Systematic Evaluation of the In-Sample Stability of Selected Pharmaceuticals, Illicit Drugs, and Their Metabolites in Wastewater.

The in-sample stability of selected pharmaceuticals, illicit drugs, and their metabolites in wastewater was assessed under six different conditions-untreated, addition of hydrochloric acid or sodium metabisulfite solution, combined with or without sterile filtration, and at four representative temperatures, at 35 °C for up to 28 days, 22 °C for 56 days, and 4 °C and -20 °C for 196 days, or freeze/thaw cycles for 24 weeks. Paracetamol, 6-monoacetylmorphine, morphine, and cocaine were poorly stable in untreated wastewater-e.g., with 50% transformation within 1.2-8.1 days at 22 °C, and acidification reduced their in-sample transformations. Acesulfame, carbamazepine, cotinine, methamphetamine, 3,4-methylenedioxy-methamphetamine (MDMA), ketamine, norfentanyl, 3,4-methylenedioxy-N-ethylamphetamine (MDEA), and norbuprenorphine were highly or moderately stable over the observed period, even in untreated wastewater. Fitting of pseudo-first-order kinetics and the Arrhenius equation was used to develop a multistage transformation estimation model combined with an interactive tool to evaluate possible transformation scenarios of selected biomarkers for the processes from sampling to preanalysis. However, as the wastewater composition can vary between sites and over time, the variability of in-sample stability requires further exploration.

The presence of selected UV filters in a freshwater recreational reservoir and fate in controlled experiments.

UV filters present in sunscreen and other cosmetics are directly released into the environment during aquatic recreational activities. The extent to which the wide range of UV filters pose a risk to the environment remains unclear. This study investigated the occurrence and dissipation of selected organic UV filters at a recreational site (Enoggera Reservoir, Queensland, Australia) over 12 h. Furthermore, different possible degradation processes were investigated in a controlled off-site experiment with surface water exposed to natural light. Half-lives were estimated for ten UV filters. In Enoggera Reservoir, seven UV filters were detected, of which the most prevalent were octocrylene, avobenzone (BMDBM) and enzacamene (4-MBC). Summed concentrations of the seven UV filters ranged from 7330 ng L-1 at 13:00 h to 2550 ng L-1 at 21:00 h. In the degradation experiment, four UV filters showed no significant change over time. The fate of these compounds in the environment is likely to be mainly influenced by dispersion. Half-lives of the remaining UV filters were 6.6 h for amiloxate (IMC), 20 h for benzophenone 1, 23 h for octinoxate (EHMC), 30 h for 3-benzylidene camphor, 34 h for 4-MBC and 140 h for dioxybenzone (BP8). The degree of susceptibility to photodegradation and biodegradation was generally consistent within a structural class. The fate and half-lives of UV filters are variable and should be considered on a per site basis when assessing environmental risk.

Annual release of selected UV filters via effluent from wastewater treatment plants in Australia.

Studies conducted globally have identified wastewater effluent as a key source of UV filters released into the aquatic environment. We assessed the annual release of UV filters from wastewater treatment plant effluent in Australia and evaluated the removal of these chemicals during wastewater treatment. Effluent samples were collected from 33 sites alongside matching influent samples. Sample collection predominately occurred during the Australian Census in August 2016, which allowed for accurate per capita normalisation of the results. A subset of sites was also sampled over the Southern Hemisphere summer (December-February) period. Five UV filters were detected with at least one detected in 95% of effluent samples. The summed concentration of UV filters ranged from 130 ng L-1 to 8400 ng L-1 and averaged 2800 (±1900) ng L-1. Of the target UV filters, 2-phenylbenzimidazole-5-sulfonic acid (PBSA) and benzophenone 4 (BP4) showed the lowest removal efficiencies (11 ± 36% and 51 ± 43%, respectively) across all sites and were the most abundant in effluent. Average estimated removal efficiencies of the other compounds were between 59 (±24) % (4-methylbenzylidene camphor (4-MBC)) and 74 (±22) % (benzophenone 1 (BP1)). We did not find a trend in seasonal differences in the per capita release of UV filters in effluent samples. We estimate that approximately 40% of UV filter loads measured in influent are breaking through to the effluent resulting in the release of approximately 20 kg day-1 of the selected UV filters into the aquatic environment from treated wastewater effluent in Australia.

Calibration parameters for the passive sampling of organic UV filters by silicone; diffusion coefficients and silicone-water partition coefficients.

In recent years, organic ultraviolet filters (UVFs) received considerable attention as a group of emerging contaminants, including in Australia where the use of UVFs is particularly relevant. Passive sampling using polymers has become widely used for routine monitoring of chemicals in the aquatic environment. Application of passive samplers for monitoring chemicals in the water relies on calibration data such as chemical's polymer-water partition coefficient (Kpw) and diffusion coefficients in the sampling material (Dp), for understanding uptake and kinetic limitations. In the present study, Kpw and Dp for nine UVFs were estimated. Kpw values were determined in different water - polymer partition experiments where (1) a given mass of chemicals was dosed into the water and (2) into the polymer. Diffusion coefficients were determined using the stacking method. The estimated log Kpw and log Dp ranged from 2.9 to 6.4 L kg-1 and -11.1 to -10.5 m2s-1, respectively. The sufficient high Dp allows application of kinetic models that only consider water boundary-controlled uptake for converting silicone sampler uptake into an aqueous phase concentration using the presented Kpw.

Per capita loads of organic UV filters in Australian wastewater influent.

Per capita loads of six UV filters were estimated in wastewater influent samples from 36 wastewater treatment plants in Australia collected over a weekend period during the 2016 Australian Census. Of the analysed samples, 99% contained at least one of the target compounds. Phenyl benzimidazole sulfonic acid (PBSA) was the most prevalent (99%), followed by benzophenone 4 (BP4) (97%), benzophenone 3 (BP3) (87%), benzophenone 1 (BP1) (84%), 4-methylbenzylidene camphor (4-MBC) (22%) and isoamyl 4-methoxycinnamate (IMC) (1.5%). The highest concentrations were 3780 and 5070 ng L-1 for PBSA and BP4, respectively. Total per capita UV filter loads in influent across all plants were calculated using population data from the Australian Census and ranged from 0.21 to 3.4 mg day-1 person-1. Notably, a relationship was found between latitude and total per capita daily mass load of UV filters with an increase in mass load from southern to northern catchments. Compared to international studies, mass loads were generally similar with higher loads of BP4 found in Australia. This study provides insight into the occurrence of UV filters in influent wastewater from across Australia and provides the first comprehensive nationwide baseline of UV filter loads.

Sample Enrichment for Bioanalytical Assessment of Disinfected Drinking Water: Concentrating the Polar, the Volatiles, and the Unknowns.

Enrichment methods used in sample preparation for the bioanalytical assessment of disinfected drinking water result in the loss of volatile and hydrophilic disinfection byproducts (DBPs) and hence likely tend to underestimate biological effects. We developed and evaluated methods that are compatible with bioassays, for extracting nonvolatile and volatile DBPs from chlorinated and chloraminated drinking water to minimize the loss of analytes. For nonvolatile DBPs, solid-phase extraction (SPE) with TELOS ENV as solid phase performed superior compared to ten other sorbents. SPE yielded >70% recovery of nonpurgeable adsorbable organic halogens (AOX). For volatile DBPs, cryogenic vacuum distillation performed unsatisfactorily. Purge and cold-trap with crushed ice serving as condensation nuclei achieved recoveries of 50-100% for trihalomethanes and haloacetonitriles and approximately 60-90% for purged AOX from tap water. We compared the purgeable versus the nonpurgeable fraction by combining purge-and-trap extraction with SPE. The purgeable DBP fraction enriched with the purge-and-trap method exerted a lower oxidative stress response in mammalian cells than the nonpurgeable DBPs enriched with SPE after purging, while contributions of both fractions to bacterial cytotoxicity was more variable. 37 quantified DBPs explained almost the entire AOX in the purge-and-trap extracts, but <16% in the SPE extracts demonstrating that the nonpurgeable fraction is dominated by unknown DBPs.

Fingerprinting the reactive toxicity pathways of 50 drinking water disinfection by-products.

A set of nine in vitro cellular bioassays indicative of different stages of the cellular toxicity pathway was applied to 50 disinfection by-products (DBPs) to obtain a better understanding of the commonalities and differences in the molecular mechanisms of reactive toxicity of DBPs. An Eschericia coli test battery revealed reactivity towards proteins/peptides for 64% of the compounds. 98% activated the NRf2-mediated oxidative stress response and 68% induced an adaptive stress response to genotoxic effects as indicated by the activation of the tumor suppressor protein p53. All DBPs reactive towards DNA in the E. coli assay and activating p53 also induced oxidative stress, confirming earlier studies that the latter could trigger DBP's carcinogenicity. The energy of the lowest unoccupied molecular orbital ELUMO as reactivity descriptor was linearly correlated with oxidative stress induction for trihalomethanes (r(2)=0.98) and haloacetamides (r(2)=0.58), indicating that potency of these DBPs is connected to electrophilicity. However, the descriptive power was poor for haloacetic acids (HAAs) and haloacetonitriles (r(2) (<) 0.06). For HAAs, we additionally accounted for speciation by including the acidity constant with ELUMO in a two-parameter multiple linear regression model. This increased r(2) to >0.80, indicating that HAAs' potency is connected to both, electrophilicity and speciation. Based on the activation of oxidative stress response and the soft electrophilic character of most tested DBPs we hypothesize that indirect genotoxicity-e.g., through oxidative stress induction and/or enzyme inhibition-is more plausible than direct DNA damage for most investigated DBPs. The results provide not only a mechanistic understanding of the cellular effects of DBPs but the effect concentrations may also serve to evaluate mixture effects of DBPs in water samples.