Uptake rates of thorium progeny in a semiarid environment

The release rates and transformation processes that influence the mobility, biological uptake, and transfer of radionuclides are essential to the assessment of the health effects in the food chain and ecosystem. This study examined concentrations of 222Th in both soil and vegetation at a closed military training site, Kirtland Air Force Base (KAFB), New Mexico. Brazilian sludge was intentionally introduced into the topsoil in the early 1960s to simulate nuclear weapon accidents. Soil (60) and vegetation (120) samples were collected from 1996 to 2000 and analyzed for radionuclides and progeny. High-resolution gamma-ray spectroscopy was used to determine radionuclide activities. The results indicate that the thorium progeny were the predominant contaminant in soil and vegetation. Concentration ratios (CRs) were calculated based on actinium levels.     

Discrimination of flicker frequency rates in the reptile tuatara (Sphenodon )

By investigating the mechanisms that underlie the perception of environmental cues, we may begin to understand how the sensory system governs behavioral responses. This is the first empirical study to examine learning and visual sensitivity in a reptile species, the tuatara (Sphenodon punctatus). We established a non-intrusive psychophysical method by employing an instrumental paradigm in order to examine discrimination learning and the ability to distinguish different flicker frequencies in the tuatara. Seventeen tuatara were trained under an operant conditioning task to respond to various discriminative stimuli flickering between 2.65 and 65.09 Hz. Tuatara were able to learn the operant task and discriminate between a constant light and flicker frequency rates between 2.65 and 45.61 Hz, but not at 65.09 Hz. We demonstrated a reliable psychophysical method where these reptiles could learn a basic operant task and discriminate visual stimuli in the form of flicker frequency rates. The tuatara’s ability to perceive flickering light is comparable to that of avian, mammalian, and other reptilian species. This method is thus suitable for more comprehensive examinations of vision and additional sensory abilities in other reptiles. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Evaluating the influence of nature connection and values on conservation attitudes at a tropical deforestation frontier

Inner phenomena, such as personal motivations for pursuing sustainability, may be critical levers for improving conservation outcomes. Most conservation research and policies, however, focus on external phenomena (e.g., ecological change or economic processes). We explored the factors shaping 9 conservation attitudes toward forest and wildlife protection among colonist farmers around an Amazonian deforestation frontier. Our data comprised 241 face-to-face quantitative surveys, complemented with qualitative insights from open-ended questionnaire responses and opportunistic semistructured interviews. To account for the full spectrum of possible inner motivations, we employed measures of nature connection (indicating biospheric motivation) and personal values organized around the traditionalism (traditionalist through to high openness to change) and universalism dimensions (egoistic through to altruistic motivations). We used averaged beta-binomial generalized linear models to assess the role of external factors (socioeconomic, sociodemographic, and environmental) and personal (inner) motivations on the variation in attitudes. Each attitude was modeled separately. The relative importance of each predictor was judged by the proportion of models where it appeared as significant. Proconservation views were expressed by the majority (at least 65%) of the respondents in 7 out of the 9 attitude models. The most consistent predictors were emotional nature connection and personal values (significant in 4–6 out of 9 models), rather than external phenomena (significant in 0–5 models). However, the poorest farmers had lower scores on the agreement with prioritizing nature over development (𝛽 = –0.52, 95% CI: –0.96 to –0.07). Qualitative data also indicated that economic barriers hinder forest conservation on farms. These results suggest that biospheric, traditionalistic, and altruistic motivations promote people's proconservation attitudes, but nurturing these latent motivations is unlikely to improve conservation outcomes if material poverty remains unaddressed. Integrating the inner–outer perspective into conservation thinking and practical interventions could foster environmental stewardship and increase human well-being.     

Reply to Discussion

In the Discussion, Nash et al. (2019) estimate the seasonal change in groundwater volume for a portion of the restored Sierra Nevada Meadow that we evaluated (Hunt et al. 2018) and use this estimate as an upper bound on the possible contribution to flow that is attributable to restoration. The authors conclude that raising the channel bed elevation and reconnecting the meadow floodplain most likely reduced summer streamflow. In contrast, we report at least a fivefold increase in baseflow from the meadow in the years following restoration. In addition, we observed that, after restoration, the previously intermittent stream below the meadow flowed continuously throughout the summer months, despite record drought conditions, and in 2015, the lowest snowpack on record. We suggest that the groundwater budget presented in the Discussion may not adequately represent conditions within the meadow because the authors extrapolate from 5 near‐channel groundwater wells across 62 ha of meadow and assume an area of influence that is approximately one‐sixth of the meadow area. We conclude that the conversion of an intermittent stream to perennial flow during drought conditions is a stronger check on our gauge data than the groundwater budget presented in the Discussion.     

Compliance with Canada’s Fisheries Act: A Field Audit of Habitat Compensation Projects

Loss of fish habitat in North America has occurred at an unprecedented rate through the last century. In response, the Canadian Parliament enacted the habitat provisions of the Fisheries Act. Under these provisions, a “harmful alteration, disruption, or destruction to fish habitat” (HADD) cannot occur unless authorised by Fisheries and Oceans Canada (DFO), with legally binding compensatory habitat to offset the HADD. The guiding principle to DFO’s conservation goal is “no net loss of the productive capacity of fish habitats” (NNL). However, performance in achieving NNL has never been evaluated on a national scale. We investigated 52 habitat compensation projects across Canada to determine compliance with physical, biological, and chemical requirements of Section 35(2) Fisheries Act authorisations. Biological requirements had the lowest compliance (58%) and chemical requirements the highest (100%). Compliance with biological requirements differed among habitat categories and was poorest (19% compliance) in riparian habitats. Approximately 86% of authorisations had larger HADD and/or smaller compensation areas than authorised. The largest noncompliance in terms of habitat area occurred in riverine habitat in which HADDs were, on average, 343% larger than initially authorised. In total, 67% of compensation projects resulted in net losses of habitat area, 2% resulted in no net loss, and 31% achieved a net gain in habitat area. Interestingly, probable violations of the Fisheries Act were prevalent at half of the projects. Analyses indicated that the frequency of probable Fisheries Act violations differed among provinces. Habitat compensation to achieve NNL, as currently implemented in Canada, is at best only slowing the rate of habitat loss. In all likelihood, increasing the amount of authorised compensatory habitat in the absence of institutional changes will not reverse this trend. Improvements in monitoring and enforcement are necessary to move towards achieving Canada’s conservation goals.     

Development and preparation of lead-containing paint films and diagnostic test materials

Lead in paint continues to be a threat to children's health in cities across the United States, which means there is an ongoing need for testing and analysis of paint. This ongoing analytical effort and especially development of new methods continue to drive the need for diagnostic testing materials that provide the analytical challenges of real-world paints. To this end, 31 different types of paint test materials were developed and prepared. Preparation of the materials included development of lead-containing paint films yielding an overall relative standard error for one individual test sample being less than 10%. The 31 diagnostic test materials prepared with these paint films included two lead pigments; lead concentrations from nominally 0 to 2.0 mg lead/cm(2) (0 to 5% lead by weight); overlayers of both "lead-free," oil-based and water-based paints; Al, Ba, and Mg as potential chemical interferents; red and black potential color interferents; and substrates of wood, metal, masonry, and plaster. These materials challenge each step in method development and evaluation, including paint sample collection and preparation, lead extraction, and measurement of solubilized lead. When the materials were used to test performance of a new lead-in-paint testing method based on extraction using a rotor/stator method and measurement using turbidimetry, the results agreed to within ±20% of the expected lead values for 30 out of 31 of the diagnostic test materials, thereby demonstrating their levels of quality and utility.     

Biannual spawning, rapid larval development and evidence of self-seeding for scleractinian corals at an isolated system of reefs

Some of the most important demographic parameters underlying the resilience of coral communities are determined by their patterns of reproduction. In this study, a variety of methods were used to investigate the patterns of spawning, larval development and dispersal for scleractinian corals at an isolated reef system off northwestern Australia. Two distinct periods of gamete maturation and multi-specific spawning occurred each year, during Spring and Autumn, in contrast to the single season of mass spawning described on most other reefs around Australia. The subsequent rates of embryogenesis and larval development were among the fastest described for corals, with pre-competency periods of approximately 3 days. Within 3 days of spawning, slicks of spawn and current drifters had dispersed up to 5 km, and up to 10 km after 6 days, while the times taken for drifters to travel between adjacent (>240 km) reef systems were similar to or greater than the upper competency periods of most coral larvae. Thus, under these conditions, the entire reef system, and to some extent the reefs within the system, may largely be self-seeded; rates of immigration from other systems are probably insufficient to rapidly increase the recovery of communities within years of a major disturbance. These results have implications for the management of isolated reef systems, highlighting the need to minimize local stressors and maximize community resilience to the increasing scale of disturbance and habitat fragmentation.     

Evaluation of exposure reduction to indoor air pollution in stove intervention projects in Peru by urinary biomonitoring of polycyclic aromatic hydrocarbon metabolites

Burning biomass fuels such as wood on indoor open-pit stoves is common in developing regions. In such settings, exposure to harmful combustion products such as fine particulate matter (PM(2.5)), carbon monoxide (CO) and polycyclic aromatic hydrocarbons (PAHs) is of concern. We aimed to investigate if the replacement of open pit stoves by improved stoves equipped with a chimney would significantly reduce exposure to PAHs, PM(2.5) and CO. Two stove projects were evaluated in Peru. Program A was part of the Juntos National Program in which households built their own stoves using materials provided. In Program B, Barrick Gold Corporation hired a company to produce and install the stoves locally. A total of 30 and 27 homes participated in Program A and B, respectively. We collected personal and kitchen air samples, as well as morning urine samples from women tasked with cooking in the households before and after the installation of the improved stoves. Median levels of PM(2.5) and CO were significantly reduced in kitchen and personal air samples by 47-74% after the installation of the new stoves, while the median reduction of 10 urinary hydroxylate PAH metabolites (OH-PAHs) was 19%-52%. The observed OH-PAH concentration in this study was comparable or higher than the 95th percentile of the general U.S. population, even after the stove intervention, indicating a high overall exposure in this population.     

A Preliminary Evaluation of the DDT Contamination of Sediments in Lakes Natron and Bogoria (Eastern Rift Valley,Africa)

Dichlorodiphenyltrichloroethane (DDT) is still used in Africa for the indoor control of malaria and it may represent a potential hazard for wildlife. The littoral sediments of two alkaline-saline lakes, Natron (Tanzania) and Bogoria (Kenya), in the Eastern Rift Valley, supporting large populations of lesser flamingos (Phoeniconaias minor), were analysed for DDT residues. Physical–chemical analyses (temperature, conductivity, pH and dissolved oxygen) were also performed on the water of the two lakes and in the tributaries of Lake Natron, to evaluate the influence of the environmental variables on pollutant occurrence. At Lake Natron, around 1 km from the sediment collection sites, tree leaves of Acacia tortilis were also collected. The main metabolite found in all sediment samples was pp’DDE, whilst equal concentrations of pp’DDT and pp’DDE were measured in acacia leaves. The levels of DDTs measured in the sediments were within 5.9–30.9 ng g⁻¹ d.w., reaching the maximum value in a tributary of Lake Natron. On the whole, the contamination of Lake Natron and Lake Bogoria basins seems to be quite moderate. Nevertheless, the pp’DDE/pp’DDT ratio equals 1 in the Acacia tortilis leaves, which makes one suppose that the input of the parent compound was rather recent and could have been from aerial transport or dust from relatively close-by old pesticides storage sites.     

Modelling of discharge and atmospheric dispersion for carbon dioxide releases

This paper discusses the modelling of the discharge and subsequent atmospheric dispersion for carbon dioxide releases using extensions of models in the consequence modelling package Phast. Phast examines the progress of a potential incident from the initial release to the far-field dispersion including the modelling of rainout and subsequent vaporisation. The original Phast discharge and dispersion models allow the released chemical to occur only in the vapour and liquid phases. As part of the current work these models have been extended to also allow for the occurrence of liquid to solid transition or vapour to solid transition. This applies both for the post-expansion state in the discharge model, as well as for the thermodynamic calculations by the dispersion model. Solid property calculations have been added where necessary. The above extensions are generally valid for fluid releases including CO₂. Using the extended dispersion formulation, a sensitivity study has been carried out for mixing of solid CO₂ with air, and it is demonstrated that solid effects may significantly affect the predicted concentrations.