Determination of pesticides and PCBs in honey by solid-phase extraction cleanup followed by gas chromatography with electron-capture and nitrogen-phosphorus detection.

A multiresidue method for determination of 15 organochlorine pesticides (OCPs), six polychlorinated biphenyls (PCBs), and seven organophosphorus pesticides (OPPs) is implemented for routine determinations of residues in honey. The method involves solid-phase extraction cleanup and determination by GC-ECD/NPD. Quantitation limits ranged from 0.1 to 0.6 microg kg-1 honey for OCPs and PCBs, and from 5.0 to 25.0 microg kg-1 honey for OPPs. Recoveries of OCPs ranged between 77.4 and 94.0%; for PCBs they were from 63.8 to 73.5%. Recovery assays for OPPs varied from 66.7 to 98.1%. The method was applied to the analysis of 111 honey samples from Aragon, Spain. The results obtained indicated a low level of contamination by pesticide residues and PCBs, which can contribute to ensuring the consumer has a safe wholesome supply of honey.

Color measurement of rosemary honey in the solid state by reflectance spectroscopy with black background.

A colorimetric method was developed to measure the color of rosemary honeys in the solid state, without liquefaction. The color of 20 solid samples of rosemary honeys was measured by reflectance spectroscopy with white and black background in cells of 1 cm pathlength. The Kulbelka-Munk theory of turbid media was applied to calculate the spectral distribution of reflectivity, internal transmittance, and coefficients of absorbance and scattering of light. From these spectral distributions, 2 different types of honey were found. The honey colors measured from reflectivity and internal transmittance are well grouped. The colors obtained from reflectivity and those obtained from reflectance with black background show high linear correlation (r2 > 0.99). As a practical application, measurements of reflectance with black background in cells of 1 cm pathlength can be used to determine the color of these honeys in the solid state.

Estimates of mean daily intakes of persistent organochlorine pesticides from Spanish fatty foodstuffs.

In many countries pesticide residues in foods are monitored to ensure that public health is not endangered by residue daily intakes in excess of the recommended tolerance levels (van Dokkum and de Vos 1987). In Spain, there is only a total diet study carried out during 1971-72 by Carrasco et al. (1976). In that study, mean daily intakes of 11.5 mu g alpha-HCH, 13.8 mu g lindane and 78.4 mu g DDTs were calculated. Livestock meat and dairy products were the prime sources of human dietary exposure to organochlorines, since between 60-85% of the mean daily intakes arose from these particular food classes. These percentages are in accordance with the well documented fact that organochlorines predominantly accumulate in the lipid fractions of the human food chain, by which animal fatty foods have become a major route of exposure for humans (Kannan et al. 1992). Since the current daily intakes of organochlorines in Spain are not known, it was considered necessary to carry out a pesticide survey in several foods that compose an average Spanish diet. To accomplish that, we have determined residues of a list of priority organochlorine compounds in several fatty foodstuffs collected between 1987 to 1990, and prepared in the way in which they would normally be eaten. This study is merely an attempt to estimate the actual intakes, since only a selected number of food classes were investigated and no age-sex group, or seasonal differences were taken into account. In spite of these disadvantages, there are merits to such an approach. Approximate intake figures are available for comparison with toxicologically acceptable intakes and with retrospective studies in Spain and other countries around the world, and they serve to outline the temporal trends in organochlorine contamination that have occurred during the last decades. Also, it may contribute to diminish the consumer's concern about possible health risks involved in the consumption of food products and help to restore confidence in the quality of our food supply.