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Результаты 691-700 из 2,512
Pyrene induces a reduction in midbrain size and abnormal swimming behavior in early-hatched pufferfish larvae Полный текст
2014
Sugahara, Yuki | Kawaguchi, Masahumi | Itoyama, Tatsuya | Kurokawa, Daisuke | Tosa, Yasuhiko | Kitamura, Shin-Ichi | Handoh, Itsuki C. | Nakayama, Kei | Murakami, Yasunori
Spills of heavy oil (HO) have an adverse effect on marine life. We have demonstrated previously that exposure to HO by fertilized eggs of the pufferfish (Takifugu rubripes) induces neural disruption and behavioral abnormality in early-hatched larvae. Here, two kinds of polycyclic aromatic hydrocarbons, pyrene and phenanthrene, were selected to examine their toxic effects on larval behavior of another pufferfish species (T. niphobles). Larvae exposed to pyrene or phenanthrene exhibited no abnormalities in morphology. However, those exposed to pyrene but not phenanthrene swam in an uncoordinated manner, although their swimming distance and speed were normal. The optic tectum, a part of the midbrain, of pyrene-exposed larvae did not grow to full size. Thus, these findings are indicated that pyrene might be a contributor to the behavioral and neuro-developmental toxicity, although there is no indication that it is the only compound participating in the toxicity of the heavy oil mixture.
Показать больше [+] Меньше [-]Increased zooplankton PAH concentrations across hydrographic fronts in the East China Sea Полный текст
2014
Hung, Chin-Chang | Ko, Fung-Chi | Gong, Gwo-Ching | Chen, Kuo-Shu | Wu, Jian-Ming | Chiang, Hsin-Lun | Peng, Sen-Chueh | Santschi, Peter H.
The Changjiang has transported large quantities of polycyclic aromatic hydrocarbons (PAHs) to the East China Sea (ECS), but information of these pollutants in zooplankton is limited. To understand PAHs pollution in zooplankton in the ECS, total concentrations of PAHs in zooplankton from surface waters were measured. Values of PAHs ranged from 2 to 3500ngm−3 in the ECS, with highest PAHs levels located at the salinity front between the Changjiang Diluted Water (CDW) and the mid-shelf waters. In contrast, concentrations of zooplankton PAHs in the mid-shelf and outer-shelf waters were significantly lower (2–23ngm−3) than those in the CDW. These results demonstrate that PAHs are conspicuously accumulated in zooplankton at the salinity front between the CDW and the mid-shelf waters. These higher levels of PAHs in zooplankton at the salinity front may be further biomagnified in marine organisms of higher trophic levels through their feeding activities.
Показать больше [+] Меньше [-]Polychlorinated dibenzo-p-dioxins and dibenzofurans detected in bivalve samples from the NOAA National Status and Trends Program Полный текст
2014
Wade, Terry L. | Sweet, Stephen T. | Sericano, José L. | DeFreitas, Debra A. | Lauenstein, Gunnar G.
Bivalve samples from 142 sites were analyzed to determine the concentration and toxicity equivalents (TEQ) of dioxins and furans (D/F) as part of the NOAA National Status and Trends Program. The total concentration of 17 D/F ranged from not detected to 203pg/g wet weight of tissue. Octachlorinated dibenzo-p-dioxin, OCDD, had a concentration range from not detected to 189pg/g and a mean concentration of 8.65pg/g. OCDD was the dominant D/F compound detected and accounted for, on average, over 70% of the total D/F concentration. The TEQ (compared to 2,3,7,8-TCDD) ranged from 0.12 to 7.32pg TEQ/g. The TEQ for 39% of the bivalves analyzed were below 0.238pg TEQ/g. TEQ above human consumption advisory concentration of 1.2pg TEQ/g were found in 9.3% of the samples analyzed. TEQ for D/F indicate very limited human health concerns from consumption of bivalves at most of the locations sampled.
Показать больше [+] Меньше [-]Metal pollution status in Zhelin Bay surface sediments inferred from a sequential extraction technique, South China Sea Полный текст
2014
Surface sediments collected from Zhelin Bay, the largest mariculture base of eastern Guangdong Province, were analyzed for total metal concentrations and chemical speciation. The results demonstrated that the average total concentration (mg/kg) ranges were 36.7–65.8 (Pb), 53.8–98.8 (Cr), 39.0–87.1 (Ni), 50.9–144.5 (Cu), and 175.0–251.2 (Zn), which were clearly higher with respect to their corresponding benchmark values. The predominant speciation of Pb was reducible and comprised a residual fraction, whereas a major portion (57.6–95.4%) of Cr, Ni, Cu, and Zn was strongly associated with the residual fractions. Taking as a whole, surface sediments of Zhelin Bay had a 21% probability of toxicity based on the mean effects range–median quotient.
Показать больше [+] Меньше [-]Baseline survey of trace metals in ambient PM10 at Tummalapalle uranium mining site Полный текст
2014
Trace metals (Ag, Al, As, Cd, Co, Cr, Cs, Cu, Fe, Mn, Ni, Pb, Se, Sr, Tl, U, V and Zn) in PM10 were measured at 10 different sites in the surrounding areas of Tummalapalle Uranium Mining (India). The PM10 samples were collected on glass fiber/EPM 2000 filter using high volume air samplers in 10 different sampling sites during November–2010 to February–2012. Trace metals in PM10 were analyzed using Inductively Coupled Plasma Mass Spectrometer (ICP–MS). The observed trace metal concentrations varied from 0.01 to 2 640ng/m3. It was found that metals associated with crustal sources like Al and Fe were in higher concentrations. The elements Tl, U, Cs and Co were found to be in very low concentrations. Obtained trace metal data in PM10 were subjected to statistical analyses using correlation matrices and factor analysis to examine the interrelationship between the investigated trace elements and possible source identification of the elements. Enrichment factors of trace metals were also determined to determine the anthropogenic contribution to ambient PM10. The daily intake of analyzed trace metals by the adult population in the surrounding of Tummalapalle Uranium mining (30km radial distance) was estimated and it was found to be in the range of 1 to 13 401ng/day through the inhalation route.
Показать больше [+] Меньше [-]The mass concentration and optical properties of black carbon aerosols over a semi–arid region in the northwest of China Полный текст
2014
Black Carbon (BC) is the predominant absorption component of atmospheric aerosols, and it is believed to be the second largest contributor to global warming. Calculating its radiative forcing requires observational data regarding its physical, chemical and optical properties, so observation is the foundation of this research. The Semi–Arid Climate and Environment Observatory of Lanzhou University aims to improve our understanding in this regard by capturing direct evidence of the impact of human activity on the semi–arid climate over the Loess Plateau of Northwestern China. In this paper, the period from November 2010 to February 2011, which is within the heating period, was selected in order to study the optical properties of BC, such as its depolarization ratio, extinction coefficient, optical depth, Ångström exponent and effective radius. The average BC concentration was 2 334±1 546ng/m3 during the observation. The diurnal evolution of BC concentration had two maximums, which appeared at 10:00 and 20:00 (local time), and two minimums, which appeared at 03:00 and 16:00. The average Aerosol Optical Depth (AOD) during the observation was 0.26±0.2, the aerosols existed mostly between the surface of the Earth and a height of 3km, and the extinction coefficient decreased with height. The average of the depolarization ratio between the surface of the Earth and a height of 3km, the Ångström exponent (α440/870nm) and the effective radius of black carbon aerosols were 0.24, 0.86±0.30 and 0.54±0.17μm, respectively. The maximum distribution frequency of α440/870nm was 27%, with a range of 1.0 to 1.2. The maximum distribution frequency of the effective radius was 28%, with a range of 0.4μm to 0.5μm.
Показать больше [+] Меньше [-]Ethylene vinyl acetate polymer as a tool for passive sampling monitoring of hydrophobic chemicals in the salmon farm industry Полный текст
2014
Current monitoring programs are focused on hydrophobic chemicals detection in aquatic systems, which require the collection of high volumes of water samples at a given time. The present study documents the preliminary use of the polymer ethylene vinyl acetate (EVA) as a passive sampler for the detection of a hydrophobic chemical used by salmon industries such as cypermethrin. Initially, an experimental calibration in laboratory was performed to determine the cypermethrin equilibrium between sampler and aquatic medium, which was reached after seven days of exposure. A logarithm of partitioning coefficient EVA–water (logKEVA–W) of 5.6 was reported. Field deployment of EVA samplers demonstrated average concentrations of cypermethrin in water to be 2.07±0.7ngL−1 close to salmon cages, while near-shore was 4.39±0.8ngL−1. This was a first approach for assessing EVA samplers design as a tool of monitoring in water for areas with salmon farming activity.
Показать больше [+] Меньше [-]History of bioavailable lead and iron in the Greater North Sea and Iceland during the last millennium – A bivalve sclerochronological reconstruction Полный текст
2014
Holland, Hilmar A. | Schöne, Bernd R. | Marali, Soraya | Jochum, Klaus P.
We present the first annually resolved record of biologically available Pb and Fe in the Greater North Sea and Iceland during 1040–2004 AD based on shells of the long-lived marine bivalve Arctica islandica. The iron content in pre-industrial shells from the North Sea largely remained below the detection limit. Only since 1830, shell Fe levels rose gradually reflecting the combined effect of increased terrestrial runoff of iron-bearing sediments and eutrophication. Although the lead gasoline peak of the 20th century was well recorded by the shells, bivalves that lived during the medieval heyday of metallurgy showed four-fold higher shell Pb levels than modern specimens. Presumably, pre-industrial bivalves were offered larger proportions of resuspended (Pb-enriched) organics, whereas modern specimens receive fresh increased amounts of (Pb-depleted) phytoplankton. As expected, metal loads in the shells from Iceland were much lower. Our study confirms that bivalve shells provide a powerful tool for retrospective environmental biomonitoring.
Показать больше [+] Меньше [-]Communities of sediment ammonia-oxidizing bacteria along a coastal pollution gradient in the East China Sea Полный текст
2014
Hou, Manhua | Xiong, Jinbo | Wang, Kai | Ye, Xiansen | Ye, Ran | Wang, Qiong | Hu, Changju | Zhang, Demin
Anthropogenic nitrogen (N) discharges has caused eutrophication in coastal zones. Ammonia-oxidizing bacteria (AOB) convert ammonia to nitrite and play important roles in N transformation. Here, we used pyrosequencing based on the amoA gene to investigate the response of the sediment AOB community to an N pollution gradient in the East China Sea. The results showed that AOB assemblages were primarily affiliated with Nitrosospira-like lineages, and only 0.4% of those belonged to Nitrosomonas-like lineage. The Nitrosospira-like lineage was separated into four clusters that were most similar to the sediment AOB communities detected in adjacent marine regions. Additionally, one clade was out grouped from the AOB lineages, which shared the high similarities with pmoA gene. The AOB community structures substantially changed along the pollution gradient, which were primarily shaped by NH4+–N, NO3−–N, SO42−–S, TP and Eh. These results demonstrated that coastal pollution could dramatically influence AOB communities, which, in turn, may change ecosystem function.
Показать больше [+] Меньше [-]Environmental variabilities and the distribution of octocorals and black corals in Hong Kong Полный текст
2014
Yeung, C.W. | Cheang, C.C. | Lee, M.W. | Fung, H.L. | Chow, W.K. | Ang, P.
A recent comprehensive survey covering 125 sites in Hong Kong waters recorded 29 soft coral species in 14 genera, 38 species of gorgonians in 19 genera and six species of black corals in two genera. Environmental variabilities based on water quality data collected by Hong Kong Environmental Protection Department were analyzed using multivariate statistics to find variables that are significantly correlated with coral distribution patterns. Eleven water quality zones with similar environmental variabilities were recognized, which could further be classified into five groups, namely Inner Bay, Outer Bay, Eastern, Western and Southern waters. LINKTREE analysis provided an overall trend indicating the importance of salinity, sediment and nutrient loadings in affecting octocoral and black coral distribution from west to east of Hong Kong waters, and from inner to outer bays. Furthermore, water turbidity and wave exposure could also affect the coral distribution patterns from north, northeast to southern waters.
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