Data on highway runoff pollution caused by organic compounds such as softener, adhesives, tensides, gasoline additives, anticorrosion coatings, and additives used in the tire manufacturing process are rare. In the framework of this project runoff quality from German highways was monitored at three sites: A6 (Sinsheim-Steinsfurt), A7 (Großburgwedel) and A37 (Hannover-Kirchhorst). Sampling was conducted between October 2011 and September 2012. Concentrations of Bezothiazole, Alkylphenole, Bisphenol A, Methyl-tert-butylether (MTBE), Bis(2-ethylhexyl)phtahalat DEHP), PAH, PCB, AOX/EOX, MOH and the heavy metals Zn, Cu, Pb und Cd were analyzed in all samples. According to the specific properties of each particular organic pollutant sampling equipment and procedure were adjusted. High volume (900 l) stainless steel tanks were used to collect total runoff from a well-defined highway area without any contact to further materials. Therefore, funnels were constructed at the side verge of the different sites to capture runoff from about 26 m2 area of road pavement. The runoff was transported to the sampling tanks by gravity using stainless steel trenches. The volume of the tanks counts for around 35 mm runoff. Thus, between 61 % and 82 % of the annual runoff could be collected at the different sites. After the tanks were filled completely or at the latest after a period of three months, samples from supernatant and sediment were taken. In any case the aim was to produce quarterly mixture samples for further analyses. Both, the long term mixture samples and the separate analysis of the particulate and solute phase allowed obtaining reliable results. Laboratory experiments were conducted to quantify the impact of the long storage of the samples on the concentration of the considered pollutants. The observed alterations were small and hence acceptable. The analyzed heavy metal concentrations are reflecting typical concentrations for highway runoff with a high particle-bound share (Zn > 77 %, Cu > 81 %, Pb > 91 %). Only Cd shows a considerable lower particle-bound proportion of 41 to 54 %. A significant seasonal variation of heavy metals concentrations with the highest values at the first quarter in winter could be shown. Total concentrations and particulate fraction for the organic compounds at the three sites are shown in table 5.19 in the report. For MTBE, ETBE, MBT and MeBT, the concentrations were reported to be below the detection limit. Particulate fractions of the pollutants Benzol, Bisphenol A, Nonylphenol and Octylphenol could not be determined due to the high detection limits in water. The values obtained for PAH16 and MOH are common and occur frequently in highway runoff. In regard to the other organic compounds, there are no similar studies in the literature available. High maximum values found in a random sample survey at highways (Stachel et al. 2007) cannot be confirmed. A consistent high particulate fraction (> 83 %) was established for the pollutants MKW, PAK-16, PCB-6 and DEHP whereas for the three Benzothiazole (MTBT, BT, OHBT) a particulate fraction of up to 53 % was determined. Small particulate fractions (? 10 %) of BTSA were observed in two locations while at one location a high value (79 %) was measured. A first flush effect could not be detected. The pollutant concentrations of successive rain events resulted to be similar. The pores in the pavement cover of the road shoulder seemed to be a sediment deposit which empties itself over a long period of time. In regard to the storm water treatment, the removal of fine particles becomes of paramount importance mainly because of the high particulate fraction that was measured for all pollutants under investigation. (Author/publisher)
Samenvatting