The distribution of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) was examined according to particle size in marine sediments, with a particular focus on fine particulates. Samples from different coastal sites were fractionated into five size groups (<2, 2-5, 5-10, 10-20, and 20-63 microm diameter) by gravitational split-flow thin fractionation. Despite the different size profil...

An intermediate-scale flow cell experiment was conducted to study the removal of a DNAPL mixture from a layered porous medium through soil vapor extraction (SVE) with moist and dry air. A dual-energy gamma radiation system was used at various times to non-intrusively determine fluid saturations. The mixture, which contained the volatile organic carbon tetrachloride, mimics the DNAPL disposed at...

Groundwater contamination by fuel spills from aboveground and underground storage tanks has been of growing concern in recent years. This problem has been magnified by the addition of oxygenates, such as ethanol and methyl-tertiary-butyl ether (MTBE) to fuels to reduce vehicular emissions to the atmosphere. These additives, although beneficial in reducing atmospheric pollution, may, however, in...

The Holocene Rajang River delta plain, which covers an area of 6500 km, has developed in a tropical, ever-wet climatic setting. Peat deposits, up to 15 m thick, occur in this delta plain. The tributary system to the delta is about 50,000 km in area. Elevations exceed 2000 m in the drainage basin and hill slopes are steep. Rainfall in the region exceeds 370 cm/year, with highest rainfall levels ...