Presence of organochlorine pesticides in breast milk samples from Colombian women Ximena Rojas-Squella a , Laura Santos a , Wolfram Baumann b , Diana Landaeta c , Adriana Jaimes a , Juan C. Correa c , Olga L. Sarmiento d , Juan Pablo Ramos-Bonilla a,⇑ a Department of Civil and Environmental Engineering, School of Engineering, Universidad de los Andes, Bogotá, Colombia b Department of Chemistry, School of Science, Universidad de los Andes, Bogotá, Colombia c Community Health Division, Fundación Santa Fe de Bogotá, Bogotá, Colombia d School of Medicine, Universidad de los Andes, Bogotá, Colombia highlights " Chlorine pesticides were quantified in breast milk samples collected in Colombia. " For the study, 32 women were recruited in the city of Bogota. " 4,4 0 DDE concentrations ranged between <25 and 14 948 ng g À1 (median = 126 ng g À1 ). " 4,4 0 DDE average concentration was similar to the results from other countries. " Results suggest no significant changes in pesticide concentration during lactation. article info Article history: Received 22 August 2012 Received in revised form 22 January 2013 Accepted 9 February 2013 Available online 15 March 2013 Keywords: Breast milk Organochlorine pesticides Biomarker of exposure Colombia abstract The presence of Organochlorine Pesticides (OCPs) in biological and environmental samples has been studied for decades in many countries. Nonetheless, studies in Latin American countries like Colombia have been scarce. Determining the presence of OCPs in breast milk will be of relevance to assess expo- sures, potential health risks, and for surveillance among Latin American populations. Thirty-two breast-feeding mothers were selected to voluntarily participate in the study. Breast milk samples were analyzed for 10 OCPs (a-, b-, c-, d-HCH, Heptachlor, a-, c-Chlordane, 4,4 0 DDT, 4,4 0 DDE, 4,4 0 DDD). Milk samples were analyzed using liquid–liquid extraction, followed by sulfuric acid clean- up, and quantified using GC/lECD. Results were confirmed by GC/MS. OCPs concentrations were normal- ized using fat content. In all but one sample, 4,4 0 DDE was quantified in concentrations ranging between <17 and 14 948 ng g À1 (ng of OCP per g of lipids), with a mean value of 203 ng g À1 . One woman had 4,4 0 DDE concentrations that were orders of magnitude above the average concentrations observed worldwide. Concentrations of 4,4 0 DDE in a second breast milk sample collected in a different time period of lactation from a sub-group of 13 women from the original participants, showed no statistically signif- icant difference with the concentrations found in the first sample. Based on the results obtained from the Persistent Organic Pollutants Global Monitoring Plan report of 2009 of the Stockholm Convention, Colom- bia ranks fourth from bottom to top in terms of 4,4 0 DDE average concentrations. Ó 2013 Elsevier Ltd. All rights reserved. 1. Introduction Persistent Organic Pollutants (POPs) are a group of chemical compounds used in agriculture and industry, which degrade very slowly in the environment and bioaccumulate and biomagnify in the trophic chain (EPA, 2002). Due to their ubiquity, ecological impact, and potential toxicological effects, the Stockholm Conven- tion on Persistent Organic Pollutants was adopted in May 2001 (POPS, 2001). Some Organochlorine Pesticides (OCPs) are included in the treaty. OCPs are lipophilic, non-polar compounds that tend to accumulate in the adipose tissue of living organisms, including humans (EPA, 2002). After being absorbed by the body, most OCPs are partially dechlorinated, oxidized, and conjugated in the pro- cesses of metabolic biotransformation of exogenous substances (EPA, 2002). However, the highest proportion of absorbed com- pounds is accumulated in adipose tissue of individuals, without major changes in their molecular structure (Skaare and Polder, 0045-6535/$ - see front matter Ó 2013 Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.chemosphere.2013.02.026 ⇑ Corresponding author. Address: Department of Civil and Environmental Engi- neering, School of Engineering, Universidad de los Andes, Carrera 1 este No. 19A-40, Of. ML 328, Colombia. Tel.: +57 1 3394949x3693; fax: +57 1 3324313. E-mail address: jramos@uniandes.edu.co (J.P. Ramos-Bonilla). Chemosphere 91 (2013) 733–739 Contents lists available at SciVerse ScienceDirect Chemosphere journal homepage: www.elsevier.com/locate/chemosphere