Impacts of NCP-priority chemicals on endocrine function, energetics, and behavior, in conjunction with changing ice conditions, will be examined in thick-billed murres (Coats Island) where climate change is impacting their health. When ice breaks up earlier, energetics of adult murres is increased, they obtain less food, and nestling growth is slowed. Endocrine changes from e.g., chemical exposure, may decouple relationships between corticosterone, thyroid hormones, energy expenditure, and behavior. Specifically, because high energy expenditure is necessary to access food when ice is far away versus when ice is near, chemical disruption of these relationships may explain the inappropriate foraging behavior responses of some birds to changing ice conditions.

In this study we will conduct laboratory and mesocosm exposures with wood frogs (Lithobates sylvaticus) and, possibly, surrogate amphibian species to assess potential environmental impacts stemming from industrial development in the Oil Sands. Toxicogenomics and other exposure and effects endpoint data generated will be added to other data being collected on wood frogs in the Oil Sands region and incorporated into the Adverse Outcome Pathway model to provide a consolidated assessment of potential Oil Sands environmental impacts based on the health and disease status of wood frogs and wood frog populations.

There is a need to estimate effect thresholds for the lanthanides, and in particular, using natural soils relevant to Canada. Prior research to address these data gaps specific to soil media have included the evaluation of cerium and lanthanum in forest soils, and the effect of aging and leaching on toxicity over time (EC, 2014). The study demonstrated low risk of these metals to the plant species assessed, but did demonstrate increased sensitivity to the soil invertebrate species, which then decreased with aging of the soil for ten months (EC, 2014). This study proposal aims to widen the applicability of soil toxicity assays to other priority metals, where such data is lacking. The project objectives are: • To provide soil effects data for four (4) lanthanide REEs: Praseodymium (Pr); Samarium (Sm); Terbium (Tb); and Erbium (Er). Specifically, effects data will be derived using a natural boreal forest and test organisms (soil invertebrates and indigenous microorganisms) representative of Canadian boreal ecozones; and • To provide soil effects data for the impact of aging on two toxic lanthanide rare earthworm elements • To develop a Species Sensitivity Distribution (SSD) based on the point estimate results generated for each rare earth element The lanthanides can be divided into two groups: the ‘light’ lanthanides (e.g., Pr, Nd, Pm and Sm) and ‘heavy’ lanthanides (e.g., Tb, Dy and Er). It has been hypothesized that the heavy lanthanides will be more toxic, however, given the limited data available, no trend has been identified with certainty (Gonzalez et al., 2014). Also, given that REES are readily bound to soil (Sheppard et al., 2009), the bioavailability may be low resulting in reduced toxicity. As a result, the effects of the lanthanide REEs on the proposed test organisms and soil microbial communities will be evaluated to determine whether these proposed trends exist across the metals and species studied.

This project sheet is for the last year of an OMOECC and ECCC agreement, on the toxicity of neonicotinoids. Half of the money was split with Stacey Robinson (20K). This portion of the work for this project was to assess the hazard of these pesticides to mussels and benthic invertebrates, along with scientists from ACRD, at CCIW.

Snapping turtles have been used by the EC since the early 1980s to determine spatial and temporal trends in PCB (and other organochlorine) concentrations, and have furthermore been used extensively for assessing AOCs. There is some concern, however, that their longevity may pose problems in interpreting body burdens. Given that Chelydra can live for over 50 years, individuals would be exposed to temporally varying levels of PCBs over their lifetime. Assessment of their body burdens, either through eggs, plasma, or other tissues, will indicate the temporal integration of PCBs over their lifetime, with the caveat that the proportion of PCBs from any given time period to the current burden will decline over time. The objective is to estimate depuration rates of PCBs in turtles to determine how much contribution past exposures have on the current tissue burden. In addition, there is very little information on the toxicity of PCBs to turtles. This project will assess toxicity, using genetic biomarkers (e.g. P450, oxidative stress, heat shock proteins, thyroid, and others), of PCB exposure to snapping turtles exposed through diet.

The Chemicals Management Plan (CMP) requires information for risk evaluation of novel CMP3-Priority flame retardants (FRs), whose occurrence and potential toxic effects on birds is unknown. Research will determine concentrations of CMP-priority FRs in terrestrial birds (e.g., peregrine falcons) and evaluate in vivo effects of ≤ 4 Priority FRs utilizing captive quail (McGill). Thus, pending the extent of funding, we will conduct research in the context of an avian AOP that supports CMP3’s current themes: exposure and toxicity, provide novel avian exposure and toxicity data for substances to inform CEPA risk assessment, and support the development of future environmental scientists and risk assessors (e.g., post-doctoral fellow, Melanie Guigueno; graduate student).

The tumor suppressor gene (TP53) is a biomarker of exposure and toxicity of PAHs, or other mutagens and genotoxins. The TP53 pathway regulates gene repair, cellular growth, and apoptosis, following induced genetic damage. We will be using avian (double crested cormorant) models from laboratory egg injection studies to develop these assays. Our goal is to assess the effects of PAH containing mixtures to cormorants in ovo (egg injections), by examining transcriptomics of the TP53 pathway in the embryo. Cormorant eggs will be injected with the PAH mixture, and at pipping. embryos will be sacrificed, genomic DNA extracted from tissues, and sequenced for mRNA to evaluate the TP53 signalling pathway, and the up- or down-regulation of key promoter and regulator genes such as P21, BAX, GADD45, P53R2, and MDM2.

Environmental pollutants can cause genetic damage to wildlife, which can have impacts at the population level. Thus, identifying chemicals and complex mixtures that can cause genetic damage and monitoring their effects in exposed wildlife populations is an important component of chemical and ecological risk assessment and management. This project will apply modern methods in molecular biology to develop tools for measuring genetic damage in cultured cells, laboratory animals, and wild species. These tools will be used to screen large numbers of chemicals for potential genotoxicity in the laboratory, and to monitor the genetic health of wildlife species in polluted areas.

Mercury has been increasing in some marine birds in the Canadian Arctic over the past several decades. To evaluate the potential reproductive impact of mercury exposure, eggs of two species of arctic-breeding seabirds, the thick-billed murre and arctic tern, were dosed with graded concentrations of methylmercury and artificially incubated in the laboratory to determine species differences in sensitivity. Based on the dose-response curves, the median lethal concentrations (LC50) for thick-billed murre and arctic tern embryos were calculated. Compared with published LC50 values for other avian species, the murres and terns had a medium sensitivity to methylmercury exposure.

The objective of this experiment was to expose plants to a mixture of the three most common and widely used Rare Earth Elements (REEs) in soils: lanthanum (La), neodymium (Nd) and cerium (Ce). It was hypothesized that plant sensitivity to La, Nd and Ce would be additive, and would increase with overall soil REE concentration. In addition, it was hypothesized that REE uptake would be similar for all three REEs (measured concentrations in plants would be equal) if REE soil concentrations were equal (La = Nd = Ce). Deviations in uptake would indicate potential higher risks of one REE over the others. Ny, Ce, and La were tested in soil mixture with doses based on the previously identified IC25 and IC50 values for native plant species (see Experiments 1 and 2). Doses were equal for all REEs in a given dose (i.e. 100 mg/kg Nd, Ce, and La), and followed a geometric progression. Due to the presumed influence of pH and calcium (Ca) on bioavailability and uptake, two soil pH levels (one acidic, one closer to neutral) and two Ca levels were also be tested. Two species were tested: the native common milkweed, Asclepias syriaca as well as the crop tomato, Solanum lycopersicum var. Beefsteak. The full experimental set-up was: 2 soil pH levels x 2 Ca concentrations x 4 REE doses (including controls) x 2 plant species x 6 replicates = 192 pots. The experiment was conducted in NWRC greenhouses of Environment and Climate Canada with plants tested individually in pots. Measured endpoints included germination percent and rates, aboveground and below ground biomass. In addition, to address plant accumulation rates, tissue concentrations (roots and shoots) of the REEs, as well as calcium, were measured. There was no obvious effect of treatment on the overall number of germinating seeds of A. syriaca or S. lycopersicum. Speed of germination of both species was found to be significantly affected by the soil treatments. For A. syriaca, a marginally significant main effect of soil REE dose was found but no main effects for soil pH or soil Ca; however, there was a significant soil pH x soil Ca interaction. Speed of germination of S. lycopersicum was found to be significantly affected by both soil pH and soil total REE concentration but there was no main effect of soil Ca levels, and no significant interactions were identified. Effects of soil parameters (pH, Ca, and REE) on A. syriaca and S. lycopersicum root and shoot biomass were complex. In general, a reduction in biomass was observed at high REE doses but there were multiple interactions with soil pH and Ca. The measured concentrations of each individual REE in plant tissues (both roots and shoots) were found to consistently increase with increasing soil REE dose within a given soil pH, soil Ca treatment. For all treatments, the measured concentration of a given REE was always greater in the roots than in the corresponding shoots. Measured REE soil concentrations tended to follow a consistent pattern of [Ce] > [Nd] > [La] for all soil treatment levels (soil pH, soil Ca, soil REE). However, results for the REE-dosed soils across all soil pH x soil Ca treatments consistently followed a pattern of [La] > [Ce] > [Nd] for both tissues in both species with the only exceptions found for the roots of both A. syriaca and S. lycopersicum in the high soil pH, low Ca, 150 mg REE kg-1 treatment ([Ce] > [La] > [Nd]). The overall result for REE-dosed soils appears to indicate that La may be more readily taken up by plants, followed by Ce and then Nd. All REE control soils were found to contain background levels of the three tested REEs: La (3.16 ± 0.01 mg kg-1 dry soil), Ce 6.94 ± 0.21 mg kg-1 dry soil), and Nd (3.91 ± 0.10 mg kg-1 dry soil). REE recovery rates, calculated as: (measured REE soil concentration – background level concentration)/nominal REE soil concentration, spanned from 93-117%, 98-124%, and 96-127% for La, Ce, and Nd respectively.