Isolation of tributyltin-degrading bacteria citrobacter braakii and enterobacter cloacae from butyltin-polluted sediment

Tributyltin compound (TBT) released into the aquatic environment is generally degraded by bacteria in water and sediment. The isolation of TBT-degrading bacteria from TBT polluted sediment leads to the indication of specific potential TBT degraders. Two new strains of bacteria designated as B2 and B3 were successfully isolated using glycerol medium containing tributyltin chloride (TBTC) at 130 μM from contaminated sediment collected from Bowling Basin in Glasgow. The observed degradation after 14 days of the microcosm from the sediment and the isolated bacteria were investigated at an initial concentration of 1 μM TBTC. It was found that TBT was degraded by the bacterial strains B2 and B3 at 8.3 and 16.9 %, respectively. The results indicate that B2 and B3 are effective as TBT degraders. EC50 of B2 and B3 in water were 88.73 and 112.53 μM TBTC, which were significantly higher than the concentration of TBT measured at the basin, suggesting a low effect of TBT on the growth and activity of bacteria. After identification using API 20E and 16S sequencing, the bacterial isolate strain B2 is Citrobacter braakii and B3 is Enterobacter cloacae. Therefore, this study has discovered two species of high resistance TBT degrader which have never been previously studied or isolated based upon TBT degradation ability

Environmental fate and partition co-efficient of oestrogenic compounds in sewage treatment process

The presence of residual pharmaceuticals and environmental endocrine disrupters (EEDs) is increasingly significant due to their impact on human health and wildlife. Of the compounds implicated as EEDs, the most potent in their oestrogenic effect are the natural and synthetic oestrogens. As these compounds will be present in the sewage matrix, it is necessary to establish their fate during sewage treatment with a view of removal and safe disposal to avoid unnecessary exposure. Using methodology developed by the author this paper describes the results of a study undertaken to determine both the Kow and the adsorption characteristics of these oestrogens. The experimental values obtained were compared to a computational default model. However, there was disparity between the default model and the values determined experimentally. This was especially the case in the determination of the Koc which impacts directly on the sludge adsorbance potential. The calculated results ranged from log 4.21 for β-oestradiol to log 4.68 for 17α-EE-3-ME, the experimental results were higher log(5.04-log 5.83), respectively. The implications of the findings in terms of water recycling and sewage sludge disposal are also discussed

Synchronous fluorescence spectroscopic technique: the tool for rapid identification of polycyclic aromatic hydrocarbons (PAHs) at sub-ppm level in liquid samples

Various polycyclic aromatic hydrocarbons (PAHs) at sub-ppm level were identified qualitatively by synchronous scanning fluorescence technique at various wavelength intervals. Due to the difference in chemical structure, each PAHs gives specific characteristic spectrum for each wavelength intervals. This work demonstrated that the synchronous scanning fluorescence method can be used as a tool for the rapid identification of PAHs in ethanolic sample which contain three or six types of PAHs such as fluorene, truxene, benzo(k) fluoranthene, carbazole, chrysene, anthracene, acenaphthene and indeno(1,2,3,cd)pyrene in mixture

Introduction and overview of the Thai-Laos Mekong River

The Mekong is an essential source of water and protein for the denizens of Thai Laos countries. However historic pollution is adversely affecting the water and sediment quality that threatens the short- and long-term supply-use of this major river system. This can have a major impact on the health and population of the marine life and ultimately adversely affect human health and the economy for both countries

The ecological complexity of the Thai-Laos Mekong River : II. Metals and polyaromatic hydrocarbons (PAHs) monitoring, modelling and environmental fate

The Mekong is an essential source of water and protein for the denizens of Thai Laos countries. It is hypothesized that pollution may be adversely affecting the water and sediment quality, which threatens the short and long-term use of this major river system. This directly impacts on the health and population of the aquatic life and ultimately human health and the economy for both countries is affected. The quality of the river can be assessed from various chemical and physical parameters, such as PAHs and metals content of both the water and the sediment. The introduction of Environmental Quality Standards (EQS) allows comparison of the values obtained with the guidelines. Furthermore the modelling program EPISUITE was used to determine the environmental partitioning of pollutants within the different environmental compartments. Using the data produced for PAHs and metals the experimental model was compared to the default model. This involved experimentally measuring the log Koc forMekong sediments and from this determining the log Kow. High availability in sediment of pollutants may lead to greater biomagnification in bethnic fish, which may then be hazardous for human consumption even if it is safe for the species that is accumulating pollutants. The potential for this is shown by the calculated accumulation in biota Cbio values exceeding both the Chronic value (ChrV) and Lethal Concentration 50 (LC50) for fish in the Mekong River. When compared to the EQS guidelines the amount of some PAHs, cadmium and lead in sediment were above the lowest effect level but below the severe effect level

The effect of KD and KOC on the environmental fate of cadmiun and benzo(a)pyrene in the Mekong river

Paper discussing the effect of KD and KOC on the environmental fate of cadmiun and benzo(a)pyrene in the Mekong river

Comparative evaluation of the microwave-assisted extraction on closed system and sonication for the extraction of polycyclic aromatic hydrocarbons from sediments

This paper discusses the comparative evaluation of the microwave-assisted extraction on closed system and sonication for the extraction of polycyclic aromatic hydrocarbons from sediments. It was discussed at the 2nd Asian international conference on ecotoxicology and environmental saftey in 2004

Environmental monitoring of the sediment pollution along the Thai: Laos Mekong

The Mekong is an essential source of water and protein for the denizens of Thai Laos countries. However historic pollution is adversely affecting the water and sediment quality that threatens the short- and long-term supply/use of this major river system. This can have a major impact on the health and population of the marine life and ultimately adversely affect human health and the economy for both countries. As a first stage in the assessment of the scale and extent of the pollution problem, an in-depth program of sampling and analysis has been carried out for both water and sediments for three seasons since 2000. A range of water quality parameters were measured from ten sampling stations. These included the PolyAromatic Hydrocarbons (PAHs) initially measured as chrysene equivalents, then as individual compounds of fluorene, phenanthrene, anthracene, fluoranthene, pyrene, benzo(a)anthracene, chrysene, benzo(b)fluoranthene, benzo(k)fluoranthene, benzo(a)pyrene, dibenzo(a,h)anthracene, benzo(g,h,i)perylene, and indeno(1,2,3,cd)pyrene. A range of heavy metals were measured including chromium, cadmium, mercury, copper, zinc, lead, and titanium. This paper presents the results of the field study to date and provides a preliminary evaluation of the extent of the pollution and potential for bioaccumulation within the local food chain

Optimization of microwave-assisted extraction of polycyclic aromatic hydrocarbons from sediments

The extraction methods for the determination of polycyclic aromatic hydrocarbons (PAHs) from spiked sediment containing benzo[k]fluoranthene, chrysene, acenaphthene, anthracene, carbazole and indeno[1,2,3-c,d]pyrene, using pressurised microwave-assisted extraction (PMAE) and sonication extraction were optimised. Each PAH in the spiked sediment was quantified by using the spectrofluorometric method. The optimised methods were compared on the extraction efficiency of 14 PAHs in a certified sediment reference material, LGC6188. Recoveries of 14 PAHs were performed by HPLC-DAD at 254 nm using the standard addition method. The results showed that the most extraction efficient method was pressurised microwave-assisted extraction with cyclohexane:acetone (3:2) for 15 min at 140% boiling point of acetone. Under this condition for the extracted certified sediment reference material recovery was 96.55%. It can be concluded from the experimental results that pressurised microwave-assisted extraction in a closed system provides a good alternative to sonication extraction for the extraction of PAHs from sediments. Furthermore, the PMAE was also applied to determine PAHs from sediments taken from the main entrance of Kasetsart University on Paholyotin road in Bangkok

Monitoring and modeling of metals, bis-phenol A and PAH contaminants in the Thai-Laos Mekong

Paper discussing the monitoring and modeling of metals, bis-phenol A and PAH contaminants in the Thai-Laos Mekong