Data from : Benzalkonium runoff from roofs treated with biocide products - In situ pilot-scale study.

The dataset gives the concentrations of benzalkonium chloride (C12 and C14), a biocide used for tile roof maintenance, to fight against moss, lichens and algae, in the runoff of 10 pilote scale roof frames. Concentrations were measured over a one year period following biocidal tratment of the roof frames.
Results show a major contamination of roof runoff immediately after treatment (from 5 to 30 mg/L), followed by an exponential decrease. 175 to 375 mm of cumulated rainfall is needed before the runoff concentrations become less than EC50 values forfish (280mg/l). The residual concentration in the runoff water remains above 4mg/L even after 640 mm of rainfall. The level of benzalkonium ions leaching depends on the roofing material, with lower concentrations and total mass leached from ceramic tiles than from concrete tiles, and on the state of the tile (new or worn out).