• 关键词：城市工业区环境  杭州  镉  环境系统  生物有效性  健康风险

• 基金项目：国土资源大调查项目(No.12120100511103)

• 喻超
• 1. 山东省地质调查院, 济南 250013;
  2. 中国地质大学生物地质与环境地质教育部重点实验室,武汉 430074;
  3. 中国地质大学地球科学学院,武汉 430074

• 凌其聪
• 1. 中国地质大学生物地质与环境地质教育部重点实验室,武汉 430074;
  2. 中国地质大学地球科学学院,武汉 430074

• 彭振宇
• 浙江省地质调查院, 杭州 311203

• 严莎
• 南开大学环境科学与工程学院, 天津 300071

• 李晶
• 1. 中国地质大学生物地质与环境地质教育部重点实验室,武汉 430074;
  2. 中国地质大学地球科学学院,武汉 430074

• 陈忠大
• 浙江省地质调查院, 杭州 311203

• 摘要：为揭示重金属元素Cd在城市环境系统多种介质中的迁移途径及其潜在危害性,系统分析了杭州市半山工业区主要环境介质(土壤-尘埃-水-底泥-生物)样品中Cd的指标含量,并用连续提取法分析了土壤、尘埃、底泥中Cd的化学形态特征.结果表明,Cd的迁移途径主要有两种,一是以尘埃为媒介在地表环境中迁移,二是通过水介质进入水体环境(水和水体底泥).研究区的主要环境介质均已受到一定程度的Cd污染,Cd含量普遍较高,其中以街尘Cd污染最为严重,其平均Cd含量为表层土壤背景值的14.1倍,最高可达64倍.绿地表层土中Cd超标率(GB15618—1995)达到14%,区内水样中有10%的样品超过IV类水限值(GB3838—2002),水体底泥样品中有50%超过了III类土壤标准(GB15618—1995)限值,最大超标倍数达14.6倍.环境介质中的Cd元素均具较高的化学活性,弱酸可提取态Cd含量范围为32%~59%,Cd在不同介质中的化学活性排序为:底泥>土壤>尘埃.苔藓和农作物中的Cd含量表明,环境介质中的Cd已经具备了现实的生物可利用性,而区内蔬菜和稻谷米粒样中Cd超标率分别达到39%和60%,表明Cd污染对居民存在健康风险.

• Abstract：The mobilization and potential biohazard of Cd contaminants in circumstance are among the most critical issues in environmental risk assessment. In order to investigate behaviors and health risks of Cd in urban environment, an extensive survey was conducted in north Hangzhou, in which the total concentrations of heavy metals (Cd, etc.) in the main environmental media (soil-dust-water-plant), and Cd chemical partitioning in soil, dust and mud samples were determined. The results suggested that Cd in urban environment migrated in two paths. The first one was spread through dust in surface environment, and the other was transferred by surface runoff or effluent into aquatic environment (water and bottom muds). The main environmental media in the studied area mentioned above were contaminated by Cd in different degree, and Cd load was generally high. Among these media, street dusts were the most seriously polluted with Cd content 14.1 times higher than the average background value of surface soils in the city, and locally even up to 64 times. Moreover, 14% of the green-land soil samples were classified into III Grade based on the National Environmental Quality Standards in Soils of China (GB15618—1995). 10% of water samples were classified into V Grade based on the National Environmental Quality Standards for surface water of China (GB3838—2002). And 50% of bottom mud samples exceeded the III Grade based on GB15618—1995 with the highest content up to 14.6 times of the III Grade's. Chemical partitioning analysis revealed that Cd in soil, dust, and mud were highly mobile with 32%~59% of Cd bounded in acetic acid extractable phase, and the mobility of Cd was in the order of bottom mud > soil > dust. Elevated contents of Cd in crops and moss samples revealed that Cd in urban environment presented high bioavailability. Furthermore, 39% of vegetable and 60% of rice samples with Cd contents exceeding the limited values of National Food Sanitary Standards showed clearly that Cd contamination in the study area posed potential hazard to human health.

• Key words：urban industrial environment  Hangzhou  Cd  environmental system  bioavailability  health risks

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