Risk assessment of environmental impacts of a former petroleum industry site in relation to the residential population of the neighbourhood

 

Study objective::

The contamination of soil, groundwater and soil air at a former petroleum industrial site and of groundwater/water for domestic use (WFDU) of directly adjacent residential estates were to be assessed toxicologically. It was also to be evaluated whether earlier BTEX emissions of a cold-gas flare were a health threat. The increased awareness of the residents of these subjects is based on the observed childhood leukaemias in the Steimbke Community from 1987 – 2014.

Methodology::

Basic information on environmental data was gathered from five reports from 1998, 2011, 2014, and 2016 as well as from new groundwater data. The toxicological risk assessment was carried out taking into account the relevant exposure scenarios soil-human, soil-groundwater, ground air-human by means of appropriate assessment criteria (BBodSchV, LAWA's Insignificance Threshold Values). The ambient air assessment was based on „TA Luft” and comparable guidelines. WFDU was assessed by means of the German TrinkwV limit values (2001).

Results::

The focal point of the partly considerable soil pollution with benzene, BTEX and hydrocarbons was along the hazard pathway soil-groundwater. In contrast, the parameters measured for the direct pathway soil-human fell below the guide values of BBodSchV in all subareas or where measurements of the emissions performed for benzene in 1988 exceeded the mass concentrations and mass flows by factors of 333 – 380 and 4 – 4.5, respectively. The immission prediction results in total benzene levels which do not exceed benzene's immission value of „TA Luft”.

Conclusions::

The observed local contamination of soil and groundwater on the site did not have any health relevance for the neighborhood. However, they definitely established a remediation requirement, which has been complied with. The monitoring of WFDU should be continued after remediation. The pollution of ambient air was much lower than initially feared.