Persistent, bioaccumulative, and toxic compounds in the central and eastern European countries--the-state-of-the-art report--human exposure.

This review describes problems with persistent and bioaccumulative organic substances which posses toxic characteristics likely to cause adverse human health or environmental effects in countries of Central and Eastern Europe as far as human exposure is concerned. This paper is a part of a more detailed report on the subject.

Persistent, bioaccumulative, and toxic compounds in central and eastern Europe--hot spots.

The sources and environmental levels of the PBTs in the countries of Central and Eastern Europe are broadly described. Most of the countries in the region produce and/or formulate pesticides. The pesticide registration is a primary requirement for import, production and distribution. The special attention must be given to unwanted pesticides. The problem of unwanted and expired pesticides pose the greatest danger to the natural environment and people which is brought about by the use of chemicals in agriculture in CEE countries. Countries still have not solve the problem of safety storage for PBTs and other chemicals classified as poisons and they have no special sites or facilities for destruction of these chemicals. This region has very specific problems of environmental pollution, which are the results of the recent wars. Destruction of industrial facilities and spilling of chemicals have the worst effect for the environment (Bosnia and Herzegovina, Croatia, Serbia and Montenegro).

The use of mosses and pine needles to detect persistent organic pollutants at local and regional scales.

Polycyclic aromatic hydrocarbons (PAHs) were analysed in mosses (Hypnum cupressiforme) and pine needles (Pinus sylvestris) collected in the Czech Republic between 1988-94 at a regional background site in Kosetice, south Bohemia (1988-94) and two industrial sources. One industrial site (sampled 1989-91) in middle Moravia, was near a factory producing PAHs, carbon black and phthalates, the other (sampled 1991-93) near a coal and gas fuel production plant in western Bohemia. Selected chlorinated pesticides and polychlorinated biphenyl congeners were also analysed in samples at the regional background site. This study clearly shows that vegetation sampling can be used to show spatial differences in the atmospheric burden of a range of persistent organic pollutants with differences in the mixtures of compounds reflecting differences in their regional or local use/atmospheric emission.

TOCOEN project.

The basic goals of the TOCOEN project (Toxic Organic COmpounds in the ENvironment) are to detect and understand the fate of selected organic pollutants (PAHs, PCBs and PCDDs/Fs mainly) in the environment. The TOCOEN project was established in 1988 as a free association of Czech and Slovak environmental chemists, ecototoxicologists and other environmentalists.

Mechanisms of tolerance of the Ia antigen disparate skin allografts.

Transplantation tolerance was induced in A.TL mice to donors having disparity in the Ia antigens and identity at the H-2K, H-2D and non-H-2 antigens. After neonatal injection of 12 X 10(6) semiallogeneic lymphoid cells, permanent survival of A.TH skin allografts was observed in more than 90% of the recipients. Adoptive transfer of 50 X 10(6) lymphoid cells from normal A.TL donors to tolerant mice resulted in rejection of the tolerated grafts only in half of the animals. When cells from tolerant mice were tested in MLC and GVH assays, they reacted positively as did cells from normal mice. After sensitization in vitro, cells from tolerant mice were cytotoxic to A.TH antigens. Serum from tolerant mice did not inhibit cell proliferation in MLC assay nor blocked cytotoxic reaction in vitro and also did not enhance survival of A.TH skin grafts in normal A.TL mice. When the enhancing effect of this serum was tested in the recipients treated with ALS, prolonged survival of allografts was observed. Attempts to prolong survival of A.TH skin allografts by transfer of spleen cells from tolerant donors failed in normal A.TL recipients, while they were successful in the recipients treated with ALS. Long-term tolerated A.TH allografts, when transferred to normal A.TL recipients, were rejected. The findings show that loss of antigenicity of the tolerated skin allografts is not the mechanism of tolerance in this model and that cells capable of recognizing antigens of the tolerated allografts and reacting against them are still present in tolerant animals. Tolerance of skin allografts disparate only in Ia antigens, as has been shown at least for the strain combination tested, is probably mediated by the positive serum and cell suppressor mechanisms that block in vivo the effector phase of allotransplantation reaction.