Abstract: An account is given of the assessment of chlororganic pesticides in Bulgaria. Information is provided on the distribution of pesticides treated by the Stockholm Convention as persistent organic pollutants (POPs). Stockpiles of available and obsolete POPs pesticides are reported.

Abstract: The prominent Bulgarian scientist and university professorNikola Pentcheff was born on 31 July 1901 in Sofia and passed away on 30 June 1983. He was a student in chemistry at the University of Sofia (1920−1924) and graduated with excellent scores in 1924. Nikola Pentcheff had spent very fruitful specializations in Paris − CollPge de France and Institut d’Optique (1926, 1930−1931). Further academic career of Nikola Pentcheff was closely connected during over half a century with the St. Kliment Ohridski University of Sofia, where he was Assistant Professor of Chemistry (1924), Inorganic Chemistry (1924−1927) and Analytical Chemistry (1927−1942), Associate Professor of Analytical Chemistry (1942−1947), Professor of Analytical Chemistry (1947−1971) and Head of the Chair of Analytical Chemistry (1943−1971). Professor Pentcheff was granted a D.Sc. Degree in 1958 and was elected Corresponding Member of the Bulgarian Academy of Sciences in 1961. Professor N. P. Pentcheff was lecturing courses of analytical chemistry, microanalysis and special analytical practicum; he introduced the modern theories of Arrhenius, Broensted and Lowry as well as physical methods, semi-micro techniques and organic reagents in teaching analytical chemistry. Three textbooks written together with Prof. B. Sagortschev have been the main analytical chemistry textbooks for thousands of students as well as a favourite book in many chemical laboratories for several decades (‘Concise Course of Analytical Chemistry’ (1950); ‘Course of Analytical Chemistry’ (six editions 1951, 1955, 1959, 1961, 1963, 1966); and ‘Qualitative Analysis’ (three editions 1953, 1955, 1964). Professor Nikola P. Pentcheff is well known for his scientific contributions in the field of analytical chemistry and geochemistry of noble gases; introduction of original atomic emission spectrographic and isotopic mass spectrometric techniques, involving cryogenic, microenrichment and fractionation approaches to noble gases; analytical chemistry of waters and particularly of Bulgarian natural and mineral waters; development of analysis of soils, minerals and meteorites; gas and gasogenic analysis of soil humus, nitrogen, carbonates, ammonium salts, nitrates and nitrites; gravimetric analysis, with emphasis on Al, Cr and Sr determinations. These studies and scientific achievements are well recognized and cited worldwide in numerous papers, handbooks, and textbooks. Their impact on other fields of science such as geochemistry, geochronology and space chemistry, soil and aquatic chemistry, inorganic chemistry, radiochemistry, etc., cannot be overemphasized. Prof. Pentcheff has published 62 papers in French, German, English, and Bulgarian languages. Co-workers of Prof. N. Pentcheff were Professors N. Jordanov, E. Pencheva Assoc. Professors L. Kocheva, D. Nonova, N. Piperov, St. Belchev, etc. He was member of Bulgarian Chemical Society, Union of Scienists in Bulgaria (1954) and SociJtJ de Chimie-Physique, Paris (1931). Prof. Pentcheff has been decorated with numerous Bulgarian orders.

Abstract: Polymethine dyes are briefly discussed and their application in dye lasers is outlined.