Biomonitoring of dialkylphosphate metabolites (DAPs) in urine and hair samples of sprayers and rural residents of Crete, Greece Aikaterini Kokkinaki a , Manolis Kokkinakis b , Matthaios P. Kavvalakis a , Manolis N. Tzatzarakis a , Athanasios K. Alegakis a , George Maravgakis a , Fotoula Babatsikou c , Georgios A. Fragkiadakis d , Aristidis M. Tsatsakis a,n a Center of Toxicology Science & Research, Medical School, University of Crete, Heraklion 71003, Greece b Food Quality Laboratory, Technological Education Institute of Crete, Ierapetra, Greece c Department of Public Health, Technical Education Institute of Athens, Athens, Greece d Department of Nutrition and Dietetics, School of Health and Welfare Professions, Technological Education Institute of Crete, Siteia, Greece article info Article history: Received 18 May 2014 Received in revised form 10 July 2014 Accepted 22 July 2014 Keywords: Hair Urine DAPs Exposure Sprayers abstract Purpose: The aim of this study was to evaluate the exposure of rural residents (control group) and occupational exposed population group of sprayers to organophosphorus pesticides (OPs) by measuring their non-specific dialkylphosphate metabolites (DAPs) in hair and in urine samples. All subjects (n ¼120) were residents of the municipality of Ierapetra, an area of intensive cultivation in Crete, Greece. Methods: The determined OPs metabolites were DMP, DEP, DETP and DEDTP. Two different approaches were used for the analysis of the collected samples; solid–liquid extraction with sonication for hair and liquid–liquid extraction for urine. Gas chromatography–mass spectrometry (GC–MS) analysis was performed after derivatization of the isolated analytes. Results and discussion: The detection rates of DMP, DEP and DETP for both control and sprayers groups were high in both matrices, ranging from 91% to 100%. DEDTP was detected only in 9% of sprayers hair samples, while its detection rates in urine samples ranged from 83% to 90% for both population groups. Data analysis revealed significantly higher sumDAPs levels in urine of sprayers than in the urine of control group (p o0.001) and this is justified since sampling occurred during spraying periods. SumDAPs levels in hair samples of the sprayers were also significantly higher than in the hair of control group (p o0.001), confirming the long-term exposure to OPs. SumDAPs found levels in urine and hair samples of subjects were significantly correlated (Spearman's rho ¼0.728, p o0.001). Our study confirmed the elevated levels of DAPs in hair and urine samples in occupationally exposed group of sprayers in comparison to control group, even detected levels were similar in logarithmic scale. & 2014 Elsevier Inc. All rights reserved. 1. Introduction As already mentioned by several researchers, hair analysis is a powerful toxicological method due to its unique ability to docu- ment exposure due to the long-term storage of xenobiotics (Dulaurent et al., 2008). Hair seems to be of particular interest as marker of drugs, metals and several organic pollutants (Appenzeller and Tsatsakis, 2012). Amongst published studies, a great number of them concern pesticide exposure assessment via hair analysis (Cirimele et al., 1999; Tsatsakis and Tutudaki, 2004; Tutudaki et al., 2003; Gill et al., 2004; Zhang et al., 2007; Tsatsakis, 2006; Ostrea et al., 2006). Hair analysis is also frequently used in pesticide exposure diagnosis, mainly for organochlorines (Neuber et al., 1999; Covaci et al., 2002; Dulaurent et al., 2008; Barbounis et al., 2012), organophosphates (OPs) (Tutudaki and Tsatsakis, 2005), pyrethroids (Mwangala et al., 1993; Kavvalakis et al., 2014), neonicotinoids (Kavvalakis et al., 2013) and carbamates (Tsatsakis et al., 1998). In addition, hair can provide useful and safe data for the burden of the subject in time-depth, since it is a matrix that no biological activities are occurred and targeted compounds levels' remain almost stable in the hair shaft for a long time (Kavvalakis and Tsatsakis, 2012). On the other hand, urine as a conventional biological matrix has already been used for biomonitoring several xenobiotics and/or their metabolites. A generalized outcome of the numerous studies which used urine as an exposure indicator is that this matrix provides data for the recent exposure of the subject to the target compound (or compounds) (Kavvalakis and Tsatsakis, 2012). Contents lists available at ScienceDirect journal homepage: www.elsevier.com/locate/envres Environmental Research http://dx.doi.org/10.1016/j.envres.2014.07.012 0013-9351/& 2014 Elsevier Inc. All rights reserved. n Corresponding author. Fax: þ30 2810 542098. E-mail address: aris@med.uoc.gr (A.M. Tsatsakis). Environmental Research 134 (2014) 181–187