Trace metals in marine organisms from four harbours in Guam.

Historically, marine resources have provided a major protein source for the people of Guam, and fishing is still and important commercial and recreational activity. Local inhabitants commonly harvest a variety of algae, molluscs, crustaceans, sea cucumbers and fish for sale and home consumption (Amesbury et al., 1986). These resources have been relatively protected from the adverse effects of pollution generated by the industrial nations of the world due to Guam’s geographic isolation (13 48 0N, 144 80 0E). However, the island has supported a sizable military presence since WWII and has undergone tremendous commercial growth (especially in the tourism and hospitality industry) and urban expansion over the last 20 years. Such developments have greatly contributed to the waste disposal, pollution and environmental management problems confronting the island today. Prior to the mid-1990s, very little was known about the degree of chemical contamination in Guam’s coastal waters. Management strategies are currently being developed for the sustainable development of resources within this ecologically sensitive area. These include the identification and evaluation of major coastal pollution sources and the health risks to consumers of contaminated fisheries, through the establishment of a major monitoring program. This paper reports on the baseline study of trace metals in marine organisms from four harbours (Fig. 1) where contaminated and clean sites had been identified in an earlier sediment study (Denton et al., 2005). Species selected for study were from various trophic levels, in addition to those frequently harvested for human consumption. Attention was also paid to biotic groups popularly used as bioindicators of trace metal pollution. Biota sampling sites were selected on the basis of sediment contamination profiles identified by Denton et al. (1997) and preliminary biodiversity assessments. Full details are given in Denton et al. (1999), and are summarised in Table 1. A full list of species sampled at each site is given in Table 2. Not all species were available at all the sites studied. Biota were collected between June 1998 and January 1999. In most cases, sampling was by scuba diving, handpicking off the reef, ocean floor or from the sides of submerged structures. Shellfish were removed from their point of attachment using a hammer and chisel. Fish were captured by spear gun and hook and line. All samples, except bivalves were immediately wrapped in aluminium foil and placed on ice. The bivalves were held in clean seawater for approximately 6 h to facilitate depuration. In the laboratory, all organisms were thoroughly cleaned of epiphytic growth and/or adhering particulate material before sub-sampling for analysis. With algae, the holdfasts and older, more encrusted portions of the plant were discarded and only the fronds were taken for analysis. With the sponges, it was necessary to carefully pare away sediment laden portions of the exterior and interior surfaces prior to sub-sampling. The sponges and ascidians were analysed whole, and the entire soft parts of the bivalves were taken for analysis. In contrast, specific tissues were removed from the sea cucumbers (dorsal body wall The objective of BASELINE is to publish short communications on different aspects of pollution of the marine environment. Only those papers which clearly identify the quality of the data will be considered for publication. Contributors to Baseline should refer to ‘Baseline—The New Format and Content’ (Mar. Pollut. Bull. 42, 703–704).