A High-Resolution Spatial Model to Predict Exposure to Pharmaceuticals in European Surface Waters: ePiE

Environmental risk assessment of
pharmaceuticals requires the determination
of their environmental exposure concentrations. Existing exposure
modeling approaches are often computationally demanding, require extensive
data collection and processing efforts, have a limited spatial resolution,
and have undergone limited evaluation against monitoring data. Here,
we present ePiE (exposure to Pharmaceuticals in the Environment),
a spatially explicit model calculating concentrations of active pharmaceutical
ingredients (APIs) in surface waters across Europe at ∼1 km
resolution. ePiE strikes a balance between generating data on exposure
at high spatial resolution while having limited computational and
data requirements. Comparison of model predictions with measured concentrations
of a diverse set of 35 APIs in the river Ouse (UK) and Rhine basins
(North West Europe), showed around 95% were within an order of magnitude.
Improved predictions were obtained for the river Ouse basin (95% within
a factor of 6; 55% within a factor of 2), where reliable consumption
data were available and the monitoring study design was coherent with
the model outputs. Application of ePiE in a prioritisation exercise
for the Ouse basin identified metformin, gabapentin, and acetaminophen
as priority when based on predicted exposure concentrations. After
incorporation of toxic potency, this changed to desvenlafaxine, loratadine,
and hydrocodone.