翅碱蓬-沙蚕对Cu污染沉积质理化性质的影响研究

以中国北方滩涂湿地的优势种植物翅碱蓬(Suaeda heteroptera Kitag.)和优势多毛类动物双齿围沙蚕(Nereis succinea)为实验对象,以向沉积质中添加Cu2+来模拟重金属污染,通过盆栽实验,分别测定翅碱蓬、沙蚕及两者混合培养对Cu污染沉积质的pH、氧化-还原电位(Eh)、总氮含量、总磷含量及脱氢酶活性的影响,研究它们对Cu污染沉积质理化性质的改善作用。结果表明,翅碱蓬、沙蚕对Cu污染沉积质理化性质的影响与Cu处理浓度有关。翅碱蓬-沙蚕体系对Cu污染沉积质理化性质的影响与两者单独作用时均不同,且对不同Cu处理浓度沉积质的影响效果也不尽相同;总体来看,对于Cu污染沉积质,翅碱蓬-沙蚕体系可促使pH升高,Eh下降,总氮含量升高,脱氢酶活性升高,而对总磷含量的影响不明显。     

沙蚕生物扰动对河口沉积物中菲释放的影响

生物扰动是一个重要沉积物-水界面过程,影响沉积物中污染物的归趋.为了探究生物扰动对沉积物中多环芳烃释放的影响.在室内进行30 d的沙蚕生物扰动对河口沉积物中菲释放的影响实验.结果表明,相对于对照,生物扰动提高水体中颗粒态菲达到2.96~10.35倍,溶解态菲为9.55~17.44倍.由此可见,沙蚕的生物扰动极大的促进了沉积物中菲向水体释放.在生物扰动处理中,两种形态的菲所占比例不同,其中溶解态菲占释放总量的80%以上,表明沙蚕的生物扰动主要是提高水体中溶解态菲.由于溶解态菲能被生物所利用,通过食物链威胁人类健康.因此,沙蚕生物扰动造成的沉积物中的污染物释放具有潜在的生态风险.     

Modelling the reworking effects of bioturbation on the incorporation of radionuclides into the sediment column: implications for the fate of particle-reactive radionuclides in Irish Sea sediments

A microcosm laboratory experiment was conducted to determine the impact of biological reworking by the ragworm Nereis diversicolor on the redistribution of particle-bound radionuclides deposited at the sediment-water interface. Over the course of the 40-day experiment, as much as 35% of a ¹³⁷Cs-labelled particulate tracer deposited on the sediment surface was redistributed to depths of up to 11 cm by the polychaete. Three different reworking models were employed to model the profiles and quantify the biodiffusion and biotransport coefficients: a gallery-diffuser model, a continuous sub-surface egestion model and a biodiffusion model. Although the biodiffusion coefficients obtained for each model were quite similar, the continuous sub-surface egestion model provided the best fit to the data. The average biodiffusion coefficient, at 1.8 ± 0.9 cm² y⁻¹, is in good agreement with the values quoted by other workers on the bioturbation effects of this polychaete species. The corresponding value for the biotransport coefficient was found to be 0.9 ± 0.4 cm y⁻¹. The effects of non-local mixing were incorporated in a model to describe the temporal evolution of measured ⁹⁹Tc and ⁶⁰Co radionuclide sediment profiles in the eastern Irish Sea, influenced by radioactive waste discharged from the Sellafield reprocessing plant. Reworking conditions in the sediment column were simulated by considering an upper mixed layer, an exponentially decreasing diffusion coefficient, and appropriate biotransport coefficients to account for non-local mixing. The diffusion coefficients calculated from the ⁹⁹Tc and ⁶⁰Co cores were in the range 2-14 cm² y⁻¹, which are consistent with the values found by other workers in the same marine area, while the biotransport coefficients were similar to those obtained for a variety of macrobenthic organisms in controlled laboratories and field studies.     

石油烃、Cu2+对沙蚕的毒性效应及对其抗氧化酶系统的影响

在实验室模拟条件下,研究了石油烃和不同浓度的Cu²⁺对沙蚕(Nereis diversicolor)种群的毒性效应及对其抗氧化酶系统活性的影响.结果表明:石油烃和Cu²⁺对沙蚕均表现出较强的毒性,暴露3d后,其LD₅₀值分别为117.5μL·L^-1和864.0μg·L^-1.Cu²⁺单因子污染暴露5d后,沙蚕体内过氧化物酶(POD)的活性受到显著影响,表现出先受到抑制后缓慢增加的趋势,超氧化物歧化酶(SOD)的活性也发生显著变化,其变化趋势为先被诱导而后抑制.石油烃以其约为半致死剂量水平单因子暴露5d后,POD的活性并未被显著诱导,SOD的活性则低于对照组.在石油烃与Cu²⁺复合污染的条件下,暴露5d后沙蚕体内POD和SOD活性表现出相同的变化趋势,即先下降后上升.通过比较,还发现沙蚕体内SOD的活性变化更能灵敏地反映出污染物对沙蚕的毒性作用.     

Metal concentrations in sediment and Nereis diversicolor in two Moroccan lagoons: Khnifiss and Oualidia

Metal concentrations were measured monthly during an annual cycle (December 2004 to January 2006) in the tissues of Nereis diversicolor ragworms and sediment from two Moroccan Atlantic coastal lagoons: Oualidia in the north, situated in a highly industrialised urban area and Khnifiss in the south, far from anthropogenic influences. Relatively high levels of Zn, Ag and Cd were found in the sediment of Oualidia lagoon, while Ni concentrations were shown to be high at Khnifiss. The significant metal levels at Oualidia are a result of industrial and urban discharges, coupled with discharges from adjacent phosphate ore processing plants. Trace metal concentrations in worms vary according to season; they are usually high in winter and spring, in relation to the animal's reproductive cycle. Comparing the two lagoons, trace metal levels appear to be higher in worms from Khnifiss lagoon, suggesting a higher bioavailability of these elements in a relatively pristine area.     

Influence of anthropogenic stress on fitness and behaviour of a key-species of estuarine ecosystems, the ragworm Nereis diversicolor

Fitness, (biometric measurements, reproduction) and behaviour that are ecologically relevant biomarkers in assessing the quality of estuarine sediments were studied by comparing the responses of the polychaete worm Nereis diversicolor - a key species in estuaries - along a pollution gradient. Intersite differences were shown for all the measured parameters: size-weight relationships, energy reserves as glycogen and lipids, sexual maturation patterns, total number of oocytes per female, total and relative fecundity, burrowing behaviour. The physiological and behavioural status of N. diversicolor was consistently disturbed in the larger, most contaminated estuaries (Loire and Seine, Fr.) compared to reference sites (Bay of Bourgneuf, Goyen estuary, Fr.). Many classes of potentially toxic chemicals present in these estuaries most likely contribute to these impairments but food availability may act as a confounding factor, interfering with the potential impact of contaminants.     

Cysteine-glutathione disulfide, the sperm-release pheromone of the marine polychaete Nereis succinea (Annelida: Polychaeta)

Summary. In the marine polychaete Nereis succinea (Frey & Leuckart 1847) a sex pheromone was isolated from the coelomic fluid of sexually mature females and identified by NMR studies and independent synthesis. This pheromone is released by the females during reproduction together with eggs and coelomic fluid into the free water column and induces sperm release of surrounding males. Its structure was ascertained as L-cysteine-glutathione disulfide. It exhibited a response threshold of 0.6 · 10⁻⁷ M. Received 15 July 1997; accepted 25 November 1997.     

Influences of petroleum on accumulation of copper and cadmium in the polychaete Nereis diversicolor

Using the exposure simulation experiment, the action of petroleum affecting the accumulation of the trace metals including copper （Cu） and cadmium （Cd） in littoral polychaete Nereis diversicolor collected from the Shuangtaizi Estuary in Liaoning Province, China was examined. The results showed that there was a markedly non-linear relationship between the accumulation of Cu in worms and the experimental concentration of Cu in exposure solutions when the concentration of petroleum remained at 0, 100, and 220 μl/L, respectively. However, significantly non-linear relationship for worms exposed to Cd was observed only when the concentration of added petroleum was 0 and 220 μl/L. The accumulation of Cu in worms did not differ significantly among the three different levels of petroleum concentrations combined with various concentrations of Cu. So was the accumulation of Cd in worms （p〉0.05）. However, the addition of petroleum in exposure solutions brought about an increase in the accumulation of Cu in Nereis diversicolor, in comparison with single Cu pollution. On the other hand, when the concentration of added petroleum remained at 100 μl/L, the accumulation of Cd in worms was lower than that in worms exposed to various concentrations of only cadmium. However, the worms exposed to Cd and petroleum 220 μl/L did not show obvious and identical increase in the accumulation of Cd, compared with single Cd exposure. The accumulation of both Cu and Cd in worms did not increase significantly with the increases in concentrations of Cu or Cd in exposure solutions combined with petroleum （0, 100, and 220μl/L） under the experimental conditions. Although Nereis diversicolor is exposed to very high Cu and Cd in exposure solutions, accumulation and detoxification mechanisms are sufficient to cope with the extra metal influx in order to survive.     

Chromium in intertidal sediments of the Clyde,UK: potential for remobilisation and bioaccumulation

Detailed surveys of intertidal sediments have been performed along the north and south shores of the Inner Clyde estuary, UK. Surface sediment data reveal significant spatial variation in Cr content and an association with major sediment characteristics and location within the estuary. Depth variation for Cr and other heavy metals cannot be explained by variation in major geochemical controls such as grain size and organic matter and highlights the impact of historical contamination on sediment quality. These elevated levels at depth may still have environmental impact through redox-reactivity, in association with iron and manganese. Sequential extraction of sediments and pore water analysis of Cr(VI) and Cr(III) provide detailed information on release potential from the sediments. The implication of Cr mobility for biota in the estuary has been assessed by the analysis of a common marine bivalve, Mytilus edulis (Blue Mussel) and a burrowing polychaete, Nereis diversicolor (rag worm) from a number of survey sites. Bioconcentration factors for Mytilus indicate that the weakly held portion of sediment Cr is available for uptake and in the case of Nereis, bioaccumulation appears to be inhibited by sediment organic matter.