Over the past years remarkable progress has been made in the ubiquitousness, abundance and significance of natural organohalogens compounds in aquatic and terrestrial environments (Grimvall and de Leer, 1995). Only recently Müller et al. (1996) reported the occurrence of natural organohalogens in biogenic sediments from various epochs and representing different stages of coalification (peat-lignite-bituminous coal-anthracite). AOX (Adsorbable Organic Halogens) measurements, expressed as chlorine equivalents, have been carried out on four meteorites from four independent fall events (Murray, Murchison, Orgueil and Cold Bokkeveld). The concentrations range between 123.6 and 209.4µg/g dw (Table 1).
Table 1. AOX content of different carbonaceous meteorites
Meteorite Subgroup No. of AOX
Carbonaceous Chondrites [mg/g dw]
Murray II 130.7
Murchison II 182.1
Cold Bokkeveld II 209.4
Orgueil I 123.6
From an earlier study (Mueller, 1953) it was already known that the Cold Bokkeveld meteorite contains "over 1 percent of chlorinated resinous extracts" termed "chlorobitumens". Studier et al. (1965) reported the occurrence of alkyl chlorides and chlorobenzenes in both the Cold Bokkeveld and Orgueil meteorites. In addition, EOX- (Extractable Organic Halogen) and Ion chromatographic analyses were conducted on the Cold Bokkeveld meteorite (Table 2). Summing up the concentrations of halogens shows that only about 30 % of the bulk AOX was extractable when comparing the residue with the extracted amount. The distribution pattern of organically bound halogens studied by ion chromatography revealed that chlorinated and brominated compounds were up to 70% extractable , whereas only trace amounts of organic fluorine could be extracted.
Defined chlorinated benzoic acids (4-chloro, 2,4 and 2,6-dichlorobenzoic acid) in the concentrations range of 0.2 to 10 µg/g dw could be detected in the Cold Bokkeveld meteorite
by gas chromatography. The results strongly suggest that
chlorinated organic compounds constitute the major portion of halogenated compounds measured as AOX and EOX or detected by GC/AED.
The occurrence of organic halogens in the carbonaceous chondrites provides the evidence of naturally produced (abiotic) halogenated organic compounds. The results raise the question about the origin of halogenated organic compounds in primitive planetary matter.
Grimvall, A.& de Leer, E.W.B. (eds.), Naturally-Produced Organohalogens. Environment and Chemistry, Vol. 1. (Kluwer Academic Publishers, Dordrecht/Boston/London, 1995).
Mueller, G., Geochim. Cosmochim. Acta 4, 1-10 (1953).
Müller, G., Nkusi, G. & Schöler, H.F., J. prakt. Chemie-Chemiker Ztg. 338, (1996, in press).
Studier, M.H., Haytsu, R. & Anders, E., Science 149, 1455-1459 (1965).
Table 2. The distribution of organic halogens in different fractions of the Cold Bokkeveld meteorite sample (F III was obtained according to a modified standard humic acids extraction method)
Fraction AOX EOX Fluorine Chlorine Bromine
[*g/g dw] [*g/g dw] [*g/g dw][ *g/g dw] [*g/g dw]
A I (Bulk) 209.4 - 65.9 136 22.8
F I (n-Hexane) - 12.5 n.d. 31.8 6.05
F II (Ethylacetate) - 9.8 n.d. 35.4 5.35
F III (Alkaline) - 28.4 4.15 40.2 6.25
Residue 150.0 - 49.1 42.7 6.25
n.d. not detectable - not measurable with the method