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Effects of H2S injection on the CO2-brine-sandstone interaction under 21MPa and 70°C
2016
Li, Chenyang | Zhang, Fengjun | Lyu, Cong | Hao, Jie | Song, Jianbin | Zhang, Shengyu
In this study, laboratory experiments were conducted to investigate the influences of H2S injection on the capacity of CO2’s solubility trapping and mineral trapping. Results demonstrated that the preferential dissolution of H2S gas into brine (compared with pure CO2) resulted in the decrease of pH, consequently inhibiting the CO2’s solubility trappings to some extent. Then, the lower pH droved more severe corrosion of primary minerals, favored more secondary mineral to be formed. In addition, the discovery of pyrite demonstrated that H2S could precipitate by the formation of sulfide mineral trapping. As the secondary carbon sink minerals, ankerite and dawsonite were observed in the pure CO2-brine-sandstone interaction. However, there were no secondary carbonates found through the SEM images and EDS analyses, implied that the injection of H2S probably may partially inhibit the precipitation of Fe-bearing carbonate minerals such as ankerite in the CO2-H2S-brine-sandstone interaction in this short term experiments.
Show more [+] Less [-]A semi-automated Raman micro-spectroscopy method for morphological and chemical characterizations of microplastic litter
2016
L., Frère | I., Paul-Pont | J., Moreau | P., Soudant | C., Lambert | A., Huvet | E., Rinnert
Every step of microplastic analysis (collection, extraction and characterization) is time-consuming, representing an obstacle to the implementation of large scale monitoring. This study proposes a semi-automated Raman micro-spectroscopy method coupled to static image analysis that allows the screening of a large quantity of microplastic in a time-effective way with minimal machine operator intervention. The method was validated using 103 particles collected at the sea surface spiked with 7 standard plastics: morphological and chemical characterization of particles was performed in <3h. The method was then applied to a larger environmental sample (n=962 particles). The identification rate was 75% and significantly decreased as a function of particle size. Microplastics represented 71% of the identified particles and significant size differences were observed: polystyrene was mainly found in the 2–5mm range (59%), polyethylene in the 1–2mm range (40%) and polypropylene in the 0.335–1mm range (42%).
Show more [+] Less [-]Variations in nitrate isotope composition of wastewater effluents by treatment type in Hong Kong
2016
Archana, A. | Li, Luo | Shuh-Ji, Kao | Thibodeau, Benoit | Baker, David M.
Stable isotopes (δ15N, δ18O) can serve as tracers for sources of nitrogen in the receiving environment. Hong Kong discharges ~3×106m3d−1 of treated wastewater into the ocean from 68 facilities implementing preliminary to tertiary treatment. We sampled treated sewage from 18 plants across 5 treatment types and examined receiving seawater from northeast Hong Kong. We analyzed nitrate and nitrite (NO3−+NO2−, hereafter NOx) ammonium (NH4+), phosphate (PO4+) concentrations and δ15NNOx, δ18ONOx. Sewage effluents contained high mean nutrient concentrations (NO3−=260μmolL−1, NH4+=1400μmolL−1, PO4+=50μmolL−1) with some indication of nitrogen removal in advanced treatment types. Mean δ15NNOx of sewage effluents from all plants and treatment types (12‰) was higher than natural sources and varied spatially and seasonally. There was no overall effect of sewage treatment type on δ15NNOx. A mass balance model indicated that sewage (>68%) remains a dominant source of nitrate pollution in seawater in Tolo Harbor.
Show more [+] Less [-]Environmental sensitivity mapping and risk assessment for oil spill along the Chennai Coast in India
2016
Kankara, R.S. | Arockiaraj, S. | Prabhu, K.
Integration of oil spill modeling with coastal resource information could be useful for protecting the coastal environment from oil spills. A scenario-based risk assessment and sensitivity indexing were performed for the Chennai coast by integrating a coastal resource information system and an oil spill trajectory model. The fate analysis of spilled oil showed that 55% of oil out of a total volume of 100m3 remained in the water column, affecting 800m of the shoreline. The seasonal scenarios show major impact during the southwest (SW) and northeast (NE) monsoons and more fatal effects on marine pelagic organisms during SW monsoon. The Oil Spill Risk Assessment Modeler tool was constructed in a geographic information systems (GIS) platform to analyze the risks, sensitivity mapping, and priority indexing of resources that are likely to be affected by oil spills along the Chennai coast. The results of sensitivity mapping and the risk assessment results can help organizations take measures to combat oil spills in a timely manner.
Show more [+] Less [-]Comparison of heavy metal contamination during the last decade along the coastal sediment of Pakistan: Multiple pollution indices approach
2016
Saher, Noor Us | Siddiqui, Asmat Saleem
Heavy metals concentrations (Fe, Cu, Zn, Ni, Cr, Co, Pb, and Cd) were scrutinized during two monitoring years (2001 and 2011) in the coastal sediment of Pakistan. The status of metal contamination in coastal sediment was interpreted using sediment quality guidelines, and single and combined metal pollution indices. Ni, Cr, and Cd were recognized for their significant (p<0.05) intensification in the sediment during the last decade. Sediment quality guidelines recognized the frequent adverse biological effect of Ni and the occasional adverse biological effect of Cu, Cr, Pb and Cd. Single metal pollution indices (Igeo, EF, CF, and ER) revealed that sediment pollution is predominantly caused by Pb and Cd. Low to moderate contamination was appraised along the coast by multi-metal pollution indices (CD and PERI). Correlation study specifies that heavy metals were presented diverse affiliations and carriers for distribution in the sediment during the last decade.
Show more [+] Less [-]Assessment of metal enrichment and their bioavailability in sediment and bioaccumulation by mangrove plant pneumatophores in a tropical (Zuari) estuary, west coast of India
2016
Noronha-D'Mello, Cheryl A. | Nayak, G.N.
Sediment collected from the estuarine mangroves of the Zuari estuary and Cumbharjua canal were analyzed to assess the concentration, contamination and bioavailability of metals. Mangrove pneumatophores were also analyzed to understand the metal bioaccumulation in mangrove plants. The results indicated the variation of metal concentrations in sediment along the estuary was attributed to changing hydrodynamic conditions, type of sediment and metal sources. Further, speciation studies revealed that Fe, Cr, Co, Ni, Cu and Zn were mainly of lithogenic origin and less bioavailable while high Mn content in the sediment raised concerns over its potential mobility, bioavailability and subsequent toxicity. The mangrove plants exhibited difference in metal accumulation due to variations in sediment parameters and metal availability, in addition to difference in plant species and tissue physiology that affect metal uptake. Moreover, the mangrove plants reflected the quality of the underlying sediment and can be used as a potential bio-indicator tool.
Show more [+] Less [-]Ultraviolet radiation as a ballast water treatment strategy: Inactivation of phytoplankton measured with flow cytometry
2016
Olsen, Ranveig Ottoey | Hoffmann, Friederike | Hess-Erga, Ole-Kristian | Larsen, Aud | Thuestad, Gunnar | Hoell, Ingunn Alne
This study investigates different UV doses (mJ/cm2) and the effect of dark incubation on the survival of the algae Tetraselmis suecica, to simulate ballast water treatment and subsequent transport.Samples were UV irradiated and analyzed by flow cytometry and standard culturing methods. Doses of ≥400mJ/cm2 rendered inactivation after 1day as measured by all analytical methods, and are recommended for ballast water treatment if immediate impairment is required. Irradiation with lower UV doses (100–200mJ/cm2) gave considerable differences of inactivation between experiments and analytical methods. Nevertheless, inactivation increased with increasing doses and incubation time. We argue that UV doses ≥100mJ/cm2 and ≤200mJ/cm2 can be sufficient if the water is treated at intake and left in dark ballast tanks. The variable results demonstrate the challenge of giving unambiguous recommendations on duration of dark incubation needed for inactivation when algae are treated with low UV doses.
Show more [+] Less [-]Trace metal bioavailability in sediments from a reference site, Ribeira Bay, Brazil
2016
Chiappetta, Janine M.M. | Machado, Wilson | Santos, Joana M. | Lessa, Josane A.
Surface sediments were collected near potential contamination sources impacting Ribeira Bay (Brazil), a system considered as a ‘reference site’ for trace metals. Physicochemical properties (pH and Eh), grain size and concentrations of total organic carbon (TOC), total phosphorus (TP), acid-volatile sulfides (AVS) and simultaneously-extracted metals (Fe, Mn, Cd, Cu, Ni, Pb and Zn) were analyzed. Although relatively low metal concentrations were found, correlations of Zn and Ni with high TP levels suggested an association with sewage inputs, while other metals presented associations with specific geochemical carriers (TOC, Fe and Mn compounds). AVS levels exceeding those of the sums of Cd, Cu, Ni, Pb and Zn (ΣSEM) by at least one order of magnitude and TOC-normalized differences between ΣSEM and AVS ((ΣSEM–AVS)/fOC) near to or below than −200μmolgOC−1 indicated that there were sufficient AVS and TOC levels to control trace metal bioavailability in sediment pore water.
Show more [+] Less [-]Response of humpback whales (Megaptera novaeangliae) to ramp-up of a small experimental air gun array
2016
Dunlop, Rebecca A. | Noad, Michael J. | McCauley, Robert D. | Kniest, Eric | Slade, Robert | Paton, David | Cato, Douglas H.
‘Ramp-up’, or ‘soft start’, is a mitigation measure used in seismic surveys and involves increasing the radiated sound level over 20–40min. This study compared the behavioural response in migrating humpback whales to the first stages of ramp-up with the response to a ‘constant’ source, ‘controls’ (in which the array was towed but not operated) with groups in the absence of the source vessel used as the ‘baseline’. Although the behavioural response, in most groups, resulted in an increase in distance from the source (potential avoidance), there was no evidence that either ‘ramp-up’ or the constant source at a higher level was superior for triggering whales to move away from the source vessel. ‘Control’ groups also responded suggesting the presence of the source vessel had some effect. However, the majority of groups appeared to avoid the source vessel at distances greater than the radius of most mitigation zones.
Show more [+] Less [-]SPECIEUROPE: The European data base for PM source profiles
2016
Pernigotti, Denise | Belis, Claudio A. | Spanò, Luca
A new database of atmospheric particulate matter emission source profiles in Europe (SPECIEUROPE) developed in the framework of the Forum for air quality modeling in Europe (FAIRMODE, Working Group 3) is accessible at the website http://source-apportionment.jrc.ec.europa.eu/Specieurope/index.aspx. It contains the chemical composition of particulate matter emission sources reported in the scientific literature and reports drafted by competent authorities. The first release of SPECIEUROPE consists of 151 measured (original), 13 composite (merging different subcategories of similar sources), 6 calculated (from stoichiometric composition) and 39 derived (results of source apportionment studies) profiles. Each profile is related to one or more source categories or subcategories. The sources with the highest PM relative mass toxic pollutants such as PAHs are fuel oil burning, ship emissions, coke burning and wood burning. Heavy metals are most abundant in metal processing activities while halogens are mostly present in fertilizer production, coal burning and metallurgic sector. Anhydrosugars are only measured in biomass and wood burning source categories, because are markers for these categories. The alkaline earth metals are mostly present in road dust, cement production, soil dust and sometimes coal burning. Source categories like traffic and industrial, which contain heterogeneous subcategories, show the greatest internal variability.The relationships between sources profiles were also explored using a cluster analysis approach based upon the Standardized Identity Distance (SID) indicator. The majority of profiles are allocated in 8 major clusters. Some of the clusters include profiles mainly from one source category (e.g. wood burning) while others, such as industrial source profiles, are more heterogeneous and spread over three different clusters.
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