Observation of hazardous chemicals in seawater using a regular ferryboat service

Abstract

Hazardous chemicals in the sea are liable to be accumulated in marine ecosystems, and are transported by such mechanisms as oceanic and atmospheric currents. It is important to study these mechanisms in the ocean in order to understand the nature and extent of marine pollution from hazardous chemicals. A continuous-extraction sampling system for hazardous chemicals was developed and set up on a ferry (Kurosiwo). We tested the extraction rate of this system in a laboratory and in situ. The extraction rate was determined to be over 90%. The detection limit in 100 l of extracted seawater was about 5 pg l-1 for chlordane and 10 pg l-1 for HCHs. More than 70 samples were collected on the ferry (Kurosiwo) route from Osaka to Naha. Hazardous chemicals were collected by solid-phase extraction and analyzed by the GC/MS-SIM method. We determined the levels of hazardous chemicals, such as trans-chlordane, which ranged from the detection limit to 50 pg l-1, and α-HCH and β-HCH, which varied from 30 to 800 pg l-1. The spatial distribution of β-HCH was similar in all observations, while that of α-HCH varied with the weather condition.