Conference paper
LEVELS AND DAILY INTAKES OF ORGANOCHLORINE COMPOUNDS IN POPULATION GROUPS IN CROATIA
Blanka Krauthacker
; Institut za medicinska istraživanja i medicinu rada
Abstract
Persistent organic pollutants (POPs) are organic compounds resistant to photolytic, chemical and biological degradation. They are characterised by low water solubility and high fat solubility, which results in bioconcentration in fatty tissues of living organisms. In the environment, POPs are present at low levels and can travel long distances via water and air. This is why POPs can be found all over the world, including areas where they have never been used. Organochlorine pesticides (DDT, aldrin, dieldrin, hexachlorobenzene, and hexachlorocyclohexane) and polychlorinated biphenyls (PCB) are two groups of POPs intensively used worldwide. Unlike these compounds, polychlorinated dibenzo-p-dioxins (PCDD) and polychlorinated dibenzofurans (PCDF), widely known as »dioxins« do not have practical application in industry. These four groups include over four hundred compounds; some of them are classified as carcinogens while others are considered potential carcinogens. Levels of organochlorine compounds in our population have been monitored since 1975. Initially, the investigation was limited to organochlorine pesticides, but later it expanded to all PCBs. Investigations included serum samples collected from general population and from exposed workers as well as human milk samples from general population of lactating women. Samples were collected in Zagreb, Osijek, Labin, Jastrebarsko, Karlovac, Sisak, and on the island of Krk. The main DDT metabolite p,p’-DDE and PCB were found in all analysed samples, serum and milk. Other pesticides or their metabolites (_-, _- and _- HCH, HCB, p,p’-DDT, p,p’-DDD) were not found in all samples. No marked differences were found between samples taken from individuals living in different geographic areas, but the levels indicated a downward trend. Since 1975 serum p,p’-DDE levels, which were then 31 μg/L, have dropped about ten times. Human milk levels were 1,900 μg/kg milk fat in 1981/82 and now are about six times lower. For the past twenty years PCB levels in serum and milk have also dropped about three times, yet they seem to have stabilised over the past five years. As lack of equipment bars dioxin analyses in Croatia, it was performed by qualified institutions in the USA, the Netherlands, and Sweden. Dioxin levels found in human milk samples collected in Zagreb, Krk, Jastrebarsko, Labin, and Osijek in 1981–1997 kept between 8.4–26.7 I-TEQ ng/kg milk fat (expressed as TCDD toxic equivalents according to international toxicity factors). A comparative study organised by the World Health Organization showed a 1.8% annual decrease from year 1992 to 1987 in samples collected in Zagreb and Krk. By contrast, other European countries and Canada showed a 7.2% decrease. However, one should take into account that levels in milk samples collected in Croatia are in the lower half of the concentration range determined in samples from other European countries, Canada, and Pakistan and it would not be reasonable to expect that the Croatian samples show a similar drop in dioxin levels. Samples collected from occupationally exposed workers who worked either with organochlorine pesticides or PCB showed slightly higher levels than samples from general population, but still kept below a threshold at which acute signs of exposure are expected. The daily intake of organochlorine compounds was evaluated for breast-fed infants from levels in human milk, and for adults from the analysis of foodstuffs. The intake by the adult population in our country was below the acceptable daily intake (ADI) values; nursing women showed higher levels than nonnursing women of the same age. This was not the case with breast-fed infants whose daily intake was higher than the ADI values in previous studies, but below ADI in recent studies. It may appear that the population of breast-fed infants is more exposed than adults, but one should keep in mind that the breast-feeding period is short in relation to the whole life, and that the benefites of breast-feeding prevail over the risk of intake of organochlorine compounds. To sum up, our investigations show that levels of organochlorine pesticides, polychlorinated biphenyls, and dioxins in Croatia keep within the lower half of the concentration range found in developed and industrialised countries.
Keywords
human milk; food; organochlorine pesticides; PCB; PCDD/F; serum
Hrčak ID:
65661
URI
Publication date:
26.7.2000.
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