Pesticide hair analysis: development of a GC-NCI-MS method to assess chronic exposure to diazinon in rats.

The present study aimed to improve the gas chromatography-mass spectrometry (GC-MS) method, already developed in our laboratory, for trace analysis of diazinon in hair. Furthermore, it aimed to compare the disposition of the pesticide in the hair of two different animal species, one susceptible to diazinon toxicity and one resistant, under identical experimental conditions. Sprague Dawley rats were systemically exposed to two dose levels (6 mg/kg/day and 3 mg/kg/day) of the pesticide, through their drinking water, for a period of one and a half months. Hair samples from the back of the rats were removed before commencing the experiment and at the end of the dosing period. Diazinon was selectively isolated from pulverized hair, sample or spiked, by stepwise consequent extractions with methanol and ethyl acetate and quantified by GC-negative chemical ionization-MS. It was found that the concentration of diazinon in the hair of exposed animals was dose dependent and was found to be 0.24 +/- 0.01 ng/mg (n = 5) and 0.53 +/- 0.05 ng/mg (n = 5) for the low and high dosage, respectively. The concentration in both dose groups was much higher than the corresponding rabbit hair (rabbits were exposed to the pesticide under similar experimental conditions) as previously reported. Our results strongly point to the possibility of using hair analysis for low-level exposure monitoring of diazinon.

Progress in pesticide and POPs hair analysis for the assessment of exposure.

The present paper reviews the work that has been done in the field of pesticide and persistent organic pollutants (POPs) hair analysis during the last 15 years. It summarizes the compounds of interest, the methods of analyte extraction from the hair matrix, the analytical techniques employed and the results obtained. The most widely studied POPs are the polychlorinated dibenzodioxins (PCDDs), the dibenzofurans (PCDFs) the co-planar biphenyls (co-PCBs) and total biphenyls (PCBs). The most widely studied pesticides are the organochlorine ones, like the hexachlorocyclohexanes and the DDTs, which nowadays are only found as environmental pollutants, some organophosphates, selected pyrethroids and the carbamate methomyl. The most widely applied technique was gas chromatography (GC) coupled to mass spectrometry (MS). Other detectors like the ECD in the case of organochlorine analysis and the NPD in the case of organophosphate analysis were also used. The presented data concern human and animal studies. The levels of DDTs detected in hair were between 19 and 400 ng/g, of co-PCBs 0.27 and 0.45 ng/g, of total PCBs 5-13 ng/g of PCDDs and PCDFs 0.1-10 pg/g of lindane 20-400 ng/g of HCHs 14-40 ng/g of diazinon 110-520 ng/g and of methomyl 900-1800 ng/g. These results strongly support the possibility of using hair as a suitable indicator for the assessment of long-term exposure to POPs and pesticides.

Hair analysis used to assess chronic exposure to the organophosphate diazinon: a model study with rabbits.

The main purpose of the present study was to determine whether hair analysis would be a suitable method to assess chronic exposure of rabbits to the pesticide diazinon. A controlled study was designed, in which white rabbits of the New Zealand variety were systemically exposed to two dosage levels (15 mg/kg per day and 8 mg/kg per day) of the pesticide, through their drinking water, for a period of 4 months. Hair samples from the back of the rabbits were removed before commencing the experiment and at the end of the dosing period. Parallel experiments with spiked hair were carried out in order to design a simple and efficient method of extraction of diazinon from hair. The hair was pulverized in a ball mill homogenizer, incubated in methanol at 37 degrees C overnight, liquid-liquid extracted with ethyl acetate and measured by chromatography techniques (GC-NPD and GC-MS) for confirmation. The concentration of the diazinon in the hair of the exposed animals ranged from 0.11 to 0.26 ng/mg hair. It was concluded that there is a relationship between the administered dose and the detected pesticide concentration in hair. Finally, it seems that hair analysis may be used to investigate chronic exposure to the pesticide.

Hair analysis: another approach for the assessment of human exposure to selected persistent organochlorine pollutants.

Hair analysis was used for the assessment of exposure to organochlorine pollutants in specimens from Greece, Romania and Belgium. A simple method (using 3 N HCI as incubation reagent, liquid-liquid extraction with hexane/ dichloromethane (DCM), alumina/acid silica clean-up and GC-ECD/GC-MS analysis) was used for screening of specimens. The highest organochlorine load (up to 148 ng/g hair for the sum of PCB, DDT and hexachlorocyclohexane (HCH) isomers) was found in samples from a group of Greek women with past occupational exposure to pesticides. DDTs were the main organochlorine pollutants in Greek samples (up to 70%), while in Belgian hair samples their contribution was reduced to 40%. PCB mean concentration was higher in Belgian specimens (up to 14 ng/g hair). Lindane (y-HCH) was the main HCH isomer found in the samples (up to 82% in the Greek samples). Contribution of p,p'-DDT to the sum of DDTs was higher in Greek samples and indicates recent exposure to technical DDT. Similar PCB 153/sum PCBs ratios were found for each of the three countries suggesting similar sources of pollution with PCBs (mainly dietary). Artificially coloured hair samples were found to have lower, but not statistically significant concentrations of organochlorine pollutants than the non-coloured hair.