Field Methods 
Since metals were chosen as the initial pollutants of interest, a completely 
metal-free apparatus was desired for deploying mussels in the Field. In view of 
potential use by other investigators, a simple, relatively inexpensive apparatus 
which was easy to deploy and service was a secondary goal of the design 
process. The present apparatus is shown in Figure 3-3. 
A plastic float is attached to a concrete weight by approximately two meters 
of polypropylene line. The mussel holding baskets, 15 x 15 x 15 cm 
polypropylene test tube baskets with snap-on lids, are suspended from the line 
approximately 1 meter above the sediment surface. 
A Mytilus monitoring station is deployed in a two-step operation. The 
apparatus, minus the mussel baskets, is lowered to the bottom in 5 to 8 m of 
water, after which typically eight mussel baskets are taken down and 
suspended in groups of four from the line by SCUBA DIVERS. The 
deployment operation requires 10 to 15 minutes on-station and subsequent 
sampling of about five minutes. Each basket of 20 mussels serves as a 
subsample, thereby allowing removal of the desired sample without disturbing 
the remaining mussels. Samples for metals analyses are immediately transferred 
to “ziploc” polypropylene bags and frozen until analyzed. 
plastic 
float 
polypropylene 
line 
mussel 
baskets 
Approx. I m 
Figure 3-3. Schematic of subsurface mussel station. 
30 
