Runoff transport of pyrethroids from a residential lawn in central California

An irrigation runoff study on a residential lawn was conducted in California, northeast of Sacramento, during the summer and fall of 2008 to investigate the contribution of turf uses of pyrethroids to residues in Californian urban creek sediments. This study examined how over irrigation (i.e., irrigation that produces runoff) in the summer season may transport recently applied pyrethroids. The study included liquid and granular applications of both bifenthrin [(2-methyl-3-phenyl-phenyl) methyl 3-(2-chloro-3,3,3-trifluoro-prop-1-enyl)-2,2-dimethyl-cyclopropane-1-carboxylate] and beta-cyfluthrin [Cyano(4-fluoro-3-phenoxyphenyl)methyl 3-(2,2-dichloroethenyl)-2,2-dimethyl-cyclopropanecarboxylate]. Generally, runoff did not occur at irrigation rates of 2.03 cm/h (0.8 in/h) but did occur when the irrigation rates were increased to about 3.81 cm/h (1.5 in/h), generating chemical losses in the first runoff event of up to 0.58 and 0.08% of applied for beta-cyfluthrin and bifenthrin, respectively. Chemical runoff losses dropped significantly between over-irrigation events with the third over-irrigation event chemical runoff losses representing 0.026 and 0.015% of applied for beta-cyfluthrin and bifenthrin, respectively. Runoff losses were generally less for liquid formulations than granular formulations but within a factor of three. Additionally, the study included a simulated winter rainstorm 8 wk after application. The low runoff losses from turf seen in this study suggest that other sources could be contributing to observed residues in urban streams. Other sources could include pyrethroids ending up on impervious surfaces, such as concrete driveways from off-target applications to turf, spills, and other poor handling practices, or pyrechroids applied directly to impervious surfaces for insect control.     

Dynamic selective environments and evolutionary traps in human-dominated landscapes

Human activities can alter selective environments in ways that can reduce the usefulness of certain ornamental traits as honest signals of individual quality and, in some cases, may create evolutionary traps, where rapid changes in selective environments result in maladaptive behavioral decisions. Using the sexually dichromatic, socially monogamous Northern Cardinal (Cardinalis cardinalis) as a model, we hypothesized that urbanization would erode the relationship between plumage coloration and reproductive success. Because the exotic Amur honeysuckle (Lonicera maackii) provides carotenoids, is a preferred habitat attribute, and increases vulnerability to nest predation, we predicted the presence of an evolutionary trap, whereby the brightest males would achieve the lowest reproductive success. Working at 14 forests in Ohio, USA, 2006-2008, we measured plumage color, monitored reproduction, and quantified habitat within territories. In rural landscapes, the brightest males bred earliest in the season and secured more preferred territories; however, annual reproduction declined with plumage brightness. Coloration of urban males was not associated with territory attributes or reproduction. Female redness across all landscapes was negatively related to reproduction. Poor reproductive performance of otherwise higher-quality males probably resulted from preferences for honeysuckle, which reduces annual reproduction when used as a nesting substrate early in the season. In this way, exotic shrubs prompted an evolutionary trap that was avoided in urban forests where anthropogenic resources disassociated male color and reproductive phenology and success. Our study illustrates how modified selective environments in human-dominated landscapes might shape microevolutionary processes in wild bird populations.     

A dual channel gas chromatograph for atmospheric analysis of volatile organic compounds including oxygenated and monoterpene compounds

A dual channel gas chromatograph with flame ionisation detectors has been used extensively for analysis of volatile organic compounds in the atmosphere and forms the basis of two monitoring instruments contributing VOC data to the World Meteorological Organisation - Global Atmosphere Watch network. Recent modifications to the methodology have broadened the scope of the instrument; to incorporate measurements of selected monoterpenes, and achieve improved accuracy in the measurement of oxygenated volatile organic compounds. Analysis of selected monoterpenes has been achieved without any significant loss of resolution of the non-methane hydrocarbons or oxygenated compounds. Quantification of 64 different VOCs of varying functionalities are reported with detection limits in the range 1-5 parts per trillion. Here we present a summary of the instrumental and calibration details for the methodology, which continues to be used on many field projects, along with a discussion of the associated measurement uncertainties.     

Climate change impacts on freshwater recreational fishing in the United States

We estimated the biological and economic impacts of climate change on freshwater fisheries in the United States (U.S.). Changes in stream temperatures, flows, and the spatial extent of suitable thermal habitats for fish guilds were modeled for the coterminous U.S. using a range of projected changes in temperature and precipitation caused by increased greenhouse gases (GHGs). Based on modeled shifts in available thermal habitat for fish guilds, we estimated potential economic impacts associated with changes in freshwater recreational fishing using a national-scale economic model of recreational fishing behavior. In general, the spatial distribution of coldwater fisheries is projected to contract, being replaced by warm/cool water and high-thermally tolerant, lower recreational priority (i.e., “rough”) fisheries. Changes in thermal habitat suitability become more pronounced under higher emissions scenarios and at later time periods. Under the highest GHG emissions scenario, by year 2100 habitat for coldwater fisheries is projected to decline by roughly 50 % and be largely confined to mountainous areas in the western U.S. and very limited areas of New England and the Appalachians. The economic model projects a decline in coldwater fishing days ranging from 1.25 million in 2030 to 6.42 million by 2100 and that the total present value of national economic losses to freshwater recreational fishing from 2009 to 2100 could range from $81 million to $6.4 billion, depending on the emissions scenario and the choice of discount rate.     

Evaluation of Current Approaches to Stream Classification and a Heuristic Guide to Developing Classifications of Integrated Aquatic Networks

Conservation and management of fresh flowing waters involves evaluating and managing effects of cumulative impacts on the aquatic environment from disturbances such as: land use change, point and nonpoint source pollution, the creation of dams and reservoirs, mining, and fishing. To assess effects of these changes on associated biotic communities it is necessary to monitor and report on the status of lotic ecosystems. A variety of stream classification methods are available to assist with these tasks, and such methods attempt to provide a systematic approach to modeling and understanding complex aquatic systems at various spatial and temporal scales. Of the vast number of approaches that exist, it is useful to group them into three main types. The first involves modeling longitudinal species turnover patterns within large drainage basins and relating these patterns to environmental predictors collected at reach and upstream catchment scales; the second uses regionalized hierarchical classification to create multi-scale, spatially homogenous aquatic ecoregions by grouping adjacent catchments together based on environmental similarities; and the third approach groups sites together on the basis of similarities in their environmental conditions both within and between catchments, independent of their geographic location. We review the literature with a focus on more recent classifications to examine the strengths and weaknesses of the different approaches. We identify gaps or problems with the current approaches, and we propose an eight-step heuristic process that may assist with development of more flexible and integrated aquatic classifications based on the current understanding, network thinking, and theoretical underpinnings.     

The Nutrient Status of Some Graminaceous Species in Britain. 2. Deschampsia Flexuosa (L.) Trin

Above-ground biomass of Deschampsia flexuosa from 40 sites throughout Britain was analysed for concentrations of elements (N, P, K, Ca, Mg, Fe, Mn, Cu, Zn and Na), with matching analyses of nutrient levels in the soils, together with pH and LOI. Seasonal variation in the nutrients was also studied in detail at one of the sites. the grass was found on acid sites ranging between pH 3.1 and 4.7. the soil humus content varied widely, and there were significant correlations between that and elements (N, P, K, Ca, Mg, Zn and Na) in the soil. Concentrations of zinc and manganese in the plant material were the only elements that significantly correlated with extractable levels in the soils. Tissue concentrations of nitrogen, phosphorus, and potassium declined throughout the growing season, whereas the other elements showed a tendency to build up until the end of September. Calcium, magnesium and manganese concentrations then declined as growth ceased. the results are compared with above-ground concentrations of minerals in other plants and the growth strategy of this perennial grass.     

Role of iron chemistry in controlling the release of pollutants from resuspended sediments

Aquatic sediments often contain a large number of chemical contaminants that are potential pollutants. It is often presumed that such contaminants are released to the water column during sediment resuspension and, in there, adversely impact aquatic life and other beneficial uses of the water. However, extensive laboratory and field studies of about 100 contaminated sediments from across the United States that specifically addressed this type of release showed that of about 30 common heavy metals, organic compounds, and other potential pollutants, only manganese II and ammonia were released to then remain in the water column after sediment resuspension. These results indicated that the chemistry of aqueous iron controls the availability of many contaminants in resuspended sediment. The formation of ferric hydroxide during sediment suspension into the water column, as a result of the reaction between ferrous iron in the sediments and dissolved oxygen in the water column, leads to rapid scavenging of many contaminants in the Fe(OH)₃ precipitate. The scavenged contaminants are redeposited in the sediments. This article reviews the role of the aqueous chemistry of iron as it relates to controlling the release of potential pollutants from resuspended sediments. © 2005 Wiley Periodicals, Inc.     

Synchrotron micro-scale measurement of metal distributions in Phragmites australis and Typha latifolia root tissue from an urban brownfield site

Liberty State Park in New Jersey,USA,is a "brownfield" site containing various levels of contaminants.To investigate metal uptake and distributions in plants on the brownfield site,Phragmites australis and Typha latifolia were collected in Liberty State Park during the growing season(May–September)in 2011 at two sites with the high and low metal loads,respectively.The objective of this study was to understand the metal(Fe,Mn,Cu,Pb and Zn)concentration and spatial distributions in P.australis and T.latifolia root systems with micro-meter scale resolution using synchrotron X-ray microfluorescence(μXRF)and synchrotron X-ray computed microtomography(μCMT)techniques.The root structure measurement by synchrotron μCMT showed that high X-ray attenuation substance appeared in the epidermis.Synchrotron μXRF measurement showed that metal concentrations and distributions in the root cross-section between epidermis and vascular tissue were statistically different.Significant correlations were found between metals(Cu,Mn,Pb and Zn)and Fe in the epidermis,implying that metals were scavenged by Fe oxides.The results from this study suggest that the expression of metal transport and accumulation within the root systems may be element specific.The information derived from this study can improve our current knowledge of the wetland plant ecological function in brownfield remediation.