Browsing by Author "Molenaar, Danielle"
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Item Estimated discharge of microplastics via urban stormwater during individual rain events(2023) Ross, Matthew S.; Loutan, Alyssa; Groeneveld, Tianna M.; Molenaar, Danielle; Kroetch, Kimberly; Bujaczek, Taylor; Kolter, Sheldon; Moon, Sarah; Huynh, Alan; Khayam, Rosita; Franczak, Brian C.Urban stormwater runoff is an important pathway for the introduction of microplastics and other anthropogenic pollutants into aquatic environments. Highly variable concentrations of microplastics have been reported globally in runoff, but knowledge of key factors within urban environments contributing to this variability remains limited. Furthermore, few studies to date have quantitatively assessed the release of microplastics to receiving waters via runoff. The objectives of this study were to assess the influence of different catchment characteristics on the type and amount of microplastics in runoff and to provide an estimate of the quantity of microplastics discharged during rain events. Stormwater samples were collected during both dry periods (baseflow) and rain events from 15 locations throughout the city of Calgary, Canada’s fourth largest city.Item Estimated discharge of microplastics via urban stormwater during individual rain events(2023) Ross, Matthew S.; Loutan, Alyssa; Groeneveld, Tianna M.; Molenaar, Danielle; Kroetch, Kimberly; Bujaczek, Taylor; Kolter, Sheldon; Moon, Sarah; Franczak, Brian C.Urban stormwater runoff is an important pathway for the introduction of microplastics and other anthropogenic pollutants into aquatic environments. Highly variable concentrations of microplastics have been reported globally in runoff, but knowledge of key factors within urban environments contributing to this variability remains limited. Furthermore, few studies to date have quantitatively assessed the release of microplastics to receiving waters via runoff. The objectives of this study were to assess the influence of different catchment characteristics on the type and amount of microplastics in runoff and to provide an estimate of the quantity of microplastics discharged during rain events. Stormwater samples were collected during both dry periods (baseflow) and rain events from 15 locations throughout the city of Calgary, Canada’s fourth largest city. These catchments ranged in size and contained different types of predominant land use. Microplastics were found in all samples, with total concentrations ranging from 0.7 to 200.4 pcs/L (mean = 31.9 pcs/L). Fibers were the most prevalent morphology identified (47.7 ± 33.0%), and the greatest percentage of microplastics were found in the 125–250 µm size range (26.6 ± 22.9%) followed by the 37–125 µm size range (24.0 ± 22.3%). Particles were predominantly black (33.5 ± 33.8%), transparent (22.6 ± 31.3%), or blue (16.0 ± 21.6%). Total concentrations, dominant morphologies, and size distributions of microplastics differed between rain events and baseflow, with smaller particles and higher concentrations being found during rain events. Concentrations did not differ significantly amongst catchments with different land use types, but concentrations were positively correlated with maximum runoff flow rate, catchment size, and the percentage of impervious surface area within a catchment. Combining microplastic concentrations with hydrograph data collected during rain events, we estimated that individual outfalls discharged between 1.9 million to 9.6 billion microplastics to receiving waters per rain event. These results provide further evidence that urban stormwater runoff is a significant pathway for the introduction of microplastics into aquatic environments and suggests that mitigation strategies for microplastic pollution should focus on larger urbanized catchments.Item Silicone wristbands as personal passive samplers: assessing exposure to organophosphate flame retardants(2020) Molenaar, Danielle; Ross, Matthew S.Organophosphate flame retardants (OPFRs) are used as additives in a variety of industrial and commercial products, such as furniture and electronics, to meet fire resistance standards. However, OPFRs have been associated with health effects, including neurotoxicity, hormonal changes, and cancer; therefore, insight into levels of exposure is necessary for health and risk assessments. An individual’s exposure to OPFRs can be measured using silicone wristbands as passive samplers, which make use of the tendency for a chemical to equilibrate between the solid phase (the sampler) and air to measure personal exposure to contaminants over time. Because OPFRs are frequently used in electronics, this study aimed to examine correlations between electronic use and personal exposure to OPFRs. Silicone wristbands were cleaned to remove surface contaminants, and then deployed to participants to wear for one week. Following deployment, the adhered compounds were extracted and analyzed using gas chromatography-mass spectrometry. While deployed, participants filled out a questionnaire indicating their weekly electronic use, which was used to draw correlations between electronics and exposure to OPFRs. The median concentration of OPFRs on wristbands were found to be about 6300ng/wristband, with high variability between individual wristbands. This project will be one of the first in Canada to use silicone wristbands as personal samplers to address exposure to OPFRs in relation to electronic use, and thus will prove useful in risk assessment due to the increasing use of electronics in society.