Is hair analysis for dialkyl phosphate metabolites a suitable biomarker for assessing past acute exposure to organophosphate pesticides?

In the present paper, the possibility to use dialkyl phosphate metabolites (DAPs) hair segmental analysis as a biomarker of past acute exposure to organophosphates is examined. Hair samples of four acute poisoning survivors were collected and segmental hair analysis was performed. The total hair samples were divided to 1 cm segments and analysed by gas chromatography-mass spectrometry (GC-MS) for the presence of four DAP metabolites, dimethyl phosphate (DMP), diethyl phosphate (DEP), diethyl thiophosphate (DETP) and diethyl dithiophosphate (DEDTP). Results were examined under the light of pesticide type and time of hair sample collection. Although DAPs were detected all along the hair shaft, higher concentrations (peaks) were detected in the segments proximate to the suicide period. It was also observed that the elevated concentrations of the present metabolites corresponded to the ones produced by the ingested parent compound. Conclusively, measurements of DAPs in the appropriate hair segments of OP-poisoned patients can be used for assessing past acute exposure to organophosphates in certain cases.

Assessment of levels of organochlorine pesticides and their metabolites in the hair of a Greek rural human population.

We present the assessment of chronic exposure of the rural population of Helia Peloponnesus, Greece to banned organochlorine pesticides, hexachlorocyclohexane (HCH), and 1,1,1-trichloro-2,2-bis(4-chlorophenyl)ethane (DDT), using hair analysis. A total of 222 head hair samples were collected and analyzed for the presence of those organochlorine pesticides and their metabolites or isomers. Gas chromatography coupled to mass spectrometry was used to measure the levels of the pollutants. The median concentrations of alpha-HCH, hexachlorobenzene, lindane, ortho para 1,1-dichloro-2,2-bis-(4-chlorophenyl)ethylene (opDDE), para para 1,1-dichloro-2,2-bis(4-chlorophenyl)ethylene (ppDDE), ortho para 1,1-dichloro-2,2-bis(4-chlorophenyl)ethane (opDDD), para para 1,1-dichloro-2,2-bis(4-chlorophenyl)ethane (ppDDD) + ortho para 1,1,1-trichloro-2,2-bis(4-chlorophenyl)-ethane, and para para 1,1,1-trichloro-2,2-bis(4-chlorophenyl)-ethane were determined at 40.4, 19.7, 124.2, 6.2, 7.8, 73.1, 8.0, and 5.7 pg/mg. The median concentration of total HCHs and DDTs were 117.8 pg/mg and 9.4 pg/mg, respectively. The levels of total HCHs were much higher than the levels of DDTs in the hair samples of the studied population. This may be attributed to the presence of lindane, a pesticide officially banned in 2002. It is interesting to see that DDTs are still traced in samples despite their use being banned for more than three decades. There was no difference in the levels of the detected pesticides in hair sampled from men or women. The concentration of HCHs remains high and relatively stable across the age groups, suggesting constant exposure until very recently. The concentration of the total DDTs and the parent compound, pp-DDT presents a statistically significant decreasing trend across the age groups.

Pesticide levels in head hair samples of Cretan population as an indicator of present and past exposure.

In the present work we assessed chronic exposure of different working population groups of Messara and Sitia districts, Crete, Greece, to common currently used pesticides (diazinon, fenthion, methyl parathion and malathion) and two banned pesticides hexachlorocyclohexane (HCH) and DDT. The study population (211 persons, 110 females and 101 males) was divided to three groups; people working in greenhouses, animal breeders and people working in open cultivations. Methanolic extraction of pulverized hair was used for organophosphate pesticides extraction, followed by liquid-liquid extraction with water-ethyl acetate as a clean up step. The extraction of organochlorine pollutants was performed by acidic hydrolysis of the hair matrix followed by liquid-liquid and solid phase extraction. The levels of the aforementioned pesticides were measured by GC-ECD and gas chromatography-mass spectrometry (GC-MS). The median concentrations of a-HCH, HCB, lindane, opDDE, ppDDE, opDDD, ppDDD + opDDT and ppDDT were determined at 7.2, 2.2, 70.2, 2.7, 5.7, 3.1, 2.6 and 23.2 pg/mg. The median concentration of total HCHs and DDTs detected in the three working groups were: 95.0 and 8.9 pg/mg for the greenhouse workers, 38.2 and 3.3 pg/mg for the animal breeders and 24.1 and 5.2 pg/mg for the open cultivation group. Ten head hair samples were positive for diazinon at a mean concentration of 2.8 pg/mg. Fenthion, methyl parathion and malathion were not detected. Our results demonstrated the ability to assess chronic human past pesticides exposure, offering valuable information to epidemiological clinical studies.

Three-year study of fenthion and dimethoate pesticides in olive oil from organic and conventional cultivation.

Residues of fenthion and dimethoate pesticides were determined in organic and conventional olive oils by liquid-liquid and solid-phase extractions with subsequent gas chromatography and mass spectrometric analysis. The olive oil samples were collected from Crete during 1997-99. The average concentrations of fenthion in conventional olive oils were 0.1222, 0.145 and 0.1702 mg x kg(-1), and for dimethoate were 0.0226, 0.0264 and 0.0271 mg x kg(-1) for 1997, 1998 and 1999, respectively. The average concentrations of fenthion in organic olive oils were 0.0215, 0.0099 and 0.0035 mg x kg(-1) for 1997, 1998 and 1999, while for dimethoate they were 0.0098, 0.0038 and 0.0010 mg x kg(-1), respectively. All the olive oils contained residue levels lower than the maximum residue levels according to the FAO/WHO Codex Alimentarius. The organic olive oil contained significantly lower concentrations of the two pesticides. The levels of fenthion and dimethoate in organic olive oils exhibited a decreasing trend following the implementation of the new cultivation method. We propose procedures that should be established in the organic cultivation in order to maximize its effectiveness.

Characterisation of cannabis plants phenotypes from illegal cultivations in Crete.

In the present study samples of cannabis plants presented to us by the Drug Enforcement Units were characterised, based on the analysis of active substances. The fresh samples were dried in a dark room were they were kept until analysis. The samples included leaves, flowers roots and trunks. The analysis was performed by High Performance Liquid Chromatography (HPLC) and Gas Chromatography (GC) using standard solutions of cannabidiol, D-9 tetrahydrocannabinol, D-8 tetrahydrocannabinol and cannabinol. Chemical analysis of the flowers revealed that 80% of the plants were classified as resinous phenotype while the remaining 20% were found to be of the textile phenotype (low concentration of active cannabinoids). The concentration of D-9 tetrahydrocannabinol in the flowers and leaves ranged from 0.014 to 21.06 mg/g, of cannabinol from 0.0002 to 0.350 mg/g and of cannabidiol from 0.03 to 29.6 mg/g. Roots and trunks contained very small quantities of active substances and should not be used for phenotype identification. No delta-8 THC was detected in any sample. Leaves gave less resinous phenotypes than flowers. The use of either mathematical formula, A or B produced the same phenotype character for each separate part of the plant.

Pesticide deposition in hair: preliminary results of a model study of methomyl incorporation into rabbit hair.

This work studied the incorporation of methomyl, a carbamate insecticide, into the hair of New Zealand white rabbits. A total of 600 mg methomyl was administered by drinking water over 4 mo, and acetylcholinesterase activity in serum was monitored. At the end of the dosing period, hair from the back of the rabbits was cut off, and the methomyl concentration was measured using ELISA and HPLC. A decrease of serum acetylcholinesterase occurred. The top cm of hair contained no methomyl, the second cm contained 0.9 ng/mg and the 3rd cm of hair contained 3 ng methomyl/mg. Methomyl was incorporated into the rabbit hair in a process independent of gender but dependent on the hair growth rate.