Distributions of persistent pollutants in surficial sediments in the coast of southwestern Taiwan

Compared with volatile or biodegradable compounds, persistent pollutants present different problems and behaviors in a marine environment. They are not subject to any breakdown within a practical time-scale; in other words, they are a permanent addition to the environment. In south western Taiwan, there are many pollution sources such as large petrochemical complexes, harbors, electrochemical industries, etc. along the coast line. Chlorobenzenes, unavoidable by products of petrochemical and agrochemical manufacturing professes, and metals were selected for study in this investigation. Two cruises (ORIII, Taiwan, ROC) were taken to collect surficial sediments in estuaries of major rivers and outfall fields in the coast of southwestern Taiwan. Assessment of metallic input from human activities, as opposed to input from natural biogeochemical processes, is very complicated. Results from metallic contents analysis showed that the <63 μm portion sediment analysis gave much more reasonable data than the total fraction analysis. For example, the lowest metallic contents from analysis of <63 μm fraction were samples from Feng Kung estuary, which should be the least polluted area. The analysis of total sediment did not show this trend