by Dr. Maria Tasheva

A registration procedure in Bulgaria has been in operation since 1964 and has been improved regularly according to international standards. The leading principle is that regulatory decisions should be based on science with high protection for humans and the environment.

One of the early actions of the regulatory authority included the bans of organochlorine insecticides such as DDT, aldrin, dieldrin, endrin and HCH (a , b and d ). All of them (as well as lindane and chlordane) have been included as "banned for use in agriculture in Bulgaria" in the United Nations Consolidated List of Products Whose Consumption and/or Sale Have Been Banned, Withdrawn, Severely Restricted or not Approved by Governments (1994) but they are banned for all uses. One of the alternatives to organochlorine insecticides available that time was parathion but it was evaluated as highly hazardous and was also banned in 1970. In 1985 was banned toxaphene (camphechlor). Chlordane, chlordecon, HCB and mirex have never been registered for use in Bulgaria.

The economic reforms in 90s have resulted in novel problems in pesticide regulation. Previously, a centralised trade organisation functioned as the main national focus for pesticide import and distribution. After decentralization, responsibilities for import and distribution of pesticides have been dispersed among a number of small units, many of which lack the required experience. A large part of the farming population has insufficient education and training in plant protection. To cope with the increased potential hazards associated with pesticide use in Bulgaria, the system for registration and classification has been revised (Tasheva, 1995).

New rules and criteria were introduced in Bulgaria in 1991 and all existing pesticides have been re-evaluated (Tasheva & Kaloyanova, 1991). The registered pesticides have been classified into three use categories: for use only by professionally trained operators; for use only by persons with certificate of having passed a training course in the pesticide use; for free use. Many pesticides were banned or severely restricted. In the list of banned pesticides in 1991 have been included heptachlor and lindane (g -HCH).

Nevertheless that all pesticides listed as POPs are banned or never registered for production and use they still represent potential source of pollution. The major problem now is the storage of relatively large quantities of banned pesticides due to the lack of proper waste disposal technologies. The inventory of pesticides in stocks in 1996 showed that only banned organochlorine pesticides were about 35 tons which is relatively high quantity for the small territory of Bulgaria.

In 1972-1975 a comprehensive study on persistent pesticide residues in soils with analysis of 650 soil samples from 14 regions of the country has been carried out in Bulgaria (Kujumdgieva, 1976). HCH-a and g were found in more than 90% of the samples varying from 0.004 to 0.028 mg/kg. DDT and its main metabolite DDE were determined in almost 100% of the samples ranging between 0.012 and 0.54 mg/kg depending on the pesticide use in the respective regions.

During the same period waters from almost all ponds (total of 19), major rivers (Iskar, Maritza, Struma,etc.) as well as ground water from 9 regions have been analyzed for residues of HCH (a and g ), DDT and metaboltes, aldrin, dieldrin, heptachlor (incl. heptachlorepoxide) (Gizova, 1976). Residues of aldrin, dieldrin, heptachlor and heptachlorepoxide were not found in any sample. All studied samples showed a presence of a and g HCH and DDT and/or metabolites. In the River Iskar, the biggest Bulgarian Danube tributary, the highest concentration of HCH (a and g ) was 0.162 m g/l in water and 0.250 m g/kg in sediment. DDT (total) in water and sediment was 0.228 m g/l and 0.915 m g/kg, respectively.

Twenty years later (1990-1996) DDT and HCH (a and b ) were not found in the River Iskar. Only lindane has been identified in 3 points ranging 0.006-0.008 m g/l. The fact that DDT (and its metabolites) and HCH (a and b ) are not detected in the recent studies is a logical sequence of their 30-year period of ban. The presence of lindane more likely depends on its migration capacity due to its weakest adsorption ability and highest volatility if compared with the other persistent organochlorine pesticides (Vasilev ,1997).

Daily intake of DDT and lindane by drinking water and food has been surveyed (Georgiev et al., 1972, Georgiev, 1974). The daily intakes of DDT and lindane were estimated to be 55.6 and 22.4 m g/person/day, respectively. These levels are much below than Acceptable daily intake and comparable with the levels found in West European countries such as Italy, The Netherlands etc.

The control of exported food required by some countries now shows no residues of both DDT and HCH (a and g ) in any food sample (personal communication with responsible laboratory).

If compared with industrial POPs for pesticides is easier to be replaced by less hazardous alternatives. It was also recognized that available alternatives are not always safer than previously used pesticides.

The last remained in Bulgaria cyclodiene organochlorine insecticide endosulfan is under re-evaluation procedure. Even it classified in the most restrictive category the evaluation will be made using proposed criteria for identifying persistent organic pollutants such as persistence, bioaccumulation, long range transport, toxicity to humans and non-target organisms.

Recently in the country was introduced phenylpyrazole insecticide fipronil acting on the same receptor (GABA receptor regulating chloride channel) as cyclodienes including endosulfan. It appeared to be less toxic than cyclodienes with a rapid metabolism and elimination in mammals, less toxic for fish than pyrethroids with moderate accumulation.

Use of biopesticides still represent a small percentage (about 3.8%) of total pesticide use in Bulgaria. The majority of biopesticides are based on Bacillus thuringensis. Due to their relatively high prices in comparison with agrochemicals their use is only supplementary in wheat, maize, cotton, sugar beet, rice, horticulture, fruit production and forestry (Tasheva, 1995).

The integrated system for plant protection (Integrated Pest Management) using all available methods including use of pest resistant crops, adequate crop rotation, proper soil treatment, use of biological pesticides, application of agrochemicals based on prognoses for development of economically significant pests, will play a very significant role in the future plant protection.

Georgiev G. (1974) Methods of determination of pesticide residues in foods. Doctoral thesis, Sofia.

Georgiev et al. (1972) Concentrations of organochlorine pesticides in drinking waters. Abstracts Vth International Congress of Rural Medicine (Varna, Bulgaria), May 1972.

Gitzova S. (1976) Water pollution by organochlorine pesticides residues and methods for their determination. Dissertation, Sofia.

Kujumdgieva T. (1976) Determination of organochlorine pesticides in soil and their levels in some regions in Bulgaria. Dissertation, Sofia.

Tasheva M. (1995) Pesticide regulation during social transition in Eastern Europe: The Bulgarian approach. Pesticide Outlook,6 (1), 32-36.

Tasheva M; Kaloyanova F. (1991) Criteria for registration of pesticides. Ministry of Health, Sofia, Bulgaria, 4 pp.

Tasheva M. (Team leader) (1995) Danube Regional Pesticide Study, Report on phase I, Bulgaria, Environmental Programme for the Danube River Basin.

Vasilev K. (Team leader) (1997) Control of non-point pollution from agricultural sources; Phase report; National Integrated Programme on Environment and Health Bulgaria (1994-1997).