Animal collections. Tube-forming amphipods, Ampehsca abdita, were obtained from tidal 

 flats in Bourne Cove, a small inlet in Buzzards Bay, Massachusetts by collecting sediments 

 and sieving them through a 0.5-mm screen. A. abdita were collected by flotation from the 

 air/ water interface (Gentile et al., 1987). The animals were transferred to 3-L jars containing 

 approximately 5 to 7 cm of collection site sediment in aerated ambient seawater. The 

 amphipods were gradually acclimated under static seawater conditions at 1-3°C per day to 

 the test temperature of 20°C. During acclimation, they were fed Skeletonema sp. (1.0 x lO'' 

 cells per mL) at the rate of 200 mL of algae per 3-L jar daily. Temperature, dissolved 

 oxygen, salinity, and pH were measured in alternating jars daily during acclimation. 



Test Procedures. Dense populations of native Ampehsca abdita had been previously observed 

 at many locations in San Francisco Bay (Chapman et al, 1987; Hopkins, 1986) Therefore, 

 sediments were press-sieved wet through 2-mm mesh in an attempt to remove any native 

 animals. If additional amphipods or tubes were observed in the samples, they were 

 removed. Approximately 12 h prior to the initiation of the test, 200 mL (about 4 cm) of the 

 test sediment was placed into the exposure chambers with flowing, gently aerated seawater. 

 Test animals were sieved from the holding sediments. Twenty healthy amphipods of 

 uniform size were placed into each exposure chamber. Moribund or outsized animals were 

 replaced. Test animals were either subadults or females to avoid the natural mortality of 

 males associated with reproductive activity. The test organisms were not fed during the 10-d 

 exposure. The exposure chambers were 1-L mason jars with a 2-cm diameter overflow hole 

 covered with a 0.5-mm mesh Nitex screen near the top. An inverted 9-cm finger bowl with a 

 2-cm diameter hole functioned as a lid. Air delivery and seawater delivery tubes were fixed 

 through the hole in the lid and positioned to minimize sediment disturbance. Inflowing 

 filtered seawater was delivered via an intermittent flow system at a rate of about 18 

 turnovers per vessel per day. The 90 percent volume replacement time was estimated to be 

 approximately 3 h according to the method of Sprague, 1973. 



Tests under static exposure conditions similar to those used with the R. abronius test were 

 set up for aliquots from 3 of the 15 stations. A capillary tube was inserted through each lid 

 for air delivery. 



The exposure chambers were monitored daily for dead and emerged amphipods. Dead 

 animals were removed and the number recorded. Additionally, the number of emerged 

 animals (on the sediment or water surface) and molts were recorded daily for each test 

 chamber and the molts were removed. At the end of the 10-d exposure, all sediments were 

 sieved through a 0.5-mm mesh screen. All survivors were enumerated and those unaccounted 

 for were counted as dead. In order to minimize sample storage time, two batches of samples 

 were tested: The first batch consisting of sample numbers 1, 2, 3, 4, 5, 6, 7, 8, and 9; the second 

 consisting of sample numbers 10, 11, 12, 13, 14, and 15. Static and flow-through tests were 

 performed concurrently in the same manner on samples from the amphipod collection site 

 (Bourne Cove) which were regarded as control samples. 



Water temperature and salinity were measured daily in the batch controls and 

 maintained at 20 ± 1°C and 31 to 34 ppt, respectively. Deionized water was added to all 

 samples in a batch if the salinity in the respective batch controls reached 34 ppt. The 

 dissolved oxygen concentration and pH were measured each day in one of the five replicates 

 of each sample on a rotating basis so that these parameters were measured twice in each 

 replicate during the 10-d exposures. Based upon all of the measurements, the dissolved 

 oxygen concentration and pH ranged from 6.2 to 8.2 mg/L and 7.3 to 8.3, respectively. 



Sediment Elutriate Toxicity Test with Embryos of the Mussel Mytilus edulis 



This toxicity test was developed for use in Puget Sound (Chapman and Morgan, 1983) and 

 has been used in many environmental surveys (Chapman et al., 1987; Tetra Tech, 1985; 

 Williams et al, 1986). 



Animal collections. Adult mussels (M. edulis) were collected from Deep Cove, Indian Arm, 

 British Columbia. Mussels were placed in a 70-L polypropylene conditioning tray to permit 



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