Effects of salinity on sublethal toxicity of atrazine to mummichog (Fundulus heteroclitus) larvae

In coastal marshes, fish larvae may be exposed simultaneously to extreme salinities and to atrazine, a widely used herbicide. To assess the effects of salinity on the toxicity of atrazine, newly-hatched mummichog (Fundulus heteroclitus) were exposed to atrazine (0, 5, 50 and 500 microg/L) at three salinities (3, 15 and 35PSU). Whole body cortisol was measured after 24 h. Body length, condition factor, whole body proteins, lipids, residual masses and water contents were assessed after 96 h. Significants effects were found for both condition factor and water content. Condition factors were lower at salinity 3 and 35 compared to near isoosmotic salinity, 15PSU. In addition, atrazine decreased condition factor at 500 microg/L. Reduction in condition was likely due to retardation in axial growth since body length, percentages of proteins or lipids were not affected. In the absence of atrazine, salinity had no effect on the prevalence of dehydrated (81% water) or hyperhydrated (85% water) larvae. In larvae exposed to atrazine, the prevalence of hyperhydrated larvae increased at 3PSU and 5 microg/L atrazine and that of dehydrated larvae increased at 15 and 35PSU and 5 microg/L atrazine. Severity of dehydratation increased with atrazine concentration at salinity 35PSU. Thus, a short-term exposure to environmentally realistic concentrations of atrazine affects osmotic control in mummichog larvae with possible effects on buoyancy, survival and recruitment.     

Oxidative damage in rainbow trout caged in a polluted river

Sewage treatment works (STWs) are a common source of chemicals entering into the aquatic environment. In order to assess effects of these effluents on oxidative stress parameters in aquatic organisms, we caged rainbow trout at five sites: upstream, near an STW effluent, and three sites downstream in the river Viskan in western Sweden for 14 days during autumn, 2006. We then measured protein carbonyls in plasma as well as 20S proteosome activity and lipid peroxidation products, i.e. MDA and 4-HNE, in liver samples. Levels of both lipid and protein oxidative damage products were elevated in fish caged near the STW effluent while 20S activity showed no differences. This argues that complex mixtures of chemicals entering into the aquatic environment do have deleterious effects on fish. Additionally, oxidative stress parameters can serve as a biomarker in aquatic organisms.     

Cellular energy allocation in the Arctic sea ice amphipod Gammarus wilkitzkii exposed to the water soluble fractions of oil

Increasing offshore oil and gas activities in the European Arctic has raised concerns of the potential anthropogenic impact of oil-related compounds on the polar marine ecosystem. We measured cellular energy allocation (CEA) in the sea ice amphipod Gammarus wilkitzkii after exposure for one month to the water soluble fraction (WSF) of oil. The CEA biomarker measures the energy budget of organisms by biochemically assessing changes in carbohydrates, protein and lipid content as well as the electron transport system activity. A significantly higher protein content was observed in the medium dose compared to controls, while the total energy budget was not affected in G. wilkitzkii. This indicates that parts of the energy budget of G. wilkitzkii, which is a key species in the Arctic ecosystem, is affected by a WSF of oil.     

Interference by atrazine and bisphenol-A with progestin binding to the ovarian progestin membrane receptor and induction of oocyte maturation in Atlantic croaker

Recent studies have shown that several environmental chemicals which disrupt classical genomic steroid actions can also interfere with nongenomic steroid actions initiated at the cell surface. The effects of bisphenol-A and atrazine on the nongenomic actions of a progestin, 17,20 beta,21-trihydroxy-4-pregnen-3-one (20 beta-S), on oocyte maturation (OM) were investigated an in vitro Atlantic croaker (Micropogonias undulatus) oocyte bioassay. Treatment of croaker follicle-enclosed oocytes with either bisphenol-A or atrazine blocked OM in response to 20 beta-S in a concentration-dependent manner at 10-25 microM (2.2-5.7 ppm) and higher concentrations. These compounds were also effective competitors at concentrations of 10(-6)-10(-5)M of [3H]-20 beta-S binding to the ovarian progestin membrane receptor that mediates the OM response to 20 beta-S. The results suggest that diverse classes of environmental chemicals can disrupt nongenomic progestin actions via receptor-mediated mechanisms.     

Is delta-aminolevulinic acid dehydratase activity in bivalves from south-west Iberian Peninsula a good biomarker of lead exposure?

The coast of Huelva is considered as a heavily contaminated area where the Tinto and Odiel rivers discharge after running through a metalliferous mining area in the Iberian Pyrite Belt and end in common estuary called Ría of Huelva. Lead is a highly toxic and widely distributed element in the aquatic environment; therefore there is a great interest in assessing the impact of this contaminant on aquatic organisms. To study the bioavailability and sources of lead, the bivalve species Chamelea gallina was collected from six sampling sites along the coast of Huelva. Besides the effect of this metal on the enzyme activity, delta-aminolevulinic acid dehydratase (ALA-D) was determined in the whole tissue. Results show the inverse relationship between the lead concentration and the activity of ALA-D measured in whole tissues (r2=0.7). Individuals collected from the Ría of Huelva estuary had the highest levels of total lead concentrations and the lowest activity of ALA-D. Lead isotope analyses demonstrated the different sources of lead contamination and also confirmed the influence of Ría of Huelva on the metal input to the marine environment.     

Land use and the spatial distribution of perfluoroalkyl compounds as measured in the plasma of bottlenose dolphins (Tursiops truncatus)

The distribution of perfluoroalkyl compounds (PFCs) in the environment is well documented with higher concentrations observed in wildlife located in industrial and urban areas. This study examined the distribution of PFCs in relation to land use using blood samples collected from bottlenose dolphins during capture-release health assessment surveys conducted in Charleston, SC. The study area was partitioned into three subareas (ACW, CHS, and SRE) based upon habitat and land use characteristics. The ACW and CHS subareas are characterized by high degrees of industrial and urban land uses, while the SRE subarea is more residential and characterized by a lower degree of developed land use. Long-term monitoring data from photo-identification surveys were used to group bottlenose dolphins based on their proportions of sightings in the different subareas. Dolphins affiliated with both the ACW and CHS subareas were observed to have significantly higher mean plasma concentrations of perfluorooctane sulfonate (PFOS), perfluorodecanoic acid (PFDA) and perfluoroundecanoic acid (PFUnA) than those affiliated with the SRE subarea. Dolphins affiliated with the ACW subarea were found to have a significantly higher mean plasma concentration of PFUnA than those affiliated with the CHS subarea. Further examination of the distribution of the PFCs revealed positive correlations with developed land uses and negative correlations with wetland/marsh land cover. A positive correlation was also observed between PFUnA and agricultural land use. The variability and scale of the observed contaminant burdens have important implications for the conservation and management of living marine resources and illustrates the importance of long-term monitoring of free-ranging wildlife species.     

地球化学驱动的勘探模式-挪威巴伦支海

挪威巴伦支海盆地由于含多套烃源岩,因此可作为过充注石油系统的一流代表。古新世到上新世一更新世的多幕隆升、及随后的侵蚀作用导致储层压力下降,是造成本区烃聚集损耗的主要原因。压力释放使聚集区的烃变为油气两相,气相进一步膨胀,使其下的石油高出圈闭的溢出点。然而,很重要的一点是这种隆升事件虽然造成潜在的破坏性,但是却引起巴伦支海地区的油气在横向上长距离重新分配。     

非火山型大陆边缘从张裂到破裂分离时岩石圈伸展：流变学、蛇纹岩化和对称性

在过去二十年中,大陆破裂分离过程的对称性和非对称性存在许多争论,一些作者提出了非对称性的简单剪切模式,另一些作者则强调对称性、纯剪切模型和部分二者的结合。在非火山型边缘大陆下的地幔上涌侵蚀使得一些作者认为简单剪切模式是正确的,但缺乏足够的支持证据。从共轭边缘对的沉降史之证据是可疑的,这些边缘详细的地壳和岩石圈结构不十分了解,不能得到确定的结论。在Porcupine盆地,这里大陆破裂分离的最后阶段是可知的,不对称构造的发育是存在的,它们显然与在随着地壳完全脆裂过程中地壳和地幔的后期耦合作用有关。这和理论模拟的结果是一致的,只有当地壳和地幔紧密耦合时,仅仅在岩石圈尺度上可预测不对称模型的发育。然而,对在地幔连续剥露过程中是否一直是存在这样不对称性仍不清楚。     

DNA adducts and polycyclic aromatic hydrocarbon (PAH) tissue levels in blue mussels (Mytilus spp.) from Nordic coastal sites

DNA adducts in gills and digestive gland, as well as polycyclic aromatic hydrocarbon (PAH) tissue levels were analysed in blue mussels (Mytilus spp.) from Nordic coastal areas (Iceland, Norway and Sweden) with diffuse or point sources of PAHs of various origins. Both DNA adduct and PAH tissue levels were generally low, indicating low PAH exposure to the mussels in the areas studied. DNA adducts were found to be higher in gills than in digestive gland of the mussels at all sites studied. Elevated DNA adduct levels in gills were found at 6 sites out of 18 compared to reference sites in respective coastal zones. Adduct levels ranged from 0.5 to 10 nmol adducts/mol normal nucleotides, being highest in mussels from Reykjavík harbour, Iceland (intertidal mussels), and from Fiskaatangen, Norway (subtidal mussels). Total PAH tissue levels in the mussels ranged between 40 and 11,670 ng/g dry wt., and were significantly correlated with DNA adduct levels (r(2)=0.73, p<0.001). PAH ratio values indicated that the PAHs were in most cases of pyrolytic origin, but with petrogenic input near harbours and an oil refinery.     

中国内蒙古白云鄂博Fe—Nd—REE矿床地质特征与陨石撞击成因

中国内蒙古白云鄂博Ｆｅ－Ｎｂ－ＲＥＥ矿床由于其独特的矿床地质与矿物地球化学特征而明显有别于世界上其它绝大多数的Ｆｅ,Ｎｂ,ＲＥＥ矿床,本文提出该矿床是约１５００Ｍａ前一块富含ＲＥＥ,Ｎｂ的铁陨石撞击在华北地台北缘碳酸盐沉积陆架上形成的。现在矿床矿体中心的块状铁矿石更多地代表了陨石的成分,矿体外侧富含ＲＥＥ,Ｎｄ的环状白云岩是形成的含金属热液蚀变沉积成因方解石质碳酸盐沉积物的结果。