Bioassessment in A Harsh Environment: A Comparison of Macroinvertebrate Assemblages at Reference and Assessment Sites in An Australian Inland River System

The Lachlan River system of inland New South Wales, which extends into semi-arid areas, is prone to natural extremes of climate and water quality and has been almost entirely modified since European settlement in Australia. We used this system as a proving ground for the mainly qualitative bioassessment metrics for river macroinvertebrates that are used widely in Australia – the EPT (Ephemeroptera, Plecoptera and Trichoptera) index, the SIGNAL (Stream Invertebrate Grade Number Average Level) biotic index and the AUSRIVAS O/E (Australian River Assessment System Observed over Expected) index – plus a recently developed qualitative index, the observed proportion of potential taxa (OPP). We tested these metrics on their ability to discriminate between sites judged to be less disturbed by human activities (reference sites) and sites selected by a semi-random process and therefore expected to have a higher average level of human disturbance (assessment sites). All metrics except the AUSRIVAS O/E index differed significantly between the two types of sites at higher altitudes, with SIGNAL showing the greatest discrimination. Assessment at these altitudes was more effective if based on composite data from multiple mesohabitats rather than data from single mesohabitats. No metric differentiated the two types of sites in the more arid, lowland, floodplain region of the river system. We suggest that Australia relies too heavily on bioassessment concepts developed to assess water pollution in well-watered regions of the Northern Hemisphere. Effective assessment of human impacts on macroinvertebrates in the rivers of inland Australia requires a better understanding of the roles of flow regimes, including flood and drought sequences, and of microhabitat structure and invasive alien species. Quantitative approaches may also be required.     

Unexpected effects of sublethal doses of insecticide on the peripheral olfactory response and sexual behavior in a pest insect

Pesticides have long been used as the main solution to limit agricultural pests, but their widespread use resulted in chronic or diffuse environmental pollutions, development of insect resistances, and biodiversity reduction. The effects of low residual doses of these chemical products on organisms that affect both targeted species (crop pests) but also beneficial insects became a major concern, particularly because low doses of pesticides can induce unexpected positive—also called hormetic—effects on insects, leading to surges in pest population growth at greater rate than what would have been observed without pesticide application. The present study aimed to examine the effects of sublethal doses of deltamethrin, one of the most used synthetic pyrethroids, known to present a residual activity and persistence in the environment, on the peripheral olfactory system and sexual behavior of a major pest insect, the cotton leafworm Spodoptera littoralis. We highlighted here a hormetic effect of sublethal dose of deltamethrin on the male responses to sex pheromone, without any modification of their response to host-plant odorants. We also identified several antennal actors potentially involved in this hormetic effect and in the antennal detoxification or antennal stress response of/to deltamethrin exposure.     

Estimation and simulation for geospatial porosity and permeability data

Reservoir simulation of \(\hbox {CO}_2\) sequestration, energy recovery, and environmental contamination scenarios must be accompanied by uncertainty quantification. Typically this is done by stochastically modeling porosity and permeability fields, simulating realizations based on the model, and then numerically simulating flow and transport. The challenge is to generate simulated porosity and permeability fields with characteristics as similar as possible to those known of the reservoir under study. In this paper we focus on the first two steps above in analyzing a large 3-dimensional array of geospatial porosity data and using the results to produce simulated data with characteristics mimicking those of the original porosity observations. The spatial covariance is empirically approximated from horizontal cross sections of the data via a kernel principle component analysis yielding dimension reduction. Simulations in three dimensions are produced by linking consecutive parallel cross sections via conditioning on a small subarray of the data. The conditional simulations effectively reproduce observed channeling, an important large scale feature of interest in the sub-surface relevant to transport of contaminates. The original porosity data is non-Gaussian and requires additional analysis and transformation to generate both porosity and permeability fields.     

Development and Evaluation of a Method to Determine Indicator Microorganisms in Air Emissions and Residue from Medical Waste Incinerators

To allow testing of microbial destruction in medical waste incinerators, methods were developed to determine indicator microorganisms (Bacillus Stearothermophilus spores) in incinerator air emissions and residue. The emission trapping train consisted of a water cooled glass probe and impingers containing a neutral phosphate buffer. In field tests, spores were injected directly into the probe, and results showed that approximately 60 percent of the spores were recovered. Spores were analyzed with adequate precision using a microbial membrane filter unit. Lab experiments indicated that spores were stable in neutral pH phosphate buffer for up to 20 days, and heat shocking samples (heating to 80°C for 20 minutes) reduced spore numbers in acidic or basic buffer. Laboratory tests also showed that 60 to 70 percent of spores initially added to ash were recovered up to 22 days after addition of the spores. In addition, lab tests showed that spores can be effectively recovered from residue test pipes spiked with indicator spores.     

A rapid method for screening of the Stockholm Convention POPs in small amounts of human plasma using SPE and HRGC/HRMS

A rapid analytical screening method allowing simultaneous analysis of 23 persistent organic pollutants (POPs) in human plasma was developed. Sample preparation based on solid-phase extraction (SPE) with additional clean-up using small multilayer silica gel columns. SPE was performed using a custom made polystyrene-divinylbenzene sorbent for the extraction of chlorinated and brominated POPs. Special efforts to reduce sample volume and improve speed and efficiency of the analytical procedure were made. Determination of 16 polychlorinated biphenyls (PCBs), 5 organochlorine (OC) pesticides, octachlorinated dibenzo-p-dioxin (OCDD) and polybrominated diphenyl ether (BDE #47) in 0.5 mL human plasma was performed by using high resolution gas chromatography coupled to high resolution mass spectrometry (HRGC/HRMS). Recovery of POPs ranged between 46% and 110%, and reproducibility was below 25% relative standard deviation (RSD) for all target compounds, except for trans-nonachlor and OCDD, which were present only at low levels. Limits of detection (LOD) were for the PCBs between 0.8 and 117.7 pg mL⁻¹ plasma and for the OC pesticides between 5.9 and 89.1 pg mL⁻¹ plasma. The LOD for OCDD and BDE #47 were 1.4 pg mL⁻¹ plasma, and 9.2 pg mL⁻¹ plasma, respectively. The presented method was successfully applied to 1016 human plasma samples from an epidemiological study on cardiovascular disease.     

Sodium borohydride reduction of individual polybrominated diphenyl ethers

Many chemicals in use today lack appropriate documentation on their environmental properties, fate, and effects. To counteract this lack of documentation it is vital to thoroughly investigate a compound’s fate in the environment before it comes into use. The present study is describing a novel method for assessing the reduction potential of polybrominated diphenyl ethers (PBDEs), as a part of a project aimed to create an experimental model for determination of chemical persistence. The reductive transformation of 15 PBDE congeners using sodium borohydride was determined. Pseudo-first-order reaction rate constants of the transformations were determined by monitoring the disappearance of the investigated congeners. The reductions lead primarily to formation of lower brominated PBDEs. Each PBDE congener was tested in a total of ten replicates which showed a relative standard deviation of 31% or less. The decaBDE, BDE-209 was approximately 3 times as prone to reductive transformation as BDE-207. The three nonaBDEs, BDE-206, BDE-207, and BDE-208, showed similar reductive potential. The reactivity of the tested octaBDEs was quite variable, from 5% to 24% of the reactivity of BDE-209 for BDE-196 and BDE-198, respectively. The heptaBDEs studied were in the range of the less reactive octaBDEs, except for BDE-181 which was as high as 13% of the reactivity of BDE-209. The results presented give a method for measuring the propensity of PBDEs, and possibly similar compounds, to undergo reductions. They indicate a potential route to a vital piece of information in the assessment of environmental persistence of chemicals.     

Creating sense of community: The role of public space

A strong sense of community has been associated with improved wellbeing, increased feelings of safety and security, participation in community affairs and civic responsibility. Although interest in how the broader built environment influences sense of community is gaining momentum, there is a dearth of empirical research examining the association between sense of community and the quality of public space. This study investigates the relationship between four public spaces – Public Open Space (POS), community centres, schools and shops – and sense of community in residents of new housing developments in the Perth metropolitan area, Western Australia. Data was obtained from a cross-sectional survey (n = 911), a POS audit, and Geographical Information Systems, and analysed using linear regression. The perceived quality of neighbourhood POS and shops was significantly and positively associated with sense of community. This relationship appears to be unaffected by how frequently people use these spaces. High quality public spaces may be important settings for enhancing sense of community within residents of new housing developments.     

Oak Conservation and Restoration on Private Forestlands: Negotiating a Social-Ecological Landscape

In the midwestern United States, oak (Quercus spp.) forests are considered critical habitat for conserving biodiversity and are a declining resource. Ecological conditions, such as deer herbivory and competition from more mesic broad-leaved deciduous species, have been linked to poor oak regeneration. In the Midwest, where up to 90% of forestland is privately owned, a greater understanding of social dimensions of oak regeneration success is especially critical to designing effective restoration strategies. We sought to determine factors that serve as direct and indirect constraints to oak restoration and identify policy mechanisms that could improve the likelihood for restoration success. We conducted in-depth qualitative interviews with 32 natural resource professionals working in the Midwest Driftless Area. We found that most professionals anticipate that oak will remain only a component of the future forest. Furthermore, they identified the general unwillingness of landowners to adopt oak restoration practices as a primary driving force of regional forest change. The professionals pointed to interdependent ecological and social factors, occurring at various scales (e.g., economic cost of management, deer herbivory, and exurban residential development) as influencing landowner oak restoration decisions. Professionals emphasized the importance of government cost-share programs and long-term personal relationships to securing landowner acceptance of oak restoration practices. However, given finite societal resources, ecologically- and socially-targeted approaches were viewed as potential ways to optimize regional success.     

Predicting EDC concentrations in a river mixing zone

The fate and transport of endocrine disrupting chemicals (EDCs) in ambient river waters is a major concern associated with effluents from municipal wastewater treatment plants (WWTPs). This paper presents a methodology for quantifying the spatial distribution of EDCs in a river mixing zone. The core of the technical analysis is based on a two-dimensional steady-state analytical model characterized by ambient turbulence in the receiving water. This model was first calibrated with mass transport data from field measurements for a conservative substance (electrical conductivity) and then used to predict aqueous-phase EDC concentrations throughout a WWTP mixing zone. To demonstrate the usefulness of this methodology for water quality management purposes, the modeling framework presented in this paper was used to determine a lumped in-stream attenuation rate constant (k_d = 3 d⁻¹) for 17β-estradiol under natural conditions. This rate constant likely accounts for the combined contributions of physical sorption, photolysis, microbial and chemical degradation, and the measured value is highly consistent with previously published results from bench-scale removal experiments.