Emissions of ammonia and greenhouse gases during combined pre-composting and vermicomposting of duck manure

Combined pre-composting and vermicomposting has shown potential for reclamation of solid wastes, which is a significant source of ammonia (NH₃), and greenhouse gases (GHG), including nitrous oxide (N₂O), methane (CH₄), and carbon dioxide (CO₂). Earthworms and amendments may both affect physico-chemical characteristics that control gas-producing processes, and thus affect NH₃ and GHG emissions. Here, we used two-way ANOVA to test the effects of addition of reed straw and combined addition of reed straw and zeolite on NH₃ and GHG emissions during pre-composting of duck manure, either with or without a follow-up phase of vermicomposting. Results showed that cumulative N₂O, CH₄, and CO₂ emissions during pre-composting and vermicomposting ranged from 92.8, 5.8, and 260.6 mg kg^?1 DM to 274.2, 30.4, and 314.0 mg kg^?1 DM, respectively. Earthworms and amendments significantly decreased N₂O and CH₄ emissions. Emission of CO₂ was not affected by earthworms, but increased in responses to addition of reed straw. Cumulative NH₃ emission ranged from 3.0 to 8.1 g kg^?1 DM, and was significantly decreased by reed straw and zeolite addition. In conclusion, combined pre-composting and vermicomposting with reed straw and zeolite addition would be strongly recommended in mitigating emissions of N₂O, CH₄, and NH₃ from duck manure. Moreover, this method also provides nutrient-rich products that can be used as a fertilizer.     

A GIS-based decision support system for regional eco-security assessment and its application on the Tibetan Plateau

Regional eco-security assessment is an intricate, challenging task. In previous studies, the integration of eco-environmental models and geographical information systems (GIS) usually takes two approaches: loose coupling and tight coupling. However, the present study used a full coupling approach to develop a GIS-based regional eco-security assessment decision support system (ESDSS). This was achieved by merging the pressure-state-response (PSR) model and the analytic hierarchy process (AHP) into ArcGIS 9 as a dynamic link library (DLL) using ArcObjects in ArcGIS and Visual Basic for Applications. Such an approach makes it easy to capitalize on the GIS visualization and spatial analysis functions, thereby significantly supporting the dynamic estimation of regional eco-security. A case study is presented for the Tibetan Plateau, known as the world’s “third pole” after the Arctic and Antarctic. Results verified the usefulness and feasibility of the developed method. As a useful tool, the ESDSS can also help local managers to make scientifically-based and effective decisions about Tibetan eco-environmental protection and land use.     

分光光度法测定氯化氢的实验条件改进

硫氰酸汞分光光度法测定大气中的氯化氢,所使用的硫氰酸汞-乙醇溶液配置时间长,浓度低,曲线线性不好,不适用于环境现场监测。通过对氯化氢测定过程中遇到的问题进行分析,对硫氰酸汞-乙醇溶液的配置方法进行改进,提高该溶液的浓度。实验证明,使用定性滤纸过滤后的0.40%硫氰酸汞-乙醇溶液,曲线线性关系好,标样准确度高,适用于现场监测分析。     

京津冀电子废弃物回收利用潜力预测及环境效益评估

电子废弃物是京津冀区域重要的"城市矿山"之一,全面系统地评估该地区电子废弃物产生量及其回收利用的资源环境效益,可为该区域通过电子废弃物协同精准管理来解决资源环境问题提供科学依据和方法支撑.基于改进的保有量系数法、物料系数法、市场价值法及污染系数法,通过估算废弃电视、电冰箱、空调、洗衣机和计算机5类主要产品（"四机一脑" ）的产生量、资源可回收量、资源回收价值及资源环境效益等,对2010~2025年京津冀电子废弃物的回收利用潜力及环境效益进行预测和评估.结果表明,2010~2025年京津冀废弃"四机一脑"产生量不断增加,2010~2018年期间年均增长率为7.75%,此后预计将以年均3.07%的速度递增,2025年废弃"四机一脑"总量将达到1861.74万台,可回收普通金属27.19万t、塑料12.75万t和贵金属19.45 t.2019~2025年期间,废弃空调和计算机的资源回收经济价值较高,二者之和占年回收总价值的77.22%;铜和金的回收经济价值贡献比分别为43.37%和19.82%,显著高于其他资源.预计2025年资源回收总价值达50.24亿元,是2010年的3.13倍,其中普通金属、贵金属和塑料的回收价值分别为28.68、13.27和8.29亿元.若2025年产生的电子废弃物全部被规范回收利用,能够减少原生矿石开采913.23万t,减少标准煤利用122.71万t,减少废水、废气、废渣及重金属排放量分别为1231.19、473.89、785.10和6.08万t,减少温室气体排放32.92万t （以CO₂-eq计）.废弃空调的回收利用潜力最大,但资质处理企业废弃空调回收处理能力亟待提高.为高效回收利用京津冀电子废弃物,未来应尽快完善基金补贴制度,加强对非正规拆解部门的监督与管理,通过建立区域信息共享平台,实现电子废弃物全生命周期区域协同管理.     

成都市气温与PM2.5和O3交互作用对疾病死亡人数的影响研究

利用成都市2014~2016年逐日呼吸系统疾病和心脑血管疾病死亡资料、同期气象资料和PM_2.5日均浓度和每日臭氧最大8h平均浓度（O₃）资料,采用分布滞后模型以及广义相加模型中的独立效应模型、非参数二元响应模型和温度分层模型探究了成都市气温、PM_2.5和O₃单效应,以及气温与PM_2.5（或O₃）交互作用对当地呼吸和心脑血管疾病死亡人数的影响.单效应分析结果表明,气温与两种疾病死亡人数的累计暴露-反应关系均呈反“J”型分布,最适温度在22.2℃,该温度对应的疾病死亡人数最少;累积滞后1d的PM_2.5（或O₃）对应的健康风险最大,此时,PM_2.5和O₃浓度每升高10μg/m³,呼吸系统疾病死亡风险分别增加0.58%和0.54%,心脑血管疾病死亡风险分别增加0.35%和0.66%.分季节研究结果表明,PM_2.5对两种疾病死亡影响的健康风险冬季最高,而O₃的健康风险在秋季最显著.交互作用的研究结果表明,高温与高浓度的PM_2.5（或O₃）对疾病死亡的影响存在协同放大效应,当气温高于22.2℃时,PM_2.5和O₃浓度每升高10μg/m³,对应的呼吸系统疾病死亡风险分别增加2.30%和1.14%,心脑血管疾病死亡风险分别增加1.09%和1.03%.研究结果提示O₃对人群健康的影响也不容忽视,应该引起足够的重视.     

炼钢厂混铁炉粉尘污染治理的研究

在对混铁炉粉尘成分分析的基础上,认为烟气中的粉尘主要来源于铁水碳的析出,提出了通过高炉铁水保温和脱碳处理,治理混铁炉粉尘污染的方法。实验和现场试验研究表明高炉铁水温度变化100℃,铁水碳溶解度平均变化0.24%;加入铁水重量2.05%的滇滩矿粉后,平均可脱除0.18%的碳,并且试验铁罐中片状石墨漂浮物明显减少,达到了减少混铁炉烟气中粉尘含量的目的。     

Denaturing gradient gel electrophoresis fingerprinting of soil bacteria in the vicinity of the Chinese Great Wall Station, King George Island, Antarctica

Bacterial diversity was investigated in soil samples collected from 13 sites around the Great Wall Station, Fildes Peninsula, King George Island, Antarctica, using denaturing gradient gel electrophoresis (DGGE) of 16S rRNA genes. The classes α-, β-, and γ-Proteobacteria, as well as the phylum Actinobacteria, were found to be the dominant bacteria in the soils around the Great Wall Station. Although the selected samples were not contaminated by oil, a relationship between soil parameters, microbial biodiversity, and human impact was still seen. Sample sites in human impacted areas showed lower bacterial biodiversity (average H′= 2.65) when compared to nonimpacted sites (average H′= 3.05). There was no statistically significant correlation between soil bacterial diversity and total organic carbon (TOC), total nitrogen, or total phosphorus contents of the soil. Canonical correlation analysis showed that TOC content was the most important factor determining bacterial community profiles among the measured soil parameters. In conclusion, microbial biodiversity and community characteristics within relatively small scales (1.5 km) were determined as a function of local environment parameters and anthropogenic impact.     

含铬浸出渣调质解毒规律研究

为了研究含铬浸出渣的调质解毒机理,建立了CaO-MgO-FeO-Na2O-SiO2-Al2O3-Cr2O3七元渣系活度模型,基于共存理论的活度模型得出了铬渣中主要组分及复合氧化物在不同条件下的活度。所得的结果表明,铬渣中Cr2O3主要形成了Na2Cr2O4和CaCr2O4,这两种复合氧化物不稳定,在自然环境中分别会被氧化为水溶性的铬酸钠(Na2CrO4)和酸溶性的铬酸钙(CaCrO4),释放出具有强毒性的Cr(Ⅵ),是造成铬污染的主要原因。温度、碱度以及渣中FeO含量都能影响渣系组分的活度。在1700K下,将铬渣碱度调至1.14,并加入30%的FeO能够使Cr2O3的有效固定率提高至88.2%,基本实现了铬渣的解毒。