A near real-time system for continuously monitoring airborne subtilisin-type enzymes in the industrial atmosphere

We describe the development and validation of a portable system comprising an air sampler coupled to an automated flow injection analysis device. The system is able to monitor airborne concentrations of subtilisin-type enzymes in the workplace atmosphere on a continuous basis. Sampling is in two stages: using a sampling head that is designed to mimic human respiration at approx. 1 m s(-1) at a sampling rate of 600 l min(-1). In the second stage, the captured particles are deposited by impaction from the air stream onto the inner surface of a cyclone that is continuously washed with a jet of buffer solution. Deposited particles are then washed into a reservoir from which samples are taken every 5-6 min and injected automatically into a continuous flow injection analysis system. Proteolytic enzyme in the sample passes through a bioreactor maintained at about 40 degrees C. This contains a cellulose solid phase matrix on which is covalently immobilised Texas Red-labelled gelatin as substrate. The passing enzyme partially digests the substrate releasing fluorophore that is detected down stream in a flow cell coupled to a fluorimeter. The system is calibrated using enzyme standards and the intensity of the resulting peaks from the ex-air samples is converted to airborne concentrations using a mathematical model programmed into a PC. The system has a limit of detection of 4.8 ng m(-3) and a dynamic range of 5-60 ng m(-3). The within assay precision (RSD) is 6.3-9.6% over this range. The within batch precision is 20.3% at 20 ng m(-3) and the corresponding between batch value is 19.5%. The system has been run for periods up to 8 h in the laboratory and for up to 4 h at a factory site and the values obtained compared with time-averaged values obtained from a conventional Galley sampler and in-house analysis when reasonable agreement of the results was observed. The stability of the system over 21 days of continuous use with standards injected periodically was studied. Linearity was observed for all the standard plots throughout. At the end of 21 days, after a total exposure equivalent to 2395 ng ml(-1) of Savinase, the signal due to the 5.0 ng ml(-1) standard was still easily detectable.     

Removal of added nitrate in the single, binary, and ternary systems of cotton burr compost, zerovalent iron, and sediment: Implications for groundwater nitrate remediation using permeable reactive barriers

Recent research has shown that carbonaceous solid materials and zerovalent iron (Fe(0)) may potentially be used as media in permeable reactive barriers (PRBs) to degrade groundwater nitrate via heterotrophic denitrification in the solid carbon system, and via abiotic reduction and autotrophic denitrification in the Fe(0) system. Questions arise as whether the more expensive Fe(0) is more effective than the less expensive carbonaceous solid materials for groundwater nitrate remediation, and whether there is any synergistic effect of mixing the two different types of materials. We carried out batch tests to study the nature and rates of removal of added nitrate in the suspensions of single, binary, and ternary systems of cotton burr compost, Peerless Fe(0), and a sediment low in organic carbon. Cotton burr compost acted as both organic carbon source and supporting material for the growth of indigenous denitrifiers. Batch tests showed that cotton burr compost alone removed added nitrate at a greater rate than did Peerless Fe(0) alone on an equal mass basis with a pseudo-first-order rate constant k=0.0830+/-0.0031 h(-1) for cotton burr compost and a k=0.00223+/-0.00022 h(-1) for Peerless Fe(0); cotton burr compost also removed added nitrate at a faster rate than did cotton burr compost mixed with Peerless Fe(0) and/or the sediment. Furthermore, there was no substantial accumulation of ammonium ions in the cotton burr compost system, in contrast to the systems containing Peerless Fe(0) in which ammonium ions persisted as major products of nitrate reduction. It is concluded that cotton burr compost alone may be used as an excellent denitrification medium in a PRB for groundwater nitrate removal. Further study is needed to evaluate performance of its field applications.     

Sorption of organic contaminants by biopolymers: role of polarity, structure and domain spatial arrangement

Sorption behavior of hydrophobic organic contaminants (HOCs) (i.e., pyrene, phenanthrene and naphthalene) by native and chemically modified biopolymers (lignin, chitin and cellulose) was examined. Lignins (native and treated) showed nonlinear sorption for all compounds studied, emphasizing their glassy character. Chitins and celluloses had linear isotherms for phenanthrene and naphthalene, illustrating the dominance of partitioning, while pyrene yielded nonlinear isotherms. Sorption capacity (K(oc)) of HOCs was negatively correlated with the polarity [(O+N)/C] of the biopolymers. Aromatic and alkyl+aromatic C percentages, rather than alkyl C content, demonstrated a better correlation with K(oc) values, indicating the importance of aromatic structures for HOC affinity. Hydrophobicity (K(ow))-normalized K(oc) values decreased sharply with increasing percentage of O-alkyl C versus total aliphatic C (O-alkyl C/total aliphatic C) or with polar C/(alkyl+aromatic C) ratio of the biopolymers until their values reached 80% and 4, respectively, illustrating the effect of surrounding polar groups on reducing affinity for HOCs. Overall, the results of this study highlight the role of spatial arrangement of domains within biopolymers in sorption of HOCs, and point to sorbent properties, such as functionality, polarity and structure, jointly regulating the sorption of HOCs in biopolymers.     

Age and seasonal variability of polybrominated diphenyl ethers in free-ranging East Greenland polar bears (Ursus maritimus)

Polybrominated diphenyl ethers (PBDEs) were analysed in adipose tissue from 92 East Greenland polar bears (Ursus maritimus) sampled during 1999-2001. Mean SigmaPBDE concentrations were 70 ng/g lipid weight (lw) (range: 22-192 ng/g lw) and showed no relationship with age or sex. Of the 32 analysed PBDE congeners; BDE47, BDE153, BDE99 and BDE100 dominated, and comprised 99.6% of the SigmaPBDE concentration. The SigmaPBDE concentration had a highly significant correlation with SigmaPCB, SigmaCHL, dieldrin, HCB and SigmaHCH concentrations. We found a seasonal pattern of median SigmaPBDE concentration with 1.2 to 1.8 times higher concentrations in March to July than the rest of the year. The seasonal variation also provides a clue to the seasonal exposure, bio-availability, toxic exposure and degradation. We suggest that future geographical PBDE data comparisons may not need corrections for sex or age, but such data sets should be corrected for seasonal variability, using the presented correctional trigonometric regression.     

Managing scuba divers to meet ecological goals for coral reef conservation

Marine protected areas increasingly are challenged to maintain or increase tourism benefits while adequately protecting resources. Although carrying capacity strategies can be used to cope with use-related impacts, there is little understanding of divers themselves, their management preferences, and how preferences relate to conservation goals. By using a stated preference choice modeling approach, we investigated the choices divers make in selecting diving trips to marine protected areas as defined by use level, access, level of supervision, fees, conservation education, and diving expectations. Logit models showed that divers preferred a more restrictive management scenario over the status quo. Divers favored reductions in the level of site use and increased levels of conservation education. Divers did not favor fees to access protected areas, having less access to the resource, or extensive supervision. Finally, divers were much more willing to accept increasingly restrictive management scenarios when they could expect to see increased marine life.     

LC-MS-MS analysis and occurrence of octyl- and nonylphenol, their ethoxylates and their carboxylates in Belgian and Italian textile industry, waste water treatment plant effluents and surface waters

Alkylphenols (APs), alkylphenol ethoxylates (APEOs), ethoxycarboxylate metabolites (APECs) and bisphenol A were determined in surface water using solid-phase extraction (SPE) followed by triple-quadrupole LC-MS-MS. APs were separated by LC from APECs using an acetonitrile-water-gradient without the addition of any buffer. Nonylphenol ethoxycarboxylates (NPECs) interfere in the detection of nonylphenols (NPs) when using an acidic mobile phase, because they produce the same MS-MS fragment ions (219>133 and 147). 4n-NP shows the characteristic transition 219>106; it is well suited as internal standard. Nonylphenol ethoxylates NPE(n)Os (n=1-17) were analysed separately in a second run by positive ionization using an ammonium acetate mobile phase. Textile industry discharges, the corresponding wastewater treatment plant (WWTP) effluents and the receiving rivers in Belgium and Italy were analysed. Among the substances investigated, NPE1C and NPE2O exhibited the highest concentrations in the water samples, up to 4.5 microg l(-1) NPE1C in a WWTP effluent and 3.6 microg l(-1) NPE2O in a river. The highest NP levels were found in the receiving rivers (max. 2.5 microg l(-1)). The predicted no-effect concentration (PNEC) for NP of 0.33 microg l(-1) for water species was frequently exceeded in the surface waters investigated, suggesting potential adverse effects to the aquatic environment.     

An Evaluation of Restoration Efforts in Fishless Lakes Stocked with Exotic Trout

Abstract: Detrimental effects of introduced fishes on native amphibian populations have prompted removal of introduced cutthroat ( Oncorhynchus clarki ), rainbow ( Oncorhynchus mykiss ), and brook trout (  Salvelinus fontinalis ) from naturally fishless lakes at Mt. Rainier National Park, Washington ( U.S.A.). Using paleolimnological indicators (diatoms, invertebrates, and sediment characteristics) in eight 480-year-old sediment cores from eight lakes, we (1) derived estimates of baseline environmental conditions and natural variation, (2) assessed the effects of stocking naturally fishless lakes, and (3) determined whether lakes returned to predisturbance conditions after fish removal (restoration). Diatom floras were relatively stable between 315 and 90 years before present in all lakes; we used this time period to define lake-specific "baseline" conditions. Dissimilarity analyses of diatoms revealed sustained, dramatic changes in diatom floras that occurred approximately 80 years ago (when fish were introduced) in four of five stocked lakes, whereas the diatom floras in two unstocked lakes had not changed significantly in the last 315 years. Diatoms were not preserved in an eighth lake. State changes also occurred in two lakes over 200 years before European settlement of the Pacific Northwest. Preserved invertebrate densities fluctuated dramatically over time in all cores, providing a poor reference for assessing the effects of fishes. Nevertheless, fish-invertebrate interactions have been demonstrated in other paleolimnological studies and may be useful for lower-elevation or more productive lakes. Because diatom communities have not returned to predisturbance assemblages in restored lakes, even 20–30 years after fish removal, we conclude that Mt. Rainier lakes were not successfully restored by the removal of fishes.     

Utility of North Atlantic Right Whale Museum Specimens for Assessing Changes in Genetic Diversity

Abstract: We examined six historical specimens of the endangered North Atlantic right whale ( Eubalaena glacialis ) using DNA isolated from documented baleen plates from the late nineteenth and early twentieth centuries. Sequences from the mitochondrial DNA (mtDNA) control region from these samples were compared with those from a near-exhaustive survey (269 of approximately 320 individuals) of the remaining right whales in the western North Atlantic Ocean. Our results suggest that there has been only relatively modest change in maternal lineage diversity over the past century in the North Atlantic right whale population. Any significant reduction in genetic variation in the species most likely occurred prior to the late nineteenth century. One historical specimen was from the last documented female capable of propagating one of the maternal lineages in the population today; no females in the existing population have been found to carry this mtDNA haplotype. Analysis of the only specimens from the eastern North Atlantic right whale population ever to be examined revealed that eastern and western North Atlantic right whales may not have been genetically differentiated populations. Loss of gene diversity experienced by North Atlantic right whales over the last century has been modest, and the six decades of protection have been successful in maintaining much of the maternal lineage diversity that was present in the late nineteenth century.     

Demographic Forecasting in Koala Conservation

Abstract: The koala currently needs conservation intervention. There is clear evidence of decline in many populations, but the existence of other stable or expanding populations offers the possibility of a variety of creative solutions to their conservation problems. The 1998 National Koala Conservation Strategy emphasizes the need to obtain demographic information and to use this information to assess management options for koalas. We need accurate diagnoses of the status of koala populations and forecasts of their demographic future with and without particular management actions. In a qualitative fashion, this process has been undertaken many times on a local and national scale. Quantitative demographic forecasting tools are increasingly available, and koala management could benefit from their application both at the scale of individual populations and more broadly. There is already a considerable body of suitable data on the dispersal, effects of normal and catastrophic environmental variation on reproduction and survival, and on the effects of habitat change. Demographic forecasting, however, is hampered because the full suite of information is rarely available from a single population. In two Queensland populations, retrospective population viability analyses provided forecasts that were in agreement with observed population trends. Work is needed to determine whether data from one population can be applied to other populations. Models can then be developed to make projections at a multipopulation level on the basis of local population dynamics and dispersal. Certain koala populations, because of their long history of study, offer the opportunity to test demographic models retrospectively. These tests will not only aid in fine-tuning the models for koala biology and data but will also assist with the more general process of validating the models.     

Conservation Genetics at the Species Boundary

Abstract: Conservation genetics has expanded its purview such that molecular techniques are now used routinely to prioritize populations for listing and protection and infer their historical relationships in addition to addressing more traditional questions of heterozygosity and inbreeding depression. Failure to specify whether molecular data are being used for diagnosis-related questions or for population viability questions, however, can lead either to misinterpretation of character data as adaptive information or to misinterpretation of frequency or distance data as diagnostic or historical information. Each of these misinterpretations will confound conservation programs. The character-based approach to delimiting phylogenetic species is both operationally and logically superior to "diagnostic" methods that involve distance- or frequency-based routines, which are unstable over time. Tree-based criteria for the diagnosis of conservation "units" are also inappropriate because they can depend on patterns inferred without reference to diagnostic characters. Intraspecific studies, conservation-related or otherwise, that adopt terminology and methods designed to infer nested hierarchic relationships confuse diagnosis with historical inferences by treating diagnoses as outcomes rather than as precursors to phylogeny reconstruction. A character-based diagnostic approach recognizes the analytical dichotomy between species hierarchies and population statistics and provides a framework for the understanding of each. No species concept, however, should be viewed as an absolute criterion for protecting populations, but as part of a framework from within which identification of protection and management goals can be achieved effectively and defensibly.