Microplastics in aquatic environments: Implications for Canadian ecosystems.

Microplastics have been increasingly detected and quantified in marine and freshwater environments, and there are growing concerns about potential effects in biota. A literature review was conducted to summarize the current state of knowledge of microplastics in Canadian aquatic environments; specifically, the sources, environmental fate, behaviour, abundance, and toxicological effects in aquatic organisms. While we found that research and publications on these topics have increased dramatically since 2010, relatively few studies have assessed the presence, fate, and effects of microplastics in Canadian water bodies.

Assessment of the health status of wild fish from the Wheatley Harbour Area of Concern, Ontario, Canada.

The overall health and endocrine function of wild brown bullhead (Ameiurus nebulosus) and goldfish (Carassius auratus) from the Wheatley Harbour Area of Concern (Lake Erie, Ontario, Canada) was assessed using a suite of physiological and biochemical endpoints. Smaller gonads were detected in female brown bullhead and goldfish from Wheatley Harbour compared with Hillman Marsh (Ontario, Canada) reference fish. Female brown bullhead exhibited decreased in vitro synthesis of 17β-estradiol.

Thyroid axis disruption in juvenile brown trout (Salmo trutta) exposed to the flame retardant β-tetrabromoethylcyclohexane (β-TBECH) via the diet.

Tetrabromoethylcyclohexane (TBECH) is an additive brominated flame retardant used in domestic and industrial applications. It has been detected in wildlife, and there is early evidence that it is an endocrine disruptor. Whereas other brominated flame retardants with similar physicochemical properties have been shown to disrupt the thyroid axis, no such evaluation has been conducted for TBECH.

Effects of the synthetic estrogen ethinylestradiol on early life stages of mink frogs and green frogs in the wild and in situ.

Estrogenic contaminants are known to disrupt growth and development in amphibians. Field-based research is needed to elucidate their potential impacts on wild populations. Hatch success, larval growth and development rates, and gonad development were examined in native amphibians exposed to low ng/L concentrations of 17alpha-ethinylestradiol (EE2) in a whole-lake addition experiment at the Experimental Lakes Area, northwestern Ontario, Canada.