OMSAP Public Meeting September 1999 Boston Harbor Project Overview Effluent Quality

OMSAP Public Meeting September 1999 Effluent Quality n Historical Pollutant Loadings n Trends in TSS, BOD and PCB Concentrations n Review of PCB Control Efforts n “Total” PCB Method Issues

OMSAP Public Meeting September 1999 Review of Control Efforts n MWRA Regulations prohibit discharge of PCBs n Only two active industrial discharges have tested positive in 4 years (1700 samples tested). Both of these were stopped for remediation n Enforcement relies on an EPA approved method w/ ng/L Aroclor MDL

OMSAP Public Meeting September 1999 Review of Control Efforts n Sludge cake concentration implies a daily loading of g to DITP n Up to 15 g/day may be attributed to unabsorbed dietary intake (1 - 2 g/day is more likely) n Seasonal increases may support a groundwater I&I component

OMSAP Public Meeting September 1999 Total PCB Method Issues n Revised HHC is 0.17 ng/L “total of all congener or isomer analyses” n Methodology was not discussed in the revision n Currently measure only ~20 of 209 possible congeners n These account for only about 1/3 of the true total

OMSAP Public Meeting September 1999 Total PCB Method Issues n “Modified Method 680” as listed in the new permit does not exist n GC/MS methods lose sensitivity with increasing levels of chlorination n GC/ECD methods become increasingly difficult as more analytes are added n MWRA plans to propose 67 congener list targeted at >80% of true total

OMSAP Public Meeting September 1999 Aroclor Standard Percent Recovery