Informing the Exposure Landscape: The Fate of Microplastics in a Large Pelagic In-Lake Mesocosm Experiment.

Understanding microplastic exposure and effects is critical to understanding risk. Here, we used large, in-lake closed-bottom mesocosms to investigate exposure and effects on pelagic freshwater ecosystems. This article provides details about the experimental design and results on the transport of microplastics and exposure to pelagic organisms. Our experiment included three polymers of microplastics (PE, PS, and PET) ranging in density and size. Nominal concentrations ranged from 0 to 29,240 microplastics per liter on a log scale. Mesocosms enclosed natural microbial, phytoplankton, and zooplankton communities and yellow perch (Perca flavescens). We quantified and characterized microplastics in the water column and in components of the food web (biofilm on the walls, zooplankton, and fish). The microplastics in the water stratified vertically according to size and density. After 10 weeks, about 1% of the microplastics added were in the water column, 0.4% attached to biofilm on the walls, 0.01% within zooplankton, and 0.0001% in fish. Visual observations suggest the remaining >98% were in a surface slick and on the bottom. Our study suggests organisms that feed at the surface and in the benthos are likely most at risk, and demonstrates the value of measuring exposure and transport to inform experimental designs and achieve target concentrations in different matrices within toxicity tests.

Urban-use pesticides in stormwater ponds and their accumulation in biofilms.

Stormwater ponds frequently receive urban runoff, increasing the likelihood of pesticide contamination. Biofilms growing in surface waters of these ponds are known to accumulate a range of aquatic contaminants, paradoxically providing both water purification services and potentially posing a threat to urban wildlife. Thus, sampling biofilms in stormwater ponds may be a critical and biologically relevant tool for characterizing pesticide contamination and toxicity in urban environments. Here, we aimed to investigate pesticide occurrences at 21 stormwater ponds in Brampton, ON, one of Canada's fastest growing municipalities, and quantify their accumulation in biofilm. Over nine weeks, we collected time-integrated composite water and biofilm samples for analysis of ∼500 current-use and legacy pesticides. Thirty-two pesticide compounds were detected across both matrices, with 2,4-D, MCPA, MCPP, azoxystrobin, bentazon, triclopyr, and diuron having near-ubiquitous occurrences. Several compounds not typically monitored in pesticide suites (e.g., melamine and nicotine) were also detected, but only in biofilms. Overall, 56 % of analytes detected in biofilms were not found in water samples, indicating traditional pesticide monitoring practices fail to capture all exposure routes, as even when pesticides are below detection levels in water, organisms may still be exposed via dietary pathways. Calculated bioconcentration factors ranged from 4.2 to 1275 and were not predicted by standard pesticide physicochemical properties. Monitoring biofilms provides a sensitive and comprehensive supplement to water sampling for pesticide quantification in urban areas, and identifying pesticide occurrences in stormwater could improve source-tracking efforts in the future. Further research is needed to understand the mechanisms driving pesticide accumulation, to investigate toxicity risks associated with pesticide-contaminated biofilm, and to evaluate whether pesticide accumulation in stormwater pond biofilms represents a route through which contaminants are mobilized into the surrounding terrestrial and downstream aquatic environments.

New insights into pesticide occurrence and multicompartmental monitoring strategies in stream ecosystems using periphyton and suspended sediment.

Streams are susceptible to pesticide pollutants which are transported outside of the intended area of application from surrounding agricultural fields. It is essential to monitor the occurrence and levels of pesticides in aquatic ecosystems to comprehend their effects on the aquatic environment. The common sampling strategy used for monitoring pesticides in stream ecosystems is through the collection and analysis of grab water samples. However, grab water sampling may not effectively monitor pesticides due to its limited ability to capture temporal and spatial variability, potentially missing fluctuations and uneven distribution of pesticides in aquatic environments. Monitoring using periphyton and sediment sampling may offer a more comprehensive approach by accounting for accumulative processes and temporal variations. Periphyton are a collective of microorganisms that grow on hard surfaces in aquatic ecosystems. They are responsive to chemical and biological changes in the environment, and therefore have the potential to act as a cost-effective, integrated sampling tool to monitor pesticide exposures in aquatic ecosystems. The objective of this study was to assess pesticides detected through periphyton, suspended sediment, and conventional grab water sampling methods and identify the matrix that offers a more comprehensive characterization of a stream's pesticide exposure profile. Ten streams across Southern Ontario were sampled in 2021 and 2022. At each stream site, water, sediment and periphyton, colonizing both artificial and natural substrates, were collected and analyzed for the presence of ~500 pesticides. Each of the three matrices detected distinctive pesticide exposure profiles. The frequency of detection in periphyton, sediment and water matrices were related to pesticides' log Kow and log Koc (P < 0.05). In addition, periphyton bioconcentrated 22 pesticides above levels observed in the ambient water. The bioconcentration factors of pesticides in periphyton can be predicted from their log Kow (simple linear regressions, P < 0.05). The results demonstrate that sediment and periphyton accumulate pesticides in stream environments. This highlights the importance of monitoring pesticide exposure using these matrices to ensure a complete and comprehensive characterization of exposure in stream ecosystems.

An Assessment of the Toxicity of Pesticide Mixtures in Periphyton from Agricultural Streams to the Mayfly Neocloeon triangulifer.

Residual concentrations of pesticides are commonly found outside the intended area of application in Ontario's surface waters. Periphyton are a vital dietary component for grazing organisms in aquatic ecosystems but can also accumulate substantial levels of pesticides from the surrounding water. Consequently, grazing aquatic organisms are likely subjected to pesticide exposure through the consumption of pesticide-contaminated periphyton. The objectives of the present study were to determine if pesticides partition into periphyton in riverine environments across southern Ontario and, if so, to determine the toxicity of pesticides in periphyton when fed to the grazing mayfly Neocloeon triangulifer. Sites with low, medium, and high pesticide exposure based on historic water quality monitoring data were selected to incorporate a pesticide exposure gradient into the study design. Artificial substrate samplers were utilized to colonize periphyton in situ, which were then analyzed for the presence of approximately 500 pesticides. The results demonstrate that periphyton are capable of accumulating pesticides in agricultural streams. A novel 7-day toxicity test method was created to investigate the effects of pesticides partitioned into periphyton when fed to N. triangulifer. Periphyton collected from the field sites were fed to N. triangulifer and survival and biomass production recorded. Survival and biomass production significantly decreased when fed periphyton colonized in streams with catchments dominated by agricultural land use (p < 0.05). However, the relationship between pesticide concentration and survival or biomass production was not consistent. Using field-colonized periphyton allowed us to assess the dietary toxicity of environmentally relevant concentrations of pesticide mixtures; however, nutrition and taxonomic composition of the periphyton may vary between sites. Environ Toxicol Chem 2023;42:2143-2157. © 2023 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.

Extracellular vesicles and their microRNA cargo in ischaemic stroke.

Acute ischaemic stroke (AIS) is a leading cause of death and disability. MicroRNAs (miRNAs) are short non-coding RNAs which hold the potential to act as a novel biomarker in AIS. The majority of circulating miRNAs are actively encapsulated by extracellular vesicles (EVs) produced by many cells and organs endogenously. EVs released by mesenchymal stem cells (MSCs) have been extensively studied for their therapeutic potential. In health and disease, EVs are vital for intercellular communication, as the cargo within EVs can be exchanged between neighbouring cells or transported to distant sites. It is clear here from both current preclinical and clinical studies that AIS is associated with specific EV-derived miRNAs, including those transported via MSC-derived EVs. In addition, current studies provide evidence to show that modulating levels of specific EV-derived miRNAs in AIS provides a novel therapeutic potential of miRNAs in the treatment of stroke. Commonalities exist in altered miRNAs across preclinical and clinical studies. Of those EV-packaged miRNAs, miRNA-124 was described both as an EV-packaged biomarker and as a potential EV-loaded therapeutic in experimental models. Alterations of miRNA-17 family and miRNA-17-92 cluster were identified in preclinical, clinical and MSC-EV-mediated neuroprotection in experimental stroke. Finally, miRNA-30d and -30a were found to mediate therapeutic effect when overexpressed from MSC and implicated as a biomarker clinically. Combined, EV-derived miRNAs will further our understanding of the neuropathological processes triggered by AIS. In addition, this work will help determine the true clinical value of circulating EV-packaged miRNAs as biomarkers of AIS or as novel therapeutics in this setting.

Strategies to mitigate shifts in red oak (Quercus sect. Lobatae) distribution under a changing climate.

Red oaks (Quercus sect. Lobatae) are a taxonomic group of hardwood trees, which occur in swamp forests, subtropical chaparral and savannahs from Columbia to Canada. They cover a wide range of ecological niches, and many species are thought to be able to cope with current trends in climate change. Genus Quercus encompasses ca. 500 species, of which ca. 80 make up sect. Lobatae. Species diversity is greatest within the southeastern USA and within the northern and eastern regions of Mexico. This review discusses the weak reproductive barriers between species of red oaks and the effects this has on speciation and niche range. Distribution and diversity have been shaped by drought adaptations common to the species of sect. Lobatae, which enable them to fill various xeric niches across the continent. Drought adaptive traits of this taxonomic group include deciduousness, deep tap roots, ring-porous xylem, regenerative stump sprouting, greater leaf thickness and smaller stomata. The complex interplay between these anatomical and morphological traits has given red oaks features of drought tolerance and avoidance. Here, we discuss physiological and genetic components of these adaptations to address how many species of sect. Lobatae reside within xeric sites and/or sustain normal metabolic function during drought. Although extensive drought adaptation appears to give sect. Lobatae a resilience to climate change, aging tree stands, oak life history traits and the current genetic structures place many red oak species at risk. Furthermore, oak decline, a complex interaction between abiotic and biotic agents, has severe effects on red oaks and is likely to accelerate species decline and fragmentation. We suggest that assisted migration can be used to avoid species fragmentation and increase climate change resilience of sect. Lobatae.

Trends and predictors of wetland conversion in urbanizing environments.

Wetlands provide critical ecosystem services including flood mitigation and habitat for diverse species, but globally, many wetlands have been destroyed. In urban areas and surrounding urban-rural fringes, many lost wetlands have been indirectly replaced with stormwater management (SWM) ponds. SWM ponds are designed to manage urban stormwater and contaminants, but only provide limited ecosystem services. In our study area, historic extent of wetland loss is partially documented, while more recent losses and SWM pond creation have not been fully reported. We examine wetland loss and SWM pond creation in seven southern Ontario (Canada) municipalities from 2002 to 2010. We then apply a Markov model to project future extent of wetland losses and SWM pond creation, with and without effects of specific land use and land cover types. We find that from 2002 to 2010, 95.5 ha of wetlands were lost, with most being smaller than 2 ha in size. A total area of 111.6 ha of SWM ponds was created, but on average, created SWM ponds were smaller than lost wetlands. Our projections to 2026 suggest wetland losses of 438.1 ha and SWM pond creation of 293.8 ha. We suggest a need for more stringent wetland protection policies to conserve wetlands that still exist in growing municipalities, especially smaller wetlands. Lack of such protection will weaken provisioning of wetland-related ecosystem services, which are more critical than ever in a changing climate.

Wetland hydroperiod predicts community structure, but not the magnitude of cross-community congruence.

A major focus in community ecology is understanding how biological interactions and environmental conditions shape horizontal communities. However, few studies have explored whether cross-community interactions are consistent or non-stationary across environmental gradients. Using the relative abundance of birds, aquatic macroinvertebrates and plants, we examined how cross-community congruence varied between short and long-hydroperiod prairie pothole wetlands in southern Alberta. These wetlands are structured by their hydroperiod: the length of time that ponded water is present in the wetland. We compared the strength of cross-community congruence and the strength of congruence between each horizontal community and wetland hydroperiod in wetlands that typically contain ponded water throughout the year to wetlands that dry up every summer. The strength of cross-community relationships was similar between more permanent and more ephemeral wetland classes, suggesting that biological interactions have a near equivalent role in shaping community composition, regardless of hydroperiod. However, because cross-community congruence, measured as the Procrustes pseudo-R value, was, on average, 77% ± SE 12% greater than that between each horizontal community and measures of wetland hydroperiod, we concluded that community structure is not shaped by hydroperiod alone. We attribute the observed cross-community congruence to (1) plants and aquatic macroinvertebrates influence birds through habitat and food provisioning, and (2) birds influence plants and aquatic macroinvertebrates by dispersing their propagules.

Use of 360° Video for a Virtual Operating Theatre Orientation for Medical Students.

BACKGROUND: Operating theatres are a unique learning environment that some learners find daunting. By employing orientations some of these fears can be reduced but these require operating theatre space and personnel and are not standardized. METHODS: We utilized a 360° camera to generate a "virtual" 360° video orientation. It was filmed in first-person perspective to improve engagement and to make it more experiential. EVALUATION: It was shown to 34 medical students in a tutorial setting before their first operating theatre experience. We analyzed their knowledge gain with use of a questionnaire and change in self-reported confidence using a 7-point Likert scale. The students' knowledge improved from 38.4% to 78.2% (p < 0.01) as well as self-reported confidence from 4.3 to 6.1 (p < 0.01). DISCUSSION: The use of 360° video for a virtual operating theatre orientation improved knowledge and confidence of learners which suggests its expanded use in medical education.

Bioconcentration of glyphosate in wetland biofilms.

Wetland biofilms were exposed to the herbicide glyphosate via in situ field exposures and controlled microcosm experiments to measure bioconcentration and metabolism of glyphosate by biofilm organisms. Concentrations of glyphosate in biofilms were two to four orders of magnitude higher than the surrounding water, bioconcentration factors averaged 835 and 199 L·kg-1 in field- and lab-exposed biofilms, respectively. Glyphosate in water where it had been detected in biofilms at field-exposed sites ranged from below detection (<1 µg·L-1) up to 130 µg·L-1. Bioconcentration of glyphosate in biofilms was inversely proportional to concentrations in the surrounding water, and the retention kinetics were similar to both adsorption and enzymatic models. Microorganisms present in both the water and biofilms metabolized glyphosate to its primary breakdown product aminomethyl phosphonic acid (AMPA), with increased rates of breakdown in and around the biofilms. Photosynthetic efficiency of the algae within the biofilms was not affected by 24 h controlled glyphosate exposures. Our results demonstrate the role of biofilms in improving wetland water quality by removing contaminants like glyphosate, but also as a potential exposure route to higher trophic levels via consumption. Due to bioconcentration of pesticides, exposure risk to organisms consuming or living in biofilms may be much higher than indicated by concentrations in ambient water samples.

Accumulating Mercury and Methylmercury Burdens in Watersheds Impacted by Oil Sands Pollution.

Bitumen mining and upgrading in northeastern Alberta, Canada, releases toxic pollutants into the atmosphere, including mercury (Hg) and methylmercury (MeHg). This Hg and MeHg is then deposited to the surrounding landscape; however, the fate of these contaminants remains unknown. Here, we compare snowpack chemistry to high-frequency measurements of river water quality across six watersheds (five impacted by oil sands development and one unimpacted). Catchment scale snowpack Hg and MeHg loads normalized to watershed area were highest near oil sands operations. River water Hg concentrations and loads tracked discharge and tended to be higher downstream of mining operations, while MeHg concentrations and loads increased through the summer, reflecting peak summer MeHg production rates. Except in the reference watershed, snowpack Hg and MeHg loads equaled or exceeded the amount of Hg and MeHg exported during freshet and, in some cases, the entire hydrologic year. This suggests landscapes across the oil sands region, which are dominated by low-relief wetlands and other shallow-water systems, are accumulating Hg and MeHg. Importantly, during years of high discharge, these low-relief systems appear to become better connected and flush MeHg (and Hg) from the watershed. Thus, these watersheds may act as temporary, rather than as permanent, natural repositories of oil sands contaminants.

Low extent but high impact of human land use on wetland flora across the boreal oil sands region.

Boreal wetlands are at risk of degradation from anthropogenic activities including oil sands energy extraction. Despite efforts to monitor the impacts of oil sands energy extraction-related activities on wetland ecology, few studies examine the impacts of diverse human development types on wetland plant communities. Here, we sought to quantify the effects of human development in the Athabasca, Peace River, and Cold Lake Oil Sands Regions in Alberta, Canada, and to examine its impact on wetland plant community composition. Across the region, we found that total development and development related to energy and mining were both low; ~80% of the study area was undeveloped. Despite the low spatial extent, total anthropogenic development was negatively correlated with site-level conservatism (a metric of plant tolerance to environmental perturbation) in all five wetland classes examined. This suggests that wetlands surrounded by human development are inhabited by generalist species that are tolerant of environmental disturbance. Moreover, distinct floristic groups within each wetland class could be distinguished based on their total developed area, providing additional evidence that human development affects plant composition and diversity, despite its limited extent in the study area. In contrast to total development, energy and mining development had an inconsistent or no detectable impact on wetland plant community composition at the regional level, likely because although oils sands surface mining is intensive, it is spatially restricted to a small area within the oil sands region. Our findings show that wetland plant communities in the oil sands region are impacted by multiple types of human land use concurrently; further research should aim to evaluate both the distinct impacts of different land use types using gradients of development intensity, as well as the cumulative impacts of multiple land use types happening concurrently.

Concordance in wetland physicochemical conditions, vegetation, and surrounding land cover is robust to data extraction approach.

Concordance among wetland physicochemical conditions, vegetation, and surrounding land cover may result from the influence of land cover on the sources of plant propagules, on physicochemical conditions, and their subsequent determination of growing conditions. Alternatively, concordance may result if differences in climate, soils, and species pools are spatially confounded with differences in human population density and land conversion. Further, we expect that land cover within catchment boundaries will be more predictive than land cover in symmetrical buffers if runoff is a major pathway. We measured concordance between land cover, wetland vegetation and physicochemical conditions in 48 prairie pothole wetlands, controlling for inter-wetland distance. We contrasted land-cover data collected over a four-year period by multiple extraction approaches including topographically-delineated catchments and nested 30 m to 5,000 m radius buffers. After factoring out inter-wetland distance, physiochemical conditions were significantly concordant with land cover. Vegetation was not significantly concordant with land cover, though it was strongly and significantly concordant with physicochemical conditions. More, concordance was as strong when land cover was extracted from buffers <500 m in radius as from catchments, indicating the mechanism responsible is not topographically constrained. We conclude that local landscape structure does not directly influence wetland vegetation composition, but rather that vegetation depends on 1) physicochemical conditions in the wetland that are affected by surrounding land cover and on 2) regional factors such as the vegetation species pool and geographic gradients in climate, soil type, and land use.

A clinical carepath for obese pregnant women: a pragmatic pilot cluster randomized controlled trial.

Objectives: Obese women are at increased risks for complications during pregnancy, birth, and in their infants. Although guidelines have been established for the clinical care of obese pregnant women, management is sometimes suboptimal. Our goal was to determine the feasibility of implementing and testing a clinical carepath for obese pregnant women compared to standard care, in a pilot cluster randomized controlled trial (RCT). Methods: A pragmatic pilot cluster RCT was conducted, randomly allocating eight clinics to the carepath or standard care for obese pregnant women. Women were eligible if they had a pre-pregnancy body mass index (BMI) of ≥30 kg/m2 and a viable singleton <21 weeks. The primary outcomes were the feasibility of conducting a full-scale cluster RCT (defined as >80%: randomization of clinics, use in eligible women, and completeness of follow-up) and of the intervention (defined as >80%: compliance with each step in the carepath and recommendation of the carepath by clinicians to a colleague). Results: All eight approached clinics agreed to participate and were randomized. Half of the intervention clinics used the carepath, resulting in <80% uptake of eligible women. High follow-up (99.5%) was achieved, in 188 of 189 women. The carepath was feasible for numerous guideline-directed recommendations for screening, but less so for counseling topics. When the carepath was used in the majority of women, all clinicians, most of whom were midwives, reported they would recommend it to a colleague. The intervention group had significantly higher overall adherence to the guideline recommendations compared to control (relative risk: 1.71, 95% confidence interval: 1.57-1.87). Conclusions: In this pragmatic pilot cluster RCT, a guideline-directed clinical carepath improved some aspects of care of obese pregnant women and was recommended by clinicians, particularly midwives. A cluster RCT may not be feasible in a mix of obstetric and midwifery clinics, but may be feasible in midwifery clinics.

Acting like a doctor: oral case presentation curriculum for medical students.

This article was migrated. The article was marked as recommended. Background Verbal communication is an important element to clinical practice and an integral part of undergraduate medical education. The oral case presentation (OCP) is often used in professional verbal communication and remains commonplace in the clinical setting. The OCP additionally has a complex role in undergraduate teaching. Methods We designed a OCP curriculum taking into account reasoning, rhetorical and linguistic mechanisms. Delivered through a content and drama workshop involving a trained theatre actor to 45 pre-clinical, undergraduate medical students at our U.K. institution. Students were assessed objectively at weekly intervals by trained faculty. A paired t-test was performed to determine if the curriculum was effective in increasing OCP scores. Students' confidence was assessed using Likert scales. Findings An overall mean score improvement (M=20.3, SD 14.6, N=45) was significantly greater than zero, t (44) =9.3, two tail p <0.05, providing evidence that the curriculum was effective. A 95% confidence interval around the mean difference in score was 15.9-24.7. Confidence scores for both non-verbal and verbal elements of the OCP improved. Conclusion This curriculum led to an improvement in OCP scores and increased our students 'confidence with this modality of communication. Consideration should be given to incorporating dedicated teaching of the OCP in undergraduate education.

Maternal exercise and growth in breastfed infants: a meta-analysis of randomized controlled trials.

BACKGROUND AND OBJECTIVES: Studies have revealed that women who breastfeed their infants may be reluctant to exercise due to concerns that to do so would adversely affect their breast milk and consequently the growth of their infants. In this review, we seek to systematically review and statistically synthesize evidence from randomized controlled trials (RCTs) that have assessed the effects of maternal exercise on breastfed infant growth (weight gain and gain in length). METHODS: Searches of the following electronic bibliographic databases were performed to identify RCTs: Cochrane Library (CENTRAL), Medline/PubMed, Embase, Cumulative Index to Nursing and Allied Health Literature, and SPORT Discus. RCTs that compared any type of exercise intervention with other treatments or no treatment in women exclusively or predominately breastfeeding were eligible for inclusion, as were trials involving exercise as a cointervention. Two authors extracted data from studies independently. RESULTS: Four RCTs (5 comparisons) were included in the meta-analysis of infant weight gain that incorporated 170 participants. In breastfed infants, maternal exercise did not significantly affect infant weight gain (difference in mean weight gain = 18.6 g [95% confidence interval: -113.52 to 150.80, P = .73]). Only 1 trial assessed infant gain in length; no difference between the exercise and control groups was reported. Trials were classified as moderate or good methodological quality (moderate risk of bias). CONCLUSIONS: It appears that mothers can exercise and breastfeed without detriment to the growth of their infants, but this is based on limited evidence, and more research is required before this finding is confirmed.

Oil sands mining and reclamation cause massive loss of peatland and stored carbon.

We quantified the wholesale transformation of the boreal landscape by open-pit oil sands mining in Alberta, Canada to evaluate its effect on carbon storage and sequestration. Contrary to claims made in the media, peatland destroyed by open-pit mining will not be restored. Current plans dictate its replacement with upland forest and tailings storage lakes, amounting to the destruction of over 29,500 ha of peatland habitat. Landscape changes caused by currently approved mines will release between 11.4 and 47.3 million metric tons of stored carbon and will reduce carbon sequestration potential by 5,734-7,241 metric tons C/y. These losses have not previously been quantified, and should be included with the already high estimates of carbon emissions from oil sands mining and bitumen upgrading. A fair evaluation of the costs and benefits of oil sands mining requires a rigorous assessment of impacts on natural capital and ecosystem services.

Development and testing of an index of biotic integrity based on submersed and floating vegetation and its application to assess reclamation wetlands in Alberta's oil sands area, Canada.

We developed and tested a plant-based index of biological integrity (IBI) and used it to evaluate the existing reclamation wetlands in Alberta's oil sands mining region. Reclamation plans call for >15,000 ha of wetlands to be constructed, but currently, only about 25 wetlands are of suitable age for evaluation. Reclamation wetlands are typically of the shallow open water type and range from fresh to sub-saline. Tailings-contaminated wetlands in particular may have problems with hydrocarbon- and salt-related toxicity. From 60 initial candidate metrics in the submersed aquatic and floating vegetation communities, we selected five to quantify biological integrity. The IBI included two diversity-based metrics: the species richness of floating vegetation and the percent of total richness contributed by Potamogeton spp. It also included three relative abundance-based metrics: that of Ceratophyllum demersum, of floating leafed species and of alkali-tolerant species. We evaluated the contribution of nonlinear metrics to IBI performance but concluded that the correlation between IBI scores and wetland condition was not improved. The method used to score metrics had an influence on the IBI sensitivity. We conclude that continuous scoring relative to the distribution of values found in reference sites was superior. This scoring approach provided good sensitivity and resolution and was grounded in reference condition theory. Based on these IBI scores, both tailings-contaminated and tailings-free reclamation wetlands have significantly lower average biological integrity than reference wetlands (ANOVA: F(2,59) = 34.7, p = 0.000000000107).