Analyses of samples of runoff waters collected from the principal arterial roads in the city of Gdansk at sites characterised by heavy traffic are described in this study. Collection of the samples was carried out over a six month period, during rain events or directly after such events. Concentrations of the following analytes were determined: nitro-, chloro-, and phosphoroorganic pesticides, volatile halogenoorganic compounds, petroleum hydrocarbons, as well as cations (Na+, K+, NH4+, Ca2+) and anions (F-, Cl-, NO2-, NO3-, PO43-, SO42-). Additionally, total parameters such as toxicity and pH were also measured. The results permitted us to correlate the presence and concentration of the individual analytes with the pollution sources and evaluating the influence of the local emission sources on the degree of pollution in the area covered by this study. The analyses performed have confirmed the high pollution level in the runoff waters (from the arterial roads) and a necessity to establish a system of continuous monitoring of the concentration levels of toxic chemical compounds present in these waters. A correlation was also found between the toxicity and concentration levels of the aforementioned groups of analytes.