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.     

Towards the establishment of an environmental quality standard for aluminium in surface waters

Steps taken to establish an environmental quality standard (EQS) for aluminium are described. The range of water types in England and Wales and the concentrations of low molecular weight (active) forms of aluminium have been assessed in order to evaluate the risk posed by aluminium in surface waters. Levels of low molecular weight forms of aluminium are mainly in the range 0-25 microg l(-1). Data suggest that dissolved aluminium might form the basis of a reasonably useful prediction of active aluminium leading to a simplified approach to compliance monitoring of an EQS set in terms of active aluminium.     

Participatory monitoring and evaluation to aid investment in natural resource manager capacity at a range of scales

Natural resource (NR) outcomes at catchment scale rely heavily on the adoption of sustainable practices by private NR managers because they control the bulk of the NR assets. Public funds are invested in capacity building of private landholders to encourage adoption of more sustainable natural resource management (NRM) practices. However, prioritisation of NRM funding programmes has often been top–down with limited understanding of the multiple dimensions of landholder capacity leading to a failure to address the underlying capacity constraints of local communities. We argue that well-designed participatory monitoring and evaluation of landholder capacity can provide a mechanism to codify the tacit knowledge of landholders about the social–ecological systems in which they are embedded. This process enables tacit knowledge to be used by regional NRM bodies and government agencies to guide NRM investment in the Australian state of New South Wales. This paper details the collective actions to remove constraints to improved NRM that were identified by discrete groups of landholders through this process. The actions spanned geographical and temporal scales, and responsibility for them ranged across levels of governance.     

Screening organic chemicals in commerce for emissions in the context of environmental and human exposure

Quantitative knowledge of organic chemical release into the environment is essential to understand and predict human exposure as well as to develop rational control strategies for any substances of concern. While significant efforts have been invested to characterize and screen organic chemicals for hazardous properties, relatively less effort has been directed toward estimating emissions and hence also risks. Here, a rapid throughput method to estimate emissions of discrete organic chemicals in commerce has been developed, applied and evaluated to support screening studies aimed at ranking and identifying chemicals of potential concern. The method builds upon information in the European Union Technical Guidance Document and utilizes information on quantities in commerce (production and/or import rates), chemical function (use patterns) and physical-chemical properties to estimate emissions to air, soil and water within the OECD for five stages of the chemical life-cycle. The method is applied to 16,029 discrete substances (identified by CAS numbers) from five national and international high production volume lists. As access to consistent input data remains fragmented or even impossible, particular attention is given to estimating, evaluating and discussing uncertainties in the resulting emission scenarios. The uncertainty for individual substances typically spans 3 to 4 orders of magnitude for this initial tier screening method. Information on uncertainties in emissions is useful as any screening or categorization methods which solely rely on threshold values are at risk of leading to a significant number of either false positives or false negatives. A limited evaluation of the screening method's estimates for a sub-set of about 100 substances, compared against independent and more detailed emission scenarios presented in various European Risk Assessment Reports, highlights that up-to-date and accurate information on quantities in commerce as well as a detailed breakdown on chemical function are critically needed for developing more realistic emission scenarios.     

Fingerprinting of petroleum hydrocarbons (PHC) and other biogenic organic compounds (BOC) in oil-contaminated and background soil samples

Total petroleum hydrocarbons (TPH) or petroleum hydrocarbons (PHC) are one of the most widespread soil contaminants in Canada, the United States and many other countries worldwide. Clean-up of PHC-contaminated soils costs the Canadian economy hundreds of millions of dollars annually. In Canada, most PHC-contaminated site evaluations are based on the methods developed by the Canadian Council of the Ministers of the Environment (CCME). However, the CCME method does not differentiate PHC from BOC (the naturally occurring biogenic organic compounds), which are co-extracted with petroleum hydrocarbons in soil samples. Consequently, this could lead to overestimation of PHC levels in soil samples. In some cases, biogenic interferences can even exceed regulatory levels (300 μg g(-1) for coarse soils and 1300 μg g(-1) for fine soils for Fraction 3, C(16)-C(34) range, in the CCME Soil Quality Level). Resulting false exceedances can trigger unnecessary and costly cleanup or remediation measures. Therefore, it is critically important to develop new protocols to characterize and quantitatively differentiate PHC and BOC in contaminated soils. The ultimate objective of this PERD (Program of Energy Research and Development) project is to correct the misconception that all detectable hydrocarbons should be regulated as toxic petroleum hydrocarbons. During 2009-2010, soil and plant samples were collected from over forty oil-contaminated and paired background sites in various provinces. The silica gel column cleanup procedure was applied to effectively remove all target BOC from the oil-contaminated sample extracts. Furthermore, a reliable GC-MS method in combination with the derivatization technique, developed in this laboratory, was used for identification and characterization of various biogenic sterols and other major biogenic compounds in these oil-contaminated samples. Both PHC and BOC in these samples were quantitatively determined. This paper reports the characterization results of this set of 21 samples. In general, the presence of petroleum-characteristic alkylated PAH homologues and biomarkers can be used as unambiguous indicators of the contamination of oil and petroleum product hydrocarbons; while the absence of petroleum-characteristic alkylated PAH homologues and biomarkers and the presence of abundant BOC can be used as unambiguous indicators of the predominance of natural organic compounds in soil samples.     

Threat-sensitive generalization of predator recognition by larval amphibians

Despite the importance of acquired predator recognition in mediating predator–prey interactions, we know little about the specific characteristics that prey use to distinguish predators from non-predators. Recent experiments with mammals and fish indicate that some prey lacking innate predator recognition have the ability to display anti-predator responses upon their first encounter with those predators if they are similar to predators that the prey has recently learned to recognize. This phenomenon is referred to as generalization of predator recognition. In this experiment, we documented for the first time that larval amphibians (woodfrog, Rana sylvatica) have the ability to generalize the recognition of known predators to closely related novel predators. Moreover, we demonstrated that this ability is dependent on the level of risk associated with the known predator. When red-bellied newt, Cynops pyrrhogaster (known predator), was paired with simulated low risk, tadpoles displayed fright responses to newts and novel tiger salamanders, Ambystoma tigrinum, but not to novel African clawed frogs, Xenopus laevis. However, when the newt was paired with simulated high risk, tadpoles generalized their responses to both tiger salamanders and African clawed frogs. Larval anurans seem to have a wider generalization frame than other animals.     

Look before you leap: is risk of injury a foraging cost?

Theory states that an optimal forager should exploit a patch so long as its harvest rate of resources from the patch exceeds its energetic, predation, and missed opportunity costs for foraging. However, for many foragers, predation is not the only source of danger they face while foraging. Foragers also face the risk of injuring themselves. To test whether risk of injury gives rise to a foraging cost, we offered red foxes pairs of depletable resource patches in which they experienced diminishing returns. The resource patches were identical in all respects, save for the risk of injury. In response, the foxes exploited the safe patches more intensively. They foraged for a longer time and also removed more food (i.e., had lower giving up densities) in the safe patches compared to the risky patches. Although they never sustained injury, video footage revealed that the foxes used greater care while foraging from the risky patches and removed food at a slower rate. Furthermore, an increase in their hunger state led foxes to allocate more time to foraging from the risky patches, thereby exposing themselves to higher risks. Our results suggest that foxes treat risk of injury as a foraging cost and use time allocation and daring—the willingness to risk injury—as tools for managing their risk of injury while foraging. This is the first study, to our knowledge, which explicitly tests and shows that risk of injury is indeed a foraging cost. While nearly all foragers may face an injury cost of foraging, we suggest that this cost will be largest and most important for predators.     

Understanding and Managing Indoor Air Exposure Assessments at RCRA Sites

The 2000 RCRA National Conference was conducted August 15‐17, 2000, in Washington, D.C., to allow state and federal authorities to review regulatory issues associated with the Resource Conservation and Recovery Act (RCRA) program. One of the RCRA reform issues discussed at the conference included the Government Performance and Results Act (GPRA) Environmental Indicators (EI). EIs have been designed to provide clarity in cleanup objectives and spur progress towards meeting the U.S. Environmental Protection Agency's (USEPA's) national RCRA cleanup goals. This article focuses on the human exposure indicator and, more specifically, on indoor air exposures and how to assess whether such exposure is actually occurring. While indoor air exposure can be a critical component of the human exposure scenarios, realistic predictions of the exposures are difficult to produce. This article provides an overview of the regulatory issues related to the indoor air exposure pathway. It also discusses the use of modeling in criteria development and risk evaluation and presents a case study of how the USEPA wants the modeling to occur, and an opinion of where this RCRA reform issue is heading and how to evaluate indoor air exposures.