Short-chain polychlorinated alkanes (sPCAs) have been measured in freshwater fish samples from different lakes all over Norway and from the Norwegian Arctic. The analyses were performed with high-resolution GC coupled to high-resolution MS in electron capture negative ion mode. The species investigated were trout, Arctic char, and burbot (Lota lota). Muscle tissue in the lake trout and Arctic char, and liver in burbot, were selected for analyses because of their high lipid content. Σ Σ Σ ΣsPCA concentration ranged from 108 to 3700 ng/g fat. The highest value was found in the south of Norway near an industrial area.KEY WORDS: chlorinated paraffins, ECNI, freshwater fish, HRGC/HRMS DOMAINS: environmental chemistry, persistent organic pollutants
INTRODUCTIONPolychlorinated alkanes (PCA), or chlorinated paraffins, are straight-chain alkanes with varying degrees of chlorination. They have been produced since the 1930s to an extent of approximately 300 kilotons estimated for the western world [1]. PCA are mainly produced by direct chlorination of a petroleum fraction with molecular chlorine in the presence of UV light [2]. PCA have been used as additives in high temperature and pressure lubricants as well as secondary plasticisers and flame retardants in plastics and paints [1,4].PCA are divided into three main categories -short-(C10-C13), medium-(C14-C17), and long-chain (C18-C30) -and further by their degree of chlorination -low (<50%) and high (>50%) [4]. Because of their relatively high assimilation and accumulation potential, the short-chain, highly chlorinated PCAs have been most widely studied. Although PCA generally have shown low toxicity to mammals, short-chain PCA (sPCA) have a carcinogenic potential in rats and mice [5]. In addition, recent dose-response studies have shown that oral intake of sPCA by mice results in an increase in liver weight, which is considerable compared to reference materials [12]. They have also been shown to be toxic towards certain species in the aquatic environment [4,6,7], although at concentration levels several orders of magnitude higher than for TCDD [7]. Norwegian Freshwater TheScientificWorldJOURNAL (2002) 2, 136-140
Borgen: PCAs in Fish from
137The complexity of sPCA mixtures make it difficult to provide an analytical method for their precise and specific quantitative determination. Technical sPCA mixtures consist of several thousand components, and due to the large number of isomers, complete chromatographic separation seems impossible at this point. This analytical challenge has resulted in different analytical approaches to analysis of sPCA [1,2,3,5,8,9,10,17,18].In this study, sPCA have been measured in lake trout, burbot, and Arctic char from different locations in Norway, and in the Norwegian Arctic.
EXPERIMENTALThe fish samples were homogenised with sodium sulphate and 13C-labelled PCB 118 was added as an internal standard. The samples were then extracted with a mixture of ethyl acetate and cyclohexane (1:1). Separation of the PCAs from the fat was done on a GP...