Characterizing the intrinsic bioremediation potential of 1,4-dioxane and trichloroethene using innovative environmental diagnostic tools

An intrinsic biodegradation study involving the design and implementation of innovative environmental diagnostic tools was conducted to evaluate whether monitored natural attenuation (MNA) could be considered as part of the remedial strategy to treat an aerobic aquifer contaminated with 1,4-dioxane and trichloroethene (TCE). In this study, advanced molecular biological and stable isotopic tools were applied to confirm in situ intrinsic biodegradation of 1,4-dioxane and TCE. Analyses of Bio-Trap? samplers and groundwater samples collected from monitoring wells verified the abundance of bacteria and enzymes capable of aerobically degrading TCE and 1,4-dioxane. Furthermore, phospholipid fatty acid analysis with stable isotope probes (PLFA-SIP) of the microbial community validated the ability for microbial degradation of TCE and 1,4-dioxane. Compound specific isotope analysis (CSIA) of groundwater samples for TCE resulted in δ(13)C values that indicated likely biodegradation of TCE in three of the four monitoring wells sampled. Results of the MNA evaluation showed that enzymes capable of aerobically degrading TCE and 1,4-dioxane were present, abundant, and active in the aquifer. Taken together, these results provide direct evidence of the occurrence of TCE and 1,4-dioxane biodegradation at the study site, supporting the selection of MNA as part of the final remedy at some point in the future.     

Comparison of vehicle activity and emission inventory between Beijing and Shanghai

Vehicle emission inventory is a critical element for air quality study. This study created systemic methods to establish a vehicle emission inventory in Chinese cities. The methods were used to obtain credible results of vehicle activity in Beijing and Shanghai. On the basis of the vehicle activity data, the International Vehicle Emission model is used to establish vehicle emission inventories. The emissions analysis indicates that 3 t of particulate matter (PM), 199 t of nitrogen oxides (NO(x)), 192 t of volatile organic compounds (VOCs), and 2403 t of carbon monoxide (CO) are emitted from on-road vehicles each day in Beijing, whereas 4 t of PM, 189 t of NO(x), 113 t of VOCs, and 1009 t of CO are emitted in Shanghai. Although common features were found in these two cities (many new passenger cars and a high taxi proportion in the fleet), the emission results are dissimilar because of the different local policy regarding vehicles. The method to quantify vehicle emission on an urban scale can be applied to other Chinese cities. Also, knowing how different policies can lead to diverse emissions is beneficial knowledge for other city governments.     

Source apportionment of fine particles in Tennessee using a source-oriented model

Source apportionment of fine particles (PM2.5, particulate matter < 2 microm in aerodynamic diameter) is important to identify the source categories that are responsible for the concentrations observed at a particular receptor. Although receptor models have been used to do source apportionment, they do not fully take into account the chemical reactions (including photochemical reactions) involved in the formation of secondary fine particles. Secondary fine particles are formed from photochemical and other reactions involving precursor gases, such as sulfur dioxide, oxides of nitrogen, ammonia, and volatile organic compounds. This paper presents the results of modeling work aimed at developing a source apportionment of primary and secondary PM2.5. On-road mobile source and point source inventories for the state of Tennessee were estimated and compiled. The national emissions inventory for the year 1999 was used for the other states. U.S. Environmental Protection Agency Models3/Community Multi-Scale Air Quality modeling system was used for the photochemical/secondary particulate matter modeling. The modeling domain consisted of a nested 36-12-4-km domain. The 4-km domain covered the entire state of Tennessee. The episode chosen for the modeling runs was August 29 to September 9, 1999. This paper presents the approach used and the results from the modeling and attempts to quantify the contribution of major source categories, such as the on-road mobile sources (including the fugitive dust component) and coal-fired power plants, to observed PM2.5 concentrations in Tennessee. The results of this work will be helpful in policy issues targeted at designing control strategies to meet the PM2.5 National Ambient Air Quality Standards in Tennessee.     

Serum profiles of PCDDs and PCDFs, in individuals near the Escambia Wood Treating Company Superfund site in Pensacola, FL

The Escambia Wood Treating Company (ETC) Superfund site, Pensacola, FL, is contaminated with polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/F), benzo(a)pyrene, lead and arsenic from pentachlorophenol (PCP), creosote, and other compounds used to treat utility poles and foundation pilings. Although ETC's operations ceased in 1982, soils in the areas surrounding the facility continue to exhibit elevated levels of contaminants attributable to ETC operations. In July 2000, individuals who may have been affected by contamination from the ETC site, including current and former residents and former workers and their household members were invited to participate in a study, which included a health and exposure history and routine blood analysis. We also conducted a toxicological health evaluation of a subset of these eligible workers/residents by analyzing serum levels of 17 PCDD/F congeners. Members of the ETC cohort exhibited elevated serum PCDD/F relative to the general population, and congener profiles in members of the cohort reflected patterns commonly observed in persons exposed to PCP. Hypertension prevalence in the cohort was found to correlate with PCDD/F levels, although no other significant relationships were identified with monitored health indices.     

An ecological framework for contextualizing carnivore–livestock conflict

Carnivore predation on livestock is a complex management and policy challenge, yet it is also intrinsically an ecological interaction between predators and prey. Human–wildlife interactions occur in socioecological systems in which human and environmental processes are closely linked. However, underlying human–wildlife conflict and key to unpacking its complexity are concrete and identifiable ecological mechanisms that lead to predation events. To better understand how ecological theory accords with interactions between wild predators and domestic prey, we developed a framework to describe ecological drivers of predation on livestock. We based this framework on foundational ecological theory and current research on interactions between predators and domestic prey. We used this framework to examine ecological mechanisms (e.g., density-mediated effects, behaviorally mediated effects, and optimal foraging theory) through which specific management interventions operate, and we analyzed the ecological determinants of failure and success of management interventions in 3 case studies: snow leopards (Panthera uncia), wolves (Canis lupus), and cougars (Puma concolor). The varied, context-dependent successes and failures of the management interventions in these case studies demonstrated the utility of using an ecological framework to ground research and management of carnivore–livestock conflict. Mitigation of human–wildlife conflict appears to require an understanding of how fundamental ecological theories work within domestic predator–prey systems.     

Economics of courtship-feeding in the European bee-eater (Merops apiaster)

Summary Male bee-eaters Merops apiaster deliver food to the female before and during egg-laying. They tend to give females large items and eat the small ones themselves. We consider several hypotheses to account for size-selective feeding. The following hypotheses were rejected or considered unlikely to account for the data: (1) effects related to central-place foraging (2) differences in nutrient quality between prey (3) sexual selection (4) maximization of total feeding rate to the pair (5) maximization of intake rate to the male subject to a constraint of meeting female needs. The best account of the data was given by the hypothesis that the rate of energy delivered to the female is maximized subject to a constraint of meeting the daily energy needs of the male.     

A team approach to implementing MACT standards

The requirements of the MACT Standards for Emissions from Leaking Equipment and the requirements of the amended Clean Air Act will change how environmental control programs are administered within plants. No longer will the programs be the responsibility solely of the separate environmental function. The programs will need to be administered via a team of personnel that involves maintenance, computer systems, environmental, emissions measurement specialists, and planning personnel as well as management. Compliance with the rules will be based on an inspection of paper records and computer databases. The enforcement penalties will not be trivial. The ability of the plant to grow and be modified will need to be balanced against the potential benefits from early reduction programs, which will allow for delayed implementation of some programs.     

NEGOTIATION TECHNIQUES TO RESOLVE WESTERN WATER DISPUTES1

ABSTRACT: There is a growing literature on the resolution of natural resources conflicts. Much of it is practical, focusing on guidelines for hands-on negotiation. This literature can be a guide in water conflicts. This is especially true for negotiations over new environmental values such as instream flow. The concepts of competitive, cooperative, and integrative styles of conflict resolution are applied to three cases of water resource bargaining. Lessons for the effective use of these ideas include: break a large number of parties into small working groups, approach value differences in small steps, be cautious in the presence of an attentive public, keep decisions at the local level, and understand the opponent's interests.     

The encrusting spongeHalisarca laxus: population genetics and association with the ascidianPyura spinifera

The encrusting spongeHalisarca laxus forms a seemingly obligate association with the stalked solitary ascidianPyura spinifera. In 1991 we examined spatial variation and short-term temporal variation in this association at three neighbouring sites in southeastern Australia. This sponge dominated the surface of almost all the 500 individual ascidians examined, with mean cover usually exceeding 90%. This pattern was consistent among sites and throughout the year of the study. The domination of a small isolated patch of habitable substratum by a sponge is most unusual, given that they are regarded as relatively poor recruiters. To understand how this association might be maintained, we determined the underlying genotypic diversity of the sponge population using starch-gel electrophoresis.P. spinifera is a clump-forming ascidian and usually occurs in clumps of up to 22 individuals. Electrophoretic surveys, based on six variable allozyme loci, revealed that at a total of five plots within three neighbouring New South Wales populations, single sponge genotypes may cover entire ascidian clumps; although a clump sometimes played host to more than one sponge clone. Allele frequencies (averaged across four loci that appear to conform to Mendelian inheritance) showed little variation among populations (standardised genetic variance,F _ST=0.013). Nevertheless, sponge populations were genotypically diverse, with samples from 63 of 172 individual clumps displaying unique clonal genotypes. Moreover, multi-locus genotypic diversity within all sites approached the level expected for sexual reproduction with random mating. Taken together, these data imply thatH. laxus produces sexually-derived larvae that are at least moderately widelly dispersed. Given the relatively small size of the patches that this sponge inhabits, we also conclude that these larvae are good colonists and good spatial competitors on their ascidian hosts.     

Genetic evidence for contrasting patterns of dispersal in solitary and colonial ascidians

In situ and in vitro observations indicate that brooding colonial ascidians commonly display limited larval dispersal, whilst the larvae of most solitary species are assumed to be widely dispersed. We used allozyme data to determine the population genetic consequences of reproduction and dispersal in a broadcast-spawning solitary ascidian and two brooding colonial species along the central and southern coast of New South Wales, Australia. We surveyed genetic variation at 2 to 9 variable loci for samples collected from 6 to 8 local populations of each of the stalked solitary species Pyura gibbosa gibbosa Heller, 1878; the social Stolonica australis Michaelsen, 1927 and the compound Botrylloides magnicoecum Hartmeyer, 1912. Samples from each local population displayed levels and patterns of genotypic diversity that were consistent with expectations for sexually-derived recruitment of both solitary zooids and separate colonies. However, we found clear differences in the structure of the populations of solitary and colonial species. Genotype frequencies within all nine samples of P. gibbosa gibbosa conformed to expectations for random mating (i.e. Hardy–Weinberg equilibria). Moreover, allele frequencies showed little variation among samples [mean standardised genetic variance (F _{S T} ) =0.002], which implies that local populations are strongly connected by larval dispersal. We estimate (via Wright's “island model”) that gene flow (N _e m) within this set of local populations is 125 effective migrants per generation, which is very similar to estimates obtained for other broadcast-spawning taxa in this region. In contrast, genotype frequencies within samples of both colonial species were characterised by large and statistically significant deficits of heterozygotes, consistent with expectations for highly limited dispersal of larvae or sperm. Moreover, local populations were highly differentiated (F _{S T} =0.201 and 0.202 for S. australis and B. magnicoecum, respectively) and N _e m was estimated to be ∼1.0 in each case. These values of F _{S T} and subsequent estimates of N _e m lie within the range of values reported for other New South Wales taxa with direct larval development, and imply that local populations are effectively closed to immigration. Received: 13 February 1997 / Accepted 18 July 1997