On the occurrence and origins of hopanoids in the Chesapeake Bay (Maryland, virginia)

Analyses of surface sediment samples from the Chesapeake Bay and sediment cores from the James and the Potomac River showed that pentacyclic triterpenoids of the hopanoid skeleton were ubiquitously present in all samples. The hopanoids have been identified and quantified by gas chromatographic retention data obtained on SE-52 stationary phase, and mass spectral comparisons with the branched/cyclic fraction of a Lorraine coal extract as well as published data from authentic standards. Hopanoid acids are of extended 17(beta)(H), 21(beta)(H)-structure, ranging from C(,31) to C(,33). The 17(beta)(H), 21(beta)(H)-bishomohopanoic acid (C(,32)) is always the major acid found in the samples. All acids were present as a single epimer (22R). The 17(alpha)(H), 21(beta)(H)-hopane series is predominant in all the samples, with lesser amounts of the 17(beta)(H), 21(beta)(H)-hopane series and some hopenes also present. The extended 17(alpha)(H), 21(beta)(H)-hopanes (\u3e C(,31)) are found as mixtures of the 22R and 22S diastereomers. This indicates that there is a significant input of fossil hopanes into the Chesapeake Bay. Generally, high concentrations were found at river-mouth stations and in the northern Bay areas associated with industrial activities and intense urban development. These results are consistent with an anthropogenic source for the aromatic hydrocarbons present in the samples. Fossil hopanes appear to derive from a variety of sources including coal, crude oil, refined motor oil, asphalt particles and street dust. A comparison of hopanoid distributions in Bay sediments with possible source materials suggests that motor oil, asphalt particles and street dust are potentially important sources of fossil hopanes to the Bay. There is evidence that the input of hopanoids to surface soils is related to highway usage. These source materials and the associated fossil hopanes are reaching the Bay via natural and urban runoff, either directly or via river transport. Final accumulation in Bay sediments is evident from the elevated concentrations of fossil hopanes at river-mouth stations. These accumulations indicate that rivers are important sources of fossil hopanes to the Bay. An anomaly in the S/R ratio of the 17(alpha)(H), 21(beta)(H)-homohopane (C(,31)) in many sediment samples from the Bay is interpreted as evidence of a microbially induced isomerization of 17(beta)(H), 21(beta)(H)-C(,31) hopane (R) to 17(alpha)(H), 21(beta)(H)-C(,31) hopane (R). . . . (Author\u27s abstract exceeds stipulated maximum length. Discontinued here with permission of author.) UMI

Petroleum hydrocarbon contamination in seawater along the Western Coast of the Philippines

A study on petroleum hydrocarbon concentrations in seawater from the South China Sea off the western coast of the Philippines was conducted during April to May 1998. The concentrations of dissolved/dispersed petroleum hydrocarbons (DDPH) in seawater samples were measured at 31 stations, using Ultraviolet Fluorescence (UVF) Spectroscopy technique. The DDPH concentrations were found to be in the range of 0.02 - 1.47 µg/l as chrysene equivalent, with an average of 0.25 µg/l. An attempt was made to compare between petroleum hydrocarbons in seawater samples from the near-shore area (8 stations) and the offshore area (23 stations). It was found that the DDPH concentrations of the near-shore stations were in the range of 0.03 - 0.47 µg/l, with an average of 0.12 µg/l, whereas the DDPH concentrations of the offshore stations were in the range of 0.02- 1.47 µg/l, with an average of 0.29 µg/l. However, the student’s t-test of the two data groups indicated that the two means were not significantly different at a = 0.05

Petroleum hydrocarbon in seawater and some sediments of the South China Sea, area I: Gulf of Thailand and east coast of Peninsular Malaysia

Petroleum hydrocarbon in water samples and sediments collected during the Pre-Southwest Monsoon Cruise in the Gulf of Thailand and Eastern Peninsular Malaysia in April-May 1996 point out that land-based and sea-based sources were both important. High concentration (> 0.5 mg/l) found in coastal water of the northern part and western part near Songkhla-Pattani could be derived from land-based sources. Elevated concentration of petroleum hydrocarbons in seawater and residuals in sediments of the central area of the Gulf could be originated from offshore activities. However physical oceanography of the Gulf could also play very important roles in redistribution, dispersion and accumulation of petroleum hydrocarbon in the water

Distribution of Trace Elements in Sediments and Biota of Songkhla Lake, Southern Thailand

The concentrations of Co,Ni, Cu, Zn, Cd, Pb,As, Fe, Mn, and Al were determined in sediments and biota of Songkhla Lake, a shallow coastal lagoon located in southern Thailand. In June 2006, surface sediments were sampled in 44 stations in the three sections of the lake (inner-, middle-, and outer sections). Sediment cores were also sampled in 13 stations in three cross-sections of the lake. In surface sediments, trace and major elements, organic matter, sediment grain size analysis, and sulfides were determined, and in the sediment cores, redox profiles were made. Soil samples were also collected at garbage dumping sites in the vicinity of the lake. In addition, the metal accumulation in two catfish species (Arius maculatus and Osteogeneiosus militaris) and the crustacean (Apseudes sapensis) was also investigated. Trace element concentrations in sediments of Songkhla Lake show that, especially the Outer section of the lake, in particular the sediments atthe mouths of the Phawong, U-Taphao, and Samrong Canals are significantly enriched with trace elements due to municipal, agricultural, and industrial discharges entering the lake through the canals. Aluminumnormalized enrichment factors throughout the lake vary from 0.4 to 1.7 for Ni, 0.3 to 3.3 for Cu, 0.2 to 7 for Zn, 0.1 to 14 for As, 1 to 24 for Cd, 0.7 to 6.8 for Pb, and 0.1 to 7.8 for Mn. Correlations between the elements and sediment characteristics show that Cu, Zn, Cd, and Pb are essentially associated with the sulfide fraction; that Ni and Co are predominantly bound to the clay minerals and iron oxy-hydroxides, and that As is principally bound to iron oxy-hydroxides. The accumulation of trace elements between muscle tissue and liver and eggs of A. maculatus and O. militaris is element-specific, but concentrations of trace elements in fish muscle tissue are well within the limits for human consumption

Marine environmental status in the Thai waters

The marine environment in Thailand has been degraded by various pollutants arising both from land-based sources and from heavy shipping traffic, together with the accompanying accidental oil spills. Domestic wastes in the coastal waters of major cities are much evident. High levels of heavy metals in marine organisms are occasionally reported. The observed elevated mercury levels in some areas provide a warning of potential risk in the Gulf. Pesticide residues were detected in sediment and mussel samples. Low-level hydrocarbon pollution to some degree occurs most of the time in the Upper Gulf and the Eastern Sea Board. Polycyclic aromatic hydrocarbons (PAHs) were identified in the water, sediment and biota samples. Tributyltin (TBT) was also detected in water, sediment and biota samples. Gastropods collecting near major shipping lanes all had imposex characteristics. Although marine pollution levels have been reported to be acceptable in Thai waters, management measures to minimize pollutant loading are needed to reduce long-term risk to the marine environment

Petroleum pollution in the Gulf of Thailand: A historical review

With its rapid economic growth in the past three decades, Thailand is encountering serious environmental problems. Among these, the issue of environmental pollution caused by oil has become increasingly important because their usage in large quantities have resulted in negative impacts on marine and coastal ecosystems including health effects on wildlife. Major oil spills are of public concern and usually under control of pollution authorities. However, small oil spills occurring in offshore areas due to ship operations are usually uncontrolled, unaccounted in oil spill balance and have smaller public concern. A review is presented of the database generated to the present concerning petroleum hydrocarbons in waters and sediments of the Gulf of Thailand. Historical changes in the extent of contamination are discussed and assessed by comparison to data produced elsewhere. In general, the level of petroleum contamination in the Thai waters is low to medium level compared with more urbanized and industrialized countries. Nevertheless, continuous monitoring and investigations on the level of petroleum contamination are still needed in Thailand.Proceedings of the Horiba International Conference "New Direction of Ocean Research in the Western Pacific" : Past, Present and Future of UNESCO/IOC/WESTPAC Activity for 50 years and the JSPS Project "Coastal Marine Science"Section II: Historical Review of Coastal Research in Southeast Asi

Status of butyltin contamination in Thailand coastal waters

The aquatic pollution by tributyltin (TBT) arising from anti-fouling paints has been of great concern due to their effect of shell malformation in oysters, mortality of the larvae of mussels and imposex in gastropods, which occur at a very few nanogram per liter of aqueous TBT concentrations. Studies show that TBT is a widespread problem and posing a threat to sensitive species in coastal areas where shipping traffic intensities are above a certain level and in the vicinity of harbours. The occurrences of gastropod imposex and butyltin contamination in seawater, sediments, and green mussels from coastal waters of Thailand have been carried out since 1995 in order to assess the status of TBT contamination in the Thai coastal waters. Studies indicated that TBT contamination was a problem in areas with shipyards and repairing facilities or associated with elevated activities of ocean-going vessels or commercial shipping. The situation of TBT contamination in the Thai waters, however is improving; although several TBT hotspots in sediments still exist in the inner Gulf of Thailand and high levels of imposex are still being reported from the east coast of Phuket Island. Restrictions on the use of TBT antifouling paints are in the process of being implemented whereas Coastal Water Quality Standard for TBT has already been imposed. More data are needed on TBT levels in other marine organisms for further evaluation