Potentially Harmful Pesticides Found In All Human Subjects Tested

The study, conceived by Juan Pedro Arrebola Moreno and directed by professors Piedad Martín Olmedo, Nicolás Olea Serrano and Mariana F. Fernández Cabrera, measured the contamination levels of some persistent organic compounds (POC’s) in a sample of the adult population from two areas, an urban one (Granada capital city) and a semi-rural one (Motril), and intended to find the determining factors associated with such levels: diet, lifestyle, activities or residence.

A total of 387 adults, from both sexes, were volunteers for surgeries in hospitals taking part in the study (Santa Ana de Motril and San Cecilio de Granada hospital). Once the volunteers had given consent, a sample of their human adipose tissue (fat) was taken during surgery and they answered a questionnaire about their place of residence, lifestyle, eating habits and activities throughout their life.

Analysis of 6 POC´s

The researchers analyzed the samples and measured 6 different POC concentration levels: DDE, a principal metabolite in DDT (a pesticide used in Spain until the 80´s); hexachlorobenzene, a compound used as fungicide and currently released by industrial processes; PCB’s: compounds related to industrial processes; and Hexaclorociclohexano, used as an insecticide and currently used in scabies and pediculosis treatment.

The study carried out by the University of Granada concluded that 100% of subjects analyzed had DDE in their bodies, a substance banned in Spain, and other very frequent components such as PCB-153 (present in 92% of people), HCB (91%), PCB-180 (90%), PCB-138 (86%9) and HCH (84%).

Juan Pedro Arrebola Moreno explains that higher levels of toxic substances were detected in women compared to men and in older volunteers compared to younger people, “possibly due to the great persistence of these substances in the environment, which results in their biomagnification in the food chain and in their bioaccumulation over time”. The scientist added that there is another theory known as “Efecto Cohorte” (Cohort effect) that explains the high quantities of these substances in older people. According to this theory, those born in periods of higher contamination suffered the consequences more than those born with the current bans on such pesticides.

impact of diet

This study indicates that diet is an important factor in POC concentration, as the ingestion of some aliments, particularly those of animal origin and high fat content, triggers a greater presence of these toxic substances in the human organism.

Juan Pedro Arrebola Moreno states, “There are few studies in Spain measuring POC levels in wide samples of the population, which means that some compound levels in the general population are unknown”. Consequently, this study will improve the knowledge of such levels, and will identify those groups at higher risk of exposure, which is the first step for subsequent follow-up studies determining the cause-effect relations.

This study is part of a project subsidized by the FIS (Sanitarian Investigation Fund) and by the Andalusian Regional Government, and in which the University of Granada, the Escuela Andaluza de Salud Pública, and the Santa Ana and San Cecilio Hospitals take part.