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Factors controlling peat chemistry and vegetation composition in Sudbury peatlands after 30 years of pollution emission reductions
2015
Barrett, Sophie E. | Watmough, Shaun A.
The objective of this research was to assess factors controlling peat and plant chemistry, and vegetation composition in 18 peatlands surrounding Sudbury after more than 30 years of large (>95%) pollution emission reductions. Sites closer to the main Copper Cliff smelter had more humified peat and the surface horizons were greatly enriched in copper (Cu) and nickel (Ni). Copper and Ni concentrations in peat were significantly correlated with that in the plant tissue of Chamaedaphne calyculata. The pH of peat was the strongest determining factor for species richness, diversity, and community composition, although percent vascular plant cover was strongly negatively correlated with surface Cu and Ni concentrations in peat. Sphagnum frequency was also negatively related to peat Cu and Ni concentrations indicating sites close to Copper Cliff smelter remain adversely impacted by industrial activities.
اظهر المزيد [+] اقل [-]Abiotic stressors and stress responses: What commonalities appear between species across biological organization levels?
2015
Sulmon, Cécile | van Baaren, Joan | Cabello-Hurtado, Francisco | Gouesbet, Gwenola | Hennion, Françoise | Mony, Cendrine | Renault, David | Bormans, Myriam | El Amrani, Abdelhak | Wiegand, Claudia | Gérard, Claudia
Organisms are regularly subjected to abiotic stressors related to increasing anthropogenic activities, including chemicals and climatic changes that induce major stresses. Based on various key taxa involved in ecosystem functioning (photosynthetic microorganisms, plants, invertebrates), we review how organisms respond and adapt to chemical- and temperature-induced stresses from molecular to population level. Using field-realistic studies, our integrative analysis aims to compare i) how molecular and physiological mechanisms related to protection, repair and energy allocation can impact life history traits of stressed organisms, and ii) to what extent trait responses influence individual and population responses. Common response mechanisms are evident at molecular and cellular scales but become rather difficult to define at higher levels due to evolutionary distance and environmental complexity. We provide new insights into the understanding of the impact of molecular and cellular responses on individual and population dynamics and assess the potential related effects on communities and ecosystem functioning.
اظهر المزيد [+] اقل [-]In situ investigation of the mechanisms of the transport to tissues of polycyclic aromatic hydrocarbons adsorbed onto the root surface of Kandelia obovata seedlings
2015
Li, Ruilong | Zhu, Yaxian | Zhang, Yong
A novel method for in situ determination of the polycyclic aromatic hydrocarbons (PAHs) adsorbed onto the root surface of Kandelia obovata seedlings was established using laser-induced time-resolved nanosecond fluorescence spectroscopy (LITRF). The linear dynamic ranges for the established method were 1.5–1240ng/spot for phenanthrene, 1.0–1360ng/spot for pyrene and 5.0–1220ng/spot for benzo[a]pyrene. Then, the mechanisms of PAHs transport from the Ko root surface to tissues were investigated. The three-phase model including fast, slow and very slow fractions was superior to the single or dual-phase model to describe the PAHs transport processes. Moreover, the fast fraction of PAHs transport process was mainly due to passive movement, while the slow and very slow fractions were not. Passive movement was the main process of B[a]P adsorbed onto Ko root surface transport to tissues. In addition, the extent of the PAHs transport to Ko root tissues at different salinity were evaluated.
اظهر المزيد [+] اقل [-]Elevated ozone and nitrogen deposition affect nitrogen pools of subalpine grassland
2015
Bassin, Seraina | Käch, David | Valsangiacomo, Alain | Mayer, J. (Jochen) | Oberholzer, Hans-Rudolf | Volk, Matthias | Fuhrer, Jürg
In a free-air fumigation experiment with subalpine grassland, we studied long-term effects of elevated ozone (O3) and nitrogen (N) deposition on ecosystem N pools and on the fate of anthropogenic N. At three times during the seventh year of exposure, N pools and recovery of a stable isotope tracer (15N) were determined in above- and belowground plant parts, and in the soil. Plants were much better competitors for 15N than soil microorganisms. Plant N pools increased by 30–40% after N addition, while soil pools remained unaffected, suggesting that most of the extra N was taken up and stored in plant biomass, thus preventing the ecosystem from acquiring characteristics of eutrophication. Elevated O3 caused an increase of N in microbial biomass and in stabilized soil N, probably resulting from increased litter input and lower litter quality. Different from individual effects, the interaction between the pollutants remained partly unexplained.
اظهر المزيد [+] اقل [-]Bioaccumulation and biomagnification of classical flame retardants, related halogenated natural compounds and alternative flame retardants in three delphinids from Southern European waters
2015
Barón, E. | Giménez, J. | Verborgh, P. | Gauffier, P. | De Stephanis, R. | Eljarrat, E. | Barceló, D.
Occurrence and behaviour of classical (PBDEs) and alternative (HNs, HBB, PBEB, DBDPE and HBCD) flame retardants, together with naturally produced MeO-PBDEs, were studied in short-beaked common dolphin (Delphinus delphis), bottlenose dolphin (Tursiops truncatus) and long-finned pilot whale (Globicephala melas) in two sampling locations from Southern European waters. PBDEs, Dec 602, Dec 603, DP, α-HBCD and two MeO-PBDEs were detected in all three species. ∑PBDEs were between 17 and 2680 ng/g lw; ∑HNs were between 1.1 and 59 ng/g lw; α-HBCD levels ranged between 3.2 and 641 ng/g lw; ∑MeO-PBDEs were between 34 and 1966 ng/g lw. Bottlenose dolphins were the most contaminated species and some individuals could present health risk for endocrine disruption since levels found were above the reported threshold (1500 ng/g lw). Stable isotope analysis was used to evaluate the biomagnification capacity of these compounds. PBDEs, MeO-PBDEs and Dec 602 showed a significant positive correlation with trophic position.
اظهر المزيد [+] اقل [-]Reproductive endocrine-disrupting effects of triclosan: Population exposure, present evidence and potential mechanisms
2015
Wang, Cai-Feng | Tian, Ying
Triclosan has been used as a broad-spectrum antibacterial agent for over 40 years worldwide. Increasing reports indicate frequent detection and broad exposure to triclosan in the natural environment and the human body. Current laboratory studies in various species provide strong evidence for its disrupting effects on the endocrine system, especially reproductive hormones. Multiple modes of action have been suggested, including disrupting hormone metabolism, displacing hormones from hormone receptors and disrupting steroidogenic enzyme activity. Although epidemiological studies on its effects in humans are mostly negative but conflicting, which is typical of much of the early evidence on the toxicity of EDCs, overall, the evidence suggests that triclosan is an EDC. This article reviews human exposure to triclosan, describes the current evidence regarding its reproductive endocrine-disrupting effects, and discusses potential mechanisms to provide insights for further study on its endocrine-disrupting effects in humans.
اظهر المزيد [+] اقل [-]Individual and population intake fractions of diesel particulate matter (DPM) in bus stop microenvironments
2015
Xu, Jia | Jin, Taosheng | Miao, Yaning | Han, Bin | Gao, Jiajia | Bai, Zhipeng | Xu, Xiaohong
Diesel particulate matter (DPM) is associated with adverse human health effects. This study aims to investigate the relationship between DPM exposure and emissions by estimating the individual intake fraction (iFi) and population intake fraction (iFp) of DPM. Daily average concentrations of particulate matter at two bus stops during rush hours were measured, and then they were apportioned to DPM due to heavy-duty diesel bus emissions using Chemical Mass Balance Model. The DPM emissions of diesel buses for different driving conditions (idling, creeping and traveling) were estimated on the basis of field observations and published emission factors. The median iFi of DPM was 0.67 and 1.39 per million for commuters standing at the bus stop and pedestrians/cyclists passing through the bus stop during rush hours, respectively. The median iFp of DPM was 94 per million. Estimations of iFi and iFp of DPM are potentially significant for exposure assessment and risk management.
اظهر المزيد [+] اقل [-]Polychlorinated biphenyls and polybrominated biphenyl ethers in adipose tissue and matched serum from an E-waste recycling area (Wenling, China)
2015
Lv, Quan-Xia | Wang, Wenyue | Li, Xing-Hong | Yu, Lianlian | Zhang, Yun | Tian, Yuan
To Date, the knowledge on relationship between PCBs/PBDEs exposure and thyroid hormones (THs) levels during pregnancy still needs to be extended. Meanwhile, studies on congener-specific adipose-serum ratios for PCBs/PBDEs were limited. This study reports the levels of PCBs/PBDEs in serum-adipose tissue samples (n = 64) from expectant women living surrounding e-waste recycling sites in Wenling, China. Their concentrations varied from several to hundreds of ng g−1 lipid. Maternal exposure to PCBs was associated with lower TSH during pregnancy, suggesting possible implication for maternal health and fetal development. The compound levels between the adipose tissue and matched serum samples were highly correlated (p < 0.001), generating a predicted adipose-serum partitioning relationship for individual PCB congener and PBDE congener. Molecular characteristics, such as Kow value, molecular weight and molecular volume, may play a key role in the variable partitioning of some compounds between serum and adipose tissue.
اظهر المزيد [+] اقل [-]The role of phytoplankton composition, biomass and cell volume in accumulation and transfer of endocrine disrupting compounds in the Southern Baltic Sea (The Gulf of Gdansk)
2015
Staniszewska, Marta | Nehring, Iga | Zgrundo, Aleksandra
Endocrine disrupting compounds (EDCs) like bisphenol A (BPA), 4-tert-octylphenol (OP) and 4-nonylphenol (NP) are introduced to the trophic webs through among others phytoplankton. This paper describes BPA, OP and NP concentrations in phytoplankton in the Gulf of Gdansk (Southern Baltic Sea) in the years 2011–2012. The assays of BPA, OP and NP in samples were performed using HPLC with fluorescence detection. The concentrations of BPA, the most commonly used of the three compounds, were over ten times higher than OP and NP concentrations. The concentrations of the studied EDCs in phytoplankton from the Gulf of Gdansk depended on anthropogenic factors and on phytoplankton properties (species composition, biomass, volume). An increase in phytoplankton biomass did not always result in an increase of BPA, OP and NP concentrations. However, the load of the studied EDCs accumulated in phytoplankton biomass increase with a rise of biomass. An increase in BPA, OP and NP concentrations was effected by biomass growth and the proportions ofciliates, dinoflagellates, diatoms and green algae. A strong positive correlation between OP and NP concentrations and negative correlation between BPA concentrations and biomass of organisms with cells measuring <1000 μm3 in volume results from the differing properties of these compounds.
اظهر المزيد [+] اقل [-]Does zebra mussel (Dreissena polymorpha) represent the freshwater counterpart of Mytilus in ecotoxicological studies? A critical review
2015
Binelli, A. | Della Torre, C. | Magni, S. | Parolini, M.
One of the fundamentals in the ecotoxicological studies is the need of data comparison, which can be easily reached with the help of a standardized biological model. In this context, any biological model has been still proposed for the biomonitoring and risk evaluation of freshwaters until now. The aim of this review is to illustrate the ecotoxicological studies carried out with the zebra mussel Dreissena polymorpha in order to suggest this bivalve species as possible reference organism for inland waters. In detail, we showed its application in biomonitoring, as well as for the evaluation of adverse effects induced by several pollutants, using both in vitro and in vivo experiments. We discussed the advantages by the use of D. polymorpha for ecotoxicological studies, but also the possible limitations due to its invasive nature.
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