Canadian freshwaters

Uthe, J.F. and E.G. Bligh. 1971. Preliminary survey of heavy metal contamination of Canadian freshwater fish. Jour. Fish. Res. Board Canada 28 786-788. 

D.W. Schindler (2001). The cumulative effects of climate warming and other human stresses on Canadian freshwaters in the new millennium. Can. J. Fish. Aquat. Sci., 58, 18-29. 

Asiatic clams are freshwater moUusks. They probably origiaated ia China or eastern Asia and were iatroduced iato North America and Europe ia the past century. They were originally found ia warm water but their territory now extends to Minnesota. They have not yet been seen ia Canadian rivers or lakes. 

Zinc ligands are soluble in neutral and acidic solutions, so that zinc is readily transported in most natural waters (USEPA 1980, 1987), but zinc oxide, the compound most commonly used in industry, has a low solubility in most solvents (Elinder 1986). Zinc mobility in aquatic ecosystems is a function of the composition of suspended and bed sediments, dissolved and particulate iron and manganese concentrations, pH, salinity, concentrations of complexing ligands, and the concentration of zinc (USEPA 1980). In freshwater, zinc is most soluble at low pH and low alkalinity 10 mg Zn/L of solution at pH 6 that declines to 6.5 at pH 7, 0.65 at pH 8, and 0.01 mg/L at pH 9 (Spear 1981). Dissolved zinc rarely exceeds 40 pg/L in Canadian rivers and lakes higher concentrations are usually associated with zinc-enriched ore deposits and anthropogenic activities. Marine... 

Cyanide hazards to fish, wildlife, and livestock are well documented. Massive kills of freshwater fish by accidental discharges of cyanide wastes are fairly common (Holden and Marsden 1964 Leduc 1978 Towill et al. 1978 USEPA 1980 Albersworth et al. 1989 Ripley et al. 1996). In one case, cyanide-containing mine effluents from a Canadian tailings pond released into a nearby creek... 

Mean concentrations of ethylbenzene in freshwater fish samples in the Canadian Arctic in 1985 and 1986 ranged from 2.45 to 49.6 pg/kg in muscle tissue and from 1.81 to 46.3 pg/kg in liver tissue from turbot in white fish muscle tissue samples, levels ranged from 7.46 to 104 pg/kg (Lockart et al, 1992). Ethylbenzene was detected in 43 of 138 fish samples at 16 of 42 sites in Japan in 1986, with concentrations ranging from 1.0 to 9.8 pg/kg wet weight (detection limit, 1 pg/kg wet weight) (WHO, 1996a). 

Clair, T. A., J. M. Ehrman, and K. Higuchi. 1999. Changes in freshwater carbon exports from Canadian terrestrial basins to lakes and estuaries under a 2 x CO2 atmospheric scenario. 

Fig. 2.22. Comparison of measured levels and environmental quality criteria (EQCs) for nonylphenol (NP) in water, soil and sediments from the various sites, in South Korea (a) water (n = 172), (b) soil (n = 105), (c) freshwater sediment (n = 131), (d) brakish sediment (n = 47), (e) marine sediment (n = 93). Range indicates minimum (min), maximum (max), and arithmetic mean (avg.). Dotted lines represent Canadian EQCs proposed for marine water (WQC-m) and freshwater (WQC-f), and marine sediment (SQG-m) and freshwater sediment (SQG-f) (see the text).

Lockhart, W.L., Wagemann, R., Tracey, B., Sutherland, D., Thomas, D.J., 1992. Presence and implications of chemical contaminants in the freshwaters of the Canadian Arctic. Sci. Total Environ. 122, 165-243. 

High-sulfur coals of Pennsylvanian age in the Canadian Maritimes Basin contain 5-8% sulfur. However, this sulfur is associated predominantly with freshwater geologic settings. Recent sulfur isotopic results support the hypothesis that the sulfur in these coals is derived from a bedrock evaporite source (122). 

Dick, T. A. Pool, B. C. (1985). Identification of Diphyllobothrium dendriticum and Diphyllobothrium latum from some freshwater fishes of central Canada. Canadian Journal of Zoology, 63 196-201. 

The earliest studies of Canadian Shield brines found that calcium chloride brines, with salinities up to 340 g were ubiquitous at more than 20 sites below depths of 1,000 m (Fritz and Frape, 1982). As these sites were active working mines, the rock mass was disturbed, so there was usually a component of freshwater circulating through the rock mass to depth. This water tended to mix with older brackish to brine solutions, but also seemed... 

Scott, W.B. and E.J. Crossman. 1973. Freshwater fish of Canada. Minister of Supply and Services, Canadian Government Publishing Centre, Ottawa, Canada. 

Evans MS, Muir D, Lockhart WL, et al. Persistent organic pollutants and mercury in the freshwater biota of the Canadian sub-Arctic and Arctic An overview. Sci Total Environ 2005 351-2 94-147. 

Tessier, A., Campbell, P.G.C., Auclair, J.C. Bisson, M. (1984) Relationships between the partitioning of trace metals in sediments and their accumulation in the tissues of the freshwater mollusc Elliptio complanata in a mining area. Canadian Journal of Fisheries and Aquatic Science 41, 1463-72. 

This section has called attention to some ways that vertical mixing complicates the photochemistry of natural waters. On the other hand, if the rates of CDOM absorption and photochemistry can be quantified, then the steady state profile of a photochemical product (i.e. dissolved hydrogen peroxide) can be used to infer vertical mixing rates. This was possible in freshwater systems (Canadian Lakes and the St. Lawrence River) that accumulate higher levels of peroxide due to their CDOM content [36,46]. A similar attempt to model the depth-time variation of hydrogen peroxide in the ocean (where CDOM is much lower) was only partially successful in reproducing the observed distribution [47,48]. 

In the case of freshwaters, the past effects of climate change on UV exposure have impacted sedimentary records in a remarkable way. Analysis of fossil diatom assemblages in Canadian subarctic lake sediments has provided evidence of the interactive impacts of climate change and solar UVR on CDOM concentrations during the Holocene [86]. 

NESCAUM (Northeast States for Coordinated Air Use Management), NEWMOA (Northeast Waste Management Officials Association), NEIWPCC (New England Interstate Water Pollution Control Commission), and EMAN ( Canadian Ecological Monitoring and Assessment Network). 1998. Mercury in Northeastern freshwater fish current level and ecological impacts. Pp. IV.1-IV.21 in Northeast States/Eastem Canadian Provinces Mercury Study — A Frame Work for Action. February, 1998. 

Investigations on the transfer of l e04 from surface water to organic-rich bottom sediments in the freshwater Perch Lake, located on the Canadian Shield, revealed very low transfer rates of only 1.4 to. 1.3 % of radioactivity per day. The same range of transfer rates was found for - I and [32]. 

---