Detailed Poster Abstract Schedule

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Monday, October 2, 2017

Author / Presenter: Alper James Alcaraz
Affiliation: University of Saskatchewan
Student: Yes

Session: Monday Poster Session
Date: Monday 02 October 2017
Time: 8:00 – 19:00
Location:

Abstract:

The need to address the disadvantages and difficulties of live animal toxicity tests serves as an impetus to develop biomarker-based risk assessment approaches. However, current methods in biomarker discovery rely heavily on known target genotype and phenotype of which the xenobiotic is designed to affect target organisms. This approach is problematic in such a way that certain adverse effects are species-specific and may not be predictive of adverse effects in non-target organisms. It is therefore important to identify universal biomarkers based on toxicity pathways that are universally perturbed in most organisms or a species-specific biomarker from pathways that are exclusively affected in certain organisms. In our study, we utilized next generation ‘omics technology to provide an unbiased approach in the characterization of toxicity pathways that allow probing of an entire biological system without a priori knowledge of the mechanism by which a chemical causes toxicity. We exposed juvenile rainbow trout (RBT) and white sturgeon (WS) to 125 µg/L fluoxetine (FLX) and 10 nM silver nanoparticles (AgNP). We employed sequence-by-synthesis-based, 125 base-pair paired-end reads whole transcriptome analysis (RNASeq) to determine global differential gene expression in excised liver of each exposed fish. Our results showed 644 and 356 common dysregulated annotated contigs with gene names for those exposed to AgNP and FLX, respectively. There were 160 downregulated annotated contigs with gene names for both RBT and WS exposed to AgNP, while 22 were upregulated. On the other hand, there were 6 downregulated and 11 upregulated annotated contigs with gene names common to RBT and WS exposed to FLX. There were 45 and 46 common pathways in RBT and WS involved in AgNP and FLX toxicity, respectively. Our result provides an array of dysregulated genes that are either common or mutually exclusive in each species which can be further investigated to establish a universal or species-specific AgNP and FLX-induced toxicity biomarker.

Author / Presenter: Alper James Alcaraz
Affiliation: University of Saskatchewan
Student: Yes

Session: Monday Poster Session
Date: Monday 02 October 2017
Time: 8:00 – 19:00
Location:

Abstract:

Pharmaceuticals and personal care products (PPCP) are becoming an increasing concern to water managers due to their toxicity to non-target organisms, pseudo-persistence and continuous discharge into surface water systems. Among these chemicals are the endocrine disrupting compound 17?-ethinylestradiol (EE2) and the selective serotonin reuptake inhibitor fluoxetine (FLX). Little is known about the (sub-)chronic effects of these compounds to aquatic organisms that are chronically exposed to low concentrations. In particular, information is limited on the molecular pathways that drive cascades of events that ultimately result in phenotypic adverse outcomes. Recent advances in next generation ‘omics technologies provide a platform for the unbiased characterization of toxicity pathways in target organisms as they allow entire biological systems to be probed without a priori knowledge of the mechanism by which a chemical causes toxicity. Therefore, the main goal of our research is to identify and validate key molecular toxicity pathways that are predictive of EE2- and FLX-induced apical responses in the model fish, Pimephales promelas. We will utilize sequence-by-synthesis-based whole transcriptome (RNASeq) and high-resolution mass-spectroscopy-based shotgun proteomics to characterize the molecular toxicity pathways and associate these with downstream biological responses of ecological and regulatory relevance in fathead minnow embryos exposed to graded concentrations of EE2 and FLX. We anticipate that this strategy will allow us to identify a set of signature toxicity pathways, including rare transcripts, that are predictive of EE2- and FLX-induced toxicity. This approach would facilitate the identification of key pathways and core genes involved in toxic responses, and therefore lead to the development an early life-stage gene expression assay that captures critical toxicity pathways for the prediction of apical outcomes of regulatory relevance beyond the two chemicals listed here. As this assay would take place prior to swim up, it would not be considered as a live animal test, hence, would address the need for alternative approaches in chemical screening. This study is part of the EcoToxChip project (@ecotoxchip).

Author / Presenter: Jordan Anderson
Affiliation: University of Ontario Institute of Technology
Student: Yes

Session: Monday Poster Session
Date: Monday 02 October 2017
Time: 8:00 – 19:00
Location:

Abstract:

Pharmaceuticals and personal care products (PPCPs) have been studied for their toxicity to non-target organisms in the aquatic environment. The majority of this research has involved understanding the toxicity of individual compounds. While this information is essential for understanding individual toxicity of a particular toxicant, it does not take into consideration the effects of chemicals in a mixture. This is a concern since PPCPs most commonly enter surface waters through wastewater treatment plant (WWTP) effluent as a complex mixture. This study examined how the odour suppressant and excipient hydroxypropyl-?-cyclodextrin (HP?CD) alters the toxicity of select synthetic steroids commonly used as human oral contraceptives. HPC?D is amphiphilic and toroidal in shape with the ability to include non-polar guest compounds within its central cavity. HPC?D is both used as an excipient in the pharmaceutical industry as well as an odour suppressant in Febreze®. The steroids of interest include: 17?-ethinylestradiol (EE2), levonorgestrel (LNG), and etonogestrel (ENG), all of which are commonly found in human oral contraceptives. To identify the individual toxicity of each compound, juvenile female rainbow trout (Oncorhynchus mykiss) were intraperitoneally injected with either 0.001 nmol/kg, 0.0032 nmol/kg, 0.010 nmol/kg, 0.032 nmol/kg, 0.100 nmol/kg or 0.320 nmol/kg of EE2, LNG, ENG, or HPC?D n=10 fish per treatment. Blood, liver, gonads, and brains were sampled 7 days post injection and analyzed for changed in vitellogenin (VTG), endogenous steroid concentration, and alterations in gene expression. Next, juvenile female rainbow trout were injected with a mixture of HPC?D and either EE2, LNG, or ENG, and sampled 7 days after injection. Results are pending. Preliminary results from this study indicate that in the presence of HPC?D, the 96 h acute toxicity of EE2 to larval American flagfish (Jordanella floridae) was significantly reduced in a 1:1 molar ratio (EE2:HP?CD) (P ? 0.05). Thus an interaction between HPC?D and EE2 appears to be able to be detected though a biological assay.

Author / Presenter: Nicole Baldwin
Affiliation: University of Saskatchewan
Student: Yes

Session: Monday Poster Session
Date: Monday 02 October 2017
Time: 8:00 – 19:00
Location:

Abstract:

Amphibians are of vital importance to aquatic ecosystems and are generally regarded as a sensitive bioindicator of ecosystem health. Exposure to contaminants can have adverse outcomes on amphibian health, such as altered rate of metamorphosis, reproductive effects, immune suppression, and behavioural effects. Alterations in molecular processes often precede these apical effects giving early indications of subsequent physiological changes and their modes of action. Toxicogenomics therefore shows great promise as an early screening tool to prioritize chemicals with potential risk for adverse effects, without the need for long-term, animal-intensive exposures. The main goal of this study is to identify and validate key molecular toxicity pathways that are predictive of contaminant-induced apical responses in the model amphibian, Xenopus laevis. Specifically, this study focused on chlorpyrifos (CPY) and ethinyl estradiol (EE2), two anthropogenic contaminants of concern with different modes of action and characterised apical effects in amphibians. Post-hatch individuals were exposed for 96 h to CPY (0.5, 2, 8 ug/L) and EE2 (0.04, 0.2, 1 ug/L) and sampled for whole transcriptome (RNASeq) and mass-spectroscopy-based shotgun proteomics to characterize their molecular toxicity pathways. A subset of tadpoles was then transferred to a flow-through diluter system for exposure to metamorphosis (~ 40 d) and assessed for developmental stage, morphometrics, organ histopathology and genetic sex. We anticipate that this work will identify critical toxicity pathways and associated specific key genes to be used in an early life-stage gene expression assay to predict apical outcomes of ecological and regulatory relevance in amphibians, providing an alternative approach in chemical screening. This study is part of the EcoToxChip project (@ecotoxchip).

Author / Presenter: Adrienne Bartlett
Affiliation: Environment Canada
Student: No

Session: Monday Poster Session
Date: Monday 02 October 2017
Time: 8:00 – 19:00
Location:

Abstract:

Perfluoroalkyl substances (PFASs) are used in a variety of industrial and commercial products, including surfactants, polymers, lubricants, adhesives, paints, household cleaners, pesticides, and fire-fighting foams. Significant environmental concerns are associated with PFASs due to their persistence, potential for bioaccumulation, toxicity, and capacity for long-range transport. PFASs, including perfluorooctanoic acid (PFOA), are widely present in the Canadian environment, particularly at some contaminated sites due to historic firefighting training operations. Despite a large body of research on environmental exposure, the toxicity of PFOA is an emerging field of study, and insufficient aquatic toxicity data exist to develop water quality guidelines. Thus, our objective was to conduct chronic, aqueous exposures with PFOA to assess the lethal and sublethal toxicity to Hyalella azteca (amphipod) and Pimephales promelas (fathead minnow). Amphipod exposures were 6 weeks (1-100 mg/L nominal) and examined survival, growth, and reproduction. Fathead minnow exposures were 21 days (0.01 to 100 mg/L nominal), and endpoints included hatching success, deformities at hatch, larval survival, and growth. Measured PFOA concentrations in exposures were 80-90% nominal; therefore, toxicity data were expressed as nominal. Amphipod survival was significantly reduced at 100 mg/L, with a 6-week LC50 of 53 mg/L. Growth and reproduction of amphipods were more sensitive endpoints than survival, with 6-week EC50s of 2.3-2.4 mg/L. Fathead minnows were less sensitive than Hyalella, with only a 10% decrease in larval survival at 100 mg/L. There were some indications of increased deformities in larval fish at 100 mg/L, but these were not statistically significant. Hatching success and growth of larval fish were not affected by PFOA exposure up to 100 mg/L. Maximum concentrations of PFOA in the surface waters of the Great Lakes are generally < 50 ng/L, and as the toxicity of PFOA to amphipods and fathead minnows occurred at concentrations > 1 mg/L, it is likely that most environmental concentrations are far below those that cause toxicity to these species. However, localized areas could be highly contaminated due to historical activities or recent spills (where concentrations as high as 11 µg/L have been found). Our data will provide valuable information with which to assess the risk of PFOA at contaminated sites, and to set a target for site remediation.

Author / Presenter: Adrienne Bartlett
Affiliation: Environment Canada
Student: No

Session: Monday Poster Session
Date: Monday 02 October 2017
Time: 8:00 – 19:00
Location:

Abstract:

Canada?s Chemicals Management Plan (CMP) was implemented by the federal government in 2006 to regulate chemicals detrimental to human health and the environment. Few toxicological data are associated with the numerous industrial chemicals listed in the CMP. Thiocarbamates are high production volume chemicals, and are imported into Canada primarily for uses related to rubber and motor vehicle parts manufacturing, although they are also used as pesticides. Despite their widespread use, there is little information on the ecotoxicity of thiocarbamates, and the research that is available focuses primarily on acute lethality. Therefore, our objective was to conduct chronic, spiked-sediment exposures to assess the toxicity of two thiocarbamate compounds, tetramethyl thiuram disulfide (TMTD or Thiram, CAS RN 137-26-8) and dipentamethylene thiuram tetrasulfide (DPTT, CAS RN 120-54-7), to three species of aquatic invertebrates: Hyalella azteca (amphipod), Hexagenia spp. (mayfly), and Daphnia magna (cladoceran). Three-week range-finding tests with Hyalella and Hexagenia were conducted initially, and as DPTT demonstrated little toxicity, chronic DPTT exposures were only conducted with Daphnia. Chronic sediment exposures were six weeks (Hyalella and Hexagenia; Thiram only) or three weeks (Daphnia; Thiram and DPTT), and effects on survival (all species), growth (all species), and reproduction (Hyalella and Daphnia only) were assessed. Results are currently based on nominal concentrations (mg/kg dry weight sediment), as chemical analysis of water and sediment is ongoing. Survival in Thiram exposures was significantly reduced at 100 mg/kg, with LC50s of 86, 110, and 48 mg/kg for Hyalella, Hexagenia, and Daphnia, respectively. Thiram also caused a significant decrease in growth of Hexagenia (EC50 = 69 mg/kg). Growth and reproduction of Hyalella and Daphnia were not affected by Thiram (up to 300 and 1000 mg/kg, respectively). Chronic DPTT exposures with Daphnia caused a significant decrease in survival (LC50 = 1000 mg/kg), but there were no significant effects on growth or reproduction (up to 1000 mg/kg). Thiram was similarly toxic to the three invertebrate species tested, with effects occurring between 48-110 mg/kg, and was 10-fold more toxic than DPTT. The results of this study will be compared to thiocarbamates measured in Canadian environmental samples, and will support environmental risk assessments to determine if thiocarbamates could impact aquatic organisms.

Author / Presenter: Lindsay Beyger
Affiliation: University of Ontario Institute of Technology
Student: Yes

Session: Monday Poster Session
Date: Monday 02 October 2017
Time: 8:00 – 19:00
Location:

Abstract:

Over the years a large focus has been placed on the effects of individual pharmaceutical compounds on non-target organisms. While this is highly important from a mechanistic point of view it is also important to consider the real environment in which fish would be exposed. In surface waters, wild fish are exposed to numerous compounds over multiple generations with many different stressors and modifying factors. Adult American flagfish (Jordanella floridae) were exposed to ibuprofen, naproxen, and 17 ?-ethinylestradiol alone, and in mixtures during a short-term reproduction study. Offspring were collected and used in a copper reference toxicant challenge. The challenge was completed to assess if their sensitivity would alter based on prior life history. Both control and exposed offspring exhibited a slight change in sensitivity during the challenges. The methodology of testing subsequent exposures on offspring as a secondary stressor has not been well studied. This research aims to contribute to a better understanding of the impact of multiple factors including single and mixture pharmaceutical exposures and subsequent toxicant challenges which fish may encounter in the environment.

Author / Presenter: Kerstin Bluhm
Affiliation: University of Saskatchewan
Student: No

Session: Monday Poster Session
Date: Monday 02 October 2017
Time: 8:00 – 19:00
Location:

Abstract:

Chlorpyrifos is an organophosphate insecticide that acts as a neurotoxicant through inhibition of the enzyme cholinesterase. The mode of action of organophosphates in target and non-target organisms, including mammals, is similar. The aim of the project is to develop an early life-stage gene expression assay (EcoToxChip) that captures critical toxicity pathways of chlorpyrifos for the prediction of apical outcomes of regulatory relevance. As this assay is intended to use early life-stages that are not feeding independently, it would not be considered as a live animal test, and therefore, would address the need for alternative approaches in chemical screening. As part of the project, critical toxicity pathways and associated core genes will be identified following exposure of fathead minnows (Pimephales promelas) at early life-stages to three sub-lethal concentrations of chlorpyrifos. Specifically, sequence-by-synthesis-based whole transcriptome (RNASeq) and high-resolution mass-spectrometry-based shotgun proteomics will be used to characterize key molecular toxicity pathways. Pathways will then be correlated with downstream biological responses of ecological and regulatory relevance, and critical genes linked to apical outcomes will be identified for inclusion on EcoToxChips. Chlorpyrifos concentrations were selected based on a preliminary test as well as concentrations in published data. These tests revealed a threshold level of mortality between 1 and 10 µg/L chlorpyrifos. To ensure the determination of solely sub-lethal effects in at least two of the tested concentrations, 0.5, 1.5 and 4.5 µg/L chlorpyrifos solutions were investigated in the fathead minnow early life-stage assay with larvae samplings after 7 and 32 days of exposure. None of these concentrations affected survival or growth, resulting in a sub-chronic NOAEC and LOAEC of 4.5 and 10 µg/L chlorpyrifos, respectively, in fathead minnows. Samples are currently being further analyzed for molecular and physiological endpoints to gain insight into critical toxicity pathways. This study is part of the EcoToxChip project (@ecotoxchip).

Author / Presenter: Markus Brinkmann
Affiliation: University of Saskatchewan
Student: No

Session: Monday Poster Session
Date: Monday 02 October 2017
Time: 8:00 – 19:00
Location:

Abstract:

An ever-increasing number of chemicals are released into the environment that are potentially toxic to humans and wildlife. Current regulations for the assessment of the toxicological risks of these chemicals rely on extensive live-animal testing using a few standard model species. In addition to the huge costs and ethical objections regarding animal testing, these approaches are often not adequately protective of organisms of concern, such as native species or humans. Recent advances in omics technologies and systems biology, as well as in the field of in vitro high-throughput testing provide promising tools to address these challenges. Application of these methodologies in context with chemical risk assessment, however, requires the translation of their results into outcomes of regulatory relevance. To bridge these gaps, this study explores the use of novel approaches in toxicokinetic modeling to extrapolate effects obtained with in vitro assays to whole organisms, as well as among species, life stages and levels of biological organization. Successful implementation of these approaches in chemical risk assessment will represent a great step towards more sustainable, efficient, and unbiased assessments of the safety of the large number of chemicals in use today and in the future, and may potentially save billions of dollars and millions of animals.

Author / Presenter: Samantha Deeming
Affiliation: WLU
Student: Yes

Session: Monday Poster Session
Date: Monday 02 October 2017
Time: 8:00 – 19:00
Location:

Abstract:

Studies on male fish in the Grand River (Southern Ontario, Canada) have shown a variety of reproductive issues such as increased intersex condition (ova-testes) and vitellogenin production, and decreased gonadsomatic index and testosterone production. Many of these effects have potentially been linked to proximity to the effluent outflows of wastewater treatment plants (WWTP). WWTP effluents are complex mixtures that contain numerous chemicals with the potential to disrupt the endocrine systems of exposed fish. This study investigated the sex steroid production levels of female rainbow darter (RBD, Etheostoma caeruleum) at two locations in the Grand River: a location upstream (reference) of the Waterloo WWTP effluent outflow and a site that is downstream of the outflow (exposed). Secondly, this study examined the impact of the collection method on the steroid production. Given that field collections of small-bodied fish in rivers often employ electrofishing methods and that stress is known to affect steroid levels, fish collected following electrofishing from both locations were sacrificed and ovaries removed at varying times over two sampling periods, one year apart. Ovarian tissue was cultured in vitro for 24h with or without the addition of human chorionic gonadotropin (hCG), an analog to endogenous luteinizing hormone that stimulates steroid production. Reference fish sacrificed 1h post-collection had stimulated ovarian estradiol production levels of 54.4 ? 4.8 pg/mg of tissue in 2015 and 46.1 ± 5.5 pg/mg in 2016, which were significantly higher than exposed fish sampled after 1h in both years (34.3 ± 2.2 pg/mg and 23.4 ± 3.5 pg/mg, respectively). In 2016, 3h post-collection stimulated estradiol production in reference fish was no longer significantly higher than the exposed fish (38.6 ± 2.6 pg/mg vs. 24.3 ± 3.2 pg/mg). In 2015, 7h post-collection, basal estradiol production levels for reference fish ovarian tissue (5.0 ± 0.44 pg/mg) were significantly higher than those of exposed fish (3.1 ± 0.40 pg/mg). Over the 24h, stimulated estradiol levels decreased significantly in reference fish ovaries (1h 54.4 ±4.8, 7h 40.7 ± 4.0, and 24h 25.6 ± 2.9 pg/mg). At 24h, there were no significant differences in basal or stimulated estradiol production levels between the reference and exposed fish ovaries in both years. These results suggest that standardized collection and sampling methods are important to interpreting reproductive steroid levels of fish collected through electrofishing and in the identification of site-specific differences. The impact of time held post-shock may be a stress-related response with enough magnitude to impact the ability to detect reproductive endocrine impacts of point/non-point sources on small-bodied fish and is being further investigated.

Author / Presenter: William Dew
Affiliation: Trent University
Student: No

Session: Monday Poster Session
Date: Monday 02 October 2017
Time: 8:00 – 19:00
Location:

Abstract:

Diltiazem is a calcium channel blocker primarily used for the treatment of angina and hypertension. The concentration of diltiazem in a waterway can be in excess of 100 ng/L due to release via wastewater treatment plants. As diltiazem is a calcium channel blocker, it is possible that it will affect calcium channel function in a wide variety of tissues. One such tissue is the olfactory epithelium, which is in constant contact with the external environment and relies on calcium channels to function. Olfaction mediates a wide variety of essential behaviours including finding food and detecting predation/predators. Therefore, fish in environments containing diltiazem may have impairment of olfactory-related behaviours due to impairment of calcium channels in the olfactory epithelium. To test if olfactory-related behaviours could be affected by diltiazem, we exposed fathead minnows (Pimephales promelas) to 0, 2, or 20 ng/L nominal treatment levels of diltiazem for 10 min or 96 hr and measured the response of fathead minnows to olfactory cues. The results demonstrate that at either time point 2 ng/L diltiazem has no effect on antipredator response in fathead minnows, however, exposure to 20 ng/L diltiazem completely blocks any response to antipredator cues. This study demonstrates that diltiazem at or below concentrations found in waterways receiving effluent from wastewater treatment plants can have a profound effect on olfactory-mediated behaviours in fish. Future studies are needed to understand the relationships among environmental exposure, internal dose, and olfactory function and behaviour in various fish species.

Author / Presenter: cory dubetz
Affiliation: Fisheries and Oceans Canada
Student: No

Session: Monday Poster Session
Date: Monday 02 October 2017
Time: 8:00 – 19:00
Location:

Abstract:

As a science-based federal government department, Fisheries and Oceans Canada (DFO) requires scientific evidence to facilitate the sound management of Canada’s fisheries, and to advance sustainable aquatic ecosystems while fostering economic prosperity across maritime sectors and fisheries. The National Contaminants Advisory Group (NCAG) provides scientific information and advice to DFO on priority issues related to the biological effects of contaminants on aquatic species. The main functions of the group are to facilitate research projects through external researchers, to synthesize results and to develop science advice in support of DFO decision-making. Current priority research themes are: (1) oil and gas, (2) pesticides, (3) aquaculture therapeutants, and (4) contaminants and issues of emerging concern. The NCAG has funded a variety of multiyear research projects at Canadian universities and non-for profit research institutions. A summary of NCAG supported research projects and their highlights is presented.

Author / Presenter: Bryanna Eisner
Affiliation: University of Saskatchewan
Student: Yes

Session: Monday Poster Session
Date: Monday 02 October 2017
Time: 8:00 – 19:00
Location:

Abstract:

Large numbers of chemicals are discharged into aquatic ecosystems as a result of human activities. While some of these compounds have been widely studied and adverse effects on fishes have been identified, there is an increasing number of emerging contaminants (ECs), including pharmaceuticals and personal care products (PPCPs) or brominated flame retardants (BFRs), for which little or no toxicity data regarding aquatic organisms is available. Many of these ECs, such as 17?-ethynylestradiol (EE2), a potent estrogen agonist used in oral contraceptives, fluoxetine, a common antidepressant, and hexabromocyclododecane (HBCD) a widely used flame retardant, may pose significant risks to aquatic ecosystems due to their prevalence in the environment. Specifically, large quantities of these chemicals have been identified in municipal wastewater effluents (MWWEs). Widespread use of ECs has raised concerns regarding their possible risks to the environment, particularly to native species of cultural, recreational and commercial importance to Canadians, including lake trout (Salvelinus namaycush), northern pike (Esox lucius) and white sturgeon (Acipenser transmontanus). While while data for some of these compounds are available on model laboratory species, such as rainbow trout (Oncorhynchus mykiss), little is known of the effects of these ECs to species in northern ecosystems, and as such, there are approaches needed that allow to assess potential effects to such species. However, there is increasing concern with regard to live animal testing, particularly with regard to endangered or long-lived species. Therefore, alternative testing methods, such as in vitro tissue explant assays, are needed. The aim of the current study is to validate the predictivity of our in vitro results by comparing to a parallel in vivo study with the same species. Following an in vitro tissue explant assay in which lake trout, northern pike, rainbow trout and white sturgeon livers were exposed to serial concentrations of EE2, fluoxetine or HBCD, transcript abundance of select genes was measured in these species and a species-specific response was characterized. Rainbow trout had the greatest response among species when exposed to EE2, followed by white sturgeon, northern pike, then lake trout. With exposure to fluoxetine, rainbow trout and white sturgeon had equal responses while lake trout and northern pike had lesser responses. With exposure to HBCD, rainbow trout was again the most responsive species, followed by northern pike, lake trout, and white sturgeon.

Author / Presenter: Darcy Fallaise
Affiliation: University of Guelph
Student: Yes

Session: Monday Poster Session
Date: Monday 02 October 2017
Time: 8:00 – 19:00
Location:

Abstract:

Non-aqueous phase liquids (NAPLs) formed from the pooling of immiscible solvents in the subsurface pose a unique challenge for characterization, risk assessment, and remediation. The lack of understanding as to exactly which compounds are present at a site impairs the ability to develop both accurate risk assessments and efficient and effective remedial strategies. Until removed or sequestered, the constituents of NAPL will continue to leach into groundwater, posing an ongoing risk to groundwater contamination. At many current and former chemical facilities, the composition of NAPL can be complex, and, for several reasons, is often incompletely characterized. Analysis of NAPL constituents by conventional chromatographic methods is impaired by the high-levels of solvents present, which require dilutions of several orders of magnitude before analysis in order to ensure the safety and integrity of the instrumentation. These dilutions reduce the ability to study the components present in NAPL mixtures at lower concentrations, including pesticides and other hydrophobic compounds that partition into the hydrophobic NAPL substrate. In addition, conventional analytical methods based on the targeted analysis of known or presumed compounds often fail to identify the structures of compounds that are unknown or for which standards are not available, including degradation products. This poster discusses the use of Nuclear Magnetic Resonance (NMR) Spectroscopy as a non-destructive and unbiased analytical tool to assist in the characterization of complex NAPL samples with minimal sample manipulation. NMR has many beneficial attributes that are of use in the characterization of these concentrated, complex mixtures of chemical contaminants, including: the non-selective fingerprinting of all classes of organic compounds present, the ability to quantify constituents without individual standards and calibrations, and the ability to provide structural information on unknown constituents. Advanced multidimensional NMR methods are discussed, including diffusion ordered spectroscopy, that are able to assist in the deconvolution of the overlapping signals in the spectra of complex NAPL mixtures such that the NMR spectra for individual constituents can be isolated.

Author / Presenter: Natalie Feisthauer
Affiliation: Agriculture and Agri-Food Canada
Student: No

Session: Monday Poster Session
Date: Monday 02 October 2017
Time: 8:00 – 19:00
Location:

Abstract:

Soil health, or soil quality, is fundamental to soil biodiversity, function and the provision of services such as food production, and is derived from characteristics of soil biological, chemical and physical components. Each of these components influences the response of soil organisms to contamination and should be considered in the interpretation of ecotoxicity assessments. However it is difficult to describe the constituents of soil physical, chemical and biological components in a manner that is succinct, repeatable and has the potential to be quantified. A unique “soil fingerprinting” framework was developed to record and monitor the impacts on soil quality from environmental stressors and land use management. The framework provides an enhanced soil A horizon descriptor methodology to systematically track and record change in soil chemical, physical and biological characteristics. The enhanced horizon designation generated is analogous to a genetic code or “soil fingerprint? for an individual soil sample at the time the sample was collected.  The framework monitors A horizon characteristics that not only represent dynamic soil properties (e.g., soil structure, organic carbon, etc.) but also soil and land information (e.g., soil texture, land use) providing data to allow comparative interpretations of soil quality changes and identify trends due to human activities (e.g., soil management practices, remediation, etc.) among different soils, or the same soils under different conditions or at different times. The design of the framework is modular, meaning any level of information can be removed and new levels can be added. For example, levels for soil microbial respiration, root biomass, microarthropod toxicity etc. can be added. The framework then generates fingerprints that are unique identifiers of the nature and context of the key dynamic soil properties related to soil quality as one integrated descriptive label together with ecotoxicity information. For instance, by including soil structure, the framework can integrate physical characteristics that significantly influence soil biological endpoints but that are not often included in ecotoxicity assessments. A database of fingerprints, generated either over time or among sites, provides enhanced opportunities to quantitatively analyse multiple lines of evidence in contaminated site assessments. Examples of the application of the soil fingerprinting framework in soil under different land uses and land management practices will be provided.

Author / Presenter: Isabelle Gosselin
Affiliation: Canadian Nuclear Laboratories
Student: No

Session: Monday Poster Session
Date: Monday 02 October 2017
Time: 8:00 – 19:00
Location:

Abstract:

Title: Assessment of the effect of water quality on copper toxicity in two strains of Hyalella azteca Author: Isabelle Gosselin1, Laura Richards2, Stephanie Walsh1, Carmen Shultz1, Christina Ng2, Nora Hickling1 and Marilyne Stuart1 1Environmental Technologies Branch, Canadian Nuclear Laboratories, Chalk River, Ontario 2University of Guelph, Guelph, ON, Canada Abstract At the Chalk River Laboratories (CRL) site, sediment toxicity testing is typically conducted using a standard 5-salt culture water (SAM-5S) that is prepared in the laboratory. However, this water may have a different composition than the water found in local water bodies. A study was undertaken to assess the copper tolerance of two strains of Hyalella azteca in SAM-5S (high ionic strength), Ottawa River water (low ionic strength) and diluted SAM-5S (similar ionic strength to Ottawa River water). Acute (96 h) copper toxicity tests were conducted with 9 to 16 day-old H. azteca. One of the strains tested was obtained from the Canadian Centre for Inland Waters (CCIW). This CCIW strain can tolerate waters with low ionic strength but cannot reproduce in Ottawa River water. The other strain tested was from Twin Lake (low ionic strength) located on the CRL property. For a given water type, the two strains of H. azteca yielded comparable responses to copper. The highest copper tolerance was found in Ottawa River water, closely followed by SAM-5S, whereas the lowest copper tolerance was found in diluted SAM-5S. This study also demonstrates no difference in sensitivity to copper between the two H. azteca strains. Keywords: Hyalella azteca, Water composition, Low ionic strength waters, Copper toxicity

Author / Presenter: Beverley Hale
Affiliation: University of Guelph
Student: No

Session: Monday Poster Session
Date: Monday 02 October 2017
Time: 8:00 – 19:00
Location:

Abstract:

Surface deposition of trace metal contaminated particulates onto soil often results in the non-proportional distribution of contaminants throughout the profile. Surrounding the decommissioned Ni refinery in Port Colborne, Ontario, Ni concentrations in the upper 10 cm of the profile reached upwards of 4500 mg kg-1, while deeper soils remain at near background concentrations. Laboratory and field-based studies were undertaken to test the viability of reducing the trace metal concentrations in the rhizosphere by homogenizing the upper 30 cm of the soil profile. The laboratory study studied the growth of soybean in pots under controlled conditions in field-collected soils from Port Colborne and clean soil from Elora region. Three profile depth-based treatments from each soil type were used (0-15 cm, homogenized 0-30 cm, and 15-30 cm). Homogenization of the 0-30 cm depth reduced the concentrations of Ni and Cu ten-fold relative to the 0-15 cm depth, for Port Colborne soils. Soybean growth was significantly improved in the homogenized Port Colborne soils relative to the 0-15 cm treatment; however, growth was significantly reduced relative to controls. Therefore, this method of remediation will likely reduce the toxicity of Ni that would occur on soils with similar concentrations of total Ni, but will not eliminate it. A field trial is underway to evaluate soil homogenization capabilities of heavy machinery and assess how the associated reduction in trace metals in the rhizosphere affects toxicity in crops, using normal agronomic practices. Following homogenization, Ni was reduced from 3700 to 1532 mg kg-1 and Cu we reduced from 353 to 159 mg kg-1 in the top 10 cm of the profile. Crop trials have yet to begin, but the initial assessments of trace metal reductions at the profile surface demonstrate the potential of this method as a large-scale method of remediation in the Port Colborne region.

Author / Presenter: Thiviya Kanagasabesan
Affiliation: Wilfrid Laurier University
Student: Yes

Session: Monday Poster Session
Date: Monday 02 October 2017
Time: 8:00 – 19:00
Location:

Abstract:

The endocrine disrupting compound 17?-ethinylestradiol (EE2), is linked to organism-level (hormone physiology/development) and population-level (egg production) effects in fish. Compared to model freshwater teleosts, estuarine Fundulus heteroclitus (mummichog) egg production is less sensitive to EE2 exposure; this may be due to differences in ovarian physiology, including 17?-estradiol (E2) regulation. In most teleost fish, there is a shift from estrogens (such as E2) to progestogens (such as maturation inducing steroid; MIS) as follicles progress to early maturation. However, in mummichog there is no shift detected, as levels of E2 are consistently higher in all stages of follicular development. Plasma and ovarian follicles from maturing mummichog were collected and grouped into five stages of maturation; follicular steroid production and/or gene expression in hormone signalling and steroidogenic pathways were assessed by stage. Plasma and follicular production of E2 increased as the ovarian maturation cycle progressed, and dropped after maturation; whereas MIS was equally expressed during development and early maturation stages, and increased in late maturation and ovulation stages. Differences between mummichog and other teleosts in maturational gene expression include: expression of P450 c17 (converts pregnenolone to 17?-hydroxypregnenolone and dehydroepiandrosterone) and follicle stimulating hormone receptor (FSHr; key gonadotropin responsible for ovarian development) drop earlier in the maturation cycle, P450 aromatase (converts testosterone to E2) is evenly expressed through all stages prior to dropping at late maturation, and luteinizing hormone receptor (LHr; key gonadotropin responsible for ovarian maturation) peaks earlier in maturation than expected. To determine EE2 effects, follicles grouped per stage were exposed to 50, 100 and 250 nM of EE2 in vitro; after 24 hours, P450 aromatase and LHr expression show no exposure differences regardless of ovarian stage. The dissimilarity in mummichog from other model teleosts in E2 regulation plus EE2 insensitivity in maturing follicles may be partially responsible for the lack of sensitivity of egg production in EE2-exposed mummichog.

Author / Presenter: Chris Kennedy
Affiliation: Simon Fraser University
Student: No

Session: Monday Poster Session
Date: Monday 02 October 2017
Time: 8:00 – 19:00
Location:

Abstract:

The environmental consequences of aquaculture chemotherapeutant use as a treatment for sea lice was assessed by generating data on the acute and sublethal toxicity to sensitive marine organisms (crustaceans; Family Pandalidae) under environmentally realistic conditions and multiple stressor scenarios (chemical: single and multiple pulse exposure scenarios; physical: variable oxygen, temperature; biological: complete life stage testing). Exposures were short-term and based on environmental data reported near aquaculture operations of each the formulations Salmosan®, Paramove® 50, and SLICE® either individually or in a mixture. For SLICE®, exposures were done using spiked fish feed or in water; exposures with Salmosan®, and Paramove® 50 were via water. Acute toxicity of Salmosan® was greater than Paramove® 50 in both juveniles and adults of several species (coonstripe shrimp [Pandalus hypsinotus], pink shrimp [Pandalus jordani], dock shrimp [Pandalus danae], spot prawn [Pandalus platyceros], and ghost shrimp [Neotrypaea californiensis], and sand shrimp [unidentified spp.]). No mortality was seen after consumption of feed medicated with SLICE®. Species were equally sensitive to chemotherapeutants. Data for 3 developmental stages (larval stages I, III, and V) of the spot prawn indicate that these early life stages are far more sensitive to all chemotherapeutants compared to adults. Prawns actively avoided all chemotherapeutants. Sublethal exposures resulted in increases in oxygen consumption, and in some cases olfaction, and feeding behaviours. Data indicate that mixtures are more toxic than when exposure to each chemical alone, and that environmental temperature increases toxicity by as much as 3-fold. Hypoxia also exacerbated acute toxicity, however, no effects of environmental salinity were seen on toxicity thresholds. The data obtained from this project is required to ensure the proper and safe use, and appropriate regulation of these aquaculture chemicals in Canada.

Author / Presenter: Chris Kennedy
Affiliation: Simon Fraser University
Student: No

Session: Monday Poster Session
Date: Monday 02 October 2017
Time: 8:00 – 19:00
Location:

Abstract:

The environmental consequences of diluted bitumen (dilbit) exposure to estuarine and strictly marine species was assessed. WSF of dilbit (WSFd) was generated by using an oiled substrate method in which dilution water flows through a polyvinyl chloride column filled with ceramic beads pre-soaked in dilbit (Cold Lake Summer Blend) or by the CROSERF method for the preparation of a water accommodated fraction (WAF) and a chemically enhanced water accommodated fraction (CEWAF). The susceptibility of different groups of marine organisms in acute toxicity tests with WAF/CEWAF varied from being relatively non toxic at 100% WAF to lethal at less than 5% dilutions. CEWAF was always more toxic to all species compared to WAF alone, however the magnitude of CEWAFs higher toxicity was not the same in all species. Susceptibility trends for WAF were Kelp Macrocystis pyrifera > Echinoderm Strongylocentrotus purpuratus > mysid Mysidopsis bahia > Topsmelt (Atherinops affinis) = spot prawn (Pandalus platyceros) = Pink salmon (Oncorhynchus gorbuscha) = rock greenling (Hexagrammos lagocephalus) = tidepool sculpin (Oligocottus maculosus). LC50 values for the latter 5 organisms could not be determined for WAF. Several performance abilities showed significant alterations in crustaceans and teleosts upon exposure. Swimming performance in fish was affected that could reduce many aspects related to survival, migration, and predator avoidance. Physiological effects were also seen in several parameters in crustaceans and fish including growth and feeding. Teleosts and crustaceans responded variably to the presence of low concentrations of dilbit; some organisms were either not able to detect, or to respond to dilbit suggesting a greater risk of exposure (particularly if attracted). These studies also show that the olfactory ability of crustaceans is affected by exposure to dilbit. This information highlights the need for realistic toxicity testing methods that will generate toxicity data that will ensure that the risk assessments to organisms are accurate.

Author / Presenter: Chris Kennedy
Affiliation: Simon Fraser University
Student: No

Session: Monday Poster Session
Date: Monday 02 October 2017
Time: 8:00 – 19:00
Location:

Abstract:

The environmental consequences of aquaculture chemotherapeutant use as a treatment for sea lice were assessed by generating data on their environmental partitioning and persistence, and acute and sublethal toxicity to a variety of Pacific marine organisms. Deltamethrin (DM), emamectin benzoate (EB), and cypermethrin (CP) all demonstrated partitioning into sediments, while azamethiphos AZ was almost undetectable in the sediment, and hydrogen peroxide (HP) was detected in water only. The estimated water t1/2 of HP was <9 h. AZ was the next least persistent (t1/2 ~12 d), followed by DM (t1/2 water ~18 d; sediment ~45 d), CP (t1/2 water ~ 20 d; sediment ~ 557 d), and EB (t1/2 sediment ~230 d). For all toxicity experiments, exposures were short-term exposures (<96 h) and were based on environmental data reported from aquaculture facilities. Generally, susceptibility to each chemotherapeutant in acute toxicity tests with a variety of marine organisms (Giant Kelp [Macrocystis pyrifera], Topsmelt [Atherinops affinis], Mysids [Mysidopsis bahia], Blue mussels [Mytilus sp.], Pacific purple sea urchins (Strongylocentrotus purpuratus), and spot prawn [Pandalus platyceros]), was species-specific and no general trends were evident. Spot prawns were actively attracted to, and actively avoided, EB, HP, and AZ at various concentrations. Naïve Pink salmon (Oncorhynchus gorbuscha) fry avoided EB, HP, CP, and AZ. All chemotherapeutants reduced swimming performance, and sublethal exposures to CP and DM resulted in the loss of attraction to food. This research provides targeted information on the environmental fate, and acute/sublethal toxicity required to ensure the proper and safe use of chemotherapeutants through science-based regulations for these important aquaculture chemicals.

Author / Presenter: Michael Moreton
Affiliation: Simon Fraser Unvi
Student: Yes

Session: Monday Poster Session
Date: Monday 02 October 2017
Time: 8:00 – 19:00
Location:

Abstract:

Diquat dibromide is a herbicide widely used in North America for industrial and recreational control of terrestrial and aquatic weeds. The objectives of this study were to assess the lethal and sub-lethal effects of this herbicide in a commercial formulation, Reward® (240 g/L diquat dibromide). Therefore, this research provides novel toxicity data on this active ingredient combined with any additives or adjuvants in the commercial formulation of Reward®, and on application scenarios prescribed by the manufacturer. Specifically, a 14-day period between applications of Reward® in a water body undergoing treatment is required, yet the effects of these ‘pulse’ exposure scenarios on aquatic wildlife such as fish are unknown. Several experiments were conducted to address this knowledge gap. The first was an early life stage fathead minnow exposure that was conducted according to an Environment and Climate Change Canada Biological Test Method entailing a 7-day continuous, chronic exposure (0.105-12.6 mg/L). A larval LC50 of 2.04 mg/L was derived from this experiment and a significant decrease in average biomass was observed at 1.17 mg/L Reward®. The second fathead minnow larval exposure was a modified version of the 7-day chronic test whereby larvae were exposed for 24 hours and then reared in clean water for 14 days followed by a second 24 hour exposure to Reward®. The LC50 derived from this experiment was 4.19 mg/L and an EC50 for weight of 6.71 mg/L was also obtained. A third experiment on adult fathead minnows revealed an LD50 of 6.71 mg/L and while there was no change in gonadosomatic index of adults, the F1 generation reared in clean water displayed a significant non-monotonic dose-response in hatch success. These findings suggest that concentrations causing adverse effects on morphometrics occur above the maximum concentration predicted by the manufacturer upon application to water bodies (i.e. >0.37 mg/L). However, there is some evidence that effects on development of offspring occur at or below this level, and further investigations at the molecular level are currently underway to examine these sub-lethal adverse effects of this commercial formulation of diquat dibromide.

Author / Presenter: Vijay Narasimhan
Affiliation: Keenan Research Centre, Li Ka Shing Knowledge Institute, St. Michael’s Hospital, Toronto
Student: No

Session: Monday Poster Session
Date: Monday 02 October 2017
Time: 8:00 – 19:00
Location:

Abstract:

Zebrafish high throughput testing to monitor estrogenic compounds in environmental samples Vijay Narasimhan*1, Monica Nowierski2, Viraj Mane3, Glen Van Der Kraak4, Xiao-Yan Wen1 1- Keenan Research Centre, Li Ka Shing Knowledge Institute, St. Michael’s Hospital, Toronto, Canada. 2- Standards Development Branch, Ontario Ministry of the Environment and Climate Change, Toronto, Canada. 3- Manager, Business Development and Research, Ontario Genomics, Toronto, Canada 4- Department of Integrative Biology, University of Guelph, Guelph, Canada For the past 15 years researchers have demonstrated and documented the adverse effects of estrogen and other Endocrine Disrupting Compounds (EDC) on humans and wildlife. In a direct nuclear method, estrogen interacts with specific target sequences of DNA known as estrogen response elements (ERE) or units. ERE are palindromic and non-palindromic sequences through which estrogen regulation is mediated. The Zebrafish has been developed as a valuable screening tool for detection of estrogen and EDC in water samples. Zebrafish embryos are small, transparent and organs develop rapidly which facilitate the in vivo screening of estrogenic compounds. Zebrafish transgenic lines can be generated effortlessly, which makes it an exceptional choice for high-throughput screening. Our lab has expertise in generating various transgenic Zebrafish lines and we have a state-of-art Zebrafish high-throughput screening facility to screen drugs and water samples. The lowest available detection level of an estrogenic compound by a transgenic Zebrafish is approximately 2.5 ng/L. The only Canada-wide water quality criteria for an estrogenic compound for protection of aquatic life is lower (e.g. the British Columbia Ministry of the Environment criteria for the synthetic estrogen EE2 is 0.5 ng/L). In order to increase the sensitivity of the transgenic fish to detect estrogenic compounds in a water sample, we have designed and synthesized a construct containing six tandem copies of ERE sequence that will drive the expression of Green Fluorescent protein (GFP). We examined the 5? flanking sequence of Estrogen Receptor alpha, Sox9a, cyp19a1b and various other genes to identify the sequence that matched the Zebrafish ERE consensus sequence [GGTCA NNN TGACC]. We identified various potential Zebrafish EREs that roughly matched the consensus sequence. In order to generate a sensitive reporter line for detecting estrogen in water samples, we synthesized a construct containing 6 tandem repeats of ERE sequence and cloned upstream of EGFP vector. This vector also contains Cmlc2 promoter driving the expression of Blue Fluorescent Protein in the heart for selection of transgenic fish and Tol2 transposon to enable transgenesis. We have injected the donor construct with Tol2 transposases and generated the transgenic line expressing EGFP under 6X ERE in the presence of estrogen, and we are currently validating the transgenic line. This transgenic Zebrafish line will be employed as a tool for high-throughput Zebrafish-based screening assays to monitor estrogenic activities in complex mixtures such as municipal wastewater effluents and surface waters from Ontario. This Zebrafish-based in vivo reporter gene assay will add to the suite of novel tools being investigated in Ontario.

Author / Presenter: Pierre Yves Robidoux
Affiliation: AGAT Laboratories
Student: No

Session: Monday Poster Session
Date: Monday 02 October 2017
Time: 8:00 – 19:00
Location:

Abstract:

Phytotoxicity of Bi citrate and Bi nitrate were evaluated on perennial ryegrass (Lollium perenne) using filter paper and soil tests. Endpoints include seeds germination, root and shoot growth. The results showed that Bi nitrate seemed to be more toxic than Bi citrate, and root growth more sensitive than seeds germination and shoot growth. Filter paper test indicated that Bi nitrate significantly decreased root elongation at tested concentration ? 30.4 mg/L and seedling germination at 485 mg/L. Whereas, Bi citrate decreased significantly root elongation and seedling germination at concentration ? 99.52 mg/L and at 398.08 mg/L, respectively. Data from artificial soil spiked with Bi nitrate indicated a significant reduction on root wet mass at 485 mg/kg soil and no significant effect was observed on shoot wet mass and germination at concentration ? 485 mg/kg soil. In natural sandy soil, Bi nitrate significantly reduced root wet mass and root elongation at concentration ? 4.8 and 48.5 mg/kg soil, respectively, while no effect were observed on seeds germination and shoot mass. Sandy soil spiked with Bi citrate showed no significant decrease in root growth and germination. The Bi availability varied with the physicochemical soil characteristics and the toxicity of Bi nitrate/citrate on perennial ryegrass varied with the matrix in the following order: filter paper > natural sandy soil growth > artificial soil.

Author / Presenter: Robert Rutherford
Affiliation: Wilfrid Laurier University
Student: Yes

Session: Monday Poster Session
Date: Monday 02 October 2017
Time: 8:00 – 19:00
Location:

Abstract:

The hypothalamus-pituitary-gonadal axis in fish is responsible for synthesis of sex hormones testosterone (T), 17?-estradiol (E2) and 11keto-testosterone (11KT) and is a target for endocrine disrupting chemicals. Androgenic endocrine disruption is typically understudied compared to estrogenic endocrine disruption, even with a variety of anthropogenic sources, including sewage effluent and animal feedlots, introducing androgens to aquatic environments. Current research has identified decreased plasma sex steroid hormones in mummichog, an estuarine killifish, after exposure to androgenic compounds, in conjunction with decreased egg size and reduction of plasma vitellogenin. The molecular cause(s) are currently unknown. To elucidate the impacts of androgens on the gonadal steroidogenic pathway in mummichog, testis tissue was exposed in vitro to control (ethanol only), 10-6, 10-9 and 10-12 M of the non-aromatizable androgen 5?-dihydrotestosterone (DHT) and the aromatizable androgen 17?-methyltestosterone (MT) for 6, 12, 18 and 24 hours. A suite of genes encompassing the entire pathway from cholesterol mobilization into the mitochondria to the final steroidogenic pathway products of T, E2 and 11KT were analyzed to determine androgen interaction within the steroidogenic pathway. Genes were normalized to elongation factor 1-?. Temporal impacts of gene expression occurred at 18 and 24 hour timepoints, with upregulation of many genes from both MT and DHT treatments. The upregulation found in the current study does not explain the depression of plasma sex steroids as upregulation should result in higher production of steroidogenic end products. 3?HSD, responsible for the conversion of pregnenolone to progesterone, was the only gene to respond after 6 hours of exposure, indicating it may be a biomarker for androgenic activity. Downregulation of androgen receptor was found in MT treatments at 24 hours but not in DHT treatments, indicating potential estrogenic effects of MT. Comparison of aromatizable and non-aromatizable model androgen responses will increase knowledge of potential differences in androgen impact due to androgen classification. Variable impacts across time periods show the transience of gene expression alteration and indicate that gene expression may not closely correlate to noted reductions in plasma sex steroids. Further work utilizing precursors of the steroidogenic pathway, such as pregnenolone, or specific enzymatic inhibitors, such a trilostane, will further elucidate the impacts of androgens within the gonadal steroidogenic pathway. These results will strengthen the understanding of androgenic perturbation at the molecular level and may be linked to higher levels of biological organization in future studies.

Author / Presenter: Rick Scroggins
Affiliation: Ecotoxicology and Wildlife Health Division
Student: No

Session: Monday Poster Session
Date: Monday 02 October 2017
Time: 8:00 – 19:00
Location:

Abstract:

Oribatid mites are currently under-represented in soil ecotoxicity testing, but are an important taxonomic group found in abundance within surface soils. Oribatids contribute to a healthy ecosystem by assisting with nutrient cycling through litter breakdown and to soil formation processes. Method development and validation efforts directed by Environment and Climate Change Canada (ECCC) has led to a standardized ecotoxicity test method using the species, Oppia nitens (C.L. Koch, 1839). The new ECCC test method involves a 28-d soil exposure to capture effects on adult lethality and reproduction (measured as the number of live juveniles produced). Validation of the new test method is currently under way through inter-laboratory testing involving nine participating laboratories from Canada and Europe. There are three rounds of round robin testing which include a performance test in two field soils and an artificial soil (Phase 1), a reference toxicant test using boric acid in a field soil (Phase 2), and a full survival and reproduction test involving a known toxicant and standard natural soil such as Lufa 2.2 (Phase 3). The results from completed phases will be presented, along with an analysis of test variability, and performance across different soil types. The new test method is the first standardized effort for oribatid mites and will complement an existing suite of soil invertebrate test methods (e.g., earthworms and collembolan), with applicability to both forest and agricultural soils.

Author / Presenter: Leslie-Anne Stavroff
Affiliation: Maxxam Analytics
Student: No

Session: Monday Poster Session
Date: Monday 02 October 2017
Time: 8:00 – 19:00
Location:

Abstract:

Decreases in ocean pH through ocean acidification has shown to have direct negative impacts on the early life stages of the Pacific purple sea urchin, Strongylocentrotus purpuratus. Research has suggested that multiple stressors could exacerbate, cancel, or even alleviate the impacts of ocean acidification on echinoderms. This study assessed the combined effects of changes in pCO2 concentrations (390, 800, 1500 ppm), salinities (28, 31, 34 ppt) and temperatures (12, 15, 18°C) on fertilization and larval development in S. purpuratus. Increased pCO2 was the predominant stressor, with additive and antagonistic effects from temperature changes, and no effect from salinity changes. Stressor combinations significantly decreased the rate of normal larval development by 28 – 68%, whereas fertilization and larval survival were unaffected. Decreases in larval development were observed in combined stressor treatments with pH decreases as low as 0.1 – 0.3 from ambient. With the projected pH decrease of 0.3 – 0.4 by the year 2100, the detrimental effects of multiple stressors such as the combination of CO2 and ocean warming may occur sooner than realized. The strong impact on normal larval development likely indicates that later development stages could be detrimentally affected and could thereby influence the population dynamics of S. purpuratus along the Pacific Coast. This may cause detrimental cascading effects on various other species in Pacific Coastal ecosystems in the near future.

Author / Presenter: LESLY TEJEDA-BENITEZ
Affiliation: UNIVERSITY OF CARTAGENA
Student: Yes

Session: Monday Poster Session
Date: Monday 02 October 2017
Time: 8:00 – 19:00
Location:

Abstract:

Bisphenol A (BPA) is a chemical widely used in the production of polycarbonate plastics, epoxy resins, thermal paper, paints, water-pipes, electronic equipment, toys, packaging, printing inks, flame retardants, electronic devices, coatings for metal cans, dental sealants and laboratory equipment, among others. Some of these applications lead to the exposure of humans to BPA through food, dermal contact and drink. BPA binds to various receptors such as estrogen and androgen receptors, aryl hydrocarbon receptor and peroxisome proliferator-activated receptor, all of them associated with the endocrine system. BPA is prone to disrupt function of sex hormones, leptin, insulin and thyroxin. More recently, it has been suggested that BPA increases risk of obesity, diabetes and heart disease in humans, and it is related to genotoxic activity and epigenetic modifications. The objective of this work was to determine the obesogenic action of BPA on human adipoblasts. For this, an experimental study was carried out in which a sample was taken for convenience of a female voluntarily subjected to a liposuction of peripheral adipose tissue. The ADSCs (Adipocyte Derived Stem Cells) were obtained and then suspended in the basal medium and growth in 10 cm cell culture dishes. To evaluate the proliferative activity, the viable cells in each dish were counted on the trypan blue staining exclusion method at the end of the culture. Seven days after the sowing of cells in “passage 0”, cell differentiation was initiated. To determine adipogenic differentiation, confluent cultures were incubated for four weeks in the control medium with 10% FBS supplemented with 0.5 mM isobutyl methylxanthine, 1 mM dexamethasone, 10 mM insulin, and 200 mM indomethacin. Exposure was performed using DMSO as a control and concentrations of 0.1 ?M, 0.3 ?M, 1 ?M, 3 ?M, 10 ?M, 30 ?M, 100 ?M, 300 ?M, 1000 ?M BPA. Mortality of 100% of cultured cells was determined in all replicates (n = 3) for concentration of 1000 ?M BPA. For the measurement of adipocyte differentiation, staining with Oil Red O was performed as follows: 0.35 g of Oil Red O were dissolved in 100 ml of isopropanol. The filtered solution was added to the cells. The adherent cells were rinsed with PBS and fixed in 4% formaldehyde. The staining was then performed with 0.1% Oil Red O and images were taken from the dishes. To quantify, the pigment was extracted with isopropanol and the absorbance was determined with a spectrophotometer at wavelengths of 492 nm. The results were calculated in relation to the control. Triglycerides were extracted from the cells in 200 ?L of chloroform / isopropanol / nonylphenol 40 (7:11:0.1) in a microhomogenizer. The extracted cells were centrifuged for 10 min at 15,000 G and the organic liquid was transferred to a new test tube and dried at 50 °C and placed under vacuum for 30 min. The dried lipids were dissolved in newton-x-100 in 200 ?l of lipid-specific assay buffer. The% proliferation of adipoblast on exposure to 1% DMSO was similar in all 3 replicates and was lower than when exposed to minimal amounts of BPA. As the concentration of BPA was increased, a proportional increase in the percentage of adipoblast proliferation was observed until, at a concentration of 1000 ?M, adipoblasts did not survive clearly demonstrating the toxic effect of BPA on human adipoblasts. Adipoblasts exposed to DMSO 1% accumulated an equivalent amount of lipids in the 3 replicates and the value was lower than the values obtained with any concentration of BPA. As the concentration of BPA increased, a proportional increase in the amount of accumulated lipids up to a concentration of 300 ?M, where maximum values were obtained, was observed. We demonstrated the obesogenic action of BPA. When the increase of BPA concentration, the lipid accumulation of adipoblastes and the quantity of triglycerides increased until BPA 300 ?M.

Author / Presenter: Luba Vasiluk
Affiliation: University of Guelph
Student: No

Session: Monday Poster Session
Date: Monday 02 October 2017
Time: 8:00 – 19:00
Location:

Abstract:

Toxicity of cationic metals is dependent on soil chemistry, especially pH. Changes in pH not only affect bioavailability of metals but also soil nutrients and may cause adverse effects to plants. Liming of field soils contaminated with Ni in Port Colborne ON was studied as a remediation technique. Treatments of 88t/ha of calcitic or dolomitic lime as well as positive control with no lime (mechanical equipment only) and a negative control with no treatment were applied to a field in Port Colborne early in 2015. The soil was sampled before and after lime application, and soybeans planted in 2015 (Y1) and 2016 (Y2). Soybean was harvested manually in October of Y1 and yield calculated. Soil pH, pseudo-total Ni, plant-available Ni (using CaCl2) were measured on samples collected before and after liming. It was found that both types of lime increased soil pH, though calcitic lime resulted in a greater increase than dolomitic. A decrease in pseudo-total Ni was seen following liming, though this could be explained by the dilution effect of adding 88t/ha of lime to the top 5 cm of soil. Plant-available Ni was reduced by both types of lime; however calicitic had a greater effect than dolomitic. It was found that there is a very predictable relationship between soil pH and plant available Ni, which does not depend on the way the pH was increased. Soybean yield for Y1 was significantly lower than that observed for Ontario due to late seed planting on the experimental plots. The greatest yield was seen on the negative control; due to large error for that treatment the negative control yield was statistically greater than only the calcitic treatment and not the dolomitic. Higher yield was seen in the dolomitic treatment than calcitic, which may be due to calcitic pH being too high for optimal soybean production. In Y2, agricultural yield of soybean had improved in comparison to typical Ontario yield, but was still lower. It was found that type of lime, positive control (mechanical effect only) and pH before liming no longer showed a significant effect on soybean yield, although spatial variation had shown to play a key role in soybean growth in both years.