Figure 3
From: Contribution of sewage to occurrence of phosphodiesterase-5 inhibitors in natural water
Boxplots for PDE-5i mass loadings on STP#1 and STP#2 calculated for weekday and weekend. Since no datum point was off the range for each STP set by 1.5 × IQR (inter-quartile range) and both mean and median are located within IQRs, the PDE-5i data are considered as normally distributed. For both weekday and weekend, PDE-5i mass loadings on STP#2 are higher than those on STP#1.
