Organochlorine Pesticide Levels in Blood Serum Samples Taken at Autopsy from Auto Accident Victims in Veracruz, Mexico

Residues of selected polychlorinated biphenyls (PCB) and organochlorine pesticides (OCP) in postmortem lungs from Epirus, northwestern Greece

Organochlorine (OC) pesticides and polychlorinated biphenyls (PCB) are compounds characterized as persistent organic pollutants (POP) in the environment. These compounds are monitored globally since they enter the human body and accumulate in tissues, resulting in consequent adverse effects. In this study concentrations of selected OC compounds were determined in human autopsy lungs from Epirus, a relatively restricted region in northwestern Greece. This is the first epidemiologic study from Greece reporting on monitoring of environmental pollutants in human autopsy material. Thirty lungs collected from that number of autopsy cases were analyzed: 19 males and 11 females. The age range was 14-91 yr (mean ± SD = 61.8 ± 22.5 yr). Twenty-two cases (73%) were positive for at least one pollutant and eight cases were negative (27%). PCB were the most abundant class of contaminants, detected in 15 out of the 30 cases (50%). Dichlorodiphenyltrichloroethane (DDT) and hexachlorocyclohexanes (HCH) were second and third in abundance with 9 (30%) and 8 (27%) positive cases, respectively. The frequency of detection showed a tendency to increase with age of individuals. The patterns of OC found in human autopsy lungs were similar to those reported previously for other human specimens. Our results demonstrated a similar trend in contamination sources and distribution has occurred in western Greece as noted globally.

Organochlorine pesticide levels in umbilical cord blood of newborn in Veracruz, Mexico

Organochlorine pesticides accumulate in lipid rich compartments of organisms. During pregnancy, the compounds pass through the placental barrier appear in cord blood. The aim of this study was to monitor the levels of organochlorine pesticides in 70 umbilical cord blood samples taken during deliveries in Veracruz in 2009. For organochlorine pesticides, only the presence β-HCH (4%, 3.9 μg/L median concentration on wet weight), pp'DDE (100%, 0.7 μg/L) and pp'DDT (4%, 1.4 μg/L) were detected. The total pool of samples divided according to sex of new born babies, showed no statistical differences among median concentrations. The number of deliveries considered as a determinant contamination factor affirmed there were no statistical differences among median concentrations; however pp'DDE levels increased from the one to two childbirth groups. Age of pregnant women as a discriminate factor manifests in a significant increase in contamination levels among first, second and third tertile. In general, umbilical cord blood samples in Veracruz contained organochlorine pesticides, especially pp'DDE, confirming the presence of these compounds in the environment and their transfer from the mother to the developing fetus.

Comparison of organochlorine pesticide levels in human adipose tissue of inhabitants from Veracruz and Puebla, Mexico

Since the discovery of insecticide properties of DDT (1,1,1-trichloro-2,2-bis(4-chlorophenyl)ethane) and HCH (hexachlorocyclohexane), they have provided great benefits to humans in sanitary actions to combat the spread of infection-borne disease vectors. Public Health Programs in Mexico used DDT and HCH until 1999 as the insecticides of choice to control disease-transmitting organisms. Because of their persistence and accumulative properties, organochlorine pesticides bioconcentrate in lipids of the human body, reflecting the rate of environmental exposure. Eighty human abdominal adipose tissue samples from Veracruz and 80 samples from Puebla were analyzed and the obtained results were compared among both populations. The results from Veracruz showed higher contamination levels (mg/kg on lipid base) compared to Puebla: beta-HCH, 0.072 vs. 0.029; pp'DDE (Dichlorodiphenyldichloroethylene), 2.364 vs. 0.726; op'DDT, 0.022 vs. 0.025; pp'DDT, 0.192 vs. 0.061; and Sigma-DDT, 2.589 vs. 0.806. The population from Veracruz and from Puebla divided by sex, origin, and cause of death presented no statistical differences. The comparison between sexes (women and men groups) at Veracruz and Puebla indicated significantly higher levels in Veracruz and statistical significant differences. Calculating possible risks (odds ratios, OR), pp'DDE (OR = 5.04) and op'DDT (OR = 2.93) revealed significantly higher risk for the Veracruz population. The study indicated prolonged DDT exposure of Mexicans caused by the past sanitary use and persistence of its residues in soils and air.

Passive air sampling of organochlorine pesticides in Mexico

The spatial and temporal variation of organochlorine pesticides (OCs) in air across Mexico was investigated by deploying passive samplers at eleven stations across the country during 2005-2006. Integrated samples were taken over three-month periods and quantified for DDT compounds, endosulfans, toxaphenes, components of technical chlordane, hexachlorocyclohexanes (HCHs), and dieldrin. Enantiomers of chiral chlordanes and o,p'-DDT were determined on chiral stationary phase columns as an indicator of source and age. Results are discussed in combination with pumped air samples taken at four other stations in southern Mexico during 2002-2004. DDT and its metabolites, endosulfan and toxaphene were the most abundant OCs detected in all sampling sites. Atmospheric concentrations of SigmaDDT (p,p'-DDT + o,p'-DDT + p,p'-DDE + o,p'-DDE + p,p'-DDD + o,p'-DDD) ranged from 15 to 2360 pg m(-3) with the highest concentrations found in southern Mexico and the lowest found in northern and central Mexico. A fresher DDT residue was observed at sites with greater DDT use and in the southern part of the country, as shown from the higher FDDTe = p,p'-DDT/(p,p'-DDT + p,p'-DDE) and nearly racemic o,p'-DDT. This agrees with the former heavy use of DDT in the endemic malarious area of the country. A local hotspot of endosulfan was identified at an agricultural area in Mazatlan, Sinaloa, with a annual mean concentration of SigmaENDO (endosulfans I + II + endosulfan sulfate) = 26,800 pg m(-3). At this site, higher concentrations of SigmaENDO were recorded during the winter (November to February) and spring (February to May) periods. From back trajectory analysis, this coincides with a shift in the air mass coming from the Pacific Ocean (May to November) to the inland agricultural area (November to May). The elevated SigmaENDO observed is likely due to the local agricultural usage. HCHs, chlordanes, transnonachlors, and dieldrin were more evenly distributed across the country likely due to them being aged residues and more diffuse in the environment. In contrast, hotspots of endosulfans, DDTs, and toxaphenes were observed as they were heavily used in localized agricultural or malarious regions of Mexico.

Efectos a la salud y exposición a p,p'-DDT y p,p'-DDE: el caso de México

Basado en la revisión sistemática de 32 artículos publicados en PubMed-Medline hasta enero del 2006 y utilizando como palabras clave DDT exposure, human, milk y Mexico; este estudio analiza la situación acerca de la exposición en México a difenildicloroetano (DDT) y su principal metabolito p,p,'-DDE, así como, su posible repercusión sobre la salud humana. Aún cuando, el uso del DDT se suspendió en 1999, los estudios evaluados reportan niveles importantes de p,p'-DDE, en muestras biológicas de suero, tejido adiposo y leche materna de poblaciones no ocupacionalmente expuestas. Así mismo, existen evidencias sobre daños a la salud, especialmente relacionados con el área reproductiva masculina, la lactancia materna y más recientemente daños a nivel celular, así como, alteración en el desarrollo psicomotor de niños expuestos in utero. Aún cuando existen muchas lagunas, acerca de otros efectos adversos a la salud relacionados con la exposición a DDT o sus metabolitos, la experiencia lograda hasta ahora, debe ser tomada en cuenta en México y el resto de Latinoamérica, para que considerando el principio precautorio se legisle sobre el DDT y otros contaminantes orgánicos persistente que tienen actividad y características similares al DDT o sus metabolitos.

Pregnane X Receptor-Dependent Induction of the CYP3A4 Gene by o,p′-1,1,1,-Trichloro-2,2-Bis (p-Chlorophenyl)ethane

CYP3A4, the predominant cytochrome P450 (P450) expressed in human liver and intestine, contributes to the metabolism of approximately half the drugs in clinical use today. CYP3A4 catalyzes the 6beta-hydroxylation of a number of steroid hormones and is involved in the bioactivation of environmental procarcinogens. The expression of CYP3A4 is affected by several stimuli, including environmental factors such as insecticides and pesticides. The o,p'-1,1,1,-trichloro-2,2-bis (p-chlorophenyl)ethane (DDT) isomer of DDT comprises approximately 20% of technical grade DDT, which is an organochloride pesticide. We have recently shown that o,p'-DDT exposure increases CYP3A4 mRNA levels in HepG2 cells. To determine the mechanism by which o,p'-DDT induces CYP3A4 expression, transactivation and electrophoretic mobility shift assays were carried out, revealing that o,p'-DDT activates the CYP3A4 gene promoter through the pregnane X receptor (PXR). CYP3A4 gene promoter activation resulted in both an increase in CYP3A4 mRNA levels and an increase in the total CYP3A4 activity in HepG2 cells. We also observed induction of CYP3A4 and mouse Cyp3a11 mRNA in the intestine of CYP3A4-transgenic mice after exposure to 1 mg/kg o,p'-DDT. At higher doses, a decrease of CYP3A4 inducibility was observed together with an increase in levels of interleukin 6 mRNA, a proinflammatory cytokine that strongly represses CYP3A4 transcription. The present study indicates that regulation of other genes under PXR control may be altered by o,p'-DDT exposure.