Accumulation of copper in selected elements of a food chain in a pond ecosystem

Abstract

The content of elements in an aquatic environment (water and bottom sediments) is not a reliable indicator of a potential threat of toxic compounds to living organisms. The amounts of elements accumulated in living organisms depend primarily on forms in which the elements occur in the environment. The measurement of the rate of uptake of trace elements by living organisms is known as a bioaccumulation coefficient. Copper is one of the most toxic metals to water organisms. In respect of its toxicity, it is the third (after mercury and silver) most toxic element among metals commonly present in the environment. The paper aimed to determine the copper accumulation in individual links of a food chain in a water ecosystem of a pond used for extensive carp aquaculture. Based on the copper concentration in the carps, the value of the copper bioaccumulation coefficient in the water ecosystem was calculated and the degree of contamination of the pond was estimated. The study comprised a breeding fish pond situated in Mydlniki, fed with water from the Rudawa River. The following were sampled: pond water, sediment from the pond’s bottom, benthos organisms represented by larvae of Diptera family Chironomidae and carps (Ciprinus carpio L.). Organs from the fish (gills, muscles, livers and gonads) most strongly connected with the metabolism of metals were excised and prepared. Copper concentrations were determined in all samples by means of atomic emission spectrometry on a JY 238 Ultrace apparatus (Jobin Yvon Emission) after wet mineralization in a closed system using microwave energy. The results enabled us to conclude that there was no hazard of copper contamination in the examined ecosystem, although the copper content in the pond’s sediments and water suggest some enrichment from anthropogenic sources. A lower value of the copper enrichment factor was determined in the sediment than in water. The bioaccumulation coefficient for copper in benthos and fish muscles assumed higher values, being much lower in fish gills in comparison with the literature data. The values of the copper bioaccumulation coefficient in the livers of the examined carps in relation to its content in water and bottom sediments were 1,532 and 0.623, respectively. Literature references