Water Resources Research Act Program

Principal Investigators: Gary Denton, Peter Houk, Harold Wood

Abstract: Tanapag Lagoon borders the western shore of central Saipan. It harbors a rich diversity of marine life and supports a variety of commercial and recreational activities. Over the last quarter century, Tanapag Lagoon has become heavily impacted by the activities of man. Primary sources of anthropogenic disturbance in these waters include a power station and commercial port (Saipan Harbor), two small boat marinas, a sewer outfall, several garment factories, auto and boat repair shops, wood shops, government vehicle maintenance yards, a commercial laundry, and an acetylene gas producer. There are also a number of old military dumps and disposal sites in the area as well as a 50-year-old municipal dump that served as the islands only solid waste disposal site until its closure a little over a year ago.Several streams and storm drains empty into the lagoon during the rainy season and provide a mode of transport into the ocean for any land-based contaminants. Overflows from sewer lines are also commonplace at this time of the year and the whole area is inundated by storm water runoff during periods of prolonged wet weather. The effects of these perturbations on the indigenous biota within the lagoon are largely unknown. Likewise, fundamental data describing the abundance and distribution of persistent and potentially toxic pollutants within the system is also lacking.Mindful of these shortcomings, a contaminant assessment of surface sediments within Tanapag Lagoon was recently completed and a bioindicator survey of the nearshore waters is currently underway. The project described herein proposes to determine contaminants of potential concern (heavy metals, pesticides and PCBs) in important food fishes from within the lagoon and is seen as a logical extension of these studies.The study will focus on those species commonly taken by local fishermen for food and recreational purposes. Emphasis will be given to fish that are relatively restricted in their movement and spend much if not all of their time in the lagoon. Sampling will be conducted in seagrass beds and patch reef areas throughout the lagoon encompassing both nearshore and offshore habitats. Specimens will be collected by cast-net, beach-seine, spear gun, and hook and line. The assistance of local personnel and other government agencies in procuring samples will be obtained as necessary.The analytical work will be carried out at the Water and Environmental Research Institute (WERI), Water Quality Laboratory, at the University of Guam, where adequate support facilities, infrastructure, essential chemicals and items of equipment necessary for the study are present. The primary objectives of the study are to evaluate contaminant levels in popular table fish from within the lagoon and identify potential health risks (if any) associated with their long-term ingestion. By including territorial species the results will also help identify and delineate areas of contaminant enrichment, and add significantly to the contaminant database required for future trend monitoring purposes.