A National Assessment of the Potential Linkage between Soil,and Surface and Groundwater Concentrations of Phosphorus

A meta‐analysis of three national databases determined the potential linkage between soil and surface and groundwater enrichment with phosphorus (P). Soil P was enriched especially under dairying commensurate with an increase in cow numbers and the tonnage of P‐fertilizers sold. Median P concentrations were enriched in surface waters receiving runoff from industrial and dairy land uses, and in groundwater beneath dairying especially in those aquifers with gravel or sand lithology, irrespective of groundwater redox status. After geographically pairing surface and groundwater sites to maximize the chance of connectivity, a subset of sites dominated by aquifers with gravel and sand lithology showed increasing P concentrations with as little as 10 years data. These data raise the possibility that groundwater could contribute much P to surface water if: there is good connectivity between surface and groundwater, intensive land use occurs on soils prone to leaching, and leached‐P is not attenuated through aquifers. While strategies are available to mitigate P loss from intensive farming systems in the short‐term, factors such as enriched soils and slow groundwater may mean that despite their use, there will be a long‐term input (viz. legacy), that may sustain surface water P enrichment. To avoid poor surface water quality, management and planning may need to consider the connectivity and characteristics of P in soil‐groundwater‐surface water systems.     

Using Public Participation Geographic Information Systems to Identify Places of Watershed Service Provisioning

In this study, we used public participation geographic information systems methods to collect spatial data identifying places that stakeholders in Mobile Bay, Alabama think are important providers of watershed services. These methods allowed us to spatially analyze participatory data from general public respondents and directly compare them with other scientific data in a geographic information systems database. This study identified which places in the region participants believe are important providers of specific watershed services, including fish nurseries, storm protection, flood protection, and water quality protection, which would likely have public support for conservation. Additionally, we assessed the accuracy of participant watershed service identification using land cover data to identify inconsistencies and participant knowledge gaps. This information can be used to target outreach education efforts. We found that the accuracy with which participants correctly identified places with the necessary land cover to provide each service varied considerably. We believe this to be a useful tool for managers to elicit stakeholder input and to identify knowledge gaps regarding the provisioning of watershed services.     

Ecological differences and coexistence in a guild of microparasites: Bartonella in wild rodents

The study of ecological differences among coexisting microparasites has been largely neglected, but it addresses important and unusual issues because there is no clear distinction in such cases between conventional (resource) and apparent competition. Here patterns in the population dynamics are examined for four species of Bartonella (bacterial parasites) coexisting in two wild rodent hosts, bank voles (Clethrionomys glareolus) and wood mice (Apodemus sylvaticus). Using generalized linear modeling and mixed effects models, we examine, for these four species, seasonal patterns and dependencies on host density (both direct and delayed) and, having accounted for these, any differences in prevalence between the two hosts. Whereas previous studies had failed to uncover species differences, here all four were different. Two, B. doshiae and B. taylorii, were more prevalent in wood mice, and one, B. birtlesii, was more prevalent in bank voles. B. birtlesii, B. grahamii, and B. taylorii peaked in prevalence in the fall, whereas B. doshiae peaked in spring. For B. birtlesii in bank voles, density dependence was direct, but for B. taylorii in wood mice density dependence was delayed. B. birtlesii prevalence in wood mice was related to bank vole density. The implications of these differences for species coexistence are discussed.     

Effects of 17α-trenbolone and melengestrol acetate on Xenopus laevis growth, development, and survival

The synthetic growth-promoting hormones trenbolone and melengestrol acetate have been detected in the environment near beef cattle feedlots and are reportedly transported via wind-borne particulate matter. Therefore, movement of synthetic hormones from beef cattle feedlots to water bodies via particulate matter is possible. Our objective was to evaluate potential effects of 17α-trenbolone (17α-TB), melengestrol acetate (MGA), and combinations of both on growth, development, and survival of Xenopus laevis larvae. On post-hatch day 2 (stage 33/34), X. laevis larvae were exposed to three nominal concentrations of 17α-TB (10, 100, and 500 ng/L), MGA (1, 10, and 100 ng/L), a combination of both (1/10, 10/100, and 100/500 ng/L MGA/17α-TB), frog embryo teratogenesis assay-Xenopus medium, or a solvent control. Significant increases in all X. laevis growth metrics were observed among larvae in the 1 ng/L MGA?+?10 ng/L 17α-TB and 10 ng/L MGA?+?100 ng/L 17α-TB treatments. Stage of development was increased among larvae in the 1 ng/L MGA?+?10 ng/L 17α-TB treatment group and significantly decreased among those in the 500 ng/L 17α-TB treatment. Total body mass and snout–vent length of X. laevis larvae were significantly reduced in the 100 ng/L MGA and 100 ng/L MGA?+?500 ng/L 17α-TB treatment groups. Larvae exposed to 500 ng/L 17α-TB had decreased total body mass, snout–vent length, and total length. In general, growth measurements decreased with increasing concentration of MGA, 17α-TB, or a combination of both. Survival among all treatments was not significantly different from controls. Amphibians exposed to MGA and 17α-TB in the environment may experience alterations in growth and development.     

Measuring Concentrations of Volatile Organic Compounds in Vinyl Flooring

ABSTRACT

The initial solid-phase concentration of volatile organic compounds (VOCs) is a key parameter influencing the emission characteristics of many indoor materials. Solid-phase measurements are typically made using solvent extraction or thermal headspace analysis. The high temperatures and chemical solvents associated with these methods can modify the physical structure of polymeric materials and, consequently, affect mass transfer characteristics.

To measure solid-phase concentrations under conditions resembling those in which the material would be installed in an indoor environment, a new technique was developed for measuring VOC concentrations in vinyl flooring (VF) and similar materials. A 0.09-m² section of new VF was punched randomly to produce ~200 0.78-cm² disks. The disks were milled to a powder at -140 °C to simultaneously homogenize the material and reduce the diffusion path length without loss of VOCs. VOCs were extracted from the VF particles at room temperature by fluidized-bed desorption (FBD) and by direct thermal desorption (DTD) at elevated temperatures. The VOCs in the extraction gas from FBD and DTD were collected on sorbent tubes and analyzed by gas chromatog-raphy/mass spectrometry (GC/MS). Seven VOCs emitted by VF were quantified. Concentration measurements by FBD ranged from 5.1 |ig/g VF for n-hexadecane to 130 |Jg/g VF for phenol. Concentrations measured by DTD were higher than concentrations measured by FBD. Differences between FBD and DTD results may be explained using free-volume and dual-mobility sorption theory, but further research is necessary to more completely characterize the complex nature of a diffusant in a polymer matrix.     

Expert variability provides perspective on the strengths and weaknesses of citizen-driven intertidal monitoring program

Citizen scientist programs are a means to efficiently conduct large-scale surveys of ecosystems or managed species, provided that concerns over the quality and use of data generated by nonexperts can be addressed. This study presents actions taken in a citizen science program to assure data quality and demonstrates the validity of citizen-generated data. In this case the accuracy of data collected by secondary school students as citizens in a program that quantitatively sampled benthic rocky intertidal communities at 13 sites on Maui, Molokai, Oahu, and Hawai'i island during the years 2004-2007 was evaluated. In 2007, two independent research teams collected data simultaneously with students at five sites on eight sampling dates. Comparisons of Shannon diversity and Bray-Curtis similarity values computed and simulated from student and researcher collected data revealed that nonexpert students accurately collect community-level data within the range of the variation that occurs between researchers. Students were, however, likely to misidentify cryptic and rare species. These findings have direct implications for the conservation goals of the monitoring program as the assessment reveals that students are likely to misidentify early alien introductions but are able to monitor the abundances of native and introduced species once they become established. The validity assessment designed for this investigation is unique in that it directly compares consistent errors made by citizens in data collection to expert variability to identify usage limitations and can be a guide for future studies that involve the efforts of trained volunteers.