Role of surface water and groundwater in spreading pharmaceuticals ‘pollution‘

Surface water and groundwater are the crucial elements in spreading the ‘pollution‘ by pharmaceuticals in space and time. Obviously, as groundwater velocity is a few orders of magnitude smaller than river flow velocity, the ‘pollution‘ in surface waters mixes (dilutes) much faster with the resident water than in groundwater, implying that concetration in groundwater can locally reach high values. Both in surface- and groundwater the pharmaceuticals can decay and/or become part of transformation processes resulting in various metabolites.

In case of a point source type inflow of WWTP effluent into groundwater – for example from leaking sewage the ‘pollution‘ of groundwater tends to occur by means of elongated plumes of contaminated groundwater of relatively high concentration of pharmaceuticals, a few tens to many hundreds metre long. In general it is easier to model (predict) the spread of groundwater ‘pollution‘ in porous aquifers, as opposed to modelling transport and processes in a fractured-rock medium.