Hideshige Takada

Transport of sludge-derived organic pollutants to deep-sea sediments at deep water dump site 106

Linear alkylbenzenes (LABs), coprostanol and epi-co-prostanol, were detected in sediment trap and bottom sediment samples at the Deep Water Dump Site 106 located 185 km off the coast of New Jersey, in water depths from 2400 to 2900 m. These findings clearly indicate that organic pollutants derived from dumped sludge are transported through the water column and have accumulated on the deep-sea floor. No significant difference in LABs isomeric composition was observed among sludge and samples, indicating little environmental biodegradation of these compounds. LABs and coprostanol have penetrated down to a depth of 6 cm in sediment, indicating the mixing of these compounds by biological and physical processes

Molecular markers in Tokyo Bay sediments: Sources and distribution

The spatial distribution of different classes of molecular markers in Tokyo Bay sediments, a semi-enclosed system surrounded by one of the most urbanized areas in the world, has been investigated. In order to study the environmental stability of different chemical classes of sewage markers, their isomeric composition was determined in river particulate matter, waste-water influent and surficial sediments. Among the molecular markers characterized, linear alkylbenzenes (LAB) and trialkylamines (TAM) were the most useful for tracing the transport of contaminants from point-sources of pollution, because of their stability in sediments, and for assessing biodegradation processes during transport. Detection of LAB as well as TAM in the sediments outside of Tokyo Bay, more than 20 km from riverine inflow and 300 m water depth, clearly indicates long-range lateral transport of land-based pollutants.

Distribution of linear alkylbenzenes (LABs) and linear alkylbenzenesulphonates (LAS) in Tokyo bay sediments

Two types of land-derived pollutants, Linear alkylbenzenes (LABs) and linear alkylbenzenesulphonates (LAS), were measured in sediments from Tokyo Bay and the adjacent estuaries. LABs are widely distributed in the estuaries and the northern part of the bay, with relatively constant concentrations of ∼ 1 μg per g-dry sediments. In this area, ΣLAB contents showed no offshore decrease, indicating that LABs are not intensively trapped at the estuaries and can be transported great distances. The isomeric compositions of LABs indicate that the degree of LAB degradation in Tokyo Bay sediments is c. 50%. A zone with relative high LAB contents (> 2 μg g −1 ) is present c. 5 km off the mouths of the Tamagawa and Sumidagawa Rivers. LAS contents in the sediments rapidly decrease from > 10 μg g −1 in the upper estuaries to −1 in the lower estuaries. Furthermore, in Tokyo Bay sediments, LAS contents decreased offshore and fell below 0·01 μg g −1 10 km off the mouths of the rivers. These results indicate the rapid degradation of LAS in the coastal zone.

Sewage contamination in sediments beneath a deep-ocean dump site off New York

Abstract The worlds largest discharge of municipal sewage sludge to surface waters of the deep sea has caused measurable changes in the concentration of sludge indicators in sea-floor sediments, in a spatial pattern which agrees with the predictions of a recent sludge deposition model. Silver, linear alkylbenzenes, coprostanol, and spores of the bacterium Clostridium perfringens , in bottom sediments and in near-bottom suspended sediment, provide evidence for rapid settling of a portion of discharged solids, accumulation on the sea floor, and biological mixing beneath the water-sediment interface. Biological effects include an increase in 1989 of two species of benthic polychaete worm not abundant at the dump site before sludge dumping began in 1986. These changes in benthic ecology are attributed to the increased deposition of utilizable food in the form of sludge-derived organic matter.

Removal of linear alkylbenzenesulfonates (LAS) in the Tamagawa Estuary

Abstract To examine the processes for removal of organic micropollutants in an estuary, the anionic surfactants linear alkylbenzenesulfonates (LAS) were measured in the Tamagawa Estuary (Japan). Six surveys were conducted along axial transects from zero salinity to the river-mouth. The distributions of LAS in dissolved and suspended phases in the estuarine water were determined by high-performance liquid chromatography (HPLC). Mixing diagrams demonstrated that LAS are removed from the estuarine water throughout the salinity range (0.1–29ℵ.). In summer, LAS were completely removed, but in winter, 80% of LAS input from freshwater was removed in the estuary and the remaining 20% was discharged to Tokyo Bay. It is estimated that a few hundred kilograms of LAS per day are removed in the estuary. The isomeric compositions of LAS suggest that LAS were biodegraded in the estuary. LAS concentrations in the estuarine sediments also show a seaward decrease. Laboratory incubation experiments and mixing experiments as well as the above surveys indicate that LAS removal in the estuary is mainly caused by microbial degradation.

Quantitation of long-chain alkylbenzenes in environmental samples by silica gel column chromatography and high-resolution gas chromatography

Abstract A high-resolution (capillary) gas chromatographic method with preceding separation by silica gel column chromatography was established for quantitation of alkylbenzenes with normal C 10 ue5f8C 14 and branched C 11 ue5f8C 13 alkyl chains in sediment and suspended matter. This method is applicable to environmental samples containing nanogram amounts of alkylbenzenes per gram of sample (dry weight). The recoveries of alkylbenzenes are 81–94% and the reproducibility is good (relative standard deviation less than 12%).