Field Sampling

Sediment coring

The field coring study was designed to examine long term trends in the transport of PCBs. Cores were collected in the Ramford River at 30 stations using either hand coring, gravity coring, or piston coring techniques. Co-located cores at each station provided sufficient sediment for chemical and physical testing. Cores were extruded and aliquoted - 2 cm slices from the top of the core and 4 cm slices from the remainder of the core; the aliquotes were placed into appropriate containers and submitted to the contracted laboratory for analysis.

Water column

The water sampling study was designed to examine the trends in PCB concentrations in the water. Samples were collected in the Ramford River at three stations. On each date 20 water samples taken in a transect across the river. Samples were obtained using a "Nanson Bottle" deployed from a boat. The water samples were aliquoted into appropriate glass containers and submitted to the contracted laboratory for analysis. Each value is an average of three analyses,

Biota monitoring

Samples were collected by gill netting, otter trawls, electrofishing, hook and line, fish traps, and crab pots. Some samples were obtained from commercial and recreational fisherman. After collection, samples were sealed in plastic bags and stored in ice chests that had been cleaned, flushed with pesticide grade hexanes, and rinsed with distilled water.

Before processing , all samples were identified to species, weighed, and measured. Blue crabs were measured across the shell (point to pont). Samples were stored frozen until processing. The samples excised from edible finfish consisted of a scaled fillet with skin intact for all species except American eels and bullheads, for which samples consisted of a skinless fillet. These standard fillets were either used as an individual sample from a single fish or combined with other individuals of the same species and size to form a composite sample usually consisting of five fish, although some composites consisted of fewer fish. Where possible, the portion taken from each fish consisted of 100 grams, yielding a five fish composite of 500 grams. For individual fillets greater than 100 grams the portion was taken by cutting from the anterior portion of the fillet and proceeding posterior until 100 grams was reached. For extremely large fish, three cross section of the fillet were taken; one from behind the pectoral fins, one from halfway between the first slice and the vent, and one from behind the vent to yield the 100 gram portion. The samples were thoroughly homogenized, packaged in PCB-free aluminum foil, labeled, and stored frozen in prolypropylene bags until requested for analysis.

Analytical Chemistry

To verify that the laboratories selected to perform the chemical analyses each laboratory underwent an extensive audit by DEP chief chemists. The methods for the determination of PCB congeners were based on the EPA’s analytical Services Protocol Method for PCB congeners. The exact methodology and procedures for the calibration , analysis, and quantification by fuse disilicacapillary column gas chromatography with electron capture detection (GC/ECD)can be found in the EPA manual.