Metabolism of gamma‐hexachlorocyclohexah (HCH) in vivo. Metabolism of orally administered gamma‐2,3,4,5,6‐pentachlorocyclohexen (PCCH)

Abstract

Mexacarbate (4‐dimethylamino‐3,5‐xylyl N‐methylcarbamate) insecticide has potential for use in spruce budworm (Choristoneura fumiferana Clem.) control operations in Canada. Its persistence and fate in balsam fir (Abies balsamea (L.) Mill.), litter and soil samples were studied by spraying aerially oil‐based and water‐based formulations, each at 70 g A.I./ha over a coniferous forest near Bathurst, New Brunswick. The oil‐based formulation gave the maximum concentration of the chemical in the substrates studied. In fir needles, the highest concentrations observed were 0.51 ppm and 0.19 ppm (fresh weight) for the oil‐based and emulsion formulations respectively, 1 h after application. The residue levels decreased very rapidly with a half‐life of approximately 5 h. Three and eight days after the spray application of the emulsion and oil formulations respectively, the concentrations of mexacarbate in foliage decreased to trace levels ( 0.008 ppm). Only very low levels of residue were detected in litter and soil. The peak concentrations for the two formulations ranged from 0.02 to 0.11 ppm (fresh weight) in litter and from 0.01 to 0.06 ppm (fresh weight) in soil. The residue levels in both litter and soil decreased to below the detection limit (0.005 ppm) within 1 d. The ground deposit levels found on glass plates and the droplet density and size spectra measured on Kromekote® cards reflected the variations in concentrations found in fir needles, litter and soil samples and correlated with the observed maximum concentrations in them. Under the stipulated use pattern, mexacarbate concentrations found in the terrestrial components studied were low and are not likely to have any undue adverse effects on non‐target species.     

Assessment of susceptibility of olive cultivars to the Bactrocera oleae (Gmelin, 1790) and Camarosporium dalmaticum (Thüm.) Zachos & Tzav.-Klon. attacks in Calabria (Southern Italy)

Within the framework of research concerning the application of techniques alternative to chemical pesticides for control of parasites, the C.R.A. Experimental Institute for Olive Growing for many years has been performing a large investigation in order to detect sources of genetic resistance in olive germplasm. In the present study we observed the behavior related to the olive fly (Bactrocera oleae) infestation and Camarosporium dalmaticum infection of ten olive cultivars farmed under the same agronomic and climatic conditions in Calabria, Southern Italy. The sampling and the data collecting were carried out in three different ripening times.The drupe amount of oleuropein and cyanidine was detected by laboratory analyses in order to verify a possible correlation between these molecules and the level of infestation/infection of the above-mentioned parasites. The obtained data were submitted to analysis of variance. In relation to the fungal infection the results displayed that cvs Tonda nera dolce showed the lowest susceptibility, while the cv Giarraffa turned out to be the most susceptible. The less susceptible cultivars to the phytophagous were Tonda nera dolce and Bhardi Tirana. Since the less susceptible cultivar to olive fly attacks are the same observed in relation to the susceptibility to olive fruit rot, it is suggested a relation between the olive fly infestation and the fungal infection. It suggests the utility to achieve these results both to transfer directly to the farmers' world and to emphasize ecosystem health and biodiversity conservation.     

1992 Update of U.S. EPA’s Superfund Innovative Technology Evaluation (SITE) Emerging Technology Program

The Superfund Innovative Technology Evaluation (SITE) Emerging Technology Program (ETP) has encouraged and financially supported further development of bench- and pilot-scale testing and evaluation of innovative technologies suitable for use at hazardous waste sites for five years. The ETP was established under the Superfund Amendments and Reauthorization Act (SARA) of 1986. The ETP complies with the goal of the SITE Program to promote, accelerate and make commercially available the development ofalternative /innovative treatment technologies for use at Superfund sites.

Technologies are submitted to the ETP through yearly solicitations for Preproposals. Following a technical review, chosen applicants are asked to submit a detailed project proposal and a cooperative agreement application that requires Developer I EPA cost sharing. EPA co-funds selected Developers for one to two years. Second-year funding requires documentation of significant progress during the first year. Facilities, equipment, data collection, performance and development are monitored throughout the project. The U. S. Department of Energy (DOE) and the U. S. Air Force (USAF) are participants in the ETP. DOE has co-funded ETP projects since 1990 and the USAF since 1991.

A primary goal of the ETP is to move developed technologies to the field-demonstration stage. Therefore, a developer may be considered for participation in the SITE Demonstration Program provided performance in the ETP indicates the technology is field-ready for demonstration and evaluation.

Six technology categories: biological, chemical, materials handling, physical, solidification/ stabilization and thermal, are presently in the ETP.

Technologies of primary interest to EPA are those that can treat complex mixtures of hazardous organic and inorganic contaminants and provide improved solids handling and/orpretreatment.

An account of the background and progress of the ETP’s first five years is presented in this paper. Technologies currently in the ETP, including those selected from the fifth (EOS) solicitation, are noted, and developers, along with EPA Project Managers, are listed.     

Strategies for management of Sicyos polyacanthus Cogn. (Cucurbitaceae) in sugarcane crops of Tucumán, Argentina

Sicyos polyacanthus is one of the most important weed in sugarcane crops of Tucumán (Argentina). The objective of this work was to establish strategies that would decrease the weed incidence in the crop to a minimum level. The study was carried out during 1998--2003 at five localities of sugarcane production of Tucumán (Argentina). The plots were 20 m long (192 m2) with 6 furrows and each plot was replicated five times. Treatments were: (i) Mechanical-chemical cultivation without fire; (ii) Mechanical-chemical culltivation with fire; (iii) Mechanical cultivation with handle pulled and with fire; (iv) Mechanical cultivation with handle pulled without fire; (v) Mechanical and chemical variants with fertilization and without fertilization; (vi) Mechanical and chemical variants with watering and without watering; (vii) Fallow and rotation, at the sugarcane crop renovation; (viii) Mechanical and chemical variants for plant cane and ratoon cane; and (ix) Mulching of harvest rests. The results suggest that besides the use of preemergent herbicides, fire marks the entry point of control, influencing fluxes and seed viability. It appears that fallow, mulching, and rotation of crops is fundamental for eliminating seeds that live short time in the soil and increase the mortality rate of species.     

Strategies for Management of Sicyos polyacanthus Cogn. (Cucurbitaceae) in Sugarcane Crops of Tucumán,Argentina

Abstract

Sicyos polyacanthus is one of the most important weed in sugarcane crops of Tucumán (Argentina). The objective of this work was to establish strategies that would decrease the weed incidence in the crop to a minimum level. The study was carried out during 1998–2003 at five localities of sugarcane production of Tucumán (Argentina). The plots were 20 m long (192 m²) with 6 furrows and each plot was replicated five times. Treatments were: (i) Mechanical–chemical cultivation without fire; (ii) Mechanical–chemical culltivation with fire; (iii) Mechanical cultivation with handle pulled and with fire; (iv) Mechanical cultivation with handle pulled without fire; (v) Mechanical and chemical variants with fertilization and without fertilization; (vi) Mechanical and chemical variants with watering and without watering; (vii) Fallow and rotation, at the sugarcane crop renovation; (viii) Mechanical and chemical variants for plant cane and ratoon cane; and (ix) Mulching of harvest rests. The results suggest that besides the use of preemergent herbicides, fire marks the entry point of control, influencing fluxes and seed viability. It appears that fallow, mulching, and rotation of crops is fundamental for eliminating seeds that live short time in the soil and increase the mortality rate of species.     

Wet deposition of mercury in the U.S. and Canada, 1996–2005: Results and analysis of the NADP mercury deposition network (MDN)

One of the most critical measurements needed to understand the biogeochemical cycle of mercury, and to verify atmospheric models, is the rate of mercury wet-deposition. The Mercury Deposition Network (MDN) operates sites across North America to monitor total mercury in wet-deposition. MDN's primary goal is to provide both spatial and temporal continental-scale observations of mercury wet-deposition fluxes to support researchers, modelers, policy-makers and the public interest. MDN represents the only continental-scale mercury deposition database with a >10-year record of continuous values. This study provides analysis and interpretation of MDN observations at 10 years (1996–2005) with an emphasis on investigating whether rigorous, statistically-significant temporal trends and spatial patterns were present and where they occurred. Wet deposition of mercury ranges from more than 25 μg m^?2 yr in south Florida to less than 3 μg m^?2 yr in northern California. Volume-weighted total mercury concentrations are statistically different between defined regions overall (Southeast ≈ Midwest > Ohio River > Northeast), with the highest in Florida, Minnesota, and several Southwest locations (10–16 ng L^?1). Total mercury wet-deposition is significantly different between defined regions (Southeast > Ohio River > Midwest > Northeast). Mercury deposition is strongly seasonal in eastern North America. The average mercury concentration is about two times higher in summer than in winter, and the average deposition is approximately more than three times greater in summer than in winter. Forty-eight sites with validated datasets of five years or more were tested for trends using the non-parametric seasonal Kendall trend test. Significant decreasing mercury wet-deposition concentration trends were found at about half of the sites, particularly across Pennsylvania and extending up through the Northeast.     

Quantitative–spatial assessment of soil contamination in S. Francisco de Assis due to mining activity of the Panasqueira mine (Portugal)

Through the years, mining and beneficiation processes produces large amounts of As-rich mine wastes laid up in huge tailings and open-air impoundments (Barroca Grande and Rio tailings) that are the main source of pollution in the surrounding area once they are exposed to the weathering conditions leading to the formation of AMD and consequently to the contamination of the surrounding environments, in particularly soils. In order to investigate the environmental contamination impact on S. Francisco de Assis (village located between the two major impoundments and tailings) agricultural soils, a geochemical survey was undertaken to assess toxic metals associations, related levels and their spatial distribution, and to identify the possible contamination sources. According to the calculated contamination factor, As and Zn have a very high contamination factor giving rise to 65.4 % of samples with a moderate to high pollution degree; 34.6 % have been classified as nil to very low pollution degree. The contamination factor spatial distribution put in evidence the fact that As, Cd, Cu, Pb, and Zn soils contents, downstream Barroca Grande tailing, are increased when compared with the local Bk soils. The mechanical dispersion, due to erosion, is the main contamination source. The chemical extraction demonstrates that the trace metals distribution and accumulation in S. Francisco de Assis soils is related to sulfides, but also to amorphous or poorly crystalline iron oxide phases. The partitioning study allowed understanding the local chemical elements mobility and precipitation processes, giving rise to the contamination dispersion model of the study area. The wind and hydrological factors are responsible for the chemical elements transport mechanisms, the water being the main transporter medium and soils as one of the possible retention media.     

Assessment of the ozone tolerance of two soybean cultivars (Glycine max cv. Sambaíba and Tracajá) cultivated in Amazonian areas

Brazilian soybean cultivars (Glycine max Sambaíba and Tracajá) routinely grown in Amazonian areas were exposed to filtered air (FA) and filtered air enriched with ozone (40 and 80 ppb, 6 h/day for 5 days) to assess their level of tolerance to this pollutant by measuring changes in key biochemical, physiological, and morphological indicators of injury and in enzymatic and non-enzymatic antioxidants. Sambaíba plants were more sensitive to ozone than Tracajá plants, as revealed by comparing indicator injury responses and antioxidant stimulations. Sambaíba exhibited higher visible leaf injury, higher stomatal conductance, and a severe decrease in the carbon assimilation rate. Higher ozone level (80 ppb) caused an increase in cell death in both cultivars. Levels of malondialdehyde and hydrogen peroxide also increased in Tracajá exposed under 80 ppb. Sambaíba plants exhibited decreases in ascorbate and glutathione levels and in enzymatic activities associated with these antioxidants. The higher tolerance of the Tracajá soybean appeared to be indicated by reduced physiological injuries and lower stomatal conductance, which might decrease the influx of ozone and enhance oxidation-reduction reactions involving catalase, ascorbate peroxidase, ascorbate, and glutathione, most likely stimulated by higher hydrogen peroxide.     

Accumulation of As, Cd and selected trace elements in tubers of Scirpus maritimus L. from Doñana marshes (South Spain)

The collapse of a pyrite-mining, tailing dam on 1998 contaminated an area of 4286 ha along the Agrio and Guadiamar river valleys in southern Spain. Over 2700 ha of the Do?ana marshes, an important wintering area for wetland European birds, were contaminated. This study reports analyses of the tubers of Scirpus maritimus (an important food for greylag geese, Anser anser) collected in 2000 in the "Entremuros" (spill-affected area) and in nearby unaffected Do?ana marshes (control areas). In the spill-affected area mean tuber tissue concentrations of Cd (0.25 mg kg-1) and Zn (61 mg kg-1) were greater than in those tubers from the control area (0.02 mg kg-1 for Cd, and 22 mg kg-1 for Zn); values of Cd and Zn in "Entremuros" (samples collected two years after the mine spill) were much smaller than those reported only a few months after the accident. Trace elements (As, Fe, Mn and Tl, and to a lesser extent Cd and Pb) showed a preferential accumulation in the outer skin of tubers. Surprisingly, concentrations of As and Fe were greater in tubers from some marsh sites not affected by the mine-spill than in tubers from the "Entremuros". We suggest that relic river channels within the Do?ana marshes may be contaminated by trace elements from historic mining activities. An exhaustive study of macrophytes and other plant species in this area is recommended to identify potential risks to wildlife.