五种不同来源建筑废物中砷污染特征及形态分布Characteristics of Arsenic Pollution and Chemical Speciation Distribution in Construction & Demolition Waste from Five Sources
高小峰, 谷依露, 谢田, 黄晟, 曹楠楠, 苏良湖, 赵由才
建筑废物, 砷, 污染特征, 单因子评价, 化学形态Construction & Demolition Waste, Arsenic, Pollution Characteristic, Single Factor Evaluation, Chemical Speciation
《Advances in Environmental Protection》, Vol.5 No.2, 2015-04-29
本研究对化工、冶金、轻工、生活区、再生骨料等五种不同来源建筑废物中砷含量、单因子评价、元素相关性、化学形态及风险评估进行了分析。对砷含量分析表明不同来源建筑废物中砷平均含量差别不大，分别为：再生骨料 > 居民区 > 冶金 > 化工 > 土壤环境质量三级标准阈值 > 轻工。单因子评价也表明生活区和再生骨料砷污染比其他严重，为中度污染；而化工、冶金、轻工为轻度污染。同时砷含量分布极度不均，如冶锌厂清洗车间样品和南京某钢铁厂锅炉车间烟囱外壁刮落物，其含量远高于土壤环境质量三级标准阈值，化工和冶金砷污染都与其具体工艺段是否接触含砷原料有关。元素相关性分析显示，砷与铁、锰均呈较强正相关性，表明建筑废物中砷与铁锰密切相关。风险评估主要针对酸可提取态分析，结果显示CI7-CI10均为无风险，MI1为低风险，MI2为中等风险。通过化学形态分析得出，来源于电镀厂镀锌车间、镀铬车间、镀镍车间砷均以残渣态为主，且这三个车间砷含量均低于土壤三级标准阈值。但电镀厂镀铜车间和冶锌厂建筑废物中砷有较高的迁移能力，反映其与矿物结合松散，具有较大的环境风险。This study was initiated to characterize and assess the arsenic (As) concentration, single factor evaluation, correlation among elements, chemical speciation and environmental risks in construc-tion & demolition (C&D) waste samples, which come from the chemical industry (CI), metallurgical (MI), light industry (LI), residential (RS), and recycled aggregates (RC). The results illustrate that the average arsenic concentration has small difference in C&D waste from five sources, and the average concentration increased in the order of RC > RS > MI > CI > TVHM-Level-III (standard threshold values of heavy metals of environmental quality standard for soils in China) > LI. Medium level pollution was defined by the single factor evaluation in RC and RS samples which polluted more severely than other source samples which were defined as low level pollution. Arsenic distribution is extremely uneven, such as the sample from a cleaning workshop in zinc smelting factory and chimney scraping litter from a steel boiler in Nanjing iron and steel plant, of which the arsenic concentration is surpassing the TVHM-Level-III. Arsenic-contaminated of CI and MIC&D waste depend on their specific craft section whether exposure to arsenic raw materials. Element correlation analysis showed that the arsenic and iron and manganese are strong positive correla-tion, arsenic is closely related to the iron and manganese in C&D waste. Risk assessment focuses on acid extractable fraction, the results show CI7-CI10 are non-risk, MI1 as low risk, MI2 as medium risk. Through chemical speciation analysis, the arsenic concentrations of the galvanizing workshop, chrome plating workshop and nickel plating workshop samples are all below the TVHM- Level-III, and arsenic mainly existed in the residual fraction. The mobility fraction of arsenic in the copper plating workshop and zinc smelter samples was relatively high; their combination with the minerals is loose, and poses a very high risk of environment.