Application of the analytic hierarchy process to select characterization and risk-based decision-making and management methods for hazardous waste sites

Environmental managers at U.S. Department of Defense (DoD) installations overseas are faced with the challenge of managing contaminated sites at these installations with little information on the extent of contamination or the risk posed by the site. In this regard, DoD managers overseas encounter a situation quite similar to the situation faced by decision makers in the U.S. who are managing brownfields. Innovative site characterization and risk-based decision-making methods, which are currently being developed for expeditious application at brownfield sites in the U.S., may also be appropriate for application at overseas DoD sites. In this paper, the analytic hierarchy process (AHP) is used by DoD decision makers to evaluate and rank innovative site characterization technologies and risk-based decision-making and management methods, for use at installations in Korea. Results indicate that for sites with high potential risk the decision makers preferred site characterization technologies that produce data of high quality and a method that can be used to establish credible risk-based remediation goals. This study provides a framework for applying characterization technologies and risk management to poorly characterized contaminated sites in developing countries, where resources for remedial actions may be limited.     

Carbon mitigation potential and costs of forestry options in Brazil,China, India,Indonesia, Mexico,the Philippines and Tanzania

This paper summarizes studies of carbon (C) mitigation potential and costs of about 40 forestry options in seven developing countries. Each study uses the same methodological approach – Comprehensive Mitigation Assessment Process (COMAP) – to estimate the above parameters between 2000 and 2030. The approach requires the projection of baseline and mitigation land-use scenarios. Coupled with data on a per ha basis on C sequestration or avoidance, and costs and benefits, it allows the estimation of monetary benefit per Mg C, and the total costs and carbon potential. The results show that about half (3.0 Pg C) the cumulative mitigation potential of 6.2 Petagram (Pg) C between 2000 and 2030 in the seven countries (about 200× 10⁶ Mg C yr^-1) could be achieved at a negative cost and the remainder at costs ranging up to $100 Mg C^-1. About 5 Pg C could be achieved, at a cost less than $20 per Mg C. Negative cost potential indicates that non-carbon revenue is sufficient to offset direct costs of these options. The achievable potential is likely to be smaller, however, due to market, institutional, and sociocultural barriers that can delay or prevent the implementation of the analyzed options.     

The effect of metapleural gland secretion on the growth of a mutualistic bacterium on the cuticle of leaf-cutting ants

In Acromyrmex octospinosus leaf-cutting ants the metapleural glands produce an array of antibiotic compounds that serve as a general defence against unwanted microbes on the cuticle. Leaf-cutting ants also grow mutualistic Pseudonocardiaceae bacteria on their cuticle that produce antibiotics controlling a microfungal parasite of their fungus gardens. Interaction between this bacterium and gland secretion therefore seems unavoidable. We document the typical development of bacterial growth on the cuticle of young major workers, show that growth starts a few days after eclosion, and that the maximal cover is reached after 2–3 weeks and gradually declines when workers mature. Experimental closure of the metapleural glands had no effect on the initial exponential growth phase of the bacterium, but significantly reduced the cover during the decline phase. The age-dependent abundance of the bacterium and its partial dependence on metapleural gland secretion support the hypothesis that the abundance of this mutualist is actively regulated.     

Soil microbial response to herbicides applied to glyphosate-resistant canola

Adoption of glyphosate-resistant canola (Brassica napus L.) has increased glyphosate applications to this crop, and concerns have been raised about unintended consequences of these multiple applications. A field trial was conducted to evaluate the effects of pre-seed and in-crop glyphosate and alternative herbicides on soil microbial community functional structure, diversity and biomass. Pre-seed treatments were 2,4-D, glyphosate and 2,4-D + glyphosate, and in-crop treatments were glyphosate applied once, glyphosate applied twice, ethalfluralin, ethalfluralin + sethoxydim + ethametsulfuron + clopyralid, and sethoxydim + ethametsulfuron. Rhizosphere and bulk soil was collected at flowering stage of canola and analyzed for bacterial community-level substrate utilization patterns and microbial biomass C (MBC). Where differences were significant, pre-seed application of both 2,4-D and glyphosate altered the functional structure and reduced the functional diversity of soil bacteria, but increased MBC. These effects were not necessarily concurrent. The reduction in functional diversity was due to reduction in evenness, which means that the soil where both pre-seed herbicides had been applied was dominated by only few functional groups. In 1 year, two in-crop applications of glyphosate also reduced the functional diversity of soil bacteria when applied after pre-seed 2,4-D, as did in-crop sethoxydim + ethametsulfuron following pre-seed glyphosate. Even though significant differences between herbicides were fewer than non-significant differences, i.e., there were no changes in soil microbial community structure, diversity or biomass in response to glyphosate or alternative herbicides applied to glyphosate-resistant canola in most cases, the observed changes in soil microbial communities could affect soil food webs and biological processes.     

2016-2018年西宁市颗粒物来源及输送差异分析

利用HYSPLIT模式计算了2016—2018年西宁市逐日72 h气团后向轨迹,采用聚类分析方法,结合同期颗粒物PM₁₀和PM_2.5质量浓度数据,分析逐年和3年平均西宁市颗粒物输送特征及差异,运用潜在源贡献因子分析法（PSCF）和浓度权重轨迹分析法（CWT）对影响西宁市PM₁₀和PM_2.5质量浓度的污染潜在源区及不同潜在源区贡献进行了分析.结果表明,2016—2018年,西宁市颗粒物最主要输送路径源自青海北部的聚类2、甘肃中部的聚类6和甘肃东部的聚类8,占同期总轨迹比例分别为28.1%、27.4%和27.5%;3年平均则源自青海北经青海东折回西宁的聚类2,占比45.3%.最主要输送路径对应颗粒物质量浓度最低,输送距离较短、垂直高度较低、气团移速较慢;影响气团由西北向偏东转变,3年平均则以西北气团为主.2018年源自甘肃经青海东至西宁的短距离输送处于突出地位,所含轨迹占总轨迹的比例高达49.6%.PM₁₀和PM_2.5主要输送路径和污染路径由较长距离向较短距离过渡,较长距离输送路径出现比例逐年较小.PM_2.5/PM₁₀小于0.3时,主要输送路径与PM₁₀污染轨迹有很好的对应关系;PM_2.5/PM₁₀大于0.6时,主要输送路径与PM_2.5污染轨迹有较好的对应关系.PSCF和CWT分析发现,影响西宁市颗粒物质量浓度的主要污染潜在源区分布在新疆南部和青海北部,对PM₁₀质量浓度贡献大于100 μg·m^-3,对PM_2.5质量浓度贡献大于45 μg·m^-3.潜在源区分布年变化差异明显,2016年最广,2018年最小.印度北部主要贡献源区虽分布范围逐年减小,但在2017年局部贡献增大,对PM₁₀贡献超250 μg·m^-3,对PM_2.5贡献超60 μg·m^-3.主要贡献区周边区域及西宁至兰州一带为中等贡献源区,对PM₁₀贡献为50~100 μg·m^-3,对PM_2.5贡献为15~45 μg·m^-3.