Barnacles as biomonitors of trace metal availabilities in Hong Kong coastal waters: changes in space and time

The use of selected organisms as biomonitors of trace metal bioavailabiliti es allows comparisons to be made over space and time. The concentrations of 11 trace metals (arsenic, cadmium, chromium, cobalt, copper, iron, lead, m anganese, nickel, silver, zinc) were measured in the bodies of two barnacle species, Balanus amphitrite and Tetraclita squamosa, from up to 18 littora l sites from Hong Kong coastal waters in April 1998, These data provide evi dence on the geographical variation in metal bioavailabilities at this time , and are compared selectively against historical data sets for 1986 and 19 89. Geographical variation in bioavailabilities is clear for several metals , with hotspots for arsenic, copper, nickel and silver at Chai Wan Kok, and for lead in Junk Bay. Victoria Harbour sites head the rankings for silver and arsenic, and Tolo Harbour sites exhibit relatively elevated cobalt, man ganese and zinc. Many bioavailabilities of trace metals to barnacles are lo wer in Hong Kong coastal waters in 1998 than in 1986. The two barnacle spec ies are widespread and the extensive data set presented is a benchmark whic h can be compared to the results of similar biomonitoring programmes elsewh ere in the Indo-Pacific and beyond. (C) 2001 Elsevier Science Ltd. All righ ts reserved.