AimsTo perform a wastewater‐based analysis to explore the impact of newly legalized retail cannabis sales on its use and to determine if this approach could estimate the size of the legal market place, which began 1 August 2014 in the study area.DesignLaboratory study of raw wastewater samples collected and analyzed over the 3‐year period from 2014 to 2016.Setting and ParticipantsSamples obtained from the two wastewater treatment plants that serviced a municipality of 200 000 people in the state of Washington, USA.MeasurementsQuantitative analysis of 24‐hour composite influent samples for the metabolite of the active ingredient in cannabis, 11‐nor‐9‐Carboxy‐Δ9‐tetrahydrocannabinol (THC‐COOH) were performed by liquid chromatography coupled to mass spectrometry.FindingsWastewater estimates for THC‐COOH increased by 9% per quarter, suggesting a doubling in cannabis consumption from 1 December 2013 to 31 December 2016. State‐sold THC increased at nearly 70% per quarter, while stores operated from 1 August 2014 to 31 December 2016. Estimating the proportion of the total cannabis market supplied by state‐regulated cannabis from these data is not currently achievable.ConclusionA wastewater‐based measure of cannabis consumption suggests a significant increase in consumption in Washington, USA following legalization, and that legal sales appear to have displaced a large portion of the illicit market.

Strobilurin fungicides are used primarily in fruits and vegetables, but recently, a patent was issued for one strobilurin fungicide, azoxystrobin, in mold-resistant wallboard. This raises concerns about the potential presence of these chemicals in house dust and potential exposure indoors, particularly in young children. Furthermore, recent toxicological studies have suggested that strobilurins may cause neurotoxicity. Currently, it is not clear whether or not azoxystrobin applications in wallboard lead to exposures in the indoor environments. The purpose of this study was to determine if azoxystrobin, and related strobilurins, could be detected in house dust. We also sought to characterize the concentrations of azoxystrobin in new wallboard samples. To support this study, we collected and analyzed 16 new dry wall samples intentionally marketed for use in bathrooms to inhibit mold. We then analyzed 188 house dust samples collected from North Carolina homes in 2014-2016 for azoxystrobin and related strobilurins, including pyraclostrobin, trifloxystrobin, and fluoxastrobin using liquid chromatography tandem mass spectrometry. Detection frequencies for azoxystrobin, pyraclostrobin, trifloxystrobin, and fluoxastrobin ranged from 34-87%, with azoxystrobin being detected most frequently and at the highest concentrations (geometric mean = 3.5 ng/g; maximum = 10,590 ng/g). Azoxystrobin was also detected in mold-resistant wallboard samples, primarily in the paper covering where it was found at concentrations up to 88.5 µg/g. Cumulatively, these results suggest that fungicides present in wallboard may be migrating to the indoor environment, leading to exposure in the residences that would constitute a separate exposure pathway independent of dietary exposures.

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When performing basic and translational laboratory studies with aquatic organisms, particularly for bioaccumulation, toxicity, or biotransformation experiments, it is imperative to control the route and dose of exposure. Contamination of feed and the organisms prior to study could alter the results of an experiment. Furthermore, if organisms not exposed in the lab are used for quality assurance/quality control, then blank levels, method detection limits, and limits of quantitation can be affected. In an effort to determine the magnitude of this potential issue for exposure studies involving Pimephales promelas, we analyzed a suite of 24 per-and polyfluoroalkyl substances (PFAS) in four types of feed from three different companies and in organisms from five aquaculture facilities. Contamination with PFAS was found in all types of materials and organisms from all aquaculture farms. The most frequently detected PFAS in fish feed and aquaculture fathead minnows were perfluorocarboxylic acids and perfluorooctane sulfonate (PFOS). Concentrations of total and individual PFAS in feed ranged from nondetect to 76 ng/g and from nondetect to 60 ng/g, respectively. Fathead minnows were contaminated with PFOS and perfluorohexane sulfonate as well as several perflourocarboxylic acids. Concentrations of total and individual PFAS ranged from 1.4 to 351 ng/g and from nondetect to 328 ng/g, respectively. The PFOS measured in food was primarily the linear isomer, consistent with greater bioaccumulation of that isomer in organisms raised as fish food. Future studies are necessary to define the extent of PFAS contamination in aquatic culture facilities and aquaculture production operations.

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