Concentration and occurrence of the pollutants were highly seasondependent.
The maximum measured paraben concentrations were
correlated with low flow conditions (Loraine and Pettigrove, 2006;
Peng et al., 2008). During low flow seasons, the loads of the released
compounds are dissolved in smaller volume of water, which results in
an increase of their concentrations. Jonkers et al. (2009), however,
surprisingly recorded higher values of parabens during high flow
period. The reason for that was the discharge of some of the raw wastewater
from wastewater treatment plants (WWTPs) into the river.
During heavy rainfall, the capacities of the WWTPs were exceeded
and, as a result, some portion of the untreated influents was released
directly into the environment.
The seasonal variability should be taken into account while estimating
pharmaceutical and personal care products impact on the environment,
taking carefully under consideration local conditions and applied technological
solutions.
The results concerning paraben presence in drinking water are
contradictory. Ferreira et al. (2011a) reported occurrence of most commonly
used methylparaben in tap water at concentrations of around
15 ng/L (17 ± 4 ng/L), while Loraine and Pettigrove (2006) did not
detect MePB in treated drinking water from water filtration plants.