A laboratory study of the persistence of carbofuran and its 3‐hydroxy‐ and 3 keto‐metabolites in sterile and natural mineral and organic soils

Abstract

In a laboratory study, the persistence of carbofuran and its 3‐hydroxy‐ and 3‐keto‐metabolites was examined separately over 16 wk in sterile and natural organic (muck) and mineral (loam) soils. Carbofuran was relatively persistent in sterile soils; at 8 wk 77% remained in the sterile muck and about 50% remained in the sterile loam. In the natural muck 25% of initial carbofuran remained at 8 wk whereas in the natural loam carbofuran had completely disappeared by that time. The 3‐ketocarbofuran was very short‐lived even in the sterile muck where only 50% remained at 1 wk. The 3‐hydroxycarbofuran degraded appreciably on zero day in the natural soils (with conversion to 3‐ketocarbofuran) and about 90% had disappeared in 1 wk. A more detailed study of the persistence of 3‐hydroxycarbofuran in the natural soils showed complete disappearance in 2 days in loam and in 3 days in muck. The 3‐ketocarbofuran produced from the 3‐hydroxy‐carbofuran reached a maximum concentration in 1 day and then disappeared within 4 days in loam and about 1 wk in muck.     

The degradation of parathion and DDT in aqueous systems containing organic additives

Abstract

Laboratory studies were conducted to investigate some of the factors influencing pesticide degradation in‐ aqueous systems. Parathion added to natural water in ethanol, acetone or without organic solvent, was completely degraded within 2 wk. While most of the parathion was reduced to amino‐parathion when added in ethanol, no amino‐parathion was detected in the presence of acetone or when no solvent was added, suggesting that in the latter two cases the insecticide was aerobically degraded to other metabolites. No paraoxon was detected. When ethanol concentration was increased from 1% to 2 and 4%, the rate of parathion degradation was inversely related to the ethanol concentration. In the presence of glucose as a carbon source, approximately 50% of the parathion was reduced to aminoparathion. DDT degradation in natural water was more rapid when it was added in ethanol than when added in acetone. The only DDT metabolite detected was TDE, with about 36% conversion in presence of ethanol, and 20% when the DDT was added in acetone.     

Cadmium: Simulation of environmental control strategies to reduce exposure

The effects of selected environmental control strategies on human dietary and respiratory exposure to environmental cadmium (Cd) have been simulated. For each control strategy, mean Cd dietary and respiratory exposures are presented for a twenty-year simulation period.Human exposures related to cadmium are associated with both process waste disposal and product disposal. Dietary exposure is by far the dominant mechanism for Cd intake. Dietary exposure related to aqueous discharges is primarily a result of municipal sludge landspreading, whereas that associated with emissions to the atmosphere derives mainly from the deposition on cropland of airborne particulates from product incineration. Only relatively small dietary exposure reductions are possible through restrictions on anysingle Cd use. Combinations of waste management and environmental control measures promise greater reductions in dietary and respiratory exposure than those achievable through use restrictions.Work supported by Office of Toxic Substances U.S. Environmental Protection Agency.     

Effects of Changing Forest and Impervious Land Covers on Discharge Characteristics of Watersheds

Effects of changing patterns of forest and impervious land covers on hydrologic regimes of watersheds were evaluated for urban and rural areas of the lower Cedar River drainage near Seattle, Washington. Land cover characterizations were used in a spatially explicit hydrology model to assess effects of land covers on watershed hydrology during presettlement conditions (full forest cover), 1991 and 1998. For the presettlement to 1991 period, urban watersheds showed decreases in forest covers (range 63% to 83%) and increases in impervious surfaces (range 43% to 71%). Rural watersheds showed similar patterns but smaller changes, with forest covers decreasing (range 28% to 34%) and impervious surfaces increasing (range 8% to 15%). For the 1991 and 1998 period, changes in forest covers for urban and rural watershed were <24%, with losses in some watersheds and regeneration in others. Impervious surfaces continued to increase, but increases were larger in rural (range 38% to 60%) than in urban watersheds (range 4% to 27%). Flood-frequency curves indicated that discharge rates (m sec^–1) for all watersheds were higher in 1991 and 1998 than historical and suggested that chances for floods increase because of changing land covers. The largest increases in discharge rates were in urban watersheds, with rates for 2-year, 10-year, and 25-year recurrence intervals being more than two times greater than the rate during historical conditions. Changes in flow regimes were indicated by presettlement discharge levels of less frequent recurrence intervals (10-year and 25-year) occurring in posturbanization times (1991 and 1998) during more frequent intervals (2-year and 10-year). Normalized flows (m yr^–1) of watersheds for 2-year, 10-year, and 25-year recurrence intervals indicate how flow regimes in 1991 and 1998 can change as functions of different areas of land covers. During 1991 and 1998, abrupt increases in flows occurred when forest covers were low (range 17% to 37%) and impervious surfaces were >46%. In contrast, the lowest flows occurred when forest covers were most extensive (range 59% to 81%) and impervious surfaces were <23%. We conclude that our use of spatial characterizations of impervious surfaces and forested covers in a spatially explicit hydrology model provides a robust approach for revealing how variations in different types and spatial distributions of land covers can affect flood regimes and flows of different watersheds.     

Capability maturity models for offshore organisational management

The goal setting regime imposed by the UK safety regulator has important implications for an organisation's ability to manage health and safety related risks. Existing approaches to safety assurance based on risk analysis and formal safety assessments are increasingly considered unlikely to create the step change improvement in safety to which the offshore industry aspires and alternative approaches are being considered. One approach, which addresses the important issue of organisational behaviour and which can be applied at a very early stage of design, is the capability maturity model (CMM). The paper describes the development of a design safety capability maturity model, outlining the key processes considered necessary to safety achievement, definition of maturity levels and scoring methods. The paper discusses how CMM is related to regulatory mechanisms and risk based decision making together with the potential of CMM to environmental risk management.     

Spatial Pattern Analysis of Cruise Ship–Humpback Whale Interactions in and Near Glacier Bay National Park, Alaska

Understanding interactions between large ships and large whales is important to estimate risks posed to whales by ships. The coastal waters of Alaska are a summer feeding area for humpback whales (Megaptera novaeangliae) as well as a prominent destination for large cruise ships. Lethal collisions between cruise ships and humpback whales have occurred throughout Alaska, including in Glacier Bay National Park (GBNP). Although the National Park Service (NPS) establishes quotas and operating requirements for cruise ships within GBNP in part to minimize ship–whale collisions, no study has quantified ship–whale interactions in the park or in state waters where ship traffic is unregulated. In 2008 and 2009, an observer was placed on ships during 49 different cruises that included entry into GBNP to record distance and bearing of whales that surfaced within 1 km of the ship’s bow. A relative coordinate system was developed in ArcGIS to model the frequency of whale surface events using kernel density. A total of 514 whale surface events were recorded. Although ship–whale interactions were common within GBNP, whales frequently surfaced in front of the bow in waters immediately adjacent to the park (west Icy Strait) where cruise ship traffic is not regulated by the NPS. When ships transited at speeds >13 knots, whales frequently surfaced closer to the ship’s midline and ship’s bow in contrast to speeds slower than 13 knots. Our findings confirm that ship speed is an effective mitigation measure for protecting whales and should be applied to other areas where ship–whale interactions are common.     

Biophysical suitability,economic pressure and land-cover change: a global probabilistic approach and insights for REDD+

There has been a concerted effort by the international scientific community to understand the multiple causes and patterns of land-cover change to support sustainable land management. Here, we examined biophysical suitability, and a novel integrated index of “Economic Pressure on Land” (EPL) to explain land cover in the year 2000, and estimated the likelihood of future land-cover change through 2050, including protected area effectiveness. Biophysical suitability and EPL explained almost half of the global pattern of land cover (R ² = 0.45), increasing to almost two-thirds in areas where a long-term equilibrium is likely to have been reached (e.g. R ² = 0.64 in Europe). We identify a high likelihood of future land-cover change in vast areas with relatively lower current and past deforestation (e.g. the Congo Basin). Further, we simulated emissions arising from a “business as usual” and two reducing emissions from deforestation and forest degradation (REDD) scenarios by incorporating data on biomass carbon. As our model incorporates all biome types, it highlights a crucial aspect of the ongoing REDD + debate: if restricted to forests, “cross-biome leakage” would severely reduce REDD + effectiveness for climate change mitigation. If forests were protected from deforestation yet without measures to tackle the drivers of land-cover change, REDD + would only reduce 30 % of total emissions from land-cover change. Fifty-five percent of emissions reductions from forests would be compensated by increased emissions in other biomes. These results suggest that, although REDD + remains a very promising mitigation tool, implementation of complementary measures to reduce land demand is necessary to prevent this leakage.     

The SSC cycle: a PDCA approach to address site-specific characteristics in a continuous shallow water quality monitoring project

In any water quality-monitoring project there are several critical success factors that must be adequately addressed in order to ensure the implementation and realization of the monitoring objectives. Site selection is one of these critical success factors. The monitoring sites must be selected to comply with the monitoring and data quality objectives. In the real world, ideal monitoring setting conditions are difficult to achieve, and compromises must be made in order to locate the monitoring stations that best represent the environment to be monitored. Site-specific characteristics are all the environmental, logistical and management factors particular to the monitoring site, that could influence the fulfilment of the monitoring and data quality objectives. Therefore, during the site selection process, it is essential to properly consider and evaluate these site-specific characteristics. The SSC cycle was developed with this goal in mind, to assist the monitoring team to systematically address site-specific characteristics. The cycle is a methodology to organize the site-specific characteristics in different categories, and to ensure a comprehensive overview of these characteristics throughout the project life cycle.     

Relative Phytoplankton growth responses to physically and chemically dispersed South Louisiana sweet crude oil

We conducted controlled laboratory exposure experiments to assess the toxic effects of water-accommodated fractions (WAFs) of South Louisiana sweet crude oil on five phytoplankton species isolated from the Gulf of Mexico. Experiments were conducted with individual and combinations of the five phytoplankton species to determine growth inhibitions to eight total petroleum hydrocarbon (TPH) equivalent concentrations ranging from 461 to 7,205 ppb. The composition and concentration of crude oil were altered by physical and chemical processes and used to help evaluate crude oil toxicity. The impact of crude oil exposure on phytoplankton growth varied with the concentration of crude oil, species of microalgae, and their community composition. At a concentration of TPH <?1,200 ppb, dinoflagellate species showed significantly better tolerance, while diatom species showed a higher tolerance to crude oil at higher concentrations of TPH. For both groups, the larger species were more tolerant to crude oil than smaller ones. The toxicity potential of crude oil seems to be strongly influenced by the concentration of polycyclic aromatic hydrocarbons (PAHs). The addition of the dispersant, Corexit® EC9500A, increased the amount of crude oil up to 50-fold in the water column, while the physical enhancement (vigorous mixing of water column) did not significantly increase the amount of TPH concentration in the water column. The species response to crude oil was also examined in the five-species community. Each phytoplankton species showed considerably less tolerance to crude oil in the five-species community compared to their individual responses. This study provides baseline information about individual phytoplankton responses to crude oil and dispersed crude oil for subsequent research efforts seeking to understand the impacts of oil on the phytoplankton in the bigger picture.     

Characterization of DNAPL from the U.S. DOE Savannah River Site

The composition of chlorinated hydrocarbon DNAPLs (dense non-aqueous phase liquids) from field sites can be substantially different than the material originally purchased for use as a solvent. Waste management practices at the U.S. Department of Energy's (DOE) Savannah River Site (SRS) included co-disposal of a wide range of organic and inorganic wastes. In 1991, a clear, orange-colored DNAPL was found in two wells near the SRS M-area settling basin. Waste effluent from the fuel and target fabrication facilities that were discharged to this settling basin included acids, caustics, metals and chlorinated solvents. The characterization of the SRS DNAPL suggests that numerous constituents partitioned into the DNAPL during its use as a solvent, co-disposal and ultimate migration through the subsurface. Trace constituents in the DNAPL include metals, from processing operations or co-disposal practices and subsurface minerals, high molecular weight hydrocarbons and alkyl esters, and acids. This complex mixture results in DNAPL-water interfacial properties that are substantially different than would be expected from a simple mixture of PCE and TCE. Under conditions when there is a high DNAPL to water volume ratio, a semi-rigid film accumulates on water droplets suspended in the DNAPL. It is concluded that the array of precipitated metal species comprising this film contributes to the interfacial tension that is over an order of magnitude lower than expected for a "clean" PCE/TCE mixture.