共查询到18条相似文献,搜索用时 109 毫秒
1.
疏水性有机污染物进入环境水体后易于与沉积物结合,对沉积物中的底栖动物造成危害。底栖动物引起的生物扰动作用可以通过改变沉积物的地球化学性质,对其中污染物的赋存形态、迁移转化和生物可利用性产生重要影响。在综述了国内外生物扰动影响沉积物中污染物环境行为和生物可利用性的最新研究进展基础上,重点讨论了沉积物颗粒交换、水体环境条件改变、疏水有机污染物解吸释放过程以及对生物扰动影响的定量化表征。最后对该研究方向进行了展望,指出应重点研究多种污染物及不同生物共存条件下的生态效应,以及造成沉积物扰动的影响因素的定量化表征等。 相似文献
2.
药物和个人护理品简称(PPCPs)是一类具有潜在累积效果的环境污染物,其广泛分布于水体与土壤环境中.在土壤/沉积物中,PPCPs将发生一系列的物理、化学和生物作用,其中吸附是PPCPs在土壤/沉积物中极为关键的环境行为,将影响PPCPs在环境中的迁移转化及其对生物体的危害程度.重金属作为一类常见的无机污染物,它们的存在会影响PPCPs在土壤/沉积物表面的吸附行为,对土壤/沉积物吸附PPCPs的吸附效果造成不同影响.本文归纳总结了重金属存在时,PPCPs在土壤/沉积物中的吸附机理,综合探讨了PPCPs官能团组成、重金属离子类型、pH、离子强度和有机质等因素对PPCPs吸附的影响,并针对以往研究存在的问题进行了展望. 相似文献
3.
沉积物再悬浮-重金属释放机制研究进展 总被引:16,自引:0,他引:16
水-沉积物界面重金属迁移和转化行为已成为水环境质量研究的热点。因自然、生物、人为活动等驱动的沉积物再悬浮使得沉积物颗粒吸附和结合的重金属可能通过吸附-解吸平衡和氧化还原反应而释放进入上覆水体。随着外在污染源输入逐步得到控制,沉积物再悬浮释放重金属将成为水体重要的内在污染源而对水环境质量和水生生物产生影响。本文综述了最近几年的相关研究文献,对沉积物再悬浮的动力来源及发生机制、再悬浮-重金属释放机制及主要影响因素进行了阐述,探讨了该领域未来可能的研究方向。相关研究发现,当干扰切应力大于沉积物的临界切应力值时,沉积物再悬浮发生,且再悬浮颗粒量随干扰切应力的增强而增大;再悬浮使还原态沉积物暴露于有氧环境,有机质和硫化物的氧化是沉积物结合态重金属释放的主要机理,而沉积物颗粒电性吸附的重金属则通过解吸进入水体;切应力大小、再悬浮水体理化性质、沉积物理化性质以及微生物活性等因素调控着沉积物吸附态或结合态重金属的释放。本文指出再悬浮沉积物释放重金属的去向(再分配机理)以及再悬浮-重金属释放的动力学过程、沉积物悬浮-重金属释放复合预测模型的建立、沉积物悬浮-释放重金属的生物可利用性及生物毒害评价将是本领域需要进一步研究的重点。 相似文献
4.
重金属污染已经成为水环境污染防治的重要内容.研究表明,进入水体中的重金属大部分与悬浮物结合,在水流缓慢时,悬浮物逐渐沉积下来,大大降低了水中重金属元素的浓度.在特定的环境地球化学条件下,水库沉积物中重金属可通过一系列物理、化学和生物过程而释放出来,导致水环境"二次污染",严重威胁水库生态环境安全.因此,研究沉积物中重金属的含量变化规律,评价重金属污染的潜在生态风险,探讨其在水体中的迁移转化过程,对于保护区域水环境质量和防治重金属污染具有重要意义.本实验通过采集小浪底水库表层沉积物样品,对水库沉积物中重金属的含量与分布进行研究,并对其潜在的生态 相似文献
5.
6.
影响沉积物-水界面持久性有机污染物迁移行为的因素研究 总被引:4,自引:0,他引:4
沉积物-水界面是自然水体在物理、化学和生物特征等方面差异性最显著的环境边界,界面及附近发生的物理和化学反应,如吸附和解吸、迁移和转化、扩散和掩埋以及生物扰动等作用是控制和调节水体和沉积物之间物质输送和交换的重要途径.持久性有机污染物由于其具有致癌、致畸、致突变及内分泌干扰作用而受到人们的广泛关注,它们在沉积物-水界面的... 相似文献
7.
8.
9.
10.
多溴联苯醚在环境中迁移转化的研究进展 总被引:10,自引:1,他引:9
多溴联苯醚(Polybrominated Diphenyl Ethers,PBDEs)是全球广泛使用的一种添加型溴代阻燃剂,具有高亲脂性、难降解性、生物累积性和高毒性.全面了解PBDEs在环境的迁移转化规律是对其进行科学的风险评价的基础.归纳和分析了近几年国内外学者有关PBDEs在不同环境介质中的分布情况及其迁移转化的研究动态,并重点讨论了光解和生物降解的机理、产物和影响因素.结果表明,大气中以气态的低溴代联苯醚为主,具有较强的长距离迁移能力,而BDE-209等高溴代联苯醚则主要吸附在气溶胶颗粒物上,迁移能力有限;PBDEs在水中的浓度较低,主要在沉积物和生物体的脂肪中累积,并通过食物链的放大作用使处于食物链顶端的生物受到毒害.光解和生物降解是PBDEs在环境中转化的主要途径,在空气中和浅层水中以光解为主,而在深层水和沉积物中生物降解占主导.文章最后指出了今后的主要研究方向. 相似文献
11.
沉积物中酸挥发硫对上覆水中重金属含量的影响 总被引:15,自引:0,他引:15
在实验室条件下,利用装有新鲜河流沉积物和上覆水且可控制环境参数的模拟体系及参比体系,通过定时定量投放重金属溶液,研究了富含酸挥发硫的河流沉积物对上覆水中重金属(铜,镉,铅,锌)含量的影响,并观察了模拟体系更换为清洁上覆水后沉积物中重金属的静态释放;随后考察了同一沉积物样品经酸化后对上覆水重金属含量的影响能力的变化及在更换为清洁上覆水后沉积物的静态释放。研究结果表明:水相金属迅速转移到沉积物中,被其 相似文献
12.
沉积物充气过程对锌的影响 总被引:5,自引:0,他引:5
在缺氧沉积物中,酸可挥发硫(AVS)是总硫含量中的一个活性最大的部分。它控制着还原状态沉积物内孔隙水的重金属浓度又通过与重金属形成硫化物,影响着沉积物中重金属的形态。现已证明,AVS与重金属反应是重要方面。AVS的变化来自人类活动和自然现象。本项研究通过对香港河流和海湾沉积物32d的连续充气实验,探索硫含量变化对Zn对影响。 相似文献
13.
David T. Welsh 《Chemistry and Ecology》2013,29(5):321-342
Benthic macrofaunal populations through their feeding, bioturbation, burrow construction and sediment irrigation activities have profound influences on organic matter inputs to marine sediments (biodeposition) and on the vertical distribution of deposited organic matter within the sediment. These effects in turn influence the rates and pathways of organic matter mineralisation, and element cycles. Similarly, bioturbation, burrow construction and burrow irrigation are major determinants of sediment-water column fluxes of oxygen and nutrients. In this review, I discuss the influences of the different benthic macrofaunal feeding (functional) groups on mineralisation processes and sediment-water column fluxes of particulate and dissolved nutrients. How these effects influence diagenic processes, the balance between aerobic and anaerobic processes, and the redox status of the surficial sediments. Finally, I discuss some of the limitations of the predominantly laboratory techniques which have been used to study “macrofaunal effects” and how this hinders the inclusion of the effects in quantitative sediment biogeochemical models. 相似文献
14.
David T. Welsh 《Chemistry and Ecology》2003,19(5):321-342
Benthic macrofaunal populations through their feeding, bioturbation, burrow construction and sediment irrigation activities have profound influences on organic matter inputs to marine sediments (biodeposition) and on the vertical distribution of deposited organic matter within the sediment. These effects in turn influence the rates and pathways of organic matter mineralisation, and element cycles. Similarly, bioturbation, burrow construction and burrow irrigation are major determinants of sediment-water column fluxes of oxygen and nutrients.
In this review, I discuss the influences of the different benthic macrofaunal feeding (functional) groups on mineralisation processes and sediment-water column fluxes of particulate and dissolved nutrients. How these effects influence diagenic processes, the balance between aerobic and anaerobic processes, and the redox status of the surficial sediments. Finally, I discuss some of the limitations of the predominantly laboratory techniques which have been used to study “macrofaunal effects” and how this hinders the inclusion of the effects in quantitative sediment biogeochemical models. 相似文献
In this review, I discuss the influences of the different benthic macrofaunal feeding (functional) groups on mineralisation processes and sediment-water column fluxes of particulate and dissolved nutrients. How these effects influence diagenic processes, the balance between aerobic and anaerobic processes, and the redox status of the surficial sediments. Finally, I discuss some of the limitations of the predominantly laboratory techniques which have been used to study “macrofaunal effects” and how this hinders the inclusion of the effects in quantitative sediment biogeochemical models. 相似文献
15.
Wenzhong Tang Liu Sun Limin Shu Chuang Wang 《Frontiers of Environmental Science & Engineering》2020,14(6):104
16.
17.
The ecological effects of heavy metals in contaminated sediments are more determined by the chemical form and reactivity than by the level of accumulation. Dredging of anoxic sediments and disposal on land is attended by changes of redox conditions. Under oxidizing conditions some controlling solid compounds may change gradually thus changing the solubility of certain metals. Chemical extraction experiments for estimating characteristic association forms of heavy metals in anoxic sediments were carried out, both under presence and absence of air during the analytical procedure. Drying of the sediment decreases the proportion of the sulfidic metal fractions to a stronger degree, and oxidized Cd and Zn are found in the most available, exchangeable fraction. With respect to long‐term effects acidification of poorly buffered sludges after disposal on land is probably the most important factor affecting metal associations and mobility. For many metal examples a linear relationship has been found between decreasing pH values and increasing dissolved metal concentrations. To quantify these relationships and for better comparison of samples a simple test procedure is proposed which is based on pH differences before and after addition of acid. 相似文献
18.
Abstract Sediment samples were collected from the Adriatic Sea in areas near large coastal towns along the eastern Adriatic coast (Zadar, [Ncirc]ibenik, Split, Plo?e and Dubrovnik). Considerable quantities of untreated effluents are discharged via freshwater runoff and a variety of industrial waste waters, significantly affecting the quality of marine sediments. Distribution of some trace metals (Pb, Cu, Ni, Cr, Zn, Mn, Cd, and Al) involved in problems related to metal pollution in Adriatic sediment were examined. Values are expressed as a total concentration of heavy metals of sediment dry weight. Spatial distribution of some trace metal values in sediments and correlation of results for grain size effect were examined. the trace elements in marine sediments generally remain in the fine grained fraction, often in the silt-clay fraction. Higher values of heavy metals in some areas (Split, Sibenik) could be attributed to anthropogenic effects, i.e. to land-based activities. the main cause of higher values of some metals at open sea sites and in some coastal areas are probably caused naturally by sedimentation processes in those areas. Our results show that the sediments undoubtedly play a key role in determining the transport and ultimate fate of contaminants. 相似文献