LABs concentrations in sediments and suspended particles collected at the same locations during the surveys in Malaysia and Vietnam were compared on a dry weight basis (mg/g-dry). The respective ranges of PLABs concentrations in the suspended particles from Malaysia and Vietnam were 0.007–16.9 mg/g-dry and 0.013–40.6 mg/g-dry, while those in the sediments were 0.004–8.59 g/g-dry and 0.003–8.65 mg/g-dry. The
PLABs concentrations in the sediments were one order of magnitude lower than those in the suspended particles. This can be explained by a mechanism in which LABs in the rivers and coastal waters are adsorbed onto sewage particles; sewage particles are
fine, light, and readily resuspended from the bottom sediment containing large amounts of relatively heavy particles such as soil particles. Resuspension of these fine
sewage particles with LABs probably resulted in higher PLABs concentrations in the suspended particles compared to those in the sediment. However, in Jakarta,
the PLABs concentrations in sediments were almost comparable to the weight-base PLABs concentrations in raw sewage, i.e., STP influents in Tokyo of 7.51–81.4 mg/g-dry (mean=42.3 mg/g-dry, n=5). This implies that sewage particles are deposited in the locations without significant dilution with soil particles.