A comparison of speciated atmospheric mercury at an urban center and an upwind rural location

Gaseous elemental mercury (GEM), particulate mercury (PHg) and reactive gaseous mercury (RGM) were measured every other hour at a rural location in south central Wisconsin (Devil's Lake State Park, WI, USA) between April 2003 and March 2004, and at a predominantly downwind urban site in southeastern Wisconsin (Milwaukee, WI, USA) between June 2004 and May 2005. Annual averages of GEM, PHg, and RGM at the urban site were statistically higher than those measured at the rural site. Pollution roses of GEM and reactive mercury (RM; sum of PHg and RGM) at the rural and urban sites revealed the influences of point source emissions in surrounding counties that were consistent with the US EPA 1999 National Emission Inventory and the 2003-2005 US EPA Toxics Release Inventory. Source-receptor relationships at both sites were studied by quantifying the impacts of point sources on mercury concentrations. Time series of GEM, PHg, and RGM concentrations were sorted into two categories; time periods dominated by impacts from point sources, and time periods dominated by mercury from non-point sources. The analysis revealed average point source contributions to GEM, PHg, and RGM concentration measurements to be significant over the year long studies. At the rural site, contributions to annual average concentrations were: GEM (2%; 0.04 ng m(-3)); and, RM (48%; 5.7 pg m(-3)). At the urban site, contributions to annual average concentrations were: GEM (33%; 0.81 ng m(-3)); and, RM (64%; 13.8 pg m(-3)).     

Beyond pollution prevention: A vision for an integrated environmental business management strategy

In this article the authors assert that successful long-term pollution prevention will require changes in the culture and business practices of an organization such that the term “pollution prevention” eventually becomes obsolete. They envision firms evolving to a point where actions that today are referred to as pollution prevention will simply be part of standard business practices and thoroughly embedded in the firms' culture. Although pollution prevention projects and programs need to be highly visible at the outset to communicate throughout the organization and to demonstrate the benefits that can be gained, companies should adopt a long-term strategy aimed at making fundamental changes in the way they do business, rather than relying solely on piecemeal projects and special plans or programs. Such evolution of the firm will maximize the chances of meeting the dual challenges of business competitiveness and environmental stewardship. This article presents a vision for integrating environmental performance with business objectives and suggests practical steps to begin moving toward that vision.     

A first trimester trisomy 13/trisomy 18 risk algorithm combining fetal nuchal translucency thickness,maternal serum free β-hCG and PAPP-A

This study examines 45 cases of trisomy 13 and 59 cases of trisomy 18 and reports an algorithm to identify pregnancies with a fetus affected by trisomy 13 or 18 by a combination of maternal age fetal nuchal translucency (NT) thickness, and maternal serum free β-hCG and PAPP-A at 11–14 weeks of gestation. In this mixed trisomy group the median MoM NT was increased at 2.819, whilst the median MoMs for free β-hCG and PAPP-A were reduced at 0.375 and 0.201 respectively. We predict that with the use of the combined trisomy 13 and 18 algorithm and a risk cut-off of 1 in 150 will for a 0.3% false positive rate allow 95% of these chromosomal defects to be identified at 11–14 weeks. Such algorithms will enhance existing first trimester screening algorithms for trisomy 21. Copyright © 2002 John Wiley & Sons, Ltd.     

Lipid content of some Caribbean corals in relation to depth and light

Three procedures for the extraction of coral lipids were compared and a rapid and effective method for future use is suggested. This method was used to measure the lipid content of the branching coral Porites porites (Pallas) and the massive corals Montastrea annularis (Ellis and Solander) and Siderastrea siderea (Ellis and Solander) during July and August 1991. P. porites and M. annularis were sampled on two fringing reefs, each characterised by different water quality affecting light transmission, and at depths of down to 30 m on a barrier reef on the west coast of the island. m. annularis contained, on average, 29% of dry weight as lipid, and there were no significant differences in lipid levels between corals sampled on either fringing reef at 3 and 6 m, or between fringing reefs and the barrier reef at 13, 20 or 30 m depth. Five samples were also taken from a single massive colony of S. siderea at 3 m on a fringing reef and at 13, 20 and 30 m depth on the barrier reef. Values for lipid ranged from 26 to 35% of dry tissue weight. P. porites from 3 and 6 m depth on both fringing reefs contained the same amount of lipid (11% of dry tissue weight). However, at 13 m depth on the barrier reef this coral contained significantly less lipid (8.5% of dry tissue weight). This difference may be attributable to a higher nutritional intake by P. porites on the fringing reefs.     

Stabilimenta characteristics of the spider Argiope argentata on small islands: support of the predator-defense hypothesis

Summary A variety of orb-weaving spider species construct stabilimenta, patterned areas of dense silk, typically near the hub of the orb. The adaptive significance of this construction, along with associated behaviors such as shuttling and vibrating, is much debated. Arigiope argentata on small islands of the Bahamas frequently possess stabilimenta; we studied 397 individuals of this species to investigate possible functions of their stabilimenta, paying particular attention to predator-defense hypotheses. Cruciform stabilimenta were commoner in all size classes of spiders than discoid stabilimenta or no stabilimentum at all; discoid stabilimenta occurred mostly among intermediate size classes. Within the cruciform type, two-segmented stabilimenta were especially common among the very smallest spiders. Size of cruciform stabilimenta showed a curvilinear relation to spider body length; the fitted curve for total segment length had a maximum at an intermediate spider length. We argue that this relationship (among other phenomena) supports an apparently-larger-size hypothesis, whereby intermediate-sized spiders in particular appear much larger than they actually are. This could discourage predators, including those that are gape-limited such as lizards. We argue that stabilimenta in the smallest spiders, in which typically two segments are opposed, so that they more or less line up, serve as camouflage. When disturbed experimentally, spiders with discoid stabilimenta shuttle to the opposite side of the centrally located stabilimentum. This seems an obvious defensive behavior and occurs less frequently among spiders with cruciform stabilimenta. Large spiders vibrate more frequently than small ones, but no relation exists between vibration frequency and stabilimentum type. We argue (see also Tolbert 1975) that vibrating behavior, in which the spider can become a blur, renders its location more difficult to discern and the spider more difficult to grasp, rather than increasing apparent size. Correspondence to: T.W. Schoener