Fig. 3From: Chemical surveillance in freshwaters: small sample sizes underestimate true pollutant loads and fail to detect environmental quality standard exceedancesFrequency distribution of concentrations of weekly composite samples (N = 52) for a benzo(a)pyrene, b 4-tert-octylphenol, c fluoranthene and d 2007 DEHP. Red dashed lines represent the AA-EQS for inland surface waters. Black solid lines represent the mean annual loadsBack to article page