Affiner votre recherche
Résultats 1-10 de 145
Organochlorine pesticide residues in marine sediment and biota from the Northern Florida reef tract.
1995
Glynn P.W. | Rumbold D.G. | Snedaker S.C.
Gas-bubble disease in three fish species inhabiting the heated discharge of a steam-electric station using hypolimnetic cooling water.
1990
McInerny M.C.
Zirconium toxicity assessment using bacteria, algae and fish assays.
1989
Couture P. | Blaise C. | Cluis D. | Bastien C.
Primary investigation on contamination pattern of legacy and emerging halogenated organic pollutions in freshwater fish from Liaohe River, Northeast China
2013
Ren, Guofa | Wang, Zhao | Yu, Zhiqiang | Wang, Yang | Ma, Shengtao | Wu, Minghong | Sheng, Guoying | Fu, Jiamo
Legacy halogenated compounds, including polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), and emerging organo-halogen pollutants such as Dechlorane Plus (DP), were detected in fish from an old industrial region in Northeast China. PCBs and PBDEs were detected in all of the samples, with concentrations ranging from 38.15 to 170.51 ng/g lipid weight, and 9.40–39.69 ng/g lipid weight, respectively. DP was detected in more than 90% of the samples with concentrations ranging from not detected (ND) to 470 pg g/g lipid weight. Compared with similar data in other areas of the world, PCBs, PBDEs and DP in fish from Liaohe River were at medium or low level. An unusually high percentage of PCB-209 was first reported in the fish samples collected from China. Other halogenated pollutions, such as dichlorodiphenyltrichloroethane (DDT) and its metabolites, octachlorostyrene, chlorinated anisole, chlorinated thioanisole, triclosan-methyl, and other pesticides, have also been identified in the fish samples.
Afficher plus [+] Moins [-]A systematic review of the effectiveness of liming to mitigate impacts of river acidification on fish and macro-invertebrates
2013
Mant, Rebecca C. | Jones, David L. | Reynolds, Brian | Ormerod, Steve J. | Pullin, Andrew S.
The addition of calcium carbonate to catchments or watercourses – liming – has been used widely to mitigate freshwater acidification but the abatement of acidifying emissions has led to questions about its effectiveness and necessity. We conducted a systematic review and meta-analysis of the impact of liming streams and rivers on two key groups of river organisms: fish and invertebrates. On average, liming increased the abundance and richness of acid-sensitive invertebrates and increased overall fish abundance, but benefits were variable and not guaranteed in all rivers. Where B-A-C-I designs (before-after-control-impact) were used to reduce bias, there was evidence that liming decreased overall invertebrate abundance. This systematic review indicates that liming has the potential to mitigate the symptoms of acidification in some instances, but effects are mixed. Future studies should use robust designs to isolate recovery due to liming from decreasing acid deposition, and assess factors affecting liming outcomes.
Afficher plus [+] Moins [-]Sources, factors, mechanisms and possible solutions to pollutants in marine ecosystems
2013
Mostofa, Khan M.G. | Liu, Cong-Qiang | Vione, Davide | Gao, Kunshan | Ogawa, Hiroshi
Algal toxins or red-tide toxins produced during algal blooms are naturally-derived toxic emerging contaminants (ECs) that may kill organisms, including humans, through contaminated fish or seafood. Other ECs produced either naturally or anthropogenically ultimately flow into marine waters. Pharmaceuticals are also an important pollution source, mostly due to overproduction and incorrect disposal. Ship breaking and recycle industries (SBRIs) can also release various pollutants and substantially deteriorate habitats and marine biodiversity. Overfishing is significantly increasing due to the global food crisis, caused by an increasing world population. Organic matter (OM) pollution and global warming (GW) are key factors that exacerbate these challenges (e.g. algal blooms), to which acidification in marine waters should be added as well. Sources, factors, mechanisms and possible remedial measures of these challenges to marine ecosystems are discussed, including their eventual impact on all forms of life including humans.
Afficher plus [+] Moins [-]Biogeochemical malfunctioning in sediments beneath a deep-water fish farm
2012
Valdemarsen, Thomas | Bannister, Raymond J. | Hansen, Pia K. | Holmer, Marianne | Ervik, Arne
We investigated the environmental impact of a deep water fish farm (190 m). Despite deep water and low water currents, sediments underneath the farm were heavily enriched with organic matter, resulting in stimulated biogeochemical cycling. During the first 7 months of the production cycle benthic fluxes were stimulated >29 times for CO₂ and O₂ and >2000 times for NH₄ ⁺, when compared to the reference site. During the final 11 months, however, benthic fluxes decreased despite increasing sedimentation. Investigations of microbial mineralization revealed that the sediment metabolic capacity was exceeded, which resulted in inhibited microbial mineralization due to negative feed-backs from accumulation of various solutes in pore water. Conclusions are that (1) deep water sediments at 8 °C can metabolize fish farm waste corresponding to 407 and 29 mmol m⁻² d⁻¹ POC and TN, respectively, and (2) siting fish farms at deep water sites is not a universal solution for reducing benthic impacts.
Afficher plus [+] Moins [-]The interaction rainfall vs. weight as determinant of total mercury concentration in fish from a tropical estuary
2012
Barletta, M. | Lucena, L.R.R. | Costa, M.F. | Barbosa-Cintra, S.C.T. | Cysneiros, F.J.A.
Mercury loads in tropical estuaries are largely controlled by the rainfall regime that may cause biodilution due to increased amounts of organic matter (both live and non-living) in the system. Top predators, as Trichiurus lepturus, reflect the changing mercury bioavailability situations in their muscle tissues. In this work two variables [fish weight (g) and monthly total rainfall (mm)] are presented as being important predictors of total mercury concentration (T-Hg) in fish muscle. These important explanatory variables were identified by a Weibull Regression model, which best fit the dataset. A predictive model using readily available variables as rainfall is important, and can be applied for human and ecological health assessments and decisions. The main contribution will be to further protect vulnerable groups as pregnant women and children. Nature conservation directives could also improve by considering monitoring sample designs that include this hypothesis, helping to establish complete and detailed mercury contamination scenarios.
Afficher plus [+] Moins [-]Seasonal variation in mercury and food web biomagnification in Lake Ontario, Canada
2012
Zhang, Liang | Campbell, Linda M. | Johnson, Timothy B.
Seasonal variation in mercury (Hg) concentrations and food web structure was assessed for eastern Lake Ontario. Hg concentrations, measured in 6 species of invertebrates and 8 species of fishes, tended to be highest in the spring and lowest in the summer for most biota. Yellow perch (Perca flavescens) exhibited significant ontogenetic shifts in diet and Hg, although such patterns were not evident for other species. Food web structure, as indicated by stable isotope values (δ¹⁵N, δ¹³C) was not static. Log-transformed Hg data were strongly and consistently correlated with δ¹⁵N values for the whole food web in each of the three seasons (slopes, 0.17–0.24) and across the entire year (slope, 0.2). While significantly different between seasons, the regression slope values are still consistent with published global Hg biomagnification rates. Our results indicate that the assessment of Hg trends in Great Lakes must take into account seasonal patterns and time of sampling.
Afficher plus [+] Moins [-]Can the integration of multiple biomarkers and sediment geochemistry aid solving the complexity of sediment risk assessment? A case study with a benthic fish
2012
Costa, Pedro M. | Caeiro, Sandra | Vale, Carlos | DelValls, T Àngel | Costa, Maria H.
Surveying toxicity of complex geochemical media as aquatic sediments often yields results that are either difficult to interpret or even contradictory to acknowledged theory. Multi-level biomarkers were investigated in a benthic fish exposed to estuarine sediments through laboratory and in situ bioassays, to evaluate their employment either in ecological risk assessment or in more mechanistic approaches to assess sediment-bound toxicity. Biomarkers reflecting lesions (such as genotoxicity or histopathology), regardless of their low or absent specificity to contaminants, are efficient in segregating exposure to contaminated from uncontaminated sediments even when classical biomarkers like CYP1A and metallothionein induction are inconclusive. Conversely, proteomics and gene transcription analyses provided information on the mechanics of toxicity and aided explaining response variation as a function of metabolic imbalance and impairment of defences against insult. In situ bioassays, although less expedite and more affected by confounding factors, produced data better correlated to overall sediment contamination.
Afficher plus [+] Moins [-]