Analysis of triazine herbicides residues in butter and pasteurized milk.

A method has been developed for the determination of atrazine, cyanazine, prometryn, simazine, and terbutryn residues in butter. The residues were extracted from the matrix with a mixture of petroleum ether/methanol (3 + 1), and from the separated water-methanol phase extraction was carried out with chloroform. The extract was cleaned up on an alumina column. Capillary glass liquid chromatography using a 15 m x 0.32 mm glass capillary column coated with OV-1 and an alcali flame ionization detector were employed for the analysis of the residues. The analyses were evaluated by the internal standard method, using metribuzin as the internal standard. The recovery of the method was 68.7%-79.8% for the individual herbicides under study at the fortification level of 0.1 mg.kg-1 and 79.2%-91.9% at the fortification level of 0.02 mg.kg-1. The determination limit of the method was 0.005 mg.kg-1. When centrifuging full milk, residues of triazines were partitioned between the water and fat phases, whereby 17%-82% of the residues were transferred to the milk fat. Samples of commercial butter were analysed and found to contain 0.005-0.023 mg.kg-1 atrazine.

Analysis of herbicide residues in sugar beet and sugar.

A simple quantitative TLC method for the determination of the residues of herbicide inhibiting photosynthesis was compared with capillary GLC for the analysis of atrazine, chloridazone, lenacil, phenmedipham and desmedipham in sugar beet and sugar. No significant differences in the determination limit and precision of the two methods were found. Monitoring of herbicide residue levels in commercial sugar revealed low levels of atrazine (0.003 mg.kg-1 on average) in all the samples. This contamination level does not present a health hazard consumers.

Dynamics of hexachlorobenzene residues in the food chain.

Epidemiological studies of food contamination in an area of intensive agriculture for the years 1975-1983 showed that hexachlorobenzene (HCB) was present in all food-chain links, although HCB has not been used in Czechoslovakian agriculture since 1980. Samples of potatoes, wheat, milk fat, eggs, meat and human milk were analysed by gas-liquid chromatography with electron-capture detector. Levels of HCB residues ranged from 0.02 (potatoes) to 2.5 mg/kg (human milk, fat basis). A study of HCB accumulation in eggs from a poultry experiment showed that HCB levels in eggs can reach about twice the level given in feed at 7-10 weeks.

Criteria for evaluating pesticide residues in children's diet.

By studying the exposure of the human organism to chlorinated pesticide residues, revealed on the basis of ecological studies in the food chain in Czechoslovakia, the authors proved that the exposure was relatively low for the adult population (except for HCB), but with regard to the children's organism the acceptable daily intake (ADI) was in some cases overpassed. As the ADI's in DDT and gamma-HCH would be overstepped 1, 2 times and in HCB 7 times approximately even when observing the standing maximum residual limits (MRL's), the authors arrived at the conclusion that these MRL's should be reduced 15 times. The reasonability of such considerations in Czechoslovakia is supported by the assessment of the actual daily intake of pesticide residues, determined on the basis of both the actually found residue levels by 10 Czechoslovak institutes and in that of the daily consumption of fundamental foodstuffs. The intake in sigma DDT, sigma HCH, gamma-HCH and HCB reached the values of 0.424; 1.376; 1.145 and 3.085 micrograms per 1 kg of body weight a day, respectively.

[Dynamics of hexachlorobenzene residues in meat and eggs from chickens]. / Dynamik der Hexachlorbenzolrückstände in Fleisch und Eiern von Hühnern.

In a feeding experiment with poultry a more than twofold cumulation of hexachlorobenzene (HCB) in eggs and in meat and a 7.5-fold cumulation in fat, in comparison with the concentration in the feed, have been demonstrated. With the aid of a combined identification by gas chromatography (before and after a conversion into anisole derivatives) and by thin layer chromatography the presence of pentachlorophenol in the liver, in fat and in muscles after feeding the birds with HCB as well as BHC-isomers has been proved. 2,4,6-trichlorophenol and 2,4-dichlorophenol were found by thin layer chromtography (without derivatisation). While 2,4,6-trichlorophenol was found after feeding with HCB only, 1,2,4,5-tetrachlorobenzene has been demonstrated by gas chromatography after feeding with HCB as well as with BHC-isomers.

[Ecotoxicological study of chlorinated pesticides]. / Okotoxikologische Studien über chlorierte Pestizide.

The authors describe a model for the ecotoxicological investigation of pesticide residues guided by the analysis of various links of the food chain and of human materials. It is pointed to the possibility of studying the dynamics of the exposure to human beings by analyzing gynaecological material (prenatal stage) and samples obtained at necropsy from human beings of varying age (different durations of exposure). The observations of the relative accumulation of hexachlorobenzene, beta-BHC and DDT in butter, human milk and human fat in a region with intensive cultivation revealed a considerble accumulation of hexachlorobenzene which reaches the level of DDT. The conclusion drawn from ecotoxicological studies indicates that a reduction of the tolerances of pesticide residues in raw materials for baby foods is imperative. The analyses of gynaecological material (202 samples of the available content of the uterus and 24 placental and embryonic specimens) permitted to evidence a significant difference between two regions and a specific relationship of the observed substances and their metabolites to the fat-dissolving power of the analyzed materials.

Relative cumulation of beta-BHC in ecological and biological system.

During 1971-1974 a study was undertaken to analyze 1234 samples of different elements of food chain from three regions of Slovakia in order to obtain information on ecological relations of the dynamics of residues of four isomers of BHC compared with p,p-DDT and DDE. In contrast to most literature data, a higher relative cumulation of beta-BHC in animal food products compared to the other isomers was noted. The observed relations between the individual BHC isomers were verified in a model feeding experiment on poultry. Dynamics of the transfer of the BHC isomers between fodder, meat, liver, and eggs were studied in broilers and laying hens. All results of the model feeding experiment confirmed the conclusions of the ecological studies concerning beta-, gamma-, and -delta -BHC. The persistence of the alpha-BHC was not confirmed in this manner.

Cleanup of extracts using sweep co-distillation adapted to gas chromatograph.

An adaptation of the Varian Aerograph gas chromatograph to the sweep co-distillation cleanup using the modified Storherr tube is described. The recoveries of this cleanup technique were evaluated for the mixture of four organophosphoru pesticides added to extracts from ten crop and milk. Pesticides were analyzed by gas chromatography with a cesium thermionic detector.