A study of heavy metal and organochlorine contamination in marine parks using perna viridis (green mussels) as a biomonitor  

Project Title: A Study of Heavy Metal and Organochlorine Contamination in Marine Parks using Perna Viridis (Green Mussels) as a Biomonitor

Applicant: Hong Kong Baptist University

Total Approved Grant: $305,600 (Actual Expenditure: $255.099.71)

Duration: Feb 2000 - July 2001

Project Status/Remarks: Completed

Scope: To use perna viridis (green mussels) as a basis for systematic assessment fo the impact of anthropogenic pollution in marine park areas.

Summary of the Findings/Outcomes:

Monitoring of trace metals in coastal waters using marine sediments and green mussels provided updated information on metals pollution in Hong Kong from Marine Parks, mariculture zones and nearshore stations in Victoria and Tolo Harbour. Significantly higher concentrations of some metals in marine sediments were generally found in highly populated urban areas and areas close to industrial zones, such as Causeway Bay, Kwun Tong, Lo Tik Wan and Tai Po Industrial Estate.

In contrast to the metal concentrations found in marine sediments, higher concentrations of some metals in green mussels were found in the sampling sites on the west coast such as the power plant site at Tap Shek Kok and the Marine Park at Lung Kwu Chau, indicating the main contributor of metal load to the northwestern waters of Hong Kong is the Pearl River. The pollution status of metals in marine sediments and green mussels were also well reflected by metal pollution criteria. Marine sediments in Hong Kong coastal waters were contaminated by Cr, Cu, Ni, Pb and Zn to different degrees, ranging from uncontaminated to seriously contaminated according to sediment criteria set by the Hong Kong Government (WB, 2000). Marine sediments were considered to be uncontaminated by Cd and Hg.

As to metal bioavailability in green mussels, most metal concentrations were well below the local shellfish standards. In addition, the results from the public health assessment showed that metals in green mussels through dietary consumption do not pose possible health risks. Thus, at the present time, it is not necessary to be overly concerned about the consumption of green mussel from local waters. In addition, since metal bioavailability in green mussels tend to reflect "more recent" contamination, there is an apparent improvement in Cd, Cr, Cu, Pb and Ni levels in coastal waters from 1990 to 2000.