Superfund Research Program
Fate of Semivolatile Organic Compounds Discharged to Surface Drainage Systems from Superfund Sites
Project Leader: Phillip M. Gschwend
Grant Number: P42ES004675
Funding Period: 1995 - 2000
Project Summary (1995-2000)The long term objective of this proposal is to develop a quantitative means for predicting the delivery of semivolatile organic contaminants away from hazardous waste sites via nearby streams. To achieve this goal, a model of the exchange of such chemicals between the stream water and the immobile bed sediments is required. Measuring the penetration of excess Th234 and Pb210 into the bed of a stream reveals the depth of sediment which is in contact with the overlying flow, in time scales of weeks, (Th234) and which is accumulating over decades, (Pb210). Coupling this knowledge with the sorption and diffusion behavior of toxic organic chemicals enables researchers to model their bedstream exchange. Further, to estimate the long term delivery of chemicals downstream at sites of interest, scientists must be able to calculate the rates of important removal processes acting on the chemicals. By performing a series of short and long term mass balance studies on a particular stream system (the East Drainage Ditch/Aberjona River passing two Superfund Sites in Woburn, MA), researchers expect to see whether chemical degradation processes are necessary to close the mass balances. Should semivolatile"sinks" be required to explain the field data, researchers will pursue more focused studies to identify those mechanisms. In particular, it is proposed to apply some "probe" compounds to the stream in an effort to monitor that site for certain photochemical (e.g., 2,5-dimethyl furan to assess the abundance of the transient oxidant, singlet oxygen) and biochemical processes (e.g., toluene to assess microbial oxidase activity).