Effect of Treated Wood on Biosolids Composting

The possibility of using construction and demolition (C&;D) waste wood as a bulking material in biosolids composting was investigated. Potential contaminants in C&;D waste wood include arsenic (As), chromium (Cr), and copper (Cu) from treated wood, and lead (Pb) from paints. Untreated and treated woodchips from C&;D wood were mixed with biosolids, composted using an aerated static pile process, and cured. There were no significant differences between untreated and treated woodchips with respect to composting process, time to stability, or product quality. Composting parameters monitored included moisture content, pH, electrical conductivity, organic matter degradation, fecal coliform levels, and stability by respirometry. Finished compost quality was evaluated in terms of potential toxic elements (PTE) levels. PTE values in treated woodchips (26 ± 35, 29 ± 41, 56 ± 46, and 5 ± 5 µg·g^?1 for As, Cr, Cu, and Pb, respectively) were higher and more variable than those in the untreated woodchips (3 ± 3, 17 ± 8, 13 ± 2, and 0.5 ± 0.0 µg·g^?1). However, both untreated and treated wood compost products met Canadian Council of Ministers of the Environment Category B values for PTE. In addition, and only molybdenum (Mo) and Cu exceeded Category A thresholds. Biosolids were the most significant contributor of Mo, while Cu contributions came from both biosolids and wood chips; some samples of pressure-treated wood showed concentrations of Cu in the range of 765 to 8,455 µg·g^?1. The results of this study suggest that treated wood from C&;D recycling facilities will not significantly degrade the quality of biosolids compost products.     

Catchment-Scale Variation in the Nitrate Concentrations of Groundwater Seeps in the Catskill Mountains,New York,U.S.A.

Forested headwater streams in the Catskill Mountains of New York show significant among-catchment variability in mean annual nitrate (NO₃ ^-) concentrations. Large contributions from deep groundwater with high NO₃ ^-concentrations have been invoked to explain high NO₃ ^-concentrations in stream water during the growing season. To determine whether variable contributions of groundwater couldexplain among-catchment differences in streamwater, we measuredNO₃ ^- concentrations in 58 groundwater seeps distributed across six catchments known to have different annual average streamwater concentrations. Seeps were identified based on release from bedrock fractures and beddingplanes and had consistently lower temperatures than adjacentstreamwaters. Nitrate concentrations in seeps ranged from neardetection limits (0.005 mg NO₃ ^--N/L) to 0.75 mg NO₃ ^--N/L. Within individual catchments, groundwaterresidence time does not seem to strongly affect NO₃ ^-concentrations because in three out of four catchments therewere non-significant correlations between seep silica (SiO₂) concentrations, a proxy for residence time, andseep NO₃ ^- concentrations. Across catchments, therewas a significant but weak negative relationship betweenNO₃ ^- and SiO₂ concentrations. The large rangein NO₃ ^- concentrations of seeps across catchmentssuggests: 1) the principal process generating among-catchmentdifferences in streamwater NO₃ ^- concentrations mustinfluence water before it enters the groundwater flow system and 2) this process must act at large spatial scales becauseamong-catchment variability is much greater than intra-catchmentvariability. Differences in the quantity of groundwater contribution to stream baseflow are not sufficient to account for differences in streamwater NO₃ ^- concentrationsamong catchments in the Catskill Mountains.     

A method of analysis for the determination of binapacryl,bupirimate and diflubenzuron on apple foliage and fruit,and its application to persistence studies

A rapid, sensitive and specific high-pressure liquid chromatographic method was developed to analyse residues of binapacryl, bupirimate and diflubenzuron on mature foliage and fruit at intervals after application of the compounds to Worcester and Cox apple trees. The three compounds were applied as commercial formulations in trials to compare integrated pest management with routine farm spray-programmes. The identities of the residues were confirmed by a combination of thin-layer chromatography, ultraviolet spectrometry and gas chromatography/mass spectrometry. Only diflubenzuron persisted on foliage until leaf-fall. None of the applied compounds was detectable on harvested fruit, the minimum quantifiable residue levels being 1, 5 and 2.5 μg kg^?1 fresh weight for binapacryl, bupirimate and diflubenzuron, respectively.     

Neodymium:Yttrium-aluminum-Garnet (Nd:YAG) laser ablation of an obstructive urethral polyp in a dog

A miniature schnauzer presented for evaluation of a persistent lower urinary tract obstruction. Further examination revealed that the dog had developed an obstructive, inflammatory polyp secondary to a long-standing urinary tract infection. The polyp was located within the proximal urethra and interfered with normal voiding. The polyp was visualized using flexible endoscopy and then was successfully ablated using the neodymium:yttrium-aluminum-garnet (Nd:YAG) laser. The Nd:YAG laser is a potentially useful tool for treating various lesions of the lower urinary tract.     

The yield gap of global grain production: A spatial analysis

Global grain production has increased dramatically during the past 50 years, mainly as a consequence of intensified land management and introduction of new technologies. For the future, a strong increase in grain demand is expected, which may be fulfilled by further agricultural intensification rather than expansion of agricultural area. Little is known, however, about the global potential for intensification and its constraints. In the presented study, we analyze to what extent the available spatially explicit global biophysical and land management-related data are able to explain the yield gap of global grain production. We combined an econometric approach with spatial analysis to explore the maximum attainable yield, yield gap, and efficiencies of wheat, maize, and rice production. Results show that the actual grain yield in some regions is already approximating its maximum possible yields while other regions show large yield gaps and therefore tentative larger potential for intensification. Differences in grain production efficiencies are significantly correlated with irrigation, accessibility, market influence, agricultural labor, and slope. Results of regional analysis show, however, that the individual contribution of these factors to explaining production efficiencies strongly varies between world-regions.     

Carbon dioxide as a potential fumigant for termite control

Formosan subterranean termites, Coptotermes formosanus Shiraki, were exposed to ? 95% or 50% carbon dioxide atmospheres for intervals of 24-120 h at 26(±3)°C. A 24-h exposure to ? 95% carbon dioxide caused significant termite mortality, but 60 h were required for complete mortality. Exposure to 50% carbon dioxide for 60 h resulted in approximately 70% termite mortality, while complete mortality was recorded after 120 h. When termites were sealed in wooden blocks (90 × 90 × 152 mm), 72-96 h exposure to ? 95% carbon dioxide was necessary for complete control. A limited study with Cryptotermes brevis (Walker) suggested that this drywood termite is also susceptible to carbon dioxide fumigation, although slightly longer exposures may be required than with C. formosanus. Carbon dioxide-modified atmospheres are a viable alternative to conventional fumigants for vault fumigation of termite-infested materials, and may also be applicable to larger-scale fumigations to control structural pests.     

Glyphosate–sediment interactions and phytotoxicity in turbid water

In aquatic situations it was expected that adsorption by sediments and suspended solids would influence the movement of glyphosate away from the application zone and attenuate its phytotoxicity. However, the results of two experiments showed that only a minor proportion of glyphosate was adsorbed onto suspended solids, even in turbid irrigation water. Phytotoxicity, as measured by the effect on the root growth of safflower (Carthamus tinctorius L.), was not significantly reduced. Where glyphosate was intentionally injected into flowing water of contrasting quality to simulate incidental contamination of water during foliage treatment, adsorption by benthic sediments attenuated loads of glyphosate only slowly. The attenuation was 13–27% for each kilometre of travel downstream, as compared to 31% observed previously. However, when glyphosate was sprayed onto the sediment exposed after channel draining, less than 7% of the glyphosate applied was subsequently eluted. Consequently, draining before treatment should be an effective strategy for minimising the contamination of irrigation water.