Increasing numbers of industrial, agricultural and natural chemicals are present in sewage effluent and are known to elicit toxic effects in laboratory exposures, but little is known of their combined sub-lethal effect in the field. In this study, a combination of esterase activity and ventilation rate assays was performed to determine the neurological and physiological function of the freshwater crustacean Asellus aquaticus (L.) at sites above and below a sewage treatment works (STW). Cholinesterase and carboxylesterase activities were significantly inhibited (n=8, P<0.05) and ventilation rates increased (n=8, P=0.0001) in A. aquaticus at STW sites compared to those from reference sites, indicating a decrease in neurological and physiological function. The ecological relevance of these findings for the population dynamics of the organisms in the field is discussed. 相似文献
Metallothionein has been assayed in a range of aquatic animal tissues as an indicator of metal exposure. We sequenced chub (Leuciscus cephalus) metallothionein cDNA which showed over 90% homology to common carp, goldfish and stone loach and 77% homology to rainbow trout sequences for metallothionein. We then used the extended primer method to develop an accurate quantitative competitive RT-PCR assay for metallothionein mRNA. RT-PCR was used to measure metallothionein mRNA in feral chub from a range of field sites, with different levels of heavy metal pollution, in the West Midlands, UK. Measurements were complemented by analysis of liver and gill metallothionein protein by capillary electrophoresis. There was no significant difference in the metallothionein protein levels between fish of different rivers and there was no evidence of elevation of mRNA at the sites of highest metal exposure. The level of metal exposure (e.g. zinc, nickel and cadmium each ranging between 15 and 28 microg/l ) at the pH (7.5-8.5) of these rivers appears insufficient to elevate hepatic or gill metallothionein in chub. A lack of elevation of hepatic metallothionein mRNA in chub exposed to zinc, copper and manganese for 24 h and 10 days in the laboratory also suggests a non-responsiveness of this species. 相似文献
Our previous studies have demonstrated that tributyltin (TBT) is genotoxic to the early life stages of marine mussels and worms. Here, the toxicity of TBT to adult organisms was determined using a suite of biomarkers designed to detect cytotoxic, immunotoxic and genotoxic effects. Exposure of adult mussels, Mytilus edulis, to environmentally realistic concentrations of TBTO for 7 days resulted in a statistically significant decrease in cell viability at concentrations of 0.5 μg/l and above. TBT had no effect on phagocytic activity or antioxidant capacity (FRAP assay). There was a statistically significant increase in DNA damage detected using the comet and micronucleus assays between the controls and 0.5, 1 and 5 μg/l of TBTO (P > 0.0005). Furthermore there was a strong correlation between DNA strand breaks (comet assay) and formation of micronuclei (P = 0.0005; R2 = 61.5%). Possible mechanisms by which TBT could damage DNA either directly or indirectly are discussed including the possibility that TBT is genotoxic due to its ability to disrupt calcium homeostasis. 相似文献
Organic matter of nine surface sediments from the Daya Bay was Soxhlet-extracted with a mixture of 2:1 (v/v) dichloromethane-methanol and separated into five fractions: non-aromatic hydrocarbons, aromatic hydrocarbons, ketones, alcohols, and fatty acids and asphaltenes, and analyzed to determine their bulk and biomarker composition. Marine autogenic input appears to be a major source of organic matter. Generally, non-aromatic hydrocarbons are the most dominant fraction of solvent-extractable organic matter (EOM) followed by the other four fractions in decreasing amounts: fatty acids and asphaltenes, ketones, alcohols and aromatic hydrocarbons. On average, both non-aromatic hydrocarbon fraction and fatty acid and asphaltene fraction account for approximately 40% of EOM. The sources of acyclic methyl ketones, alkanols and fatty acids were examined. For n-alkan-2-ones, allochthonous input is a more important source than marine autogenetic input; the reverse is true for n-fatty acids; for n-alkanols, allochthonous and autogenetic inputs seem comparable. Both n-alkan-2-ones and n-fatty acids in the surface sediments of different areas appear to be derived from common sources. 相似文献
Geochemical analysis of dump materials from the opencast Maritsa Iztok mines, Bulgaria, was carried out based on biomarker assemblages of hydrocarbon fractions. Organic matter (OM) and secondary transformations in three representative samples (massive black claystones and materials from the Iztok and Staroselets dump sites) were studied using geochemical proxies.A number of differences were recognised in the respective OM compositions of the samples compared to both published data and between the individual dump samples themselves. The ОM of the studied samples was found to be polar, but also contains some apolar compounds. It consists mainly of resins and asphalthenes. Claystone OM is of the dispersed type, with intense oxidative-reductive interactions in a lacustrine environment resulting in its transformation into an inert material. Dump sample kerogen is of Type II and mixed Type II/III. In all samples, “odd” numbered n-alkanes are found in higher amounts. Diterpenoids (С19, С20) with pimarane, abietane and phyllocladane skeletons are preponderant. Tri- and tetracyclic terpenoids and steranes have been identified in the black claystones OM only. Hopanes are present in low amounts in extractable OM from all three samples. Biomarkers indicate that black claystone OM is formed from aqueous flora, with a minor supply of gymnosperms (mainly G. Sequoia). Iztok Dump OM is structured by higher plants with an aqueous vegetation input. The Staroselets Dump OM formation is assigned to an active microbial reworking of aqueous vegetation and bacteria with a minor coniferous supply. Different geochemical parameters admit anoxic stratified bottom waters for the black claystones with an addition of deep water stagnation for Staroselets sample in a Maritsa Iztok Basin (MIB) aqueous environment.An attempt was also made to track the effect of secondary processes (oxidation, destruction, dearomatisation), temperature, water drainage and wash-out on dump materials. Leaching and weak degradation processes in the MIB dump environment are likely for a time span of ca. 40–50 years, considering the low percentage of short-chain n-alkanes, long-chain prevalence and low Pr/nC17 and Ph/nC18 ratios, with the Iztok Dump sample experiencing more advanced transformations. 相似文献
Fluctuations in lacustrine sedimentary environments significantly affect distributions of organic matter (OM), uranium, and other elements in shales. In this study a high-resolution geochemical record of fluctuations in the paleo-depositional environment of a terrestrial lake basin is provided on the basis of extensive samples collected from the Member 3 of the Paleogene Shahejie Formation (Es3) of the Niu-38 well in the Dongying Depression, Eastern China. These samples were tested for total organic carbon (TOC), element concentrations, and biomarkers to study the evolution and fluctuation in the depositional environments of an ancient lake basin and associated geochemical response. The evolution and fluctuation of the sedimentary environment from a deep lake to a semi-deep lake and then to a shallow lake delta were indicated by geochemical response. During this evolution, the values of TOC, S1, S2, Sr, and Ts/(Ts + Tm) remarkably decreased, whereas those of Co, Ni, Rb, Na, Fe/Mn, Fe/(Ca + Mg), and C29 mortane/C29 hopane significantly increased. The deep lake basin shows depositional fluctuations, as indicated by rock lithofacies and their geochemical parameters. A close interrelationship was observed among U concentration, TOC content, and inorganic element content. Uranium concentrations are positively correlated with TOC contents, Ca and Sr concentrations, and Sr/Ba and Ca/Mg ratios but negatively with K, Na, Ba, and Rb contents and Fe/(Ca + Mg) and Fe/Mn ratios. The observed increase in U concentration in the lower Es3 section is closely related to surface adsorption by clay minerals and OM, together with some replacements of Ca and Sr by U in the shales. 相似文献
In order to evaluate the health status of fish inhabiting Port Phillip Bay, Australia, southern sand flathead (Platycephalus hassensis, N = 133) were collected at six stations throughout the Bay. Fish had a similar serum sorbitol dehydrogenase (SDH) activity level (p = 0.12), indicating that they were not experiencing hepatocellular injuries. Ethoxyresorufin-O-deethylase (EROD) activity was generally lower in the non-urbanized and non-industrialized southern part of the Bay. The highest EROD activity was observed in Hobson Bay, the closest station from Melbourne city. Naphthalene-type biliary metabolites were also highest in Hobson Bay with intermediate levels found in Corio Bay where refineries are present. An opposite trend was observed with the pyrene-type bile metabolites, the highest levels being observed in Corio Bay while intermediate levels were found in Hobson Bay. The ratio of naphthalene-type to benzo(a)pyrene (B(a)P)-type metabolites indicate that relatively to other sites sampled in Port Phillip Bay, Corio Bay is subjected to enriched petroleum hydrocarbons of pyrolytic origin. Temporal trends indicate that the availability of xenobiotics to fish remained unchanged over the 1990s. 相似文献
A large amount of deep oil has been discovered in the Tazhong Uplift, Tarim Basin whereas the oil source is still controversial. An integrated geochemical approach was utilized to unravel the characteristics, origin and alteration of the deep oils. This study showed that the Lower Cambrian oil from well ZS1C (1x) was featured by small or trace amounts of biomarkers, unusually high concentration of dibenzothiophenes (DBTs), high δ34S of DBTs and high δ13C value of n-alkanes. These suggest a close genetic relationship with the Cambrian source rocks and TSR alteration. On the contrary, the Middle Cambrian oils from well ZS1 (2a) were characterized by low δ13C of n-alkanes and relatively high δ34S of individual sulfur compounds and a general “V” shape of steranes, indicating a good genetic affinity with the Middle–Upper Ordovician source rocks. The middle Cambrian salt rock separating the oils was suggested to be one of the factors responsible for the differentiation. It was suggested that most of the deep oils in the Tazhong Uplift were mixed source based on biomarkers and carbon isotope, which contain TSR altered oil in varied degree. The percentage of the oils contributed by the Cambrian–Lower Ordovician was in the range of 19–100% (average 57%) controlled by several geological and geochemical events. Significant variations in the δ34S values for individual compounds in the oils were observed suggesting a combination of different extent of TSR and thermal maturation alterations. The unusually high DBTs concentrations in the Tazhong-4 oilfield suggested as a result of mixing with the ZS1C oil (1x) and Lower Ordovician oils based on δ34S values of DBT. This study will enhance our understanding of both deep and shallow oil sources in the Tazhong Uplift and clarify the formation mechanisms of the unusually high DBTs oils in the region. 相似文献