School of Environmental Studies Faculty Publications
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Item ‘At the end of their relationship, that man offered her a house’: Qualitatively exploring Congolese women’s agency in navigating sexual relations with UN peacekeepers within the context of a patriarchal setting in eastern DRC(Taylor & Francis, 2023-12-29) Petz, Jessica F.; Nguya, Gloria; Baguma Nguba, Martin; Goebel, Allison; Lee, Sabine; Bartels, Susan A.The UN’s Zero Tolerance Policy, which bans all relationships between UN staff and locals, portrays all relationships as exploitative, fails to account for nuances in these relationships and does not acknowledge the agency of local women or communities. This study uses community-based qualitative data from eastern DRC that shares narratives on a wide variety of consensual relationships between peacekeepers and local women. Our paper uses a data-driven approach, including a post-colonial feminist lens, and ideas of structural agency to provide an expanded definition of agency that invites readers to re-examine their views of women in conflict settings. Finally, we provide clear recommendations for the UN and other international non-governmental agencies on policies related to sexual exploitation and abuse.Item Radio- and Stable Carbon Isotope Analysis Reveals Minimal Assimilation of Petrogenic Carbon Into an Oligotrophic Freshwater Food Web After Experimental Spills of Diluted Bitumen(Elsevier, 2023-04-05) Graves, Stephanie; Mason, Johanna; Rodriguez-Gil, Jose Luis; Seguin, Jonathan Y.; Blais, Jules; Hanson, Mark; Hollebone, Bruce P.; Palace, Vince; Clark, Ian; Cundall, Leah; Layton-Matthews, Daniel; Leybourne, Matthew; Orihel, DianeFollowing an oil spill into water, bacteria can biodegrade petroleum hydrocarbons which could lead to petrogenic carbon assimilation by aquatic biota. We used changes in the isotope ratios of radio- (Δ14C) and stable (δ13C) carbon to examine the potential for assimilation of petrogenic carbon into a freshwater food web following experimental spills of diluted bitumen (dilbit) into a boreal lake in northwestern Ontario, Canada. Different volumes (1.5, 2.9, 5.5, 18, 42, 82, and 180 L) of Cold Lake Winter Blend (a heavy crude blend of bitumen and condensate) dilbit were applied to seven 10-m diameter littoral limnocorrals (approximate volume of 100 m3), and two additional limnocorrals had no added dilbit to serve as controls. Particulate organic matter (POM) and periphyton from oil-treated limnocorrals had lower δ13C (up to 3.2‰ and 2.1‰ for POM and periphyton, respectively) than the control at every sampled interval (3, 6 and 10 weeks for POM and 6, 8 and 10 weeks for periphyton). Dissolved organic and inorganic carbon (DOC and DIC, respectively) had lower Δ14C in the oil-treated limnocorrals relative to the control (up to 122‰ and 440‰ lower, respectively). Giant floater mussel (Pyganodon grandis) housed for 25 days in aquaria containing oil-contaminated water from the limnocorrals did not show significant changes in δ13C values of muscle tissue compared to mussels housed in control water. Overall, the changes in δ13C and Δ14C observed indicated small amounts (up to 11% in DIC) of oil carbon incorporation into the food web. The combined δ13C and Δ14C data provide evidence for minimal incorporation of dilbit into the food web of this oligotrophic lake, suggesting that microbial degradation and subsequent incorporation of oil C into the food web may play a relatively small role in the ultimate fate of oil in this type of ecosystem.Item Experimental Evidence from the Field that Naturally Weathered Microplastics Accumulate Cyanobacterial Toxins in Eutrophic Lakes(Wiley, 2022-09-23) Hataley, Eden K.; Shahmohamadloo, Rene; Ortiz Almirall, Xavier; Harrison, Anna L.; Rochman, Chelsea M.; Zou, Shan; Orihel, DianeFreshwater ecosystems with recurring harmful algal blooms can also be polluted with plastics. As such, the two environmental problems may interact. To test if microplastics influence the partitioning of microcystins in freshwater lakes, we examined the sorption of four microcystin congeners to different polymers of commercially available plastics (low-density polyethylene, polyethylene terephthalate, polyvinyl chloride, and polypropylene). We conducted three experiments: a batch sorption experiment in the laboratory with pristine microplastics of four different polymers, a second batch sorption experiment in the laboratory to compare pristine and naturally weathered microplastics of a single polymer, and a 2-month sorption experiment in the field with three different polymers experiencing natural weathering in a eutrophic lake. This series of experiments led to a surprising result: microcystins sorbed poorly to all polymers tested under laboratory conditions (less than 0.01% of the initial amount added), irrespective of weathering, yet, in the field experiment, all polymers accumulated microcystins under ambient conditions in a eutrophic lake (range: 0-84.1 ng/g). Furthermore, the sorption capacity for microcystins differed among polymers in the laboratory experiment yet were largely the same in the field. We also found that the affinity for plastic varied among microcystin congeners, namely more polar congeners demonstrated a greater affinity for plastic than less polar ones. This study improves our understanding of the role of polymer and congener type in microplastic-microcystin sorption, and moreover, provides novel evidence from the field, showing that naturally weathered microplastics in freshwater lakes can accumulate microcystins. Consequently, we caution that microplastics may alter the persistence, transport, and bioavailability of microcystins in freshwaters, which could have implications for human and wildlife health.Item Life under an oil slick: response of a freshwater food web to simulated spills of diluted bitumen in field mesocosms(Canadian Science Publishing, 2020-02-17) Cederwall, Jeffrey; Black, Tyler; Blais, Jules; Hanson, Mark; Hollebone, Bruce P.; Palace, Vince; Rodriguez-Gil, Jose Luis; Greer, Charles; Maynard, Christine; Ortmann, Alice; Rooney, Rebecca; Orihel, DianeHeavy crude oil transportation over land is increasing, yet the ecological impacts of spills, particularly of diluted bitumen, in freshwater environments remain poorly understood. We simulated spills of diluted bitumen in 1400 L land-based mesocosms containing water and sediments from a boreal, oligotrophic lake and monitored the response of natural planktonic communities over 11 days. Most species of phytoplankton (chrysophytes and dinoflagellates) and zooplankton (copepods and cladocerans) were sensitive to oil, exhibiting >70% overall abundance reductions in response to the spills. Declines in nano- and microphytoplankton were short-lived and began to recover after the oil sank, whereas picophytoplankton and zooplankton populations remained depressed at the end of the experiment. In contrast, oil spills stimulated bacteria known to degrade hydrocarbons, especially Alphaproteobacteria, whereas Gammaprotobacteria (a common marine oil spill bacterial class) increased less. This is the first experiment to examine the effects of diluted bitumen in a multitrophic freshwater community.Item Haloconduction as a remediation strategy: Capture and quantification of salts excreted by recretohalophytes(Elsevier BV, 2019-10-01) Yun, Kassandra B. M.; Koster, Sonja; Rutter, Allison; Zeeb, Barbara A.Recretohalophytes employ specialized glands to excrete salt ions onto their tissue surfaces, which then have the potential to be transported away from the plant via wind in a process referred to as ‘haloconduction’. Spartina pectinata and Distichlis spicata were selected to investigate the potential to remediate a cement kiln dust landfill in Bath, ON via salt excretion and haloconduction. Under ideal conditions in the laboratory, measurements of salt excreted by large (>15 shoots and > 50 cm height) plants of each species were 280 ± 164 g/m2 and 164 ± 75 g/m2, respectively, resulting in potential remediation timeframes of 1.4 ± 0.9 and 2.4 ± 1.1 years. Three salt collection methods were developed and installed in the field to test their efficacy for capturing and measuring windborne salt mobilized from plant surfaces. All three methods (two ground-level and one at 260 cm height) were successful in capturing and quantifying airborne salts up to 15 m from the plots. This study is the first to collect and quantify dispersed salt from recretohalophytes and hence confirm the theory of haloconduction, a promising new remediation technology for salt-impacted soils.