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An approach based on M-AMBI for assessing benthic ecological status of a broad intertidal zone: A case study in the Jiangsu intertidal zone, China
2017
Song, Qiaochu | Zou, Xinqing | Zhang, Hu | Yu, Wenwen | Zang, Zheng | Wang, Chenglong
Intensive anthropogenic activities have a serious negative effect on the Jiangsu coastal area of China, especially on the distinctive intertidal zone. Humans are trying to eliminate this effect by taking protection and eco-compensation measures. However, when trying to determine the ecological status and quantify the anthropogenic impact for this area, the complex relationship between ecosystems and environmental stress leads to difficulties in reflecting general environmental quality. This study assessed the benthic ecological status of 10 transects (three stations/transect) across six different typologies over six years (2007, 2009–2013) in the Jiangsu intertidal zone. A unitary assessment of each transect was conducted using the multivariate AZTI Marine Biotic Index (M-AMBI), along with a radar chart (and its parameters). In the Jiangsu intertidal zone, the ecological status was noted as good or moderate at most sampling stations. Among the six assessed years, 2010 had the highest ecological status, while 2007 had the lowest. As for transects, transect 1 had the highest ratings, and transect 3 had the lowest ratings. Various stresses and advantageous human intervention and contributed to the ecological status for the different areas. The M-AMBI could be used in the future as a suitable index to assess the benthic ecological status of the Jiangsu intertidal zone. In addition, the new unitary method validated in this study could be used to assess ecosystems with several small biotopes, while accurately reflecting environmental quality.
Afficher plus [+] Moins [-]Pollution levels and risks of polycyclic aromatic hydrocarbons in surface sediments from two typical estuaries in China
2017
Wang, Chenglong | Zou, Xinqing | Li, Yali | Zhao, Yifei | Song, Qiaochu | Yu, Wenwen
To assess the environmental risks of polycyclic aromatic hydrocarbons (PAHs), 48 and 45 sediments were collected from the Yangtze River Estuary (YRE) and Pearl River Estuary (PRE), respectively. The toxicity equivalency concentration (TEQ) in the YRE and PRE were ranged from 1.68 to 76.13 and 9.28 to 129.24ngTEQg−1, respectively. Results of risk quotient suggest that ecological risks of two estuaries are at a moderate level, but are higher in the PRE than YRE. The increment lifetime cancer risks (ILCR) from the YRE via ingestion and dermal contact were 1×10−6 to 5.6×10−5 and 4×10−6 to 1.6×10−4, and ranged from 7×10−6 to 9.4×10−5 and 2×10−5 to 2.8×10−4 in the PRE. ILCR results suggest that some low and moderate cancer risk exists in the YRE and PRE. Therefore, monitoring and control measures should be carried out immediately to reduce or eliminate the risks to human health from environmental exposure.
Afficher plus [+] Moins [-]Occurrence of antiparasitic pesticides in sediments near salmon farms in the northern Chilean Patagonia
2017
Tucca, Felipe | Moya, Heriberto | Pozo, Karla | Borghini, Francesca | Focardi, S. (Silvano) | Barra, Ricardo
Growth of the aquaculture industry has triggered the need for research into the potential environmental impact of chemicals used by salmon farms to control diseases. In this study, the antiparasitic pesticides emamectin benzoate (EB), diflubenzuron (DI), teflubenzuron (TE), and cypermethrin (CP) were measured in sediments near salmon cages in southern Chile. Concentrations for EB were between 2.2 and 14.6ngg−1, while the benzoylphenyl ureas DI and TE were detected in the ranges of 0.1 to 1.2ngg−1 and 0.8 to 123.3ngg−1, respectively. These results were similar to data reported for the Northern Hemisphere. On the other hand, the pyrethroid CP was detected in higher concentrations, ranging from 18.0 to 1323.7ngg−1. According to reported toxicity data, this range represents a potential risk for benthic invertebrates. This report is the first baseline attempt at assessing antiparasitic pesticide levels in the Chilean Patagonia.
Afficher plus [+] Moins [-]The estimation for ballast water discharged to China from 2007 to 2014
2017
Zhang, Xiaofang | Bai, Mindong | Tian, Yiping | Du, Huan | Zhang, Zhitao
Ballast water has been identified as one of the main causes for worldwide transfer of non-indigenous marine species. The volume and source of ballast water are the fundamental elements for an evaluation of the risk posed. However, it is difficult to obtain the volume of ballast water discharged to China, because of the absence of information platform, and until now there is no public report. In this paper, the total volume of ballast water discharged to China and Chinese five major port-groups were estimated. Results showed: the total volume of ballast water exhibited a trend of slow increase from 2007 to 2014, and reached 311 million tons in 2014. Yangtze River Delta received the highest volume of ballast water among all port-groups. The information provided in this research may play an important role in helping policy decision-makers manage such coastal discharges.
Afficher plus [+] Moins [-]Assessment of nutrient and heavy metal contamination in the seawater and sediment of Yalujiang Estuary
2017
Li, Hongjun | Lin, Lin | Ye, Sheng | Li, Hongbo | Fan, Jingfeng
Yalujiang River is a famous border river between China and North Korea. In this study, 22 sample sites (seawater and sediments) were investigated to determine the concentrations of nutrients (dissolved inorganic nitrogen and soluble reactive phosphorus) and trace elements (Hg, As, Pb, Cu, Cd, Cr, and Zn) during the flood season (August). Generally, the concentration of nutrients were higher in the entrance of the estuary than that in the downstream region and the trophic index ranged from moderate to high production, indicating a potential eutrophication risk. With the exception of Cd, the mean concentrations of most metals attained the first level of seawater quality. Sediment pollution assessment was undertaken using contamination factor (CF) and geoaccumulation index (Igeo). The CF values of the seven trace elements were in the following order: Cd>Hg>Pb>As>Cu>Zn>Cr. Both CF and Igeo values indicated the elevated Cd and Hg concentrations in the region. Cluster analysis indicated that the sources of Cu, Cd, Cr, and Zn were mainly derived from copper mine and coastal industrial effluents, whereas Pb, Hg, and As were mainly from vehicle emissions and oil combustion. This study could provide a basis for the sustainable management of the marine ecosystem in this region.
Afficher plus [+] Moins [-]Potential health risk assessment of heavy metals via consumption of caviar of Persian sturgeon
2017
Sobhanardakani, S.
Caviar may contain high levels of toxic metals. Therefore determination of health risk assessment of the heavy metals in this luxury product is vital. In this study, an Inductively Coupled Plasma-Optical Emission Spectrometer and a Direct Mercury Analyzer were used to assess the contents of elements in caviar of wild Persian sturgeon. The results showed that the contents of Ba, Cr, Fe, Hg, Mn and Zn (mgkg−1) in caviar samples were 0.95, 0.27, 71.3, 1.44, 0.01 and 17.0, respectively. Also, Health Risk Index values were within the safe limits (HRI<1), and there is no potential health risk for adults and children via consumption of caviar. Finally, considering the contents of Fe and Hg were higher than Maximum Permissible Limits in the caviar samples related to the discharge of pollutants into the aquatic environment, monitoring of chemicals accumulation in the foodstuff is recommended.
Afficher plus [+] Moins [-]Assessing human exposure to PM10-bound polycyclic aromatic hydrocarbons during fireworks displays
2017
Pongpiachan, Siwatt | Hattayanone, Mattanawadee | Suttinun, Oramas | Khumsup, Chukkapong | Kittikoon, Itthipon | Hirunyatrakul, Phoosak | Cao, Junji
The “Loy Krathong” festival is a major annual Thai event that includes firework displays. It takes place on the evening of the full moon in the 12th month of the traditional Thai lunar calendar. Since fireworks are widely considered a major source of PAHs, it is considered reasonable to expect a significant increase in PAH levels during this event. The overall PAH profile at the six air quality observatories operated by the Pollution Control Department (PCD), Ministry of Natural Resources and Environment (MNRE), showed that the Kingdom of Thailand's atmosphere was dominated by 5–6-ring PAHs during the firework display period. A significant increase in ΣPAHs (153%) was observed during firework displays. A statistical analysis coupled with the application of diagnostic binary PAH ratios was conducted to determine whether the detected increase in PAH congeners during the festival period was due to firework combustion or whether it was a coincidental effect caused by vehicular exhausts, long-range atmospheric transportation, photolysis and chemical degradation. The average incremental lifetime cancer risk (ILCR) values of adults and children living in Bangkok as estimated by three different TEQs for ingestion, dermal contact, and inhalation exposure pathways were greatly lesser than the US EPA baseline, further highlighting that the cancer risk of bonfire night falls into the ‘‘acceptable level’’ range.
Afficher plus [+] Moins [-]Plastic debris and microplastics along the beaches of the Strait of Hormuz, Persian Gulf
2017
Naji, Abolfazl | Esmaili, Zinat | Khan, Farhan R
Currently little is known about the prevalence of plastics and microplastics (MPs) in the Persian Gulf. Five sampling stations were selected along the Strait of Hormuz (Iran) that exhibited different levels of industrialization and urbanization, and included a marine protected area. Debris was observed and sediments were collected for MPs extraction via fluidization/floatation methodology. The order of MP abundance (par/kg) generally reflected the level of anthropogenic activity: Bostanu (1258±291)>Gorsozan (122±23)>Khor-e-Yekshabeh (26±6)>Suru (14±4)>Khor-e-Azini (2±1). Across all sites fibers dominated (83%, 11% film, 6% fragments). FT-IR analysis showed polyethylene (PE), nylon, and PET (polyethylene terephthalate) were the commonly recovered polymers. Likely sources include beach debris, discarded fishing gear, and urban and industrial outflows that contain fibers from clothes. This study provides a ‘snapshot’ of MP pollution and longitudinal studies are required to fully understand plastic contamination in the region.
Afficher plus [+] Moins [-]Perfluorocarbon emissions from electrolytic reduction of rare earth metals in fluoride/oxide system
2017
Lizhi, Zhang | Xiufeng, Wang | Bin, Gong
Perfluorocarbons (PFC) are important greenhouse gas. In the aluminum electrolysis industry, PFC emission had been valued. The electrolytic reduction of rare earth metals in fluoride/oxide system with carbon anode and tungsten cathode also has PFC emission. But the PFC emission in rare earth metals industry received less attention. The PFC emissions during the electrolysis were studied by tracking the change of CF4 concentration in the flue gas of neodymium electrolysis and dysprosium-iron alloy electrolysis. The results showed that there were continuous CF4 overflows in the electrolysis process. The CF4 was outburst when anode effect occurred. The anode effect was always accompanied with the low electrolysis temperature. In addition, because of the electrolytic dysprosium-iron alloy requires higher cell voltage, the PFC emissions are higher than rare earth electrolysis. In general, PFC emissions from rare earth metal electrolysis are quite same as the aluminum electrolysis industry.
Afficher plus [+] Moins [-]A model for the weathering of Colombian crude oils in the Colombian Caribbean Sea
2017
Ramírez, Juan | Merlano, Aura | Lacayo, Juan | Osorio, Andres F. | Molina, Alejandro
A model that describes the weathering of crude in an oil spill caused by interaction with the atmosphere and the ocean was developed. This model was adapted to the Colombian crudes Cusiana (°API43.2) and Vasconia (°API20.7). To calibrate the model, evaporation and emulsification experiments were carried out at conditions similar to those of an oil spill in the Colombian Caribbean Sea. The dependence of evaporation with wind velocity, not predicted by the state-of-the-art models, was captured by a correlation for the mass transfer coefficient calculated from the experimental data. Emulsification rate, maximum water content and required evaporation to form an emulsion were determined and their values explained considering the effect of wax precipitation for Cusiana crude oil. When compared to well-established weathering software, such as ADIOS, the proposed model predicts the weathering of Colombian oils in a way that better agrees with the experiments conducted in the laboratory.
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