Potomac Toxics Monitoring Status and Issues ICPRB March 8, 2004

Interstate Cooperation for Potomac Toxic TMDLs Cooperation and coordination of state data collection efforts by DC, MD, VA –Ongoing coordination meetings –Joint RFP for funding of fall line monitoring –Possible CBP Toxics Subcommittee Workgroup for monitoring guidelines Exploration of feasibility of single contaminant fate and transport model

Contaminants of Concern DC: –PCBs –Chlordane –PAHs –DDT and mercury? MD: –PCBs –Metals? (pending further toxicity testing) VA: –PCBs –Others?

Data Needs for TMDL Model Support Main channel water column data –For model calibration Bed sediment core data –For understanding of vertical mixing Surficial bed sediment data –For model initialization –For model calibration/verification Storm and non-storm monitoring data –For estimating mass loads

Existing/Historical Data (see ICPRB website for copies of presentations at Technical Workshop on Potomac Toxics Data) Historical CBP water column and bed sediment data found to be not really usable Potomac fall line monitoring data –1990’s data for metals –Early 1990’s data (limited) for PCBs and other organics Anacostia River data reasonably good: water column, bed sediment and loading data

Upcoming Data Collection Efforts MDE/USGS/PG County: monitoring to collect loading data for upstream tributaries of Anacostia River using automatic sampling technology DCDOH Potomac River main channel water column sampling DCDOH Potomac River sediment core study MDE Potomac estuary sediment toxicity study for metals DCDOH/MDE/VADEQ Potomac fall line monitoring and NPDES permittee monitoring to collect loading data – proposal submitted to EPA Office of Wastewater by ICPRB

Issues Limiting Usefulness of Data Inconsistent sets of parameters Inadequate detection limits Incompatible sampling methodologies

Inconsistent Sets of Parameters PCBs: 209 congeners –Most labs only measure concentrations of a subset of congeners –tPCBs (total PCBs) = sum of all 209 congeners PAHs: large family of chemicals –Labs typically measure concentrations of 10 to 30 PAHs –“Total PAHs” depends on subset of PAHs measured Chlordane: various isomers and metabolites exist –“Total chlordane” depends on species measured

Inadequate Detection Limits tPCB detection limits: –Typical NPDES permit DL: 1000 ng/L –Method 608: 65 ng/L* –Method 8082: 54 – 900 ng/L* –Method 1668A: ~ 0.01 ng/L* tPCB concentrations of interest: –Typical non-storm Anacostia River: 1 – 10 ng/L –Typical DC storm sewer water: 10 – 100 ng/L –DC Water Quality Standard: ng/L *Joel Baker (CBL), ICPRB Technical Workshop on Potomac River Toxics Data

Sampling Methodologies Used for Load Estimation Storm composite samples: several grab samples from a storm are composited before analysis Event mean concentration (EMC): flow- weighted average of storm concentrations are computed Linear regression predictions of concentration as function of flow, other: many grab samples collected for range of flows, conditions

Needs for Upcoming Monitoring States need to agree upon list of classes of chemicals to be monitored –e.g. PCBs, PAHs, chlordane, + selected metals? –Should mercury be included? Committee of chemists and modelers need to produce quick draft monitoring guidelines for each class of chemicals: –Lists of parameters for each class –Agreement on detection limits for each class –Agreement on method of monitoring for load estimates

Possible Means of Coordination CBP Toxics Subcommittee –has offered to form ad hoc Workgroup to formulate draft Potomac River monitoring guidelines –Has offered to submit proposal for STAC Workshop for peer review of guidelines