黄文,张玉龙,李海燕,冉勇.东江流域水环境中颗粒态和胶体态金属元素的分布和来源[J].环境科学学报,2015,35(1):101-107
东江流域水环境中颗粒态和胶体态金属元素的分布和来源
- Distribution and sources of heavy metals in colloidal and particulate matter in Dongjiang River basin
- 基金项目：国家自然科学基金-广东省联合基金(No.U1201235)
- 黄文
- 1. 中国科学院广州地球化学研究所 有机地球化学国家重点实验室, 广州 510640;2. 中国科学院大学, 北京 100049
- 张玉龙
- 中国科学院广州地球化学研究所 有机地球化学国家重点实验室, 广州 510640
- 李海燕
- 1. 中国科学院广州地球化学研究所 有机地球化学国家重点实验室, 广州 510640;2. 中国科学院大学, 北京 100049
- 冉勇
- 中国科学院广州地球化学研究所 有机地球化学国家重点实验室, 广州 510640
- 摘要：运用连续流离心机和切面流超滤分离技术,从东江流域的水库、河流、河口3种水体中分离了大量的悬浮颗粒物(>0.45 μm)和胶体(1 nm~0.45 μm),并用元素分析仪和电感耦合等离子体/质谱(ICP-MS)对有机碳和金属进行了表征.通过对比3种水体中颗粒态金属的含量(μg·g-1)和浓度(ng·L-1)发现,水库颗粒物有更高的重金属含量,与其在有机碳上的富集有关;河流颗粒物有更高的金属浓度,与地表径流和人为排放有关.另外,随着有机质含量的增加,湖泊水体中多种重金属的含量呈现先增加后降低的关系,显示了生物富集和生物稀释的双重作用.从东江中游到河口样品,Mg、Ti、Co、Ni等元素在颗粒物中的含量依次升高,Cu、As、Cd、Sn、Sb等元素则依次降低,这与海水的稀释作用以及与盐度变化引起的絮凝沉降有关.河流中胶体态金属的含量与浓度均大于水库,显示了河流受到更多的人类活动影响.虽然重金属主要分布在颗粒物中,但对比各种重金属的含量在颗粒态和胶体态中的顺序变化,发现地表径流带来的地壳元素倾向于分布在颗粒态中,而人为排放来源的金属倾向于分布在胶体态中.
- Abstract：Continuous flow centrifugation and tangential flow ultrafiltration were used to isolate a large amount of suspended particulate matter (> 0.45 μm, SPM) and colloidal matter (1 nm~0.45 μm, COM) in the Dongjiang River Basin. Contents of organic carbon and heavy metals were determined by elemental analyzer and inductively coupled plasma/mass spectrometry (ICP-MS), respectively. It was found that the concentrations of heavy metals in the lake were higher than river and estuary, which was related to the enrichment of metals by organic matter. The concentrations of metals in the river SPM were the highest, which was associated with surface runoff and anthropogenic sources. With the increase of organic matter, the concentrations of some metals in the lake firstly increased and then decreased, indicating the combined effect of bioaccumulation and biological growth dilution. The concentrations of metals (such as Mg, Ti, Co, Ni) in the SPM increased from the middle reaches of the Dongjiang River to the estuary, while the concentrations of other metals (Cu, As, Cd, Sn, Sb) decreased, which was due to the dilution effects of seawater and flocculation sedimentation caused by the change of salinity. The concentrations of metals in the river COM were higher than in the lake COM, suggesting higher anthropogenic sources in the river COM. Although heavy metals were mainly presented in the SPM, changes in the order of metal concentrations in the COM and SPM suggested the crustal metal elements derived from surface runoff tended to be present in SPM, but the metal elements derived from anthropogenic source tended to be present in COM.
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