Abstract:
The seasonal variability of persistent organic pollutants in Hartbeespoort Dam, South Africa, was investigated using
emipermeable membrane devices (SPMDs) as passive samplers. Freely dissolved waterborne polycyclic aromatic
hydrocarbons (PAHs), polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs) were sampled to investigate
easonal changes in their concentrations. Exposure of the passive samplers was done for 14 days at the same sampling site in
ach of the four seasons of the year, in 2011. The SPMD-derived analyte amounts enabled the calculation of time-weighted
averages of free dissolved waterborne levels of the contaminants. Concentrations ranged from 30.0 ng∙ℓ
-1
to 51.5 ng∙ℓ
-1
for
PAHs, 38 pg ℓ
-1
to 150 pg∙ℓ
-1
for PCBs, 9.2 to 10.4 ng∙ℓ
-1
for HCHs and 0.3 to 0.8 ng∙ℓ
-1
for DDTs, respectively. It was also
noted that the winter season generally exhibited higher contaminant concentrations for most compounds studied, which
ikely reflects the seasonality of their atmospheric deposition. An attempt was also made to identify possible sources of PAH
ontaminants in the dam by examining PAH ratios. These diagnostic ratios were inclined towards pyrogenic sources of
pollution, except for the winter season where both pyrogenic and petrogenic sources likely contribute to the contamination
pattern.
