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1.
城市道路沉积物重金属风险评价是表征城市环境质量的有效途径。采用重金属化学形态和生物可利用性来评估其生态风险更合理,越来越受到人们的关注。本文采集山东省青岛市崂山区10条次干道沉积物样品,分析不同粒径沉积物中Zn、Cd、Cu、Pb的含量、化学形态和生物可利用性,采用地累积指数(Igeo)和改进的生态风险指数(RIm)评价细粒径(小于75μm)沉积物中重金属污染水平和生态风险。结果表明:(1)沉积物粒径越小,重金属含量则越多。当粒径小于75μm时,Zn、Cd、Cu和Pb平均含量分别为山东省土壤元素背景值的10.63、6.07、3.39、2.70倍。(2)随粒径的减小,生物可利用性增大。小于75μm粒径的Zn、Cd、Cu和Pb的生物可利用态百分比为74%、78%、66%和55%。(3)评价结果显示,Zn、Cd、Cu和Pb的值分别为2.83、2.01、2.22和2.05,结果均为偏重度污染。(4)评价结果为较高生态风险,其中Cd属于极高风险,Cu和Pb属于中等风险,Zn属于低风险,Cd对的贡献高达75%。以重金属污染水平、迁移率、生物可利用性和生态风险为评价依据,认为Zn、Cd、Cu、Pb的风险均较大。该研究可为青岛市道路重金属污染防控提供指导。 相似文献
2.
南日岛海域溶解态Cu、Pb、Cd含量及其与营养盐的关系 总被引：3，自引：0，他引：3
本文首次报道了福建南日岛海域溶解态Cu、PB、Cd的含量，探讨了它们与营养盐的关系。1990年5月溶解态Cu、Pb、Cd的平均含量分别为0．84、0．230、0．023μg／dm3；1990年10月分别为0. 78、0．290、0. 033μg／dm3。其5月溶解态Cu与无机氮N（NO3-＋NO2-＋NH4 ）线性回归的相关式为Cu（μg／dm3）＝-0. 789＋0．328N（μmol／dm3），相关系数r＝0．853，原子比△Cu：△N＝5．17×10－3：1。 相似文献
3.
海水养殖池沉积物中重金属形态和生物酶活性的关系研究 总被引：1，自引：0，他引：1
以连云港市对虾养殖池表层沉积物为研究对象,采用Tessier连续萃取法,研究了表层沉积物中重金属(Cu、Zn、Pb、Cd、Cr、As、Mn)的赋存形态和酶(脲酶、碱性磷酸酶、过氧化氢酶、转化酶)活性的相关性。结果表明,重金属Cu和Zn以有机-硫化物结合态为主要的赋存形态,Pb以铁锰氧化物态为主要的赋存形态,Cd以可交换态(平均33.47%)和碳酸盐结合态(平均31.16%)为主要存在形态,Cr和As主要以残渣态存在,Mn的铁锰氧化物态比例最高。脲酶的活性范围为0.45—8.96mg/(g·24h),碱性磷酸酶活性范围为2.45—6.69mg/(g·24h),过氧化氢酶活性范围为0.14—2.36m L/(g·min),转化酶活性范围为0.45—10.45mg/(g·24h)。脲酶活性与Cd、As的可交换态、Cd的碳酸盐结合态、Cu、As的铁锰氧化物态、Zn、Pb、Cd、Mn的有机硫化物态之间显著相关;碱性磷酸酶活性与Zn、Cd的铁锰氧化物态显著相关;过氧化氢酶活性与Cd的可交换态、碳酸盐结合态及残渣态、Cu、Cd、As的铁锰氧化物态、Zn、Pb、Cd、Mn的有机硫结合态之间显著相关;转化酶活性与Cu、Cd、As的可交换态、Cd的碳酸盐结合态、Cu、Cd、As的铁锰氧化物态、Zn、Pb、Cd、Mn的有机硫化物态、Cd、As的残渣态之间显著相关。酶活性可以用来指示海水养殖池沉积物中重金属的形态转化过程。 相似文献
4.
原子吸收光谱法和等离子光谱法分别研究了潮滩盐沼植物翅碱蓬(Suaedaheterop-tera)根际与非根际(根上部和根下部)沉积物中Cu、Zn、Pb和Cd的总量和化学形态。结果表明,从总量来看,不同潮滩沉积物中4种重金属次序均为Zn>Pb>Cu>Cd,但同一元素随潮滩位置变化明显,尤以中潮滩差异最显著,重金属总量明显大于其他两个潮滩(低潮滩和高潮滩),特别是根际沉积物中的重金属总量远高于非根际沉积物总量,其比值分别为Cu3·4—4·2倍,Zn2·2—2·7倍,Pb3·2—3·3倍。同一潮滩均表现为根际沉积物>根上部>根下部。Cd含量相对较低,其变化不明显。从化学形态看,沉积物重金属表现为环境直接影响态(交换态和有机结合态)、环境间接影响态(碳酸盐态和铁锰氧化物态)和稳定态(残渣态)。与非根际沉积物相比,根际沉积物中重金属的化学形态发生了显著的变化,Cu和Pb以稳定态为主,其次为环境间接影响态,环境直接影响态最低;Zn与上述2种金属不同,以环境直接影响态含量最高(可交换态是有机结合态的7倍),其次分别为环境间接影响态(主要是碳酸盐结合态)和稳定态。实验结果表明,由于特异根圈效应,一方面该植物使可迁移形态的Cu和Pb在根际逐步得到矿化,使其生物可利用性降低;另一方面使Zn的生物可利用性提高,促进了植物对Zn的吸收利用。 相似文献
5.
本文研究了生物样的较佳消化方法、测定方法和影响条件。采用差示脉冲阳极溶出伏安法测定生物体中Cd、Pb 和Cu。结果表明,所采用的HNO_3-HClO_4常压湿法消化法简便、可靠且重现性好。方法的精密度(以相对标准偏差表示,Cd 为8.6%,Pb为5.8%,Cu 为6.4%)和准确度(以回收率表示,Cd 为89.7%,Pb 为97.5%,Cu 为102.3%)显示出对生物体中Cd、Pb、Cu 连续测定的可靠性。 相似文献
6.
在实验室中控制吸附反应体系的pH，研究了长江河口现场悬浮颗粒物质对添加金属Cu、Pb、Zn和Cd吸附作用。结果表明，反应体系pH值的增大使得金属在悬浮颗粒物质上的吸附百分率增大。在长江河口水体pH变化范围内，pH的变化对Cu和Pb在悬浮颗粒物上的吸附作用影响较小，而对Zn和Cd的影响则非常显著。根据固—液界面吸附模型，长江河口悬浮物质对Cu、Pb、Zn和Cd的吸附平衡常数(IgK)分别为—8．87、—6．51、—13．68和—13．65。长江河口特定的水化学环境和水、沙特征决定了金属Zn和Cd的环境行为显著受到pH变化的控制，而pH对Cu和Pb的影响可能较小。 相似文献
7.
2006年夏冬季长江口、杭州湾及邻近海域表层海水溶解态重金属的平面分布特征 总被引：3，自引：0，他引：3
利用2006年夏、冬季两个航次采集的长江口、杭州湾及邻近海域表层海水水样,分别采用石墨炉无火焰原子吸收分光光度法和火焰原子吸收分光光度法,测定了海水中溶解态Cu、Pb、Cd、总Cr的含量以及溶解态Zn的含量,研究了该海域表层海水中溶解态Cu、Pb、Zn、Cd和总Cr的平面分布状况,结果表明:(1)夏季表层海水中溶解态Cu、Pb、Zn、Cd和总Cr的平均质量浓度分别为0.90、0.54、5.80、0.080和0.46 μg/dm3;冬季则分别为1.01、0.81、9.32、0.070和0.31 μg/dm3,上述重金属元素含量基本达到国家一类海水水质标准,仅夏、冬季Pb的部分站位以及冬季Zn的部分站位达到国家二类海水水质标准.(2)表层海水溶解态Cu、Pb、Zn的质量浓度总体平面分布规律为:冬季高于夏季;Cd和总Cr的质量浓度总体平面分布规律为:夏季高于冬季.(3)影响近岸海域表层海水溶解态重金属分布的因素比较复杂,入海径流和排污口等输入海域的重金属对海水表层的重金属分布具有决定性的作用,同时,盐度、pH值、悬浮颗粒物质、营养盐等也是重要的影响因子. 相似文献
8.
本文介绍了以海水为基体的痕量金属(Cu、Pb、Cd、Cr、Zn)标准物质的制备、均匀性和稳定性,经试验,在一年零三个月时间内各元素的浓度值为Cu5.0±0.4、Pb10.0±0.6、Cd1.00±0.06、Cr5.0±0.4、Zn70±3μg/kg。 相似文献
9.
以酶学分析的方法研究4种金属离子(Cd2 、Cu2 、Pb2 、Zn2 )对可口革囊星虫纤维素酶、淀粉酶和脂肪酶活力的影响.4种重金属离子分别按《国家渔业水质标准》(GB11607-89)(Cd2 ≤0.005mg/dm3、Cu2 ≤0.01mg/dm3、Pb2 ≤0.05mg/dm3、Zn2 ≤0.10mg/dm3)的0、10、20、50和100倍设置实验梯度.实验表明,可口革囊星虫3种消化酶活力大小为纤维素酶＞淀粉酶＞脂肪酶;在实验设置的浓度范围内,Cd2 、Cu2 、Pb2 和Zn2 4种金属离子对可口革囊星虫的纤维素酶、淀粉酶和脂肪酶活力均产生显著影响.除脂肪酶外的其余2种酶各处理组的比活力均显著(P＜0.05)低于对照组.不同浓度金属离子对可口革囊星虫脂肪酶、淀粉酶和纤维素酶活力的影响表现出不同的变化趋势. 相似文献
10.
台湾海峡西部海域大气中金属的特征Ⅰ.金属的浓度和粒度分布 总被引：2，自引：0，他引：2
1991～1993年,收集了台湾海峡西部海域上空大气中的181个颗粒样品和2个颗粒分级样品．采用原子分光光度法分析了其中的颗粒金属Al、Fe、Cu、Pb、Cd和Na．台湾海峡西部海域大气中颗粒金属Fe、Cu、Pb、Cd的含量明显低于大陆城市大气中的含量．大气颗粒物中Al、Cu和Pb显示了明显的年变化．Al、Fe、Cu、Pb和Cd表现出明显的季节变化,于季大于湿季,影响大气颗粒金属元素浓度季节变化的主要因素是雨水的冲刷作用和季风．大气中颗粒Fe的粒径分布呈现双峰,Al主要分布在小于2．1μm粒径上,Na主要分布在小于等于3．6μm粒径上,而Cu、Pb和Cd则主要分布在小于等于0．52μm的小颗粒上． 相似文献
11.
为了探讨长江口水体胶体有机碳含量的季节变化, 按季度采集长江口南支表层水样, 利用切向流超滤技术(TFF)分离水样中小胶体物质(1—5kD)、中胶体物质(5—500kD)和大胶体物质(500kD— 0.45μm), 测试分离后样品的有机碳浓度。结果表明: 长江口水体中总胶体有机碳浓度有明显的季节变化, 表现为冬季>夏季>秋季>春季, 其原因可能是冬季长江流域陆源输入增加, 水生生物生物量和生物活性减弱双方面的共同作用使得含量最高, 而春季流域陆源有机碳含量输入较少, 且流域内春汛雨量多水量大对水体中有机碳浓度具有稀释作用, 从而导致该季节胶体有机碳含量较少。总胶体有机碳在不同分子量的分配上季节差异不大, 中胶体有机碳浓度及其在总胶体有机碳中所占的比例均高于小胶体有机碳和大胶体有机碳。由于长江口胶体有机碳的含量较高, 并有明显的季节变化, 对有机碳的入海通量和生物地球化学循环发挥重要的作用。 相似文献
12.
Size distribution of colloidal trace metals and organic carbon during a coastal bloom in the Baltic Sea 总被引：1，自引：0，他引：1
Johan Ingri Susanna Nordling Jenny Larsson Jenny Rnnegrd Nina Nilsson Ilia Rodushkin Ralf Dahlqvist Per Andersson
rjan Gustafsson 《Marine Chemistry》2004,91(1-4):117-130
The physico-chemical speciation of organic carbon and selected metals was measured during a coastal bloom in Ekhagen Bay, Baltic Sea, using ultrafiltration.One important objective with the study was to see if any depletion of trace metals could be measured in the directly bioavailable fraction (<1000 Da, the soluble low molecular weight fraction, LMW) during a plankton bloom. Filters with five different cut-offs were used (1 kD (1000 Da), 5 kD, 10 kD, 100 kD and 0.22 μm) in order to delineate the size distribution of colloidal organic carbon (COC) and trace metals.During the bloom in May, LMW Al, Co, Cu, Mn and Ni concentrations decreased although the colloidal and particulate concentrations were relatively high. Data show that desorption of colloidal and particulate bound trace metals to the LMW fraction was slower than the process depleting the LMW fraction.Estimates of the maximum active uptake of Cu, Ni and Mn by the phytoplankton, and the loss of non-bioactive Al from the LMW fraction, indicate that processes other than active uptake by phytoplankton must contribute to the observed depletion of trace metals in the LMW fraction. Hence, in order to estimate the bioavailable pool of trace metals for plankton during bloom conditions, these other processes must be understood and quantified.Transparent Exopolymeric Particles (TEP, reflecting sugar-rich phytoplankton exudates) increased around eight times during the plankton bloom. We hypothesize that the formation of TEP is a process that might be important for the transfer of trace metals from the LMW to the particulate fraction during the phytoplankton bloom, but the significance of TEP for this depletion in Baltic Sea surface water remains to be shown. 相似文献
13.
Marine colloidal material (1 kDa–0.2 μm) was isolated by cross-flow ultrafiltration followed by diafiltration and freeze-drying from surface waters of the Gulf of Mexico and the Middle Atlantic Bight (MAB), as well as from estuarine waters of Galveston Bay. Elemental characterization of isolated colloidal material included organic carbon (OC) and selected trace metal (Cu, Pb, Zn, Cd, Co, Ni, Cr, Be, Fe, Al, Mn, V, Ba, and Ti) determinations. It was found that levels of these metals in marine colloids ranged from <0.1 to 50 μg/g colloidal matter, except for Fe which generally had a concentration >120 μg/g. Most metals (Cu, Pb, Zn, Ni, Al, Mn, V, and Ti) had an average concentration >1 μg/g while concentrations of Cd, Co and Be were usually <1 μg/g. Metal concentrations (μg/g) in isolated colloids were, in general, higher in Galveston Bay than in the Gulf of Mexico, suggesting either high abundance of trace metals in estuarine waters or differences in organic matter composition. Higher colloidal metal concentrations in the MAB than in the Gulf of Mexico might be due to higher terrestrial inputs in the MAB. Colloidal metal concentrations (μg/g) were generally lower than those in average soils, continental crust and suspended particles. However, metal/aluminum ratios (Me/Al) in isolated marine colloids were significantly higher than those for average soils and continental crust. Most importantly, colloids had a metal composition and metal/OC ratio (Me/C) similar to humic substances and marine plankton, suggesting that marine colloids largely originate from planktonic sources and are composed of predominately organic components. The Me/C ratios of Galveston Bay colloids followed the sequence of Cu>Ni, Cr, Zn>Mn>Co>Pb, Cd, which is similar to the Irving–Williams order except for Mn, suggesting that the interaction of metals with marine colloids is determined by the affinity of metals for specific organic ligands. 相似文献
14.
Distributions of carbohydrates, including uronic acids, in estuarine waters of Galveston Bay 总被引：2，自引：0，他引：2
The concentrations of carbohydrates, including uronic acids, in dissolved (≤0.45μm) and colloidal (1 kDa—0.45 μm) phases were measured in estuarine waters of Galveston Bay, TX, in order to study their role in heavy metal detoxification. The concentrations of dissolved monosaccharides (MCHO) in Galveston Bay ranged from 13 to 62 μM-C, and those of dissolved polysaccharides (PCHO) ranged from 10 to 42 μM-C. On average, MCHO and PCHO contributed about 11% and 7% to dissolved organic carbon (DOC), respectively. The colloidal carbohydrates (CCHO) in Galveston Bay varied from 7 to 54 μM-C, and accounted for 9% to 24% of the colloidal organic carbon (COC), with an average value of 17%, suggesting that CCHO is abundant in the high molecular weight (HMW) fraction of DOC. The concentration of CCHO is generally significantly higher than that of PCHO. This result is attributed to entrainment of low molecular weight (LMW) carbohydrates into the retentate fraction during ultrafiltration. The concentration of total dissolved uronic acids (DUA) in the same samples varied from 1.0 to 8.3 μM-C, with an average value of 6.1 μM-C, while the colloidal uronic acids (CUA) ranged from 0.8 to 6.4 μM-C, with an average value of 4.8 μM-C. The concentrations of DUA are higher than the previously reported values in coastal waters. Furthermore, CUA represent a dominant component of DUA in Galveston Bay waters. More importantly, significant correlations of PCHO and DUA to dissolved Cu concentrations (≤0.45 μm) were found, suggesting that acid polysaccharides were produced in response to trace metal stressors. 相似文献
15.
16.
地质样品中硫化物形式铁的分离和测定 总被引：1，自引：0，他引：1
提出一个利用次氯酸钠氧化铁硫化物碱性磺基水杨酸提取并直接测定碳酸盐相中铁硫化物的方法。结果表明,30%的NaClO溶液浸泡样品40h以上,可以完全释放铁硫化物并形成氢氧化铁胶体。0.1g/mL的碱性磺基水杨酸溶液则较容易地溶解新生成的氢氧化铁胶体,形成黄色的铁-磺基水杨酸络合物,可被分光光度法定量测定。该方法集选择性分离、富集和测定于一体,分析流程简单,结果可靠,适合地质样品中硫化物形式铁的测定。 相似文献
17.
Natural colloids are abundant in seawater and are an intermediary in the fate, transport and bioavailability of many trace elements. Knowledge of the pathways and mechanisms of the biological uptake of colloidal Fe and other Fe species is of paramount importance in understanding Fe limitation on marine phytoplankton and thus carbon sequestration in the ocean. Whether the natural colloids serve as a source for the biological Fe requirements of marine phytoplankton, or just as a sink for particle-reactive metals in the oceans remains largely unknown. This study examined the bioavailability of Fe bound with colloids from different regions to a coastal diatom (Thalassiosira pseudonana). Natural colloids were isolated by cross-flow ultrafiltration and radiolabeled with 59Fe before being exposed to phytoplankton. Control experiments were conducted to ensure that 59Fe radiolabeled onto the colloids remained mostly in the colloidal phase. Both the natural oceanic and coastal colloidal organic matter complexed Fe (1 nm–0.2 μm) can be biologically available to the marine diatom even though its uptake was lower than the low molecular weight counterparts. By comparing the measured Fe internalization fluxes and the calculated maximum diffusive uptake fluxes, it is evident that ligand exchange kinetics on the cell surface may control the internalization of macromolecular Fe. The calculated concentration factors under dark and light conditions were generally comparable. Colloidal Fe, as an important intermediary phase, can be actively involved in the planktonic food web transfer through biological uptake and regeneration processes. The bioavailable fraction of Fe may be substantially underestimated by only considering the truly dissolved Fe or overestimated when using the external fluxes, such as aerosol Fe, as the bioavailable fraction. 相似文献
18.
使用切向流超滤系统得到粒度较均匀的Fe(OH)3胶体,进而对Fe(OH)3胶体粒子与Cu2 的作用进行了研究,并将实验结果与南沙群岛海区表层水中铜与胶体物质结合状况的调查数据进行了比较分析,得到如下结果:(1)在海水介质中,铜在Fe(OH)3胶体上结合的百分率(pH>5)随pH的升高而下降,随着Fe(OH)3胶体浓度的减小而下降?(2)在天然海水介质中,使铜在Fe(OH)3胶体上结合的百分率在50%-70%的有机物浓度为1.0mg·L-1,有机物浓度的增大使铜与无机胶体结合的百分率有下降的趋势? 相似文献
19.
Abstract. A number of coastal organisms ( e.g ., bivalves) are known as important consumers of particulate organic carbon (POC) in the sea. In this paper we present new evidence that they are also important consumers of dissolved organic carbon (DOC) in the colloidal size range down to about 0.2 μm in diameter. Those colloids play an important role in the global flux of carbon in the seas.
We compare the uptake of colloidal DOC by marine bivalves of the North Sea and of the western Indian ocean.
To measure this uptake we made use of colloidal melanin as an alternative way to measure the uptake of colloidal DOC. 相似文献
We compare the uptake of colloidal DOC by marine bivalves of the North Sea and of the western Indian ocean.
To measure this uptake we made use of colloidal melanin as an alternative way to measure the uptake of colloidal DOC. 相似文献
20.
Thermodynamic characterization of the partitioning of iron between soluble and colloidal species in the Atlantic Ocean 总被引：2，自引：1，他引：2
Recent electrochemical measurements have shown that iron (Fe) speciation in seawater is dominated by complexation with strong organic ligands throughout the water column and have provided important thermodynamic information about these compounds. Independent work has shown that iron exists in both soluble and colloidal fractions in the Atlantic Ocean. Here we have combined these approaches in samples collected from a variety of regimes within the Atlantic Ocean. We measured the partitioning of Fe between soluble (< 0.02 μm) and colloidal (0.02 to 0.4 μm) size classes and characterized the concentrations and conditional stability constants of Fe ligands within these size classes. Results suggest that equilibrium partitioning of Fe between soluble and colloidal ligands is partially responsible for the distribution of Fe between soluble and colloidal size classes. However, a significant fraction of the colloidal Fe was inert to ligand exchange as soluble Fe concentrations were generally lower than values predicted by a simple equilibrium partitioning model.In surface waters, strong ligands with conditional stability constants of 1013 relative to total inorganic Fe appeared to dominate speciation in both the soluble and colloidal fractions. In deep waters these ligands were absent, and instead we found ligands with stability constants 12–15 fold smaller that were predominantly in the soluble pool. Nevertheless, significant levels of colloidal Fe were found in these samples, which we inferred must be inert to coordination exchange. 相似文献