Utility Right-of-Way Risk Assessment

SRS staff have performed a risk assessment on a former underground storage tank (UST) site under the Pennsylvania Storage Tank and Spill Prevention Act (Act 32).  The site had been utilized as an automobile service garage and retail gasoline fueling facility.  The risk assessment evaluated on-site and off-site impacts in the right-of-way (ROW) adjacent to the on-site property.  Based on an evaluation of the analytical soil and groundwater data utilized for the adjacent ROW, more constituents of interest (COI) and higher concentrations were observed towards the northern end of the street, and less COI/lower concentrations were observed towards the southern end of the street.  Therefore, in order to reduce the potential need to restrict access along the entire ROW adjacent to the site, the ROW was conceptually divided into 3 segments to account for the variation of impacts.  Three separate sets of exposure point concentrations and 3 sets of risk calculations were completed for a construction worker and utility worker scenario in each segment.  It was assumed these receptors would spend an equal amount of time in each segment and, therefore, some of the exposure parameters were equally divided into three.  Once the risk and hazard indices were calculated for each segment, they were added to estimate the total risk and hazard index for the entire ROW.  By evaluating the ROW in this manner, this reduced the potential need to mitigate the entire ROW.