Investigation of occurrence of aromatic amines in municipal wastewaters using passive sampling

Abstract

Aromatic amines (AAs) are human-made compounds known for their mutagenic properties, entering surface waters from various sources, often originating as transformation products of dyes or pesticides. Despite their low concentrations in surface waters, AAs can exhibit mutagenicity. Our study focused on evaluating three passive samplers (PSs) for enriching these compounds from influent and effluent of a wastewater treatment plant (WWTP) in Brno, Czech Republic. The PSs tested included variants containing AttractSPE™ SDB-RPS sorbent disk, one with and one without a diffusive agarose hydrogel layer, and a modified Speedisk (Bakerbond Speedisk® H₂O-Philic). PSs were deployed in wastewater (WW) for one to four weeks in various overlapping combinations, and the uptake of AAs to PSs was compared to their concentrations in 24-hour composite water samples. A targeted LC/MS analysis covered 42 amines, detecting 11 and 13 AAs in daily composite influent and effluent samples, respectively. In the influent, AAs ranged from 1.5 ng L^-1 for 1-anilinonaphthalene to 1.0 μg L^-1 for aniline, and the highest concentration among all measured amines was observed for cyclohexylamine at 2.9 μg L^-1. In the effluent, concentrations ranged from 0.5 ng L^-1 for 1-anilinonaphthalene to 88 ng L^-1 for o-anisidine. PSs demonstrated comparable accumulation of amines, with integrative uptake up to 28 days in both influent and effluent and detection of up to 23 and 27 amines in influent and effluent, respectively; altogether 34 compounds were detected in the study. Sampling rates (R_s) were estimated for compounds present in at least 50 % of the samples and showing <40 % aqueous concentration variability, with robustness evaluated by comparing values for compounds in WWTP influent and effluent. Although all devices performed similarly, hydrogel-based PS exhibited superior performance in several criteria, including time integration and robustness of sampling rates, making it a suitable monitoring tool for AAs in WW.

Keywords: Hydrogel-based passive sampler; Removal efficiency; Sampling rate; Wastewater treatment; o-DGT.