Organic halogens: Determination in marine media of adsorbable, volatile, or extractable compound totals.

Abstract

The environmental impact of the release of halogenated organic compounds to the sea has become of increasing interest during recent decades. Most compounds in this group are xenobiotic of origin and, consequently, of potential environmental hazard. The characterization of domestic and industrial discharges with respect to their contribution of halo-organic compounds to the sea, as well as monitoring to determine the occurrence and levels of halo-organic compounds in the marine environment, have been major topics. This leaflet reviews frequently employed methods for the determination of organic halogens as group parameters in water samples. The methods are evaluated with respect to their applicability in waste water characterization and marine monitoring. Results from the analysis of organic halogens in samples of marine water, sediments, and biological organisms are sum- marized. It appears that determinations of extractable organic halogens (EOX) in marine samples are the methods of prime interest. The nature and concentrations of halogenated organic compounds in waste waters are largely dependent on the source of the waste water, and only general statements can be made on this Subject. The results of numerous investigations on the characterization of halo-organics in waste waters have been published, but the compilation of these data is beyond the scope of this leaflet. It can be stated, however, that half of the chemical substances considered 'priority pollutants' are halogenated organics (Keith and Teillard, 1979) and that halogenated organic compounds belong to the chemical substances (List 1) whose use in the European Economic Community should be minimized to the lowest possible level (Keune, 1976). Investigations of marine contamination have revealed a 'background' level in sea water of 0.1-10ng/l for individual halogenated organic compounds, such as halogenated c1-Cl-aliphatics, chlorophenols (CPs), polychlorinated biphenyls (PCBs), DoTs, and chlorinated benzenes (Fogelquist, 1984; Folke et al., 1983; Giger, 1977; Lunde and Gether, 1976; 0resund Commission, 1984). In marine sediments and organisms, the baseline levels of chloro- phenols, PCBs, DOTs, and chlorinated benzenes are generally within the range 1-100ng/g wet weight. Some species of marine organisms and some biological tissues particularly capable of bioaccumulation can show levels as high as 10~g/g wet weight, even in the absence of an actual emission zone (Brevik et Ai., 1978; Folke et al., 1983; Granby, 1987; Greig and Sennefelder, 1987; Knutzen et Ai., 1984; Schults gt Ai., 1987; Tanabe and Tatsukawa, 1987; Young and Gosset, 1980). It is to be expected that many xenobiotics, which are not easily de- tected by the commonly applied analytical methods such as gas chromatography (GC) and high performance liquid chromatography (HPLC), will occur in the marine environment in addition to the types of compounds mentioned above. Furthermore, a contribution to the total load of halo-organics in the marine environment is anticipated from the degradation products of major halogenated organic contaminants, from minor contaminants, and from naturally occurring halogenated organics, such as algal metabolites. Consequently, there is a need for analytical methods capable of de- termining the total amount of organic halogens in sea water, marine sediments, and tissues of marine organisms.