Human Health Risk Evaluation of ACQ-Treated Wood

Alkaline copper quaternary (ACQ) Type D is one of several compounds currently being used as a chemical preservative to treat wood for prevention of rot and decay. As wood weathers naturally, human exposure to ACQ might occur through dermal contact or incidental ingestion of residues from the wood surface. To understand any potential for health risks from the use of ACQ-treated wood, a health-based evaluation was undertaken on the primary components of ACQ, which are copper, didecyl dimethyl ammonium carbonate, 2-methyl-4-isothiazolin-3-one, and 5-chloro-2-methyl-4-isothiazolin-3-one. For these components, there are no formalized toxicity values in USEPA's Integrated Risk Information System, although extensive toxicity data are available in the scientific literature. Therefore, health-based toxicity benchmarks were derived from a review of existing toxicity data. The exposure assessment was based on methods developed by the Consumer Product Safety Commission in their evaluation of the potential for children's exposure to arsenic from wood treated with chromated copper arsenate. This approach entailed wipe testing the surface of treated wood to determine the amount of chemical that might be removed from the wood, and estimating the amount of chemical that a child might contact via the dermal route or incidental ingestion through hand-to-mouth activities. All calculated exposure estimates were well below toxicity benchmarks.     

Evaluation of Populus and Salix continuously irrigated with landfill leachate I. Genotype-specific elemental phytoremediation

There is a need for the identification and selection of specific tree genotypes that can sequester elements from contaminated soils, with elevated rates of uptake. We irrigated Populus (DN17, DN182, DN34, NM2, NM6) and Salix (94003, 94012, S287, S566, SX61) genotypes planted in large soil-filled containers with landfill leachate or municipal water and tested for differences in inorganic element concentrations (P, K, Ca, Mg, S, Zn, B, Mn, Fe, Cu, Al, Na, and Cl) in the leaves, stems, and roots. Trees were irrigated with leachate or water during the final 12 wk of the 18-wk study. Genotype-specific uptake existed. For genera, tissue concentrations exhibited four responses. First, Populus had the greatest uptake of P, K, S, Cu, and Cl. Second, Salix exhibited the greatest uptake of Zn, B, Fe, and Al. Third, Salix had greater concentrations of Ca and Mg in leaves, while Populus had greater concentrations in stems and roots. Fourth, Populus had greater concentrations of Mn and Na in leaves and stems, while Salix had greater concentrations in roots. Populus deltoides x P. nigra clones exhibited better overall phytoremediation than the P. nigra x P. maximowiczii genotypes tested. Phytoremediation for S. purpurea clones 94003 and 94012 was generally less than for other Salix genotypes. Overall, concentrations of elements in the leaves, stems, and roots corroborated those in the plant-sciences literature. Uptake was dependent upon the specific genotype for most elements. Our results corroborated the need for further testing and selecting of specific clones for various phytoremediation needs, while providing a baseline for future researchers developing additional studies and resource managers conducting on-site remediation.     

Not all management is equal: a comparison of methods to increase wood turtle population viability

Management generally targets the most tractable life stage to rescue declining populations; however, that stage may not have the largest influence on recovery. Freshwater turtles are declining globally and early stages are frequently targeted for management, although the effectiveness of these actions on population growth are relatively unknown because of incomplete demographic data. We estimated the hatchling yearly survival rate for a freshwater turtle in the field using in situ enclosures to collect missing demographic information. We used these data to develop demographic models to calculate growth rate for a hypothetical, declining population of wood turtles (Glyptemys insculpta) in Wisconsin, USA, 2014–2019. We modeled growth for populations across a range of scenarios from no management to combinations of nest protection and head-starting at varying levels of effort. Nest protection alone did not increase population growth rate, while head-starting alone increased population growth by 0.07, with the largest increase in growth rate, 0.11, resulting from combinations of both approaches. No combination of nest protection and head-starting, without an increase in adult survival rate from the observed 0.88 to ≥0.95, led to population stabilization or increase. Populations of freshwater turtles, like the wood turtle, will likely only recover with a multi-faceted approach that targets multiple life stages simultaneously.     

杨树胞外蛋白的提取分离及2-D电泳体系的建立

该研究以美洲黑杨杂种优良无性系NL895杨(Populus deltoides×Populus euramericana cv.)组培苗叶片和茎段为研究对象,对NL895杨叶片细胞壁蛋白(cell wall proteins,CWPs)和茎段质外体蛋白(apoplastic proteins,APPs)的提取、分离和双向电泳等技术进行了系统研究。结果表明:10g以上叶片、超声波破碎10min、CaCl2法提取的细胞壁蛋白效果较好,经G-6-PDH酶活性检测,提取的细胞壁蛋白胞质污染率较低;真空渗透法提取的茎段质外体蛋白胞质污染率较前者高,但在允许范围之内。TCA/丙酮沉淀法纯化提取的细胞壁蛋白、pH 4~7的24cm胶条、上样量为500μg的双向电泳体系,其蛋白电泳图谱中的斑点多而清晰,斑点数达550多个,是叶片细胞壁蛋白电泳分析较适合的体系;pH 3~10胶条对茎段质外体蛋白的电泳分离效果较好。该研究初步建立了杨树胞外蛋白的提取、分离及2-DE电泳体系,为木本植物胞外蛋白的研究奠定了基础。     

Solid Biomass Climate Change Interventions Examined in a Context of Inherent Safety,Media Shifting,and Emerging Risks

ABSTRACT

This article examines recent evidence from Denmark and abroad regarding climate change projects that aim to reduce global carbon dioxide emissions by converting coal-fired thermal power plants to solid biomass fuel. The article argues that projects appear to be pursued narrow-mindedly with insufficient attention paid to safety and points to evidence of media shifting—that the “resolution” of a problem within the environmental domain creates a new problem in the workplace safety domain. From the perspective of inherent safety the article argues that the conversion is a step in the wrong direction as a low risk fuel is substituted for a less safe one. Because of rapid scale-up and handling of unprecedented quantities, solid biomass qualify as an emerging risk for which proper control strategies have yet to be developed. The article finally argues that the tendency to prioritize environmental benefits over safety concerns seems to run deep and not confined to the realm of only solid biomass. Danish environmental ambitions are very high and the costs to society of introducing solid biomass fuels are breathtaking. In this setting, the general failure to address safety risks appears particularly disheartening.