A comparison of X-ray fluorescence and wet chemical analysis of air filter samples from a scrap lead smelting operation

Personal and area air samples were taken at a scrap lead smelter operation in a bullet manufacturing facility. Samples were taken using the 37-mm styrene-acrylonitrile closed-face filter cassette (CFC, the current US standard device for lead sampling), the 37-mm GSP or "cone" sampler, the 25-mm Institute of Occupational Medicine (IOM) inhalable sampler, and the 25-mm Button sampler (developed at the University of Cincinnati). Polyvinylchloride filters were used for sampling. The filters were pre- and post-weighed, and analyzed for lead content using a field-portable X-ray fluorescence (XRF) analyzer. The filters were then extracted with dilute nitric acid in an ultrasonic extraction bath and the solutions were analyzed by inductively coupled plasma optical emission spectroscopy. The 25-mm filters were analyzed using a single XRF reading, while three readings on different parts of the filter were taken from the 37-mm filters. The single reading from the 25-mm filters was adjusted for the nominal area of the filter to obtain the mass loading, while the three readings from the 37-mm filters were inserted into two different algorithms for calculating the mass loadings, and the algorithms were compared. The IOM sampler was designed for material collected in the body of the sampler to be part of the collected sample as well as that on the filter. Therefore, the IOM sampler cassettes were rinsed separately to determine if wall-loss corrections were necessary. All four samplers gave very good correlations between the two analytical methods above the limit of detection of the XRF procedure. The limit of detection for the 25-mm filters (5 microg) was lower than for the 37-mm filters (10 microg). The percentage of XRF results that were within 25% of the corresponding ICP results was evaluated. In addition, the bias from linear regression was estimated. Linear regression for the Button sampler and the IOM sampler using single readings and the GSP using all tested techniques for total filter loading gave acceptable XRF readings at loadings equivalent to sampling at the OSHA 8-hour Action Level and Permissible Exposure Limit. However, the CFC only had acceptable results when the center reading corrected for filter area was used, which was surprising, and may be a result of a limited data set. In addition to linear regression, simple estimation of bias indicated reasonable agreements between XRF and ICP results for single XRF readings on the Button sampler filters, (82% of the individual results within criterion), and on the IOM sampler filters (77% or 61%--see text), and on the GSP sampler filters using the OSHA algorithm (78%). As a result of this pilot project, all three samplers were considered suitable for inclusion in further field research studies.     

Lethal and sublethal effects of the pyrethroid, bifenthrin, on grass shrimp (Palaemonetes pugio) and sheepshead minnow (Cyprinodon variegatus)

This study investigated the lethal and sublethal effects of the pyrethroid insecticide bifenthrin on adult and larval grass shrimp, Palaemonetes pugio, and adult sheepshead minnows, Cyprinodon variegatus. The effects were determined by conducting 96-h aqueous static renewal tests and 24-h static tests with sediment. Oxidative stress biomarkers, lipid peroxidation, glutathione, and catalase were also assessed. The 96-h aqueous LC50 value for adult shrimp was 0.020 microg/L (95% CI: 0.015-0.025 microg/L) and for larval shrimp was 0.013 microg/L (95% CI: 0.011-0.016 microg/L). The 96-h aqueous LC50 for adult sheepshead minnow was 19.806 microg/L (95% CI: 11.886-47.250 microg/L). The 24-h sediment LC50 for adult shrimp was 0.339 microg/L (95% CI: 0.291-0.381 microg/L) and for larval shrimp was 0.210 microg/L (95% CI: 0.096-0.393 microg/L). The oxidative stress assays showed some increasing trends toward physiological stress with increased bifenthrin concentrations but they were largely inconclusive. Given the sensitivity of grass shrimp to this compound in laboratory bioassays, additional work will be needed to determine if these exposure levels are environmentally relevant.     

Developing an interdisciplinary and cross‐sectoral community of practice in the domain of forests and livelihoods

Although significant resources are being spent researching and fostering the relationship between forests and livelihoods to promote mutually beneficial outcomes, critical gaps in understanding persist. A core reason for such gaps is that researchers, practitioners, and policy makers lack the structured space to interact and collaborate, which is essential for effective, interdisciplinary research, practice, and evaluation. Thus, scientific findings, policy recommendations, and measured outcomes have not always been synthesized into deep, systemic understanding; learning from practice and implementation does not easily find its way into scientific analyses, and science often fails to influence policy. Communities of practice (CofPs) are dynamic sociocultural systems that bring people together to share and create knowledge around a common topic of interest. They offer participants a space and structure within which to develop new, systemic approaches to multidimensional problems on a common theme. Uniquely informed by a systems‐thinking perspective and drawing from the scientific and gray literatures and in‐depth interviews with representatives of established CofPs in the natural resource management and development domain, we argue that a well‐designed and adequately funded CofP can facilitate interdisciplinary and cross‐sectoral relationships and knowledge exchange. Well‐designed CofPs integrate a set of core features and processes to enhance individual, collective, and domain outcomes; they set out an initial but evolving purpose, encourage diverse leadership, and promote collective‐identity development. Funding facilitates effective communication strategies (e.g., in person meetings). We urge our colleagues across sectors and disciplines to take advantage of CofPs to advance the domain of forests and livelihoods.     

Factors influencing property selection for conservation revolving funds

Finding sustainable ways to increase the amount of private land protected for biodiversity is challenging for many conservation organizations. In some countries, organizations use revolving‐fund programs, whereby land is purchased and then sold to conservation‐minded owners under condition they enter into a conservation covenant or easement. The sale proceeds are used to purchase, protect, and sell additional properties, incrementally increasing the amount of protected private land. Because the effectiveness of this approach relies on selecting appropriate properties, we explored factors currently considered by practitioners and how these are integrated into decision making. We conducted exploratory, semistructured interviews with managers from each of the 5 major revolving funds in Australia. Responses indicated although conservation factors are important, financial and social factors are also highly influential. A major determinant was whether the property could be resold within a reasonable period at a price that replenishes the fund. To facilitate resale, often selected properties include the potential for the construction of a dwelling. Practitioners face with clear trade‐offs between conservation, financial, amenity, and other factors in selecting properties and 3 main challenges: recovering the costs of acquisition, protection, and resale; reselling the property; and meeting conservation goals. Our findings suggest the complexity of these decisions may constrain revolving‐fund effectiveness. Drawing from participant responses, we identified potential strategies to mitigate these risks, such as providing adequate recreational space without jeopardizing ecological assets. We suggest managers could benefit from a shared‐learning and adaptive approach to property selection given the commonalities between programs. Understanding how practitioners deal with complex decisions in the implementation of revolving funds helps identify future research to improve the performance of this conservation tool.     

农药引起的两栖动物脑部的变化：亚致死浓度的毒死蜱如何直接影响神经发育

农药虽然可以控制病虫害,但其广泛使用造成自然环境的污染,致使非靶标生物暴露于农药污染环境中。即使低浓度农药暴露也会直接或间接影响水生生物群落。前期人工池塘(中宇宙)研究结果表明痕量毒死蜱(chlorpyrifos, CPF)可改变蝌蚪体态和神经发育。造成这个结果的原因可能为：1)CPF暴露的直接影响;2)农药造成了浮游动物数量下降扰乱食物网。为了明确原因,我们在CPF耐受浮游动物存在的情况下,考察了CPF对两栖动物发育的影响,这种浮游动物是不同营养级别水生生物群落的重要组成部分。豹蛙(Lithobates pipiens)蝌蚪饲养在中宇宙的环境,经过变态期,环境中含有0或1 μg/L CPF,或CPF敏感型浮游动物Daphnia pulex。CPF发育期暴露致使蝌蚪蜕变时视顶盖、延髓、间脑相对更宽,而这一结果与中宇宙中浮游动物种群无关。因此,CPF直接影响大脑发育,与不同营养级别的群落的无关。至于身体形态方面,CPF对无CPF敏感型浮游动物的中宇宙中饲养的蝌蚪蜕变形态没有影响,但在没有CPF污染时,蝌蚪身体形态对浮游动物种群数量很敏感。研究表明,生态水平的低剂量有机磷农药暴露可直接影响脊椎动物的神经发育。 精选自Sara J. McClelland, Randall J. Bendis, Rick A. Relyea, Sarah K. Woodley. Insecticide-induced changes in amphibian brains: How sublethal concentrations of chlorpyrifos directly affect neurodevelopment. Environmental Toxicology and Chemistry,2018,37:2692–2698.
详情请见 https://doi.org/10.1002/etc.4240
     

Effects of simulated sublethal predation on the growth and regeneration rates of a spionid polychaete in laboratory flumes

Most spionid polychaetes switch from deposit feeding to suspension feeding as current speed and the flux of suspended food increase. Growth rates of juvenile Polydora cornuta are strongly affected by flow and can be as rapid as 60% day⁻¹ in moderate currents. Feeding palps that extend above the sediment–water interface during suspension feeding are especially vulnerable to sublethal predation, but individuals with damaged posteriors are also common. We performed a series of laboratory flume experiments to test the effects of sublethal tissue damage on the growth and regeneration rates of P. cornuta juveniles. Replicated experiments were conducted at three flow speeds in counter-rotating annular flumes containing field-collected sediment and a nonliving algal slurry as deposited and suspended food. In the first set of experiments, we removed 2, 1, or 0 of worms’ two feeding palps and measured the relative growth rates of worm bodies and palps after 3 days in the flumes. Worms that lost both palps grew significantly slower than the other two groups, but the growth rate of worms that had one undamaged palp was not significantly different from worms that had two undamaged palps. Faster flow speeds significantly increased rates of body growth, and there was a significant interaction between flow and the effect of palp loss. During the 3-day experiments, damaged palps fully regenerated and often grew larger than they were prior to being removed. Damaged palps also grew significantly faster than undamaged palps. The second set of experiments tested the effects of removing a worm’s posterior region (~18% of body volume). The growth rates of these damaged and undamaged worms did not differ significantly. By the end of a 3-day flume experiment, damaged worms had grown 6× larger than they were prior to the posterior damage. The rapid regeneration of damaged palps and posterior tissue in moderate flows that allow suspension feeding suggests that sublethal predation on spionids might be more frequent than previously estimated and will have little impact on the growth of juvenile recruits.     

Food or sex—males and females in a sex role reversed pipefish have different interests

In a sex role reversed pipefish, Syngnathus typhle, we found that basic life history allocations were directly influenced by sexual selection. We investigated time allocation to foraging and mating, respectively, in a choice experiment, giving males and females, of small or large body size, a choice between food and a potential partner. We found that males were more interested in foraging than mating, i.e., were more frequently observed in front of the food than in front of the partner, whereas females were more interested in the potential partner. This reflects sexual selection operating differently on the two sexes, as males and females are relatively similar in other life history traits, such as growth, mortality, age of maturity, dispersal, and parental expenditure. Moreover, large individuals allocated more time to mating activities, small to feeding. Individuals more interested in mating compared to food were subsequently more critical when given a choice between a large (high-quality) and a small (low-quality) partner, whereas individuals more interested in food were not selective. These findings are consistent with our predictions: sex-role reversed males can be relatively sure of achieving one or more matings, and should allocate more time to feeding and, hence, to parental investment, growth and/or future reproduction. Females, on the other hand, have more uncertain mating prospects and should allocate time to imminent reproductive activities, thereby foregoing other life history traits such as growth and future egg production. By this, they also sacrifice future fecundity and attractiveness.     

Biological invasions: recommendations for U.S. policy and management.

The Ecological Society of America has evaluated current U.S. national policies and practices on biological invasions in light of current scientific knowledge. Invasions by harmful nonnative species are increasing in number and area affected; the damages to ecosystems, economic activity, and human welfare are accumulating. Without improved strategies based on recent scientific advances and increased investments to counter invasions, harm from invasive species is likely to accelerate. Federal leadership, with the cooperation of state and local governments, is required to increase the effectiveness of prevention of invasions, detect and respond quickly to new potentially harmful invasions, control and slow the spread of existing invasions, and provide a national center to ensure that these efforts are coordinated and cost effective. Specifically, the Ecological Society of America recommends that the federal government take the following six actions: (1) Use new information and practices to better manage commercial and other pathways to reduce the transport and release of potentially harmful species; (2) Adopt more quantitative procedures for risk analysis and apply them to every species proposed for importation into the country; (3) Use new cost-effective diagnostic technologies to increase active surveillance and sharing of information about invasive species so that responses to new invasions can be more rapid and effective; (4) Create new legal authority and provide emergency funding to support rapid responses to emerging invasions; (5) Provide funding and incentives for cost-effective programs to slow the spread of existing invasive species in order to protect still uninvaded ecosystems, social and industrial infrastructure, and human welfare; and (6) Establish a National Center for Invasive Species Management (under the existing National Invasive Species Council) to coordinate and lead improvements in federal, state, and international policies on invasive species. Recent scientific and technical advances provide a sound basis for more cost-effective national responses to invasive species. Greater investments in improved technology and management practices would be more than repaid by reduced damages from current and future invasive species. The Ecological Society of America is committed to assist all levels of government and provide scientific advice to improve all aspects of invasive-species management.     

Extensive aerosol optical properties and aerosol mass related measurements during TRAMP/TexAQS 2006 – Implications for PM compliance and planning

Extensive aerosol optical properties, particle size distributions, and Aerodyne quadrupole aerosol mass spectrometer measurements collected during TRAMP/TexAQS 2006 were examined in light of collocated meteorological and chemical measurements. Much of the evident variability in the observed aerosol-related air quality is due to changing synoptic meteorological situations that direct emissions from various sources to the TRAMP site near the center of the Houston-Galveston-Brazoria (HGB) metropolitan area. In this study, five distinct long-term periods have been identified. During each of these periods, observed aerosol properties have implications that are of interest to environmental quality management agencies. During three of the periods, long range transport (LRT), both intra-continental and intercontinental, appears to have played an important role in producing the observed aerosol. During late August 2006, southerly winds brought super-micron Saharan dust and sea salt to the HGB area, adding mass to fine particulate matter (PM_2.5) measurements, but apparently not affecting secondary particle growth or gas-phase air pollution. A second type of LRT was associated with northerly winds in early September 2006 and with increased ozone and sub-micron particulate matter in the HGB area. Later in the study, LRT of emissions from wildfires appeared to increase the abundance of absorbing aerosols (and carbon monoxide and other chemical tracers) in the HGB area. However, the greatest impacts on Houston PM_2.5 air quality are caused by periods with low-wind-speed sea breeze circulation or winds that directly transport pollutants from major industrial areas, i.e., the Houston Ship Channel, into the city center.