Heavy metal concentrations in plants and soils at roadside locations and parks of urban Guangzhou

Introduction In 2003, 48 per cent of the world's population is estimated to live in urban areas with the proportion that is urban projected to rise to 61 per cent by 2030 (United Nations, 2004). Moreover, during 2000— 2030 the world's urban population is…     

Dynamics of soil inorganic nitrogen and their responses to nitrogen additions in three subtropical forests, south China

Three forests with different historical land-use, forest age, and species assemblages in subtropical China were selected to evaluate current soil N status and investigate the responses of soil inorganic N dynamics to monthly ammonium nitrate additions. Results showed that the mature monsoon evergreen broadleaved forest that has been protected for more than 400 years exhibited an advanced soil N status than the pine （Pinus massoniana） and pine-broadleaf mixed forests, both originated from the 1930＇s clear-cut and pine plantation. Mature forests had greater extractable inorganic N pool, lower N retention capacity, higher inorganic N leaching, and higher soil C/N ratios. Mineral soil extractable NH4^＋-N and NO3-N concentrations were significantly increased by experimental N additions on several sampling dates, but repeated ANOVA showed that the effect was not significant over the whole year except NH4^＋-N in the mature forest. In contrast, inorganic N （both NH4^＋-N and NO3^--N） in soil 20-cm below the surface was significantly elevated by the N additions. From 42% to 74% of N added was retained by the upper 20 cm soils in the pine and mixed forests, while 0%-70% was retained in the mature forest. Our results suggest that land-use history, forest age and species composition were likely to be some of the important factors that determine differing forest N retention responses to elevated N deposition in the study region.     

Free cupric ions in contaminated agricultural soils around a copper mine in eastern Nanjing City, China

To determine the environmental free metal ion activity was a recent hot issue. A method to measure low-level free cupric ion activity in soil solution extracted with 0.01 mol/L KNO3 was developed by using cupric ion-selective electrode （ISE） and calibrating with Cu-buffer solution. Three copper buffers including iminodiacetic acid （IDA）, ethylenediamine （EN）, and glycine （Gly） were compared for calibrating the Cu-ISE curves in the range of free cupric ions （pCu^2＋） 7-13. The Cu-EN buffer showed the best electrode response and thus was applied as the calibration buffer. The pCu^2＋ of 39 contaminated agricultural soils around a copper mine was measured, ranging from 5.03 to 9.20. Most Cu in the soil solutions was found to be complexed with dissolved soil organic matters, averaging 98.1%. The proportion of free Cu^2＋ ions in the soil solutions decreased with the increasing of solution pH. Soluble Cu and free Cu^2＋ ions concentrations were analyzed by multiple linear regressions to evaluate the effects of soil properties on metal levels and speciation. The results showed that soil solution pH was the most significant factor influencing pCu^2＋ （with R^2 value of 0.76）, while not important for the soluble Cu concentration.     

广东省建设用地土壤污染风险管控和修复名录

《中华人民共和国土壤污染防治法》提出“建设用地土壤污染风险管控和修复名录（简称‘名录’）管理制度”,广东省于2019年12月建立第1期名录,截至2023年7月已更新至第21期。统计广东省21期名录公开信息并分析了名录公开频次和形式、地块数量、地块分布和面积、土地使用权人、风险管控或修复进展情况、风险管控或修复技术单位、风险管控或修复委托人、地下水清单、地块后期管理情况等信息,得出了广东省污染地块分布的基本情况,并提出了推进污染地块土壤环境管理的政策建议。     

浅谈基层生态环境监测中土壤样品采集技术

土壤样品采集是土壤生态环境监测工作开展的基础,规范准确的土壤样品采集技术是土壤生态环境监测结果准确性的重要保证,对准确获得兼具代表性和典型性的土壤样品起到决定性的作用。结合工作经验,对甘肃省基层生态环境监测工作的两种情形,即土壤生态环境监视性监测和突发环境污染事故土壤生态环境监测的土壤样品采集技术做简要分析,对基层生态环境监测部门委托第三方检测机构采集样品应当注意的要点进行探讨,并就当前生态环境监测工作与生态环境执法部门有效衔接提出建议。     

重金属在土壤-作物中分布规律研究

本文研究铜冶炼厂废气排出的Cu、Pb、Cd和As污染物在周围地区土壤-粮食-人体系统中的迁移和分布规律,研究表明金属污染物主要累积在土壤耕作层,而且其可给态含量较高,分别占全量的60.1％、30％,38％和2.2％。本地区稻米和小麦中金属含量与土壤中含量间具有明显的相关性(r=0.6500—0.8485);在粮食中的平均累积率分别达到17.1—24.2％,2.1％,37.1—40.4％和1.8—2.9％,研究还表明当地居民的健康已受到重金属不同程度的影响,个体介质中四元素含量与粮食含量的相关系数达到0.8809—0.9808,分别是对照区人体介质金属负荷的1.18—6.43倍,尤以镉的影响最大。     

一株不动杆菌JBX-006对聚丙烯酰胺的降解特性研究

聚丙烯酰胺结构复杂、难降解,进入环境会造成污染。从大庆油田周边土壤中富集、驯化和分离获得1株聚丙烯酰胺降解率较高的菌株JBX-006,经形态学、生理生化和分子生物学鉴定为琼氏不动杆菌(Acinetobacter junii)。对JBX-006降解聚丙烯酰胺的影响因素开展研究,分析了不同外碳源、外氮源和金属离子对其降解聚丙烯酰胺的影响,结果表明,JBX-006在5 g/L蔗糖、10.0 g/L硝酸钾、30 mg/L Fe²⁺的基础培养液中,30℃培养5 d对300 mg/L的聚丙烯酰胺降解率达到81.65%,明显高于优化前。研究获得的高效降解聚丙烯酰胺菌株JBX-006为修复聚丙烯酰胺污染土壤提供了技术支持。     

土壤环境质量标准在工程应用中的局限性分析

为贯彻落实《中华人民共和国环境保护法》,加强建设用地土壤环境监管,管控污染地块对人体健康的风险,保障人居环境安全,生态环保部组织相关部门编制了土壤环境质量标准,并于2018年8月1日起开始实施。在标准实施的过程和应用过程中发现新发布的标准存在一些局限性。本文以土壤污染机理为基础,结合现行的治理技术,论述土壤质量标准在时间、空间及应用中的局限性。     

浅析集约化畜禽养殖废水处理模式

针对集约化畜禽养殖废水的水质特点,阐述了三种主要废水处理模式及适用范围,分析了它们在实际应用中存在的问题并提出了建议。     

儿童血铅(BL)与土壤含铅量(SL)关系的研究

本文比较了美国和中国的一些地区儿童血铅调查和研究成果,证明儿童血铅(BL)与土壤含铅量(SL)直接相关,土壤铅已经成为儿童铅暴露的主要来源。当土壤含铅量超过500–600 mg/kg时,长期暴露在这种土壤环境下的儿童血铅浓度超过10μg/dL是可以预期的。中美儿童血铅模型(IEUBK模型)的实际计算结果也表明,当表层土壤含铅量超过600 mg/kg时,其土地利用不适合任何儿童活动。为了更好地预防儿童高血铅,我国土壤修复的标准可定为居住用地Pb≤250 mg/kg,非居住用地Pb≤600 mg/kg。