This study investigates whether newer pharmaceutical organic active substances (OASs) are more recalcitrant to biodegradation than older ones, and examines possible consequences in terms of removal in wastewater treatment plants (WWTPs). 1850 unique small-molecule OASs were considered; for 1641 of them a year of introduction was found, ranging from 1840 to present. Experimental data on (i) n-octanol/water partition coefficients (logKow), (ii) ready biodegradability – as defined by the OECD Test Guidelines 301 (1992) – and (iii) removal in WWTPs, were collected from the literature as well as chemical databases; then the dataset was expanded using the common, free, quantitative structure-property software EPISuite (US EPA, 2017). After checking the goodness of fit of EPISuite predictions against the available experimental data, time series statistics were applied to the dataset. Molecular mass and logKow values displayed a positive shift over time with newly introduced OASs (Figure 1), hardly compatible with the hypothesis of same parent distributions. Readily biodegradable compounds were found to represent a relatively small proportion of all OASs, and this proportion tended to decrease over time. However, despite newer OASs being less biodegradable, the EPISuite-predicted removal in WWTPs showed an increase over time for the upper half of the values, reflecting an expected increase in adsorption to sludge. Likely reasons for this result will be discussed, together with the value of modelling tools like EPISuite for basic, initial environmental fate estimation for OASs.