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In situ investigation of the mechanisms of the transport to tissues of polycyclic aromatic hydrocarbons adsorbed onto the root surface of Kandelia obovata seedlings Full text
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.
Show more [+] Less [-]Comparison between ultrafine and fine particulate matter collected in Lebanon: Chemical characterization, in vitro cytotoxic effects and metabolizing enzymes gene expression in human bronchial epithelial cells Full text
2015
Borgie, Mireille | Dagher, Zeina | Ledoux, Frédéric | Verdin, Anthony | Cazier, Fabrice | Martin, Perrine | Hachimi, Adam | Shirali, Pirouz | Greige-Gerges, Hélène | Courcot, Dominique
During the last few years, the induction of toxicological mechanisms by atmospheric ultrafine particles (UFP) has become one of the most studied topics in toxicology and a subject of huge debates. Fine particles (FP) and UFP collected at urban and rural sites in Lebanon were studied for their chemical composition and toxicological effects. UFP were found more enriched in trace elements, secondary inorganic ions, total carbon and organic compounds than FP. For toxicological analysis, BEAS-2B cells were exposed for 24, 48 and 72 h to increasing concentrations of FP, water-UFP suspension (UFPw) and UFP organic extract (UFPorg). Our findings showed that UFP caused earlier alterations of mitochondrial metabolism and membrane integrity from the lowest concentrations. Moreover, a significant induction of CYP1A1, CYP1B1 and AhRR genes expression was showed after cells exposure to UFPorg and to a lesser extent to UFPw and FP samples.
Show more [+] Less [-]What does impacted look like? High diversity and abundance of epibiota in modified estuaries Full text
2015
Clark, Graeme F. | Kelaher, Brendan P. | Dafforn, Katherine A. | Coleman, Melinda A. | Knott, Nathan A. | Marzinelli, Ezequiel M. | Johnston, Emma L.
Ecosystems modified by human activities are generally predicted to be biologically impoverished. However, much pollution impact theory stems from laboratory or small-scale field studies, and few studies replicate at the level of estuary. Furthermore, assessments are often based on sediment contamination and infauna, and impacts to epibiota (sessile invertebrates and algae) are seldom considered. We surveyed epibiota in six estuaries in south-east Australia. Half the estuaries were relatively pristine, and half were subject to internationally high levels of contamination, urbanisation, and industrialisation. Contrary to predictions, epibiota in modified estuaries had greater coverage and were similarly diverse as those in unmodified estuaries. Change in epibiota community structure was linearly correlated with sediment-bound copper, and the tubeworm Hydroides elegans showed a strong positive correlation with sediment metals. Stressors such as metal contamination can reduce biodiversity and productivity, but others such as nutrient enrichment and resource provision may obscure signals of impact.
Show more [+] Less [-]Temperature determines toxicity: Bisphenol A reduces thermal tolerance in fish Full text
2015
Little, Alexander G. | Seebacher, Frank
Bisphenol A (BPA) is a ubiquitous pollutant around the globe, but whether environmental concentrations have toxic effects remains controversial. BPA interferes with a number of nuclear receptor pathways, including several that mediate animal responses to environmental input. Because thermal acclimation is regulated by these pathways in fish, we hypothesized that the toxicity of BPA would change with ambient temperature. We exposed zebrafish (Danio rerio) to ecologically relevant and artificially high concentrations of BPA at two acclimation temperatures, and tested physiological responses at two test temperatures that corresponded to acclimation temperatures. We found ecologically relevant concentrations of BPA (20 μg l−1) impair swimming performance, heart rate, muscle and cardiac SERCA activity and gene expression. We show many of these responses are temperature-specific and non-monotonic. Our results suggest that BPA pollution can compound the effects of climate change, and that its effects are more dynamic than toxicological assessments currently account for.
Show more [+] Less [-]Effects of atrazine on egg masses of the yellow-spotted salamander (Ambystoma maculatum) and its endosymbiotic alga (Oophila amblystomatis) Full text
2015
Baxter, Leilan | Brain, Richard A. | Hosmer, Alan J. | Nema, Mohini | Müller, Kirsten M. | Solomon, Keith R. | Hanson, Mark L.
Embryonic growth of the yellow-spotted salamander (Ambystoma maculatum) is enhanced by the presence of the green alga Oophila amblystomatis, in the egg capsule. To further assess potential impacts of herbicides on this relationship, A. maculatum egg masses were exposed to atrazine (0–338 μg/L) until hatching (up to 66 days). Exposure to atrazine reduced PSII yield of the symbiotic algae in a concentration-dependent manner, but did not significantly affect visible algal growth or any metrics associated with salamander development. Algal cells were also cultured in the laboratory for toxicity testing. In the 96-h growth inhibition test (0–680 μg/L), ECx values were generally greater than those reported for standard algal test species. Complete recovery of growth rates occurred within 96-h of transferring cells to untreated media. Overall, development of A. maculatum embryos was not affected by exposure to atrazine at concentrations and durations exceeding those found in the environment.
Show more [+] Less [-]Impact of manufactured TiO2 nanoparticles on planktonic and sessile bacterial communities Full text
2015
Jomini, Stéphane | Clivot, Hugues | Bauda, Pascale | Pagnout, Christophe
In the present study, we conducted a 2 week microcosm experiment with a natural freshwater bacterial community to assess the effects of titanium dioxide nanoparticles (TiO2-NPs) at various concentrations (0, 1, 10 and 100 mg/L) on planktonic and sessile bacteria under dark conditions. Results showed an increase of planktonic bacterial abundance at the highest TiO2-NP concentration, concomitant with a decrease from that of sessile bacteria. Bacterial assemblages were most affected by the 100 mg/L TiO2-NP exposure and overall diversity was found to be lower for planktonic bacteria and higher for sessile bacteria at this concentration. In both compartments, a 100 mg/L TiO2-NPs exposure induced a decrease in the ratio between the Betaproteobacteria and Bacteroidetes. For planktonic communities, a decrease of Comamonadaceae was observed concomitant with an increase of Oxalobacteraceae and Cytophagaceae (especially Emticicia). For sessile communities, results showed a strong decrease of Betaproteobacteria and particularly of Comamonadaceae.
Show more [+] Less [-]Colocalization of low-methylesterified pectins and Pb deposits in the apoplast of aspen roots exposed to lead Full text
2015
Rabęda, Irena | Bilski, Henryk | Mellerowicz, Ewa J. | Napieralska, Anna | Suski, Szymon | Woźny, Adam | Krzesłowska, Magdalena
Low-methylesterified homogalacturonans have been suggested to play a role in the binding and immobilization of Pb in CW. Using root apices of hybrid aspen, a plant with a high phytoremediation potential, as a model, we demonstrated that the in situ distribution pattern of low-methylesterified homogalacturonan, pectin epitope (JIM5-P), reflects the pattern of Pb occurrence. The region which indicated high JIM5-P level corresponded with “Pb accumulation zone”. Moreover, JIM5-P was especially abundant in cell junctions, CWs lining the intercellular spaces and the corners of intercellular spaces indicating the highest accumulation of Pb. Furthermore, JIM5-P and Pb commonly co-localized.The observations indicate that low-methylesterified homogalacturonan is the CW polymer that determines the capacity of CW for Pb sequestration. Our results suggest a promising directions for CW modification for enhancing the efficiency of plant roots in Pb accumulation, an important aspect in the phytoremediation of soils contaminated with trace metals.
Show more [+] Less [-]Can we improve pollen season definitions by using the symptom load index in addition to pollen counts? Full text
2015
Bastl, Katharina | Kmenta, Maximilian | Geller-Bernstein, Carmi | Berger, Uwe | Jäger, Siegfried
Airborne pollen measurements are the foundation of aerobiological research and provide essential raw data for various disciplines. Pollen itself should be considered a relevant factor in air quality. Symptom data shed light on the relationship of pollen allergy and pollination. The aim of this study is to assess the spatial variation of local, regional and national symptom datasets. Ten pollen season definitions are used to calculate the symptom load index for the birch and grass pollen seasons (2013–2014) in Austria. (1) Local, (2) regional and (3) national symptom datasets are used to examine spatial variations and a consistent pattern was found. In conclusion, national datasets are suitable for first insights where no sufficient local or regional dataset is available and season definitions based on percentages provide a practical solution, as they can be applied in regions with different pollen loads and produce more constant results.
Show more [+] Less [-]The effects of lead sources on oral bioaccessibility in soil and implications for contaminated land risk management Full text
2015
Palmer, Sherry | McIlwaine, Rebekka | Ofterdinger, Ulrich | Cox, Siobhan F. | McKinley, Jennifer M. | Doherty, Rory | Wragg, J. (Joanna) | Cave, Mark
Lead (Pb) is a non-threshold toxin capable of inducing toxic effects at any blood level but availability of soil screening criteria for assessing potential health risks is limited. The oral bioaccessibility of Pb in 163 soil samples was attributed to sources through solubility estimation and domain identification. Samples were extracted following the Unified BARGE Method. Urban, mineralisation, peat and granite domains accounted for elevated Pb concentrations compared to rural samples. High Pb solubility explained moderate-high gastric (G) bioaccessible fractions throughout the study area. Higher maximum G concentrations were measured in urban (97.6 mg kg−1) and mineralisation (199.8 mg kg−1) domains. Higher average G concentrations occurred in mineralisation (36.4 mg kg−1) and granite (36.0 mg kg−1) domains. Findings suggest diffuse anthropogenic and widespread geogenic contamination could be capable of presenting health risks, having implications for land management decisions in jurisdictions where guidance advises these forms of pollution should not be regarded as contaminated land.
Show more [+] Less [-]Levels and source apportionment of children's lead exposure: Could urinary lead be used to identify the levels and sources of children's lead pollution? Full text
2015
Cao, Suzhen | Duan, Xiaoli | Zhao, Xiuge | Wang, Beibei | Ma, Jin | Fan, Delong | Sun, Chengye | He, Bin | Wei, Fusheng | Jiang, Guibin
As a highly toxic heavy metal, the pollution and exposure risks of lead are of widespread concern for human health. However, the collection of blood samples for use as an indicator of lead pollution is not always feasible in most cohort or longitudinal studies, especially those involving children health. To evaluate the potential use of urinary lead as an indicator of exposure levels and source apportionment, accompanying with environmental media samples, lead concentrations and isotopic measurements (expressed as 207Pb/206Pb, 208Pb/206Pb and 204Pb/206Pb) were investigated and compared between blood and urine from children living in the vicinities of a typical coking plant and lead-acid battery factory. The results showed urinary lead might not be a preferable proxy for estimating blood lead levels. Fortunately, urinary lead isotopic measurements could be used as an alternative for identifying the sources of children's lead exposure, which coincided well with the blood lead isotope ratio analysis.
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