The recovery of ammonia and hydrogen sulfide from ground-level area sources using dynamic isolation flux chambers: bench-scale studies

Controlled bench-scale laboratory experiments were conducted to evaluate the recovery of ammonia (NH3) and hydrogen sulfide (H2S) from dynamic isolation flux chambers. H2S (80-4000 ppb) and NH3 (5000-40,000 ppb) samples were diffused through the flux chamber to simulate ground level area source emissions while measuring the inlet and outlet flux chamber concentrations simultaneously. Results showed that the recovery of H2S during a 30-min sampling time was almost complete for concentrations >2000 ppb. At the lowest concentration of 80 ppb, 92.55% of the H2S could be recovered during the given sampling period. NH3 emissions exhibited similar behavior between concentrations of 5000-40,000 ppb. Within the 30-min sampling period, 92.62% of the 5000-ppb NH3 sample could be recovered. Complete recovery was achieved for concentrations >40,000 ppb. Predictive equations were developed for gas adsorption. From these equations, the maximum difference between chamber inlet and outlet concentrations of NH3 or H2S was predicted to be 7.5% at the lowest concentration used for either gas. In the calculation of emission factors for NH3 and H2S, no adsorption correction factor is recommended for concentrations >37,500 ppb and 2100 ppb for NH3 and H2S, respectively. The reported differences in outlet and inlet concentration above these ranges are outside the fullscale sensitivity of the gas sensing equipment. The use of 46-90 m of Teflon tubing with the flux chambers has apparently no effect on gas adsorption, because recovery was completed almost instantaneously at the beginning of the tests.     

Improved recovery of repeat intoxicated drivers using fingernails and blood spots to monitor alcohol and other substance abuse

Objectives: This study reports the results of a pilot program in Kenosha County that used a combination of direct biomarkers extracted from blood spots and nails to monitor repeat intoxicated drivers for their use of alcohol and drugs with a detection window spanning from 3 weeks to several months. The objectives were to test whether the direct biomarkers phosphatidylethanol (PEth), ethylglucuronide (EtG), and 5 drug metabolites would (1) help assessors obtain a more objective evaluation of repeat offenders during the assessment interview, (2) allow for timely identification of relapses and improve classification of drivers into risk categories, and (3) predict recidivism by identifying offenders most likely to obtain a subsequent operating while intoxicated (OWI) offense within 4 years of enrollment in the program.

Methods: All (N = 261) repeat offenders were tested using PEth obtained from blood spots and EtG obtained from fingernails; 159 participants were also tested for a 5 drugs of abuse nail panel. Drivers were tested immediately after the assessment interview (baseline) and at 3, 6, 9, and 12 months after baseline. Based on biomarker results and self-reports of abstinence, offenders were classified into different risk categories and required to follow specific testing timelines based on the program's decision tree.

Results: The baseline analysis shows that 60% of drivers tested positive for alcohol biomarkers (EtG, PEth, or both) at the assessment interview, with lower detection rates (0–11%) for the 5 drug metabolites. The comparison of biomarkers results to self-reports of abstinence identified 28% of all offenders as high risk and assigned them to more frequent testing and more intense monitoring. The longitudinal analysis shows that 56% (completers) of participants completed the program successfully and the remaining 44% (noncompliant) terminated prematurely. Two thirds (68%) of the completers were able to reduce or control their drinking and one third relapsed at least one time during their mandated monitoring periods. After a brief intervention by the assessors, 79% of relapsers tested negative for biomarkers in their repeat tests. The rearrest analysis showed that offenders classified in the noncompliant and relapsers groups were 7 times more likely to receive a new OWI 4 years after enrollment compared to drivers classified as abstainers or controllers. Refractory drivers were monitored the longest and reported no subsequent rearrests.

Conclusion: These findings demonstrate the benefits of more individualized interventions with repeat OWI offenders and calls for further development of multimodal approaches in traffic medicine including those that use direct alcohol biomarkers as evidence-based practices to reduce recidivism.     

Ecophysiology of dorsal versus ventral cuticle in flattened sawfly larvae

Platycampus larvae are highly cryptic leaf feeders characterised by a dorso-ventrally flattened body, the dorsal integument resembling a shield. Dorsal and ventral cuticles from Platycampus luridiventris were compared by histology and gel electrophoresis. By Azan-staining, a red and a blue layer were distinguished in the dorsal cuticle, while the ventral cuticle showed one, almost uniform blue layer, as in both cuticles of control species. The two cuticles from P. luridiventris had similar amounts and sodium dodecyl sulphate-polyacrylamide gel electrophoresis profiles of soluble proteins, but not insoluble proteins. One insoluble protein (MW ≈ 41 kDa) was visible as a large band in the ventral cuticle only. It is likely that this protein renders the cuticle elastic, and that the dorsal, red layer is the exocuticle, mainly composed of insoluble proteins. We discuss eco-physiological implications of the exocuticle in insects. Further, data from the literature indicate that the defence strategy in P. luridiventris larvae relies on being visually cryptic towards avian predators and tactically cryptic towards arthropod predators and parasitoids. Crypsis in both senses is favoured by the shield effect, itself based on an abnormally thick dorsal exocuticle. Although the larvae are external feeders, they may be considered as hidden from an ecological perspective.     

Is this trail too crowded? A choice experiment to evaluate tradeoffs and preferences of park visitors in Garibaldi Park,British Columbia

Large crowds in parks can be a problem for park managers and visitors. However, perceptions of crowding are difficult to measure due to coping mechanisms deployed by park visitors. Furthermore, perceptions of crowding should not be measured in isolation, but rather as part of a suite of conditions that comprise the visitors’ outdoor experience. We used a dichotomous choice experiment with visual images and eight attributes to estimate park users’ utilities associated with their visitor experience in Garibaldi Provincial Park in British Columbia, Canada. Our visual method allowed us to control for background view and compare user preferences on hiking trails with preferences at final destinations. We find that utilities are more sensitive to crowding at viewpoints than to other aspects of the outdoor experience. Thus, visitor satisfaction and crowding perceptions are more likely to be defined by where visitors have these encounters rather than the total number of encounters.     

Molecular phylogeny and DNA barcoding of tropical eastern Pacific shallow-water gorgonian octocorals

The octocoral fauna inhabiting the shallow waters (<50 m) of the eastern Pacific has been the subject of renewed interest, and the taxonomy of the most important genera in the region has been reviewed and clarified. Many new species have been described, significantly increasing the known biological diversity of the region. Despite their importance as potential sister-groups of Caribbean octocorals, the phylogenetic relationships of eastern Pacific octocorals remain poorly studied. Here, using partial mitochondrial MutS and igr1-COI sequences, we provide a phylogenetic assessment of a broad sample of eastern Pacific shallow-water octocorals and investigate their phylogenetic relationships with Caribbean gorgonians. We corroborate the monophyly of Pacifigorgia, Leptogorgia and Eugorgia and provide evidence of a close relationship between Swiftia and Psammogorgia, currently placed in Plexauridae. In addition, the phylogenies obtained here provide insights into the historical biogeography and phylogenetic diversity of the eastern Pacific octocoral assemblages and on character evolution among this diverse faunal assemblage. Finally, we evaluate the classification power of DNA barcoding for identifying species of shallow-water eastern Pacific octocorals and assess the use of a nuclear intron (SRP54) to supplement traditional mitochondrial barcodes in this group of organisms.     

Identification and assessment of water pollution as a consequence of a leachate plume migration from a municipal landfill site (Tucumán,Argentina)

Landfills constitute potential sources of different pollutants that could generate human health and environmental problems. While some landfills currently work under the protection of a bottom liner with leachate collection, it was demonstrated that migration could take place even yet with these cautions. The purpose of this paper is to assess the pollution caused by a leachate plume from a municipal landfill that is affecting both groundwater and surface waters. The research was carried out at Pacará Pintado landfill in northwestern Argentina. Analysis of water samples indicates that leachate is affecting groundwater under the landfill area and an abandoned river channel hydraulically connected. In the center of the landfill area, the plume is anoxic and sulfate, nitrate, iron and manganese reduction zones were identified. Leachate plume presented high concentration of organic matter, Fe, Mn, NH₄ ⁺, Cl^? and Cr reaching an extension of 900 m. The presence of a leachate plume in a landfill site with a single liner system implies that the use of this groundwater pollution control method alone is not enough especially if permeable sediments are present below.     

A regional-scale sustainable development index: the case of Baja California Sur,Mexico

Sustainable development, as a multi-dimensional concept, is difficult to measure. Some efforts using indicators and indices have appeared in recent years, but most were developed on a national scale. Use of sustainability indicators has proven valuable for attaining better management of the environment by minimizing information gaps and maximizing community capabilities in terms of economic, social, environmental, and institutional sustainability dimensions. However, at least in the case of developing countries, the potential exists that national sustainability measures, based on national level indicators, may mask problems in sub-national zones with highly unsustainable conditions. This paper proposes a methodology to evaluate sustainable development at a local level, the use of which could be helpful in comparing different regions within a country or even among different countries. National sustainability indicators should result from a combination (whether additive or proportional) of regional sustainability indicators, as developed in this paper.     

Size and spatial structure in deep versus shallow populations of the Mediterranean gorgonian <Emphasis Type="Italic">Eunicella singularis</Emphasis> (Cap de Creus,northwestern Mediterranean Sea)

In the Western Mediterranean Sea, the gorgonian Eunicella singularis (Esper, 1794) is found at high densities on sublittoral bottoms at depths from 10 to 70 m. Shallow colonies have symbiotic zooxanthellae that deeper colonies lack. While knowledge of the ecology of the shallow populations has increased during the last decades, there is almost no information on the ecology of the deep sublittoral populations. In October and November 2004 at Cap de Creus (42°19′12″ N; 03°19′34″ E), an analysis of video transects made by a remotely operated vehicle showed that shallow populations (10–25 m depth) were dominated by small, non-reproductive colonies, while deep sublittoral populations (50–67 m depth) were dominated by medium-sized colonies. Average and maximum colony heights were greater in the deeper populations, with these deeper populations also forming larger patch sizes and more extensive regions of continuous substrate coverage. These results suggest that shallow habitats are suitable for E. singularis, as shown by the high recruitment rate, but perturbations may limit or delay the development of these populations into a mature stage. This contrasts with the deep sublittoral habitats where higher environmental stability may allow the development of mature populations dominated by larger, sexually mature colonies.