Motor Vehicle Wash-off Water as a Source of Phosphorus in Roadway Runoff

Algal water blooms in lakes or reservoirs are often caused by an enrichment of phosphorus. Depending on a bottom environment, dissolved phosphorus (phosphate) can be released into a water column from bottom sediments and accelerate algal and macrophyte nutrient dynamics. This study focuses on phosphorus pollutant loads in stormwater wash-off from roadways. Control of phosphorus discharge from non-point sources in urban areas is important for preventing water pollution. Sources of phosphorus in pollutant loads were explored by comparing first flush runoff with road dust/water mixture and vehicle wash-off water, where characteristics of the particulate and dissolved portions, and the relationship between road dust and wash-off from vehicles were also discussed. It was clear that the concentration of dissolved phosphorus in the vehicle wash-off water was higher than that in the first flush runoff. One of the affecting factors of the dissolved phosphorus was inferred to be the nature of the additives in engine oils or certain types of engines.