management in a Marine Protected Area

Over the past few decades, recreation and tourism use has increased at many marine protected areas, generating concerns about impacts of this increasing use on experiences and conditions at these areas (e.g., crowding, conflict). This article uses data from Molokini Shoal Marine Life Conservation District in Hawai’i to examine: (a) reported encounters, crowding, normative tolerances for various use levels, and support of use related management strategies at this site; and (b) whether users who encounter higher use levels than their norms feel more crowded and are more supportive of restrictive management strategies. Data were obtained from onsite pre-trip and post-trip questionnaires of 712 passengers on commercial snorkel and dive tours visiting this site. Norms were measured with acceptance of 12 photographs depicting levels of boat use. On average, users would accept seeing no more than approximately 16 boats at one time at Molokini and this number was observed on over 20% of trips to the site. Although the majority of users expected to escape crowds at Molokini, 67% felt crowded and up to 79% supported actions that would directly restrict use at this site (e.g., limit number of boats). Users who encountered more boats than their normative tolerance felt more crowded and were more supportive of these management strategies. Findings suggest that this marine protected area is operating over its capacity and management is needed to improve experiences and conditions.