Probabilistic risk assessment of common booster biocides in surface waters of the harbours of Gran Canaria (Spain)

► Monitoring of booster biocides levels in water samples of six different harbours. ► Greater levels of Irgarol 1051 and diuron were found in marinas than others harbours. ► Temporal evolution of booster biocides levels showed no evident fluctuation. ► The probabilistic risk assessment showed a low environmental risk.