Field Calibration of Semipermeable Membrane Devices (SPMDs) for Persistent Organic Pollutant Monitoring in a Reservoir

Abstract

Persistent Organic Pollutants (POPs) in water can reach levels below ppt (ng L−1), representing a challenge for risk assessment using long-term exposure. Therefore, sampling devices to monitor trace levels of organic compounds are suitable due to their sensitivity and low detection limits. In this work, the field calibration and monitoring for POPs, such as Polycyclic Aromatic Hydrocarbons (PAHs) and pesticides, in a drinking water reservoir were carried out using semipermeable membrane devices (SPMDs). The SPMDs were spiked with deuterated PCBs used as PRCs, and their dissipation was measured at 5, 10, 15 and 24 days. The SPMDs were dialyzed in hexane twice and the initial amount (N) and final amount (No) of PRCs in extracts were estimated by GC/MS to calculate the sampling rate (Rs) for target compounds. The PCBs were dissipated more than 30% at 24 days, and Rs were calculated between 27.8 and 72.7 L day−1 for PAHs and 35.8 and 71.3 L day−1 for pesticides. Finally, PAH congeners such as Naphthalene, Acenaphthylene, Acenaphthene, Fluorene, Phenanthrene, Anthracene, Fluoranthene and Pyrene were detected at water concentration (Cw) ranges between 0.5 and 2.7 ng L−1, whilst chlorpyrifos was the only pesticide detected at 19.0 ng L−1 in the reservoir. This calibration showed that PRCs do not dissipate entirely in 24 days and that dissipation modelling may be applied for Cw estimation of POPs in reservoirs.