Predicting Bald Eagle Collision at Wind Energy Facilities

Bald eagles (Haliaeetus leucocephalus) are currently protected in the United States under the Bald and Golden Eagle Protection Act of 1940 and Migratory Bird Treaty Act of 1918. Given these protections and the increasing development of wind energy throughout the United States, it is important for regulators and the wind industry to understand the risk of bald eagle collisions with wind turbines. Prior probability distributions for eagle exposure rates and collision rates have been developed for golden eagles (Aquila chrysaetos) by the United States Fish and Wildlife Service (USFWS). Given similar information has not been available for bald eagles, the current recommendation by the USFWS is to use the prior probability distributions developed using data collected on golden eagles to predict take for bald eagles. But some evidence suggests that bald and golden eagles may be at different risk for collision with wind turbines and the prior probability distributions developed for golden eagles may not be appropriate for bald eagles. We developed prior probability distributions using data collected at MidAmerican Energy Company's operating wind energy facilities in Iowa, USA, from December 2014 to March 2017 for bald eagle exposure rates and collision rates. The prior probability distribution for collision rate developed for bald eagles has a lower mean collision rate and less variability relative to that developed for golden eagles. We determined that the prior probability distributions specific to bald eagles from these operating facilities are a better starting point for predicting take for bald eagles at operating wind energy facilities in an agricultural landscape than those developed for golden eagles. © 2021 The Wildlife Society.     

The probability of causation under a stochastic model for individual risk

In this paper we offer a mathematical definition for the probability of causation that formalizes the legal and ordinary-language meaning of the term. We show that, under this definition, even the average probability of causation among exposed cases is not identifiable from epidemiologic data. This is because the probability of causation depends both on the unknown mechanisms by which exposure affects disease risk and competing risks, and on the unknown degree of heterogeneity in the background disease risk of the exposed population. We derive the maximum and minimum values for the probability of causation consistent with the observable population quantities. We also derive the relationship of the "assigned share" (excess incidence rate as a proportion of total incidence rate) to the probability of causation.     

Confidence Intervals of the Attributable Risk under Cross‐Sectional Sampling with Confounders

Since it can account for both the strength of the association between exposure to a risk factor and the underlying disease of interest and the prevalence of the risk factor, the attributable risk (AR) is probably the most commonly used epidemiologic measure for public health administrators to locate important risk factors. This paper discusses interval estimation of the AR in the presence of confounders under cross‐sectional sampling. This paper considers four asymptotic interval estimators which are direct generalizations of those originally proposed for the case of no confounders, and employs Monte Carlo simulation to evaluate the finite‐sample performance of these estimators in a variety of situations. This paper finds that interval estimators using Wald's test statistic and a quadratic equation suggested here can consistently perform reasonably well with respect to the coverage probability in all the situations considered here. This paper notes that the interval estimator using the logarithmic transformation, that is previously found to consistently perform well for the case of no confounders, may have the coverage probability less than the desired confidence level when the underlying common prevalence rate ratio (RR) across strata between the exposure and the non‐exposure is large (≥4). This paper further notes that the interval estimator using the logit transformation is inappropriate for use when the underlying common RR ≐ 1. On the other hand, when the underlying common RR is large (≥4), this interval estimator is probably preferable to all the other three estimators. When the sample size is large (≥400) and the RR ≥ 2 in the situations considered here, this paper finds that all the four interval estimators developed here are essentially equivalent with respect to both the coverage probability and the average length.     

Exposure Based Waiving in Environmental Risk Assessment: A Tiered Approach

The REACH legislation describes the “Exposure Based Waiving” (EBW) methodology, that allows reduction of animal tests and that facilitates the Chemical Safety Assessments. We introduced a tiered EBW decision strategy for the aquatic environment. Tier 0 in this strategy justifies waiving if it can be demonstrated that exposure of organisms to a chemical will be practically zero (i.e., if no environmental emissions during the full life-cycle of a chemical are to be expected. Tier 1 uses tabular data, derived from physical–chemical properties of a chemical and emission data, to identify whether the environmental exposure levels are less than the conservative toxicological reference value “Threshold of Toxicological Concern” (TTC). To this end, systematic exposure calculations have been carried out with a hypothetical chemical dataset, covering the full chemical spectrum for neutral organic substances. In tier 2, PEC and PNEC are to be assessed probabilistically in order to address the probability of effects. Following this strategy, risk can be shown to be sufficiently low, using minimal exposure and hazard data. Our tiered EBW concept is illustrated by a case study for the substance dibutylphthalate with the endpoint of fresh water aquatic risks.     

Extinction of marine renewable resources: a demographic analysis

A simple (deterministic) population dynamics model is used to examine the level of fishing mortality at which a population is expected to be driven to extinction (F _crash). Values for F _crash are determined for six marine fish species (Cape hake, blue grenadier, blue warehou, school shark, gummy shark, and orange roughy) subject to commercial harvest. The sensitivity of the value of F _crash to changing the selectivity pattern of the fishery and the relationship between the size of the reproductive component of the population and subsequent births to allow for depensatory effects is examined. F _crash is greatest for highly productive species and when the fishery does not target immature animals. The ratio of F _crash to the fishing mortality at which maximum sustainable yield is achieved, F _MSY, is a decreasing function of the productivity of the population. The possibility of depensation has little impact on F _MSY but can substantially reduce the ratio F _crash/F _MSY. A series of stochastic simulations is conducted to assess the probability of detecting that the extent of fishing exceeds F _crash using the current IUCN A criterion. The results of these simulations are also used to determine the probability that the IUCN A criteria will be triggered when fishing takes place at F _MSY. The results indicate that there are substantial probabilities of incorrectly identifying species being harvested at F _MSY as being threatened during the 'fishing down' phase and also of not identifying species actually at risk of extinction if fishing mortality is not reduced. Received: January 14, 1999 / Accepted: April 27, 1999     

Q fever through consumption of unpasteurised milk and milk products – a risk profile and exposure assessment

Q fever is a zoonotic disease caused by the bacterium Coxiella burnetii which is endemic in cattle, sheep and goats in much of the world, including the United Kingdom (UK). There is some epidemiological evidence that a small proportion of cases in the developed world may arise from consumption of unpasteurised milk with less evidence for milk products such as cheese. Long maturation at low pH may give some inactivation in hard cheese, and viable C. burnetii are rarely detected in unpasteurised cheese compared to unpasteurised milk. Simulations presented here predict that the probability of exposure per person to one or more C. burnetii through the daily cumulative consumption of raw milk in the UK is 0·4203. For those positive exposures, the average level of exposure predicted is high at 1266 guinea pig intraperitoneal infectious dose 50% units (GP_IP_ID₅₀) per person per day. However, in the absence of human dose–response data, the case is made that the GP_IP_ID₅₀ unit represents a very low risk through the oral route. The available evidence suggests that the risks from C. burnetii through consumption of unpasteurised milk and milk products (including cheese) are not negligible but they are lower in comparison to transmission via inhalation of aerosols from parturient products and livestock contact.     

Ecological Risk Assessment of Tebuthiuron Following Application on Tropical Australian Wetlands

The present study assessed the ecological risks of the herbicide tebuthiuron to freshwater fauna and flora of northern Australia's tropical wetlands. Effects characterization utilized acute and chronic toxicity data of tebuthiuron to local freshwater species (three animals and two plants) as well as toxicity data derived from northern hemisphere species. Species sensitivity distributions (SSDs) for four effects scenarios—plant chronic toxicity (NOEC data), plant chronic toxicity (EC/IC₅₀ data), invertebrate and vertebrate chronic toxicity (NOEC data), and vertebrate acute toxicity (LC₅₀ data)—were used to characterize effects and calculate 10, 5, and 1% hazardous concentrations (HCs). Tebuthiuron concentrations affecting 5% of species (i.e., HC₅s) for the earlier scenarios were 0.013, 0.093, 9.0, and 97 mg L^?1, respectively. Exposure characterization involved the use of historical field monitoring data of tebuthiuron concentrations following application of tebuthiuron to a large infestation of the wetland weed Mimosa pigra (Mimosa). Tebuthiuron concentrations in surface water ranged from below detection to 2.05 mg L^?1 and were still measurable up to 10 months following application. A breakpoint regression model was fitted to the field monitoring data, providing a time-dependent estimate of exposure to tebuthiuron. Risk characterization involved the comparison of the SSDs and associated HCs for each of the effects scenarios, with the time-dependent model of tebuthiuron exposure. Modeled tebuthiuron concentrations over the first 12 days post-application were in excess of concentrations required to cause major (i.e., 50% reductions in population numbers) effects to over 85% of freshwater plant species (based on data for phytoplankton and floating macrophytes). Beyond this period and up to 300 d post-application, 10–20% of species were still predicted to be affected. To quantify the probability of prolonged effects, the plant SSDs were compared to a cumulative probability distribution of tebuthiuron measured from 70 d to 293 d post-application. The probability of at least 5% of freshwater plant species experiencing chronic effects due to tebuthiruon at ≥70 d post-application was 58% based on NOEC data and 8% based on EC/IC₅₀ data. Overlap of the 95% confidence limits of the exposure distribution and plant SSDs indicated substantial uncertainty in the risk estimates. Risks of effects to freshwater invertebrates and vertebrates were generally < 1%. It was concluded that tebuthiuron appears to represent a significant and prolonged risk to native freshwater plant species, particularly phytoplankton and floating macrophytes, whereas the risks to freshwater invertebrates and vertebrates appear low. However, from a management perspective, the risks of tebuthiuron (and other herbicides) must be weighed against the known, serious environmental and economic impacts of the target weed, Mimosa. Overall, the outcomes of the risk assessment support the various management options that have been implemented with regard to the use of tebuthiuron to control Mimosa.     

Statistical analysis of a dynamic model for dietary contaminant exposure

This paper is devoted to the statistical analysis of a stochastic model introduced in [P. Bertail, S. Clémençon, and J. Tressou, A storage model with random release rate for modelling exposure to food contaminants, Math. Biosci. Eng. 35 (1) (2008), pp. 35–60] for describing the phenomenon of exposure to a certain food contaminant. In this modelling, the temporal evolution of the contamination exposure is entirely determined by the accumulation phenomenon due to successive dietary intakes and the pharmacokinetics governing the elimination process inbetween intakes, in such a way that the exposure dynamic through time is described as a piecewise deterministic Markov process. Paths of the contamination exposure process are scarcely observable in practice, therefore intensive computer simulation methods are crucial for estimating the time-dependent or steady-state features of the process. Here we consider simulation estimators based on consumption and contamination data and investigate how to construct accurate bootstrap confidence intervals (CI) for certain quantities of considerable importance from the epidemiology viewpoint. Special attention is also paid to the problem of computing the probability of certain rare events related to the exposure process path arising in dietary risk analysis using multilevel splitting or importance sampling (IS) techniques. Applications of these statistical methods to a collection of data sets related to dietary methyl mercury contamination are discussed thoroughly.     

Probabilistic Estimates of Lifetime Daily Doses from Consumption of Drinking Water Containing Trace Levels of N,N-diethyl-meta-toluamide (DEET), Triclosan,or Acetaminophen and the Associated Risk to Human Health

Risk assessments were conducted for N,N-diethyl-meta-toluamide (DEET), triclosan, and acetaminophen to evaluate the risk from exposure to trace levels of these chemicals through drinking water consumption. We estimated exposure to these chemicals through drinking water consumption by generating distributions for key exposure parameters using Monte Carlo analysis. Body weight and water consumption was modeled using data from the U.S. Environmental Protection Agency (USEPA) Exposure Factor Handbook. Water concentrations were derived from reported concentrations in streams. Dose-response was evaluated through extensive literature searches for toxicology data for each chemical. Acceptable daily intakes (ADIs) were then derived from the available toxicology data. The exposure distributions were compared to the ADIs to evaluate the potential risk to the population from drinking water exposure. ADIs of 0.100, 0.153, and 0.05 mg/kg-day were derived for DEET, acetaminophen and triclosan, respectively. The maximum estimated exposures (0.082, 0.834, and 0.193 μ g/kg/day for DEET, acetaminophen, and triclosan, respectively) were at least 100-fold lower than the corresponding ADIs. Based on these assessments, we conclude that there is minimal risk to human health from exposure to these chemicals at the reported concentrations in U.S. streams.     

Foraging in a risky environment: a comparison of Bennett's wallabies Macropus rufogriseus rufogriseus (Marsupialia: Macropodidae) and red‐bellied pademelons Thylogale billiardierii (Marsupialia: Macropodidae) in open habitats

Abstract This study aimed to establish whether red‐bellied pademelons (Thylogale billiardierii) and Bennett's wallabies (Macropus rufogriseus rufogriseus) alter their foraging distribution in open habitat, in response to food availability and distance to protective shelter, the latter used as a measure of predation risk. Scat counts were used as a measure of the presence or absence of these macropods over two plantations (Russell and Dunalley). These plantations differed in both their on‐site food and shelter characteristics (the presence or absence of windrows). Logistic regression indicated that at Russell, which had low food availability but the presence of on‐site shelter, probability of scats of both species increased with the percentage cover of both edible and inedible vegetation. The probability of both pademelon and wallaby scats decreased with increasing distance from windrows, but increased with increasing distance from forest at the plantation edge. Logistic regression indicated that at Dunalley, which had high food availability but no on‐site shelter, the probability of scats of both species increased with an increase in the percentage cover of edible vegetation. In relation to predation risk, however, the two species differed in their response. Pademelons exhibited a decrease in scat probability with increasing distance from the forest at the plantation edge, while wallabies showed an increase in scat probability with distance from the forest at the plantation edge. Results indicated some differences in antipredation strategies of the two species, which may be a function of differences in body size.     

Carrying food items to cover for consumption: the behavior of ten bird species feeding under the risk of predation

Summary In earlier work (Lima et al. 1985; Lima 1985), we found that gray squirrels (Sciurus carolinensis) and black-capped chickadees (Parus atricapillus) when exploiting a patch of food in the open often carried individual food items to protective cover for consumption. Their tendency to carry (i) decreased as distance of the patch from cover increased, and (ii) increased as size of the available food items increased. A simple model indicated that this behavior was consistent with a trade-off between efficient foraging and predation risk. Maximal feeding efficiency was achieved by always eating at the patch, whereas minimal time exposure to predators was achieved by carrying all items to cover for consumption. Because predation-riskrelated trade-offs are likely to be of importance in the determination of feeding behavior, we surveyed the behavior of 10 bird species feeding under similar conditions to assess both the generality of the above results and the adequacy of some simple assumptions concerning the assessment and perception of predation risk.We observed considerable interspecific variability in behavior. Of the 10 species studied, 4 behaved in a manner similar to the squirrels and chickadees. Five other species showed an increased tendency to carry with larger items but no clear tendency to decrease carrying from longer distances. The one remaining species exhibited neither behavioral trend.The model that predicted squirrel and chickadee behavior failed to account for all observed behavior. The behavior of all species, however, was influenced by predation risk, and the discrepancy between theory and observation most likely reflects shortcomings of the model. These discrepancies indicate that other factors, in addition to exposure time, may be of significance in the perception of predation risk by several (or all) of the species studied. Of particular importance may be a distance-dependent probability of escaping attack. Other results indicate that predation risk may influence handling times via aspects of the digestive process.     

Human Exposure to Malathion during a Possible Vector-Control Intervention against West Nile Virus. II: Evaluation of the Toxicological Risks Using a Probabilistic Approach

In order to prevent the propagation of West Nile Virus (WNV), insecticide sprayings have been carried out in several locations in North America since 1999 with the objective of controlling the mosquito populations that transmit this pathogen. An attempt to quantitatively compare the risk of developing a health response to WNV infection with the toxicological risk of insecticides is presented here. First, the acute and subchronic environmental concentrations resulting from repeated spraying events were modeled according to a reasonable worst-case spraying sequence established in an intervention program proposed by the Government of Quebec (Canada). Second, probability density functions (PDF) were established for some exposure parameters according to the data for the concerned population, when feasible. Monte Carlo analyses were performed by incorporating these PDF into the equations used to calculate the daily absorbed doses resulting from the exposure scenarios presented in the companion article (this issue). The results showed that for a significant proportion of the population, aerial and, to a lesser extent, ground sprayings of malathion can generate acute and subchronic exposure that may exceed some levels of toxicological concern based on the USEPA's reference values. Indeed, in the case of acute exposure following aerial spraying for infants, toddlers, and children, these proportions were respectively 37.1%, 59.5%, and 32.8% of the individuals, and 27.3%, 41.3%, and 24.9% following subchronic exposure. For ground spraying, these values were 12.5%, 24.2%, 8.8%; and 9.8%, 16.5%, and 7.4%. These results allowed the comparison of the probability of exceeding a level of toxicological concern for malathion exposure with the probability of developing WNV symptoms. This comparison shows that in some circumstances, the toxicological risk of malathion may exceed the infectious risk of WNV.     

A Spatially Explicit Model of the Wild Hog for Ecological Risk Assessment Activities at the Department of Energy's Savannah River Site

In North America, wild hogs (Sus scrofa) are both sought after as prime game and despised due to their detrimental impacts to the environment from their digging and rooting behavior. They are also a potentially useful indicator species for environmental health for both ecological- and human-based risk assessments. An inductive approach was used to develop probabilistic resource selection models using logistic regression to quantify the likelihood of hogs being in any area of the Department of Energy's 805 km² Savannah River Site (SRS) in west-central South Carolina. These models were derived by using available SRS hog hunt data from 1993–2000 and a Geographic Information System database describing the habitat structure of the SRS. The model's significant parameters indicated that wild hogs preferred hardwoods and avoided pine and shrubby areas. Further, landscape metric analyses revealed that hogs preferred areas with large complex patch areas and low size variation. These resource selection models were then utilized to better estimate exposure of wild hogs to radionuclides and metals in a disturbed riparian ecosystem on the SRS using two different possible diets based on food availability. Contaminant exposure can be better estimated using these resource selection models than has been previously possible, because past practices did not consider home range and habitat utilization probability in heterogeneously contaminated habitats. Had these models not been used, risk calculations would assume that contaminated areas were utilized 100% of the time, thus overestimating exposure by a factor of up to 25.     

Notes on Estimation of the General Odds Ratio and the General Risk Difference for Paired‐Sample Data

Under the matched‐pair design, this paper discusses estimation of the general odds ratio OR_G for ordinal exposure in case‐control studies and the general risk difference RD_G for ordinal outcomes in cross‐sectional or cohort studies. To illustrate the practical usefulness of interval estimators of OR_G and RD_G developed here, this paper uses the data from a case‐control study investigating the effect of the number of beverages drunk at “burning hot” temperature on the risk of possessing esophageal cancer, and the data from a cross‐sectional study comparing the grade distributions of unaided distance vision between two eyes. Finally, this paper notes that using the commonly‐used statistics related to odds ratio for dichotomous data by collapsing the ordinal exposure into two categories: the exposure versus the non‐exposure, tends to be less efficient than using the statistics related to OR_G proposed herein.     

Ecological risk assessment of polycyclic aromatic hydrocarbons in surface sediments from the middle and lower reaches of the Yellow River,China

In this research, ecological risks for eight individual polycyclic aromatic hydrocarbons (PAHs) and ∑PAH₈ in surface sediments from middle and lower reaches of Yellow River are evaluated using overlapping areas of probability density curves and margin of safety (MOS), based on the toxicity data and the exposure concentrations of PAHs in sediments collected from 23 sites. In the overlapping areas of probability density curves, the risk of Ant and Pyr are the highest, then the risk level is in the order of Flua > Nap > Phe > BaP > Flu > Ace. The values of MOS₁₀ present that Pyr (4.62 × 10^?4), Ant (5.60 × 10^?3), and Flua (6.4 × 10^?3) have a significantly high ecological risk level, while Nap and Phe have middle-level ecological risk. As for Ace, BaP, and Flu, they pose limited risk to the ecological system with MOS₁₀ greater than 1.0. The ∑PAH₈ (2.66 × 10^?5) is a higher risk level than that of any individual PAHs, where the probabilities of ∑PAH₈ in excess of the 10th percentile of the toxicity data were 86%.     

Assessment of Human Health and Ecological Risks Posed by the Uses of Steel-Industry Slags in the Environment

Steel-industry slag, a co-product of iron and steel production, is produced and sold for use in a wide range of applications. A comprehensive study of the potential human health risks associated with the environmental applications (e.g., fill, roadbase, landscaping) of iron- and steel-making slag was performed using characterization data for 73 samples of slag collected from blast furnaces, basic oxygen furnaces, and electric arc furnaces. Characterization data were compared to regulatory health-based “screening” benchmarks to determine constituents of interest. Antimony, beryllium, cadmium, trivalent and hexavalent chromium, manganese, thallium, and vanadium were measured above screening levels and were assessed in an application-specific exposure assessment using standard U.S. Environmental Protection Agency risk assessment methods. A stochastic analysis was conducted to evaluate the variability and uncertainty in the inhalation exposure and risk estimates, and the oral bioaccessibility of certain metals in the slag was quantified. The risk assessment found no significant hazards to human health as a result of the environmental applications of steel-industry slag. However, site-specific ecological risk assessment may be required for slag applications in and around small water bodies with limited dilution volume, because high pH and aluminum were found to leach at levels that may be harmful to aquatic life     

Assessing Risks to Sea Otters and the Exxon Valdez Oil Spill: New Scenarios,Attributable Risk,and Recovery

The Exxon Valdez oil spill occurred more than two decades ago, and the Prince William Sound ecosystem has essentially recovered. Nevertheless, discussion continues on whether or not localized effects persist on sea otters (Enhydra lutris) at northern Knight Island (NKI) and, if so, what are the associated attributable risks. A recent study estimated new rates of sea otter encounters with subsurface oil residues (SSOR) from the oil spill. We previously demonstrated that a potential pathway existed for exposures to polycyclic aromatic hydrocarbons (PAHs) and conducted a quantitative ecological risk assessment using an individual-based model that simulated this and other plausible exposure pathways. Here we quantitatively update the potential for this exposure pathway to constitute an ongoing risk to sea otters using the new estimates of SSOR encounters. Our conservative model predicted that the assimilated doses of PAHs to the 1-in-1000th most-exposed sea otters would remain 1–2 orders of magnitude below the chronic effects thresholds. We re-examine the baseline estimates, post-spill surveys, recovery status, and attributable risks for this subpopulation. We conclude that the new estimated frequencies of encountering SSOR do not constitute a plausible risk for sea otters at NKI and these sea otters have fully recovered from the oil spill.     

Mass Media Effect on the Operating Environment of a Wildlife-Related Risk-Communication Campaign

ABSTRACT Managers and other stakeholders may rely on wildlife-related risk communication campaigns to prevent or reduce risks associated with human-wildlife conflict. The operating environment or the sphere of activity within which a campaign functions can influence a campaign's ability to achieve outcomes. Between 1 May 2005 and 30 October 2005, we studied human-black bear conflict in southeastern New York and the wildlife-related risk communication campaign, the New York NeighBEARhood Watch (NYNW). Based on the social amplification of risk framework, our goal was to determine whether mass media affected the operating environment of the campaign, and if so, identify the magnitude and direction of the effect. We used a self-administered mail survey (N = 2,800) in 4 southeastern New York, USA, towns to collect data about residents’ perceived black bear-related risks, bear-related behavior, and exposure to the NYNW. We also conducted a content analysis of mass media coverage about black bears. Exposure to the NYNW from newspapers was positively correlated (R = 0.39, P < 0.01) with respondents’ decreased acceptance of black bear-related risks. Our results showed a small social amplification of risk associated with black bears from exposure to mass media, specifically newspapers. Mass media can influence the operating environment of a wildlife-related risk communication campaign, including through amplification of risk perception. Characterizing the operating environment of campaigns is key to HWC-intervention planning, evaluation, and policy. Wildlife practitioners can consider media effects, as well as other biological and social factors, as potential influences on a campaign's operating environment and be aware that interaction effects may occur.