2024?: Lithgow Sewage Treatment Plant
“3.1.4. PFAS
A total of 22 river samples in this study were tested for PFAS (Table 4). They were collected from streams downstream of STP outfalls. We detected measurable amounts (≥0.01 µg L−1) of PFAS in four of the twenty-two samples collected below STPs. The detected concentration, in all cases, was at the lowest LOR (0.01 µg L−1). The most frequently detected PFAS was PFHxS (three of twenty-two samples) and a single sample had a detectable amount of PFOS (0.01 µg L−1). We also tested 22 STP effluent samples for PFAS and detected concentrations (≥0.01 µg L−1) of PFAS in 17 of 22 samples of STP
effluent. The detected concentrations of effluent ranged from 0.01 to 0.07 µg L−1. The most frequently detected was PFOS (13 of 22 samples) with a mean concentration of 0.025 µg L−1 in the 13 effluent samples where it was detected (Figure 4a). PFHxS was found at detectable concentrations in seven of twenty-two effluent samples) with a mean concentration of
0.021 µg L−1, across the effluent samples where it was detected.”
Figure 4. (a) Mean PFAS concentration (∑ PFOA, PFOS, and PFHxS) in STP effluent and rivers downstream of STP outfalls. (b) Mean PFOS concentration (plus/minus standard error of mean) in river sediment downstream of STP outfalls.
PFAS chemicals were detected frequently (76.5%) in river sediment samples collected downstream of STP outfalls (Table 5). PFOS frequently (13 detections in 17 samples) was found at detectable concentrations ranging from 0.1 to 7.6 µg kg−1 (mean 1.22 µg kg−1) (Figure 4b). The PFOS concentrations in river sediment samples were highly variable. For example, the river sediment samples collected downstream of Bowral STP were tested for PFOS with results ranging from <LOR to 7.6 µg kg−1, which resulted in large error bars
in Figure 4b. Two sediment samples had detectable PFOA at the LOR (0.1 µg kg−1). One sediment sample detected PFHxS (0.6 µg kg−1).