50 research outputs found
A web GIS based study for managing mangroves of Krishna Delta, Andhra Pradesh, India
Mangroves are one among the most productive ecosystem which provide a wide range
of services to the coastal people, which includes the provision of food and timber products and coastal
defense services by reducing risk from coastal hazards. Several research found that mangrove forests
have been degraded throughout the world since 80s onwards due to anthropogenic factors and India is
no exception for the same. The current study was conducted in the Krishna’s wetland, which is
located in Krishna district of Andhra Pradesh (AP), South India, India. The Mangroves of Krishna is
second largest mangrove ecosystem in AP, fifth in East coast, eighth in India and it is rich in
biodiversity but highly vulnerable because of anthropogenic and natural factors which makes this
study area very scared. Information on Krishna mangroves and their geospatial information are owned
by different institutions to build this geospatial dataset as open to access everyone. The WebGIS is a
latest advancement and hybrid of GIS and Internet technologies for the dissemination of the
geospatial datasets and its variations through the web. The main objective of the current study is to
develop and demonstrate a WebGIS using open source software and integrate geospatial datasets of
the mangroves of Krishna into WebGIS platform and to analyse and assess areas that are degraded by
influenced parameters and in need of sustainable management.The result revealed that the area of
mangroves in Krishna was decreased from 2,454 ha in 1990 to 1,363 ha in 2000 to 1,339 ha in 2011.
On the other hand the areas of mangroves in the Krishna delta were increased to about 678 ha from
1990 to 2000 and 2,230 ha from 2000 to 2011. It may be pointed out that the variation in mangrove
covers in the study area due to land use conversion for different purposes and mangroves provides
coastal defense services by reduce risk of coastal hazards. It is may be concluded that this WebGIS
study is very useful and unique because it is sharing data through internet to everyone as it save
money, time and data duplication, which are needed to different stakeholders such as researchers,
decision makers, planners for the sustainable management of mangrove ecosystem
Investigation on the corrosion behavior of physical vapor deposition coated high speed steel
This work emphasizes on the influence of the TiN and AlCrN coatings fabricated on high speed steel form tool using physical vapor deposition technique. The surface microstructure of the coatings was studied using scanning electron microscope. Hardness and corrosion studies were also performed using Vickers hardness test and salt spray testing, respectively. The salt spray test results suggested that the bilayer coated (TiN- bottom layer and AlCrN- top layer) substrate has undergone less amount of corrosion, and this is attributed to the dense microstructure. In addition to the above, the influence of the above coatings on the machining performance of the high speed steel was also evaluated and compared with that of the uncoated material and the results suggested that the bilayered coating has undergone very low weight loss when compared with that of the uncoated substrate depicting enhanced wear resistance
Accumulation of brominated flame retardants and polychlorinated biphenyls in human breast milk and scalp hair from the Philippines: Levels, distribution and profiles
Paired human breast milk and scalp hair samples (n=. 30) were obtained in 2008 from primipara and multipara mothers living in two locations in the Philippines viz., Payatas, a waste dumpsite, and Malate, a non-dumpsite. Samples were analyzed for three groups of organohalogenated compounds, such as polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs) and hexabromocyclododecanes (HBCDs). PCBs were the predominantly identified compounds (median: 70. ng/g lipid wt.) in all the breast milk samples. In the human milk, CB-153 was the most dominant PCB congener (17-44% contribution to the sum PCB), closely followed by CB-138 (12-35%), CB-118 (4-12%), CB-180 (2-13%), CB-187 (3-13%), and CB-170 (1.5-10%). Levels of PBDEs (median: 3.0. ng/g lipid wt.) in human milk samples from the Philippines were similar to other Asian or European countries. BDE-47, -99, -100 and -153 were the major PBDE congeners. For HBCDs, the α-isomer was predominant followed by the γ-HBCD isomer in the both locations. PBDE levels in human milk were significantly higher in the dumpsite (3.9. ng/g lipid wt.) than in the non-dump site (2.2. ng/g lipid wt.). PBDE concentrations (including BDE-209) were significantly higher (median: 70. ng/g hair) than those of PCBs (median: 30. ng/g hair) and HBCDs (median: 1.0. ng/g hair) in all the scalp hair samples. To our knowledge, this is the first report on HBCDs in human scalp hair. PBDE congeners in scalp hair were dominated by BDE-209 and BDE-47. On a congener basis, the levels of PBDEs found in scalp hair were higher than those in Spain (children and adults) and China (general people). PCB levels found in scalp hair were higher than those in Greece, Romania and Belgium, but lower than those in China. In this study, there were no significant differences in the concentration of PCBs and HBCDs in human milk; and PCBs, HBCDs and PBDEs in human scalp hair from the two different locations. No significant correlations were observed between PCBs, PBDEs and HBCDs levels and age of mothers in this study, which may be due to the small number of samples. Furthermore, there was no correlation between milk and hair levels for more persistent compounds (PCB-153, PCB-138, or BDE-47), and thus it is worthy to follow-up in future studies along with more number of samples. This is the first report to provide measurement data for PCBs, PBDEs and HBCDs in paired milk and hair of populations in the Philippines. © 2012 Elsevier B.V
Development and validation of a quantitative UHPLC-MS/MS method for selected brominated flame retardants in food.
<p>An ultra-high performance liquid chromatography - tandem mass spectrometry (UHPLC-MS/MS) method was developed and validated (in-house) for the quantification of selected brominated flame retardants (BFRs), including tetrabromobisphenol A (TBBPA), hexabromocyclododecanes (HBCDs), tetrabromobisphenol S (TBBPS) and bromophenols (BPs), in various food matrices. The sample preparation consisted of extraction of TBBPS with acidified acetonitrile followed by a fast dispersive solid-phase extraction (dSPE) clean-up and extraction of the other BFRs with a mixture of hexane and dichloromethane (1:1, v/v) with subsequent clean-up using acidified silica (44%, w/w). The limits of quantification of the method varied widely for the types of food matrices and the different classes of BFRs from 4 pg g(-1) wet weight (ww) to 8 ng g(-1) ww. For most of the analytes the apparent recovery was in the range 70-120%, and the method precision (under repeatability conditions) was below 20%. The method was successfully applied in proficiency testing exercises as well as for analysis of various food items. Only 25% of the collected food samples contained BFRs, with 4-bromophenol and α-HBCD as the only detected compounds. The contaminated foodstuffs were fish and eggs with concentrations in the range from 48 to 305 pg g(-1) ww.</p></p
Determination of halogenated flame retardants in food: optimization and validation of a method based on a two-step clean-up and gas chromatography-mass spectrometry
In this work, a new simple method based on a two-step clean-up and gas chromatography-mass spectrometry analysis for the determination of emerging halogenated flame retardants (HFRs), such as dechlorane plus (DP) and brominated phthalates, and polybrominated diphenyl ethers (PBDEs) in different food items was optimized and validated. Several types of food items, i.e. fish (smoked salmon and cod fillet), meat (chicken breast), chicken eggs, cow milk, and extra virgin olive oil, were chosen as representative matrices of the main food categories. After lyophilisation, the food samples were extracted using acetonitrile:toluene (9:1, v/v). As interferences, such as lipids and pigments, were co-extracted, a two-step clean-up (including Florisil and acid silica) was performed to efficiently remove them prior to GC-MS analysis in electron capture negative ionization mode (GC-ECNI/MS). The performance criteria established by the European Commission (2014/118/EU) were achieved with this method for all target analytes, except for the LOQ achieved for BDE-209 (0.1 ng/g wet weight, ww). The trueness ranged between 75 and 125% for most compounds and the matrices analyzed and the repeatability (expressed as RSD%) was <20%, within the set performance criteria. The method was then used for the determination of PBDEs and emerging HFRs in 20 different food items purchased from Antwerp supermarkets, revealing a prevalent contamination with PBDEs (up to 2.02 ng/g ww) and tribromoanisole (up to 6.6 ng/g ww) in the fish/seafood category.</p
Contamination of benzotriazole ultraviolet stabilizers in house dust from the Philippines: Implications on human exposure
Seven compounds of benzotriazole ultraviolet stabilizers (BUVSs) were determined in house dust samples collected from a residential area (Malate: n = 17) and municipal dumping area (Payatas: n = 20) in the Philippines. Total concentrations of the 7 BUVSs in house dust ranged from ND (not detected) to 1020. ng/g in Malate and ND to 277. ng/g in Payatas. Among the target compounds, the most abundant BUVS was UV-234, with a median value of 84. ng/g (ND-813. ng/g) in Malate and 41. ng/g (ND-212. ng/g) in Payatas, respectively. Significantly higher concentrations of UV-326 (p \u3c 0.01) and UV-327 (p \u3c 0.05) were found in house dust samples from Malate than those from Payatas, suggesting that the household products are the major sources of contamination in the indoor microenvironment. The estimated daily intakes (EDIs) of BUVSs through house dust ingestion in the Philippines were two to four orders of magnitude lower than the guideline values. However, the EDI of 5 BUVSs for toddlers in this study was 5 times higher than those for adults, suggesting that toddlers are at higher risk. House dust may be an important exposure route of UV-234 (88%) and UV-326 (69%) in worst-case scenarios, which using high dust ingestion and worst-case exposure (P95). To our knowledge, this is the first comprehensive study on BUVSs in house dust samples from Asian developing countries and reporting the occurrence of UV-234 and UV-320 in dust samples. © 2012 Elsevier B.V