Water samples from day 1, 8, 16 and 29 were analyzed from the
pyrene experiment (Table 2). The results from day 1 were inconsistent.
At day 8 the measured concentrations were 30–66% lower than
nominal concentrations, followed by an increase in concentrations
between day 8 and 16 to 125–180% of the nominal concentrations.
The concentrations remained stable throughout the last part of the
experiment (day 16–29). Average pyrene concentrations from day
8, 16 and 29 were used for the calculation of the LC50 values (see
Section 3.4).