Characterizing the Occurrence,Sources, and Variability of Radon in Pacific Northwest Homes

A compilation of data from earlier studies of 172 homes in the Pacific Northwest indicated that approximately 65 percent of the 46 homes tested in the Spokane River Valley/Rathdrum Prairie region of eastern Washington/northern Idaho had heating season indoor radon (²²²Rn) concentrations above the U. S. EPA guideline of 148 Bq m^?3 (4 pCi L^?1). A subset of 35 homes was selected for additional study. The primary source of indoor radon in the Spokane River Valley/Rathdrum Prairie was pressure-driven flow of soil gas containing moderate radon concentrations (geometric mean concentration of 16,000 Bq m^?3) from the highly permeable soils (geometric mean permeability of 5 × 10^?11 m²) surrounding the house substructures. Estimated soil gas entry rates ranged from 0.4 to 39 m³h^?1 and 1 percent to 21 percent of total building air infiltration. Radon from other sources, including domestic water supplies and building materials was negligible. In high radon homes, winter indoor levels averaged 13 times higher than summer concentrations, while in low radon homes winter levels averaged only 2.5 times higher. Short-term variations in indoor radon were observed to be dependent upon indoor-outdoor temperature differences, wind speed, and operation of forced-air furnace fans. Forced-air furnace operation, along with leaky return ducts and plenums, and openings between the substructure and upper floors enhanced mixing of radon-laden substructure air throughout the rest of the building.     

The effects of opening an artificial tidal inlet on hydrography and estuarine macrofauna in Corpus Christi, Texas

Packery Channel is part of a complex of storm washover channels which, before 1912, have opened intermittently, linking the Laguna Madre and Corpus Christi Bay, Texas with the Gulf of Mexico. On 21 July 2005, with the assistance of Hurricane Emily, Packery Channel was prematurely opened to the Gulf of Mexico, months before construction of a dredged channel was scheduled to be completed. A before-versus-after, control-versus-impact (BACI) design was used to assess the effects of reopening Packery Channel on water quality and estuarine macrofauna in Mollie Beattie Coastal Habitat Community (MBCHC), Corpus Christi Bay. Two deep (approximately 1 m below m.s.l.) and two shallow (approximately 0.2 m below m.s.l.) stations were sampled monthly for physical and biological characteristics at both control and impact sites between November 2003 and March 2009. The opening of Packery Channel created a unique situation where salinities decreased after the channel opening by ameliorating hypersalinity in Laguna Madre rather than increasing salinities as would occur in most estuaries worldwide. Salinity also fluctuated in a diurnal pattern after the opening of Packery Channel. Apart from salinity, Packery Channel has caused little hydrographic change in MBCHC since opening in July 2005. There was little effect on the macrofaunal community composition. There was a greater difference in community composition between deep and shallow stations than between either before and after or control and impact sites. There have been no significant changes in abundance, biomass, or N1 diversity caused by the opening of Packery Channel.     

Road Traffic and Nearby Grassland Bird Patterns in a Suburbanizing Landscape

An extensive road system with rapidly increasing traffic produces diverse ecological effects that cover a large land area. Our objective was to evaluate the effect of roads with different traffic volumes on surrounding avian distributions, and its importance relative to other variables. Grassland bird data (5 years) for 84 open patches in an outer suburban/rural landscape near Boston were analyzed relative to: distance from roads with 3000–8000 to >30,000 vehicles/day; open-habitat patch size; area of quality microhabitat within a patch; adjacent land use; and distance to other open patches. Grassland bird presence and regular breeding correlated significantly with both distance from road and habitat patch size. Distance to nearest other open patch, irrespective of size, was not significant. Similarly, except for one species, adjacent land use, in this case built area, was not significant. A light traffic volume of 3000–8000 vehicles/day (local collector street here) had no significant effect on grassland bird distribution. For moderate traffic of 8000–15,000 (through street), there was no effect on bird presence although regular breeding was reduced for 400 m from a road. For heavier traffic of 15,000–30,000 (two-lane highway), both bird presence and breeding were decreased for 700 m. For a heavy traffic volume of ≥30,000 vehicles/day (multilane highway), bird presence and breeding were reduced for 1200 m from a road. The results suggest that avian studies and long-term surveys near busy roads may be strongly affected by traffic volume or changes in volume. We conclude that road ecology, especially the effects extending outward >100 m from roads with traffic, is a sine qua non for effective land-use and transportation policy.