• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 1
  • Tagged with
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Polychlorinated Biphenyls and Hexachlorobenzene in SurficialSediments of Kao-Ping Chi Estuary and Nearby Coastal Areas

Yang, Yi-Ning 24 August 2004 (has links)
Persistent Organic Pollutants (POPs), such as Polychlorinated Biphenyls (PCBs) or Hexachlorobenzene (HCB), released into water system. They will adsorb to particles, and incorporate into sediments. Thus the concentrations of PCBs and HCB in surface sediments provide information on recent contaminations. Besides, organisms in marine environment are influenced by the concentration in sediments, and so as the food chain. This study investigated the concentrations and characteristics of PCBs and HCB in surficial sediments of Kao-Ping Chi Estuary and nearby areas. The concentrations of PCBs and HCB in sediments were ranged from 1.432 to 6.681 (ng/g dry wt), and from 0.151 to 8.109 (ng/g dry wt¡^¡Awith an average of 3.219 and 1.978, respectively. Both of PCBs and HCB did not exceed the concentrations suggested by several sediment quality guidelines (SQGs). Compared with studies in other countries, the sediments in Kao-Ping coastal areas were more polluted by HCB. Neither PCBs nor HCB could correlate well with mean particle size or total organic carbon (TOC). The Toxic equivalents (TEQ) of dioxin-like PCBs and HCB were ranged from 0.014 to 0.061 pg-TEQ/g, and from 0.015 to 0.811 pg-TEQ/g, respectively. Using Principal Component Analysis, four possible principal components were found. These four principal components could account for 89.29% of the total variance. The first principal component was composed of highly chlorinated PCBs. The second principal component was composed of particle mean size and TOC. And the third and the fourth principal component were composed of di-, tri- PCBs and HCB. According to the factor score plot, the sample stations in this study could be divided into four groups. The first group was the stations that near the shore. The second group which contained stations were 4Km offshore. The third group contained stations with highly chlorinated PCBs. And the fourth group only contained one stations, D16. It was possible that there were other sources influenced station D16. In conclusion, the pollution in the surficial sediments was influenced by the distances from the pollutant sources and the particle size affected by tidal effect.

Page generated in 0.0571 seconds