Selenium content of marine food chain organisms from the coast of China

Abstract

Over 250 samples of phytoplankton, zooplankton, other invertebrates, fish and macroalgae were collected from coastal waters of the southeast China Sea and analyzed for their selenium (Se) content. Phytoplankton (1·2 ppm) contained about twice as much Se as seaweeds (0·08 to 0·6 ppm) and both of these algal groups accumulated Se to concentrations three to four orders of magnitude above the ambient concentration in seawater. The Se content of zooplankton (∼ 4 ppm) was three to four times higher than phytoplankton, and juvenile stages (nauplii) and small zooplankton had the highest Se content. Fish often contained less Se than zooplankton on a dry weight basis. The Se content of various tissues and organs in fish varied from a maximum in liver (1·4–28·3 ppm) to a minimum in muscle and hard tissues (1–3 ppm and 0·1–6 ppm, respectively). There was little evidence for the bioaccumulation of Se in organisms of higher trophic status. The major concentrating step in the food web was Se incorporation by phytoplankton and zooplankton, up to four orders of magnitude above ambient seawater concentrations.