1. Goals:

In examining trends in fish PCB levels, it is not clear that we understand the fate and transport of PCBs within the stream system associated with NLF. To support analysis of fish bioaccumulation, a preliminary conceptual model of PCB fate and transport is being developed by QEA. As a consequence of that effort, a number of data gaps have been identified which are intended to answer the following questions:

a. Are there any unidentified sources of flow and/or PCBs to Conard's Branch.

b. Are there significant differences between the level of PCBs upstream in Conard's Branch and downstream in Conard's Branch under different flow regimes. If so are the mechanisms creating the differences important to understand and account for in the conceptual model.

c. Preliminary analysis indicates that sediments do not contribute a significant PCB loading to the water column, and that the sediment based food web is likely not a significant source of PCBs for the fish. This is based on both PCB levels in sediments and a general characterization of the sediments in the streams (that they are sparse and transitory). However, there are a few pockets of deeper sediments near the fish sampling sites in Conard's Branch. These isolated pockets of deeper sediments have not been adequately characterized to determine if they could be a more significant source of PCBs to fish.

d. What is the dilution ratio between Richland Creek and Conard's Branch. Can this dilution ratio account for the difference between Richland Creek and CB fish pcb levels.

e. It has now been almost a year since the additional low flow collection system has been operational and it has been 3 months since the carbon was changed out at the treatment plant. The preliminary conceptual model predicts that PCB levels in fish could drop by a significant amount. Have the PCB levels in fish been affected? This may help us determine if the preliminary conceptual model is reasonable.

2. Sampling Specifics:

a. At non-storm conditions, observe the entire length of Conard's Branch. Identify where major surface water channels enter the stream. Mark these on the topo map. Then do the same at high flow conditions and note which channels carry significant water into the stream.

b. Prior to any storm sampling, a rating curve should be developed for the culverts under Vernal Pike at Conard's Branch and at Richland Creek and at Richland Creek by the SR43 bridge. A water depth continuous monitor should also be set at the inlet to each culvert.

c. At non-storm conditions, with the spring treatment plant discharge off, measure the stream flow at approximately 1000 foot intervals down the entire length of Conard's Branch and at the first fish sample station in Richland Creek. Also collect a water sample where flow is measured. The water sample should consist of 4 liters of water. Have the sample analyzed for TSS, PCBs, particulate organic carbon (POC) and field conductivity. The lab should analyze one full liter for PCBs. If the PCBs are not detectable, then the other two bottles of water should be extracted, extracts combined and concentrated to give a detection limit of about .01 ppb. The 4~" bottle is for TSS/POC analysis. Note, one of the sample locations should be designated for MS/MSD and 6 liters should be provided at that location. Note the volume of water needed for the POC sample may be greater than 1 liter. This will be verified with the lab prior to finalization of the sampling plan.

d. During storm conditions, 2 Isco samplers should be set up along Conard's Branch and two samplers in Richland Creek (at the first fish station and at the SR43 bridge). Two storm events should be monitored. One with a peak weir flow of 500 - 3000 8pm. And another with a peak weir flow of over 6000 8pm. Hourly samples are sufficient. All samples are to be analyzed for PCBs, TSS and field conductivity. The two Conard's Branch Iscos will be at the normal storm sampling upstream location and at the location of the fish sampling station. The normal station CB Isco will take an hourly 500 ml sample. The other two samplers will take an hourly 1000 ml sample. This is necessary to ensure a detection limit of . I ppb at these more downstream locations. In addition to samples taken with the autosamplers, a few grab samples at each location should also be taken. The grab samples are to be 2 liters each taken from the centroid of flow and analyzed for POC.

e. Sediment Sampling: Previous stream walks have identified areas in Conard's Branch where there are deeper pools with significant sediment accumulations. In particular there is one deep pool near where fish are taken where one can sink into mud a foot or so for about a 100 foot stretch of stream. This is the most significant pool of soft sediments in this stream. Three sediment cores are to be taken in this area. Each core is to be approximately 12 inches deep. For each core, three 4 inch sections are to be subsampled. Each subsample is to be analyzed for PCBs, TOC, and percent moisture.

f. Fish Sampling: The Conard's Branch and first Richland Creek Station should he sampled for fish. Target species are Creek Chubs at Conard's Branch (6 samples of similar size as taken in 2002 and 2003), and in Richland Creek Creek Chub and Long Ear Sunfish (6 of each of similar size as 2002/2003). All samples are to be whole body samples. The fish are to be analyzed for PCBs, lipids, and percent moisture. The PCBs are to be analyzed via method 1668A for congeners. Additonally, from all fish collect scales or otiliths. Submit 2 fish from each species and location for age-length analysis.