Aerobic Cometabolism of Halogenated Aliphatic Hydrocarbons: A Technology Overview

Bioremediation of chlorinated solvents has been moving from an innovative to mainstream technology for environmental applications. Cometablism of chlorinated solvents by monooxygenase has been demonstrated for trichloroethylene (TCE). Cl‐out microbes combine the dehalogenation of PCE with the monooxygenase destruction of TCE to complete the PCE breakdown pathway. Underthe right conditions, cometabolic bioremediation can be cost effective, fast, and complete. Aerobic bioremediation can augment mass transfer technologies such as pump and treat or sparging/vapor extraction to improve their efficiency.     

Handedness, Hand Roles, and Hand Injuries at Work

Hand injuries form a significant proportion of all workplace injuries. They are costly to treat, and lead to significant loss of time at work. This paper has two parts. First, there is a review of the literature that discusses prevalence of hand injury, and the significance of hand roles and handedness in industrial injuries. The second part represents an initial attempt to document the roles of the two hands in a particular industry, the metal manufacturing industry. The purpose of this survey of 30 different work stations in seven different industrial plants was to see whether there is a significant bias in terms of movement requirements for one or the other hand, leading to a possible differential risk of injury for the left and right hands. Overall, there was no clear bias favoring the right hand in activities assigned to the hands in seven different movement categories (MTM). However, the location of emergency controls favored the right hand unequivocally. The implications of biases favoring the left/right hand for safety of machine operation are discussed in the light of current findings on left/right hand performance in right- and lefthanders.     

Improved estimates of certainty in stable-isotope-based methods for tracking migratory animals.

The use of stable-hydrogen isotopes (deltaD) has become a common tool for estimating geographic patterns of movement in migratory animals. This method relies on broad and relatively predictable geographic patterning in deltaD values of precipitation, but these patterns are not estimated without error. In addition, deltaD measurements are relatively imprecise, particularly for organic tissue. Most models for estimating geographic locations have ignored these sources of error. Common modeling approaches include regression, range-matching, and likelihood-based assignment tests (including discriminant analysis). Here, we show the benefits of a simple stochastic extension to likelihood-based assignment tests that incorporates two estimable sources of error and describe the resulting influence on the certainty of assigning breeding origins for wintering American Redstarts (Setophaga ruticilla), a small Nearctic-Neotropical migratory bird. Through simulation, we incorporated both spatial interpolation error associated with models of deltaD in precipitation and analytical error associated with the measurement of deltaD in tissue samples. In general, assignments that did not include these sources of error fell within the ranges of the stochastic results, but the difference in proportion of birds assigned to any one breeding region varied by as much as 54%. To explore how the distribution of assignments generated from error models influenced the application of these results, we developed a simple model of winter habitat loss. We removed the proportion of Redstarts wintering at a particular site from the global population and then used the isotope-based assignments to predict the resulting population declines for each breeding region. This gave distributions of change in population sizes, some of which included no change or even a population increase. The sources of error we modeled may challenge the degree of certainty in the use of stable-isotope-based data on connectivity to predict population dynamics of migratory animals. We suggest that stronger inference will result from incorporating these sources of error into future studies that use deltaD or other stable isotopes to infer the geographic origin of individuals.     

Sulfur isotopes link overwinter habitat use and breeding condition in Double-crested Cormorants.

North American Double-crested Cormorant (Phalacrocorax auritus) populations have increased greatly. Both breeding and overwintering ground factors have likely contributed to these increases. However, demonstrating how overwintering conditions may affect breeding birds has not been possible because of the difficulty in linking breeding birds to their wintering grounds. Here, we demonstrate the utility of stable sulfur isotopes to elucidate overwintering habitat use by cormorants breeding on Lake Erie. Sulfur isotopes in feathers grown on overwintering grounds provided insights into the degree to which birds used freshwater vs. marine environments. The proportion of birds utilizing freshwater habitats increased through time. This change may have reflected increases in freshwater aquaculture (i.e., catfish) in the U.S. south. Examination of body condition in birds returning to breed on Lake Erie indicated that those individuals that solely used marine habitats for at least a portion of the overwintering period were in poorer condition than birds using freshwater. Enhanced foraging opportunities at aquaculture facilities may improve the fitness of individuals that have returned to breed after overwintering at such locations. This study is the first to demonstrate a linkage between overwinter habitat use and breeding ground parameters in Double-crested Cormorants. These results underscore that factors throughout the Mississippi flyway are likely acting together to regulate cormorant populations.     

Rainfall and soils modify plant community response to grazing in Serengeti National Park

Terrestrial plant community responses to herbivory depend on resource availability, but the separate influences of different resources are difficult to study because they often correlate across natural environmental gradients. We studied the effects of excluding ungulate herbivores on plant species richness and composition, as well as available soil nitrogen (N) and phosphorus (P), across eight grassland sites in Serengeti National Park (SNP), Tanzania. These sites varied independently in rainfall and available soil N and P. Excluding herbivores decreased plant species richness at all sites and by an average of 5.4 species across all plots. Although plant species richness was a unimodal function of rainfall in both grazed and ungrazed plots, fences caused a greater decrease in plant species richness at sites of intermediate rainfall compared to sites of high or low rainfall. In terms of the relative or proportional decreases in plant species richness, excluding herbivores caused the strongest relative decreases at lower rainfall and where exclusion of herbivores increased available soil P. Herbivore exclusion increased among-plot heterogeneity in species composition but decreased coexistence of congeneric grasses. Compositional similarity between grazed and ungrazed treatments decreased with increasing rainfall due to greater forb richness in exclosures and greater sedge richness outside exclosures and was not related to effects of excluding herbivores on soil nutrients. Our results show that plant resources, especially water and P, appear to modulate the effects of herbivores on tropical grassland plant diversity and composition. We show that herbivore effects on soil P may be an important and previously unappreciated mechanism by which herbivores influence plant diversity, at least in tropical grasslands.     

Benthic community response to petroleum-associated components in Arctic versus temperate marine sediments

We assessed the effects of crude oil and drill cuttings on sediment oxygen demand (SOD) of marine benthic communities from Arctic (Barents Sea) and temperate (Oslofjord) areas of the Norwegian continental shelf. Field-collected cores in both areas were subjected to three different treatments: two concentrations of hydrocarbon-contaminated sediments, and drill cuttings (DC). Cores were incubated for 21 days at 5°C (Barents Sea) and at 10°C (Oslofjord) during which SOD was measured five times. We observed significantly higher SOD in the high oil concentration (HOC) and DC treatments compared to control cores from the Arctic, but not in the temperate Oslofjord. No difference was observed between the low oil concentration (LOC) and control at either location. The clear differences in the response of Arctic benthic communities to petroleum compounds compared to temperate benthic communities is likely related to differences in community structure, sensitivity of individual taxa to petroleum-related compounds and different contamination history of the two study areas.     

液相色谱/离子阱质谱和飞行时间质谱分析橄榄油中的特丁津除草剂

本文摘要介绍了液相色谱／离子阱质谱和液相／飞行时间质谱对橄榄油中特丁津的定性定量分析．详细介绍了样品处理,包括液-液萃取和以氨基硅胶为基质分散的固相萃取法．样品的净化采用Florisil硅土小柱,用乙腈洗脱溶质．液相色谱／离子阱质谱的MS／MS模式采集特征离子m／z174．而利用液相／飞行时间质谱进行精确质量数分析（[M＋H]^＋,m／z230）,同时得到碎片的精确质量数和特征同位素分布．对于飞行时间质谱测得的质量精度小于ppm．此方法具有高灵敏度、线性好及精度高的优点．液相／离子阱质谱和飞行时间质谱可以作为橄榄油中特丁津的常规方法．[编者按]     

环境样品中杀菌剂的多残留分析

苯并咪唑类化合物(benzimidazoles)如涕必灵(thiabendazole)常作为杀菌剂普遍用在瓜果及农作物上．用液相色谱法分析这些物质比较困难：例如涕必灵,在硅胶基质的色谱柱上会发生严重的拖尾现象,酸性条件下尤为明显。涕必灵和多菌灵(carbendazim)在pH10的情况下使用XTerra MS C18色谱柱会得到较好的峰形,但在较高的pH值下,其它类型杀菌剂或杀虫剂可能不稳定,故难以用适合这些碱性杀菌剂的高pH值条件进行同时分析．     

Nutrient dynamics and tree growth of silvopastoral systems: impact of poultry litter

Fertilizing pastures with poultry litter has led to an increased incidence of nutrient-saturated soils, particularly on highly fertilized, well drained soils. Applying litter to silvopastures, in which loblolly pine (Pinus taeda L.) and bahiagrass (Paspalum notatum) production are integrated, may be an ecologically desirable alternative for upland soils of the southeastern USA. Integrating subterranean clover (Trifolium subterraneum) into silvopastures may enhance nutrient retention potential. This study evaluated soil nutrient dynamics, loblolly pine nutrient composition, and loblolly pine growth of an annually fertilized silvopasture on a well drained soil in response to fertilizer type, litter application rate, and subterranean clover. Three fertilizer treatments were applied annually for 4 yr: (i) 5 Mg litter ha(-1) (5LIT), (ii) 10 Mg litter ha(-1) (10LIT), and (iii) an inorganic N, P, K pasture blend (INO). Litter stimulated loblolly pine growth, and neither litter treatment produced soil test P concentrations above runoff potential threshold ranges. However, both litter treatments led to accumulation of several nutrients (notably P) in upper soil horizons relative to INO and unfertilized control treatments. The 10LIT treatment may have increased N and P leaching potential. Subterranean clover kept more P sequestered in the upper soil horizon and conferred some growth benefits to loblolly pine. Thus, although these silvopasture systems had a relatively high capacity for nutrient use and retention at this site, litter should be applied less frequently than in this study to reduce environmental risks.     

EPA worst case water microcosms for testing phage biocontrol of Salmonella

A microplate method was developed as a tool to test phages for their ability to control Salmonella in aqueous environments. The method used EPA (U.S. Environmental Protection Agency) worst case water (WCW) in 96-well plates. The WCW provided a consistent and relatively simple defined turbid aqueous matrix, high in total organic carbon (TOC) and total dissolved salts (TDS), to simulate swine lagoon effluent, without the inconvenience of malodor and confounding effects from other biological factors. The WCW was originally defined to simulate high turbidity and organic matter in water for testing point-of-use filtration devices. Use of WCW to simulate lagoon effluent for phage testing is a new and innovative application of this matrix. Control of physical and chemical parameters (TOC, TDS, turbidity, temperature, and pH) allowed precise evaluation of microbiological parameters (Salmonella and phages). In a typical application, wells containing WCW were loaded with Salmonella enterica susp. enterica serovar Typhimurium (ATCC14028) and treated with phages alone and in cocktail combinations. Mean Salmonella inactivation rates (k, where the lower the value, the greater the inactivation) of phage treatments ranged from -0.32 to -1.60 versus -0.004 for Salmonella controls. Mean log(10) reductions (the lower the value, the greater the reduction) of Salmonella phage treatments were -1.60 for phage PR04-1, -2.14 for phage PR37-96, and -2.14 for both phages in a sequential cocktail, versus -0.08 for Salmonella controls. The WCW microcosm system was an effective tool for evaluating the biocontrol potential of Salmonella phages.