A survey of heavy metals in water, sediments, macrophytes and fish in a 30 km. stretch of the Nelson River system, Manitoba

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Stepaniuk, Jeffray R.
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Total cadmium, copper and lead contents were determined for water sediment, macrophytes and fish at 28 lotic sites located within the area bounded by 56*19' and 56*42'N, and 93*56' and 94*43'W on the Nelson River system in northern Manitoba. Samples were obtained during 10 collection periods during the May to September 1988. Atomic absorption spectrophotometry and the standard additions method were used. Results showed generally that metals were least concentrated in water, and most concentrated in sediments. Metal levels in sediments were correlated with particle size and organic matter content. The 35 plant taxa examined showed a wide range in metal content. Interspecific differences were found, and belowground parts tended to show higher values than aboveground portions. Fish muscle tissue tended to show lower metal levels than those seen in macrophytes, and metal per unit dry weight of muscle tissue decreased with increasing size and age of fish. However, levels for many internal organs were higher than in muscle. While sediment metal levels were correlated with macrophyte contents in some species, in general no consistent relationships between water, sediments, macrophytes and fish could be demonstrated. Metal levels in the study area, however, were comparable to those reported by other workers for relatively unpolluted systems.