We found that benzotriazole, a corrosion inhibitor frequently used on cars and a known contaminant in road dust , had trends in sludge that corresponded to the shut down and phase one reopening that occurred during our study period (Figure ). There was a decrease in the daily and weekly composite sample concentrations at the beginning of the study period, and then an increase in weekly composite sample levels starting in the weeks before Phase 1 reopening. We hypothesize that the benzotriazole trends are due to changes in the amount of traffic. Doucette et al., found that traffic in Connecticut decreased 43%