Nitrate and other elements in Spanish bottled and running water

Cristina G. Pedraz/DICYT A research team at the Ibiomed (an institute of biomedicine at the Universidad de León, Spain) has collaborated in an article recently published in Gaceta Sanitaria, a journal edited by the Sespas (a Spanish body of public healthcare and health management); the article analyzes levels of nitrate and other elements in bottled and municipal water in Spain. The study concludes that the amount of nitrate in municipal water does not exceed legal levels but differs depending on regions; and trace elements such as arsenic, nickel and cadmium are present in such small amounts that are unquantifiable in almost all samples, for both running water and bottled water.

The study belongs to the MCC-Spain project (Population-based multicase-control study on high-incidence tumors in Spain); its ultimate goal is to analyze the influence of environmental factors and their interaction with genetic factors in five types of tumors: colorectal cancer, breast cancer, stomach cancer, prostate cancer and chronic lymphoid leukemia (CLL). One of these factors is the presence of contaminants in drinking water (arsenic, nitrates, chromium, chlorination by-products, etc.), but also endocrine disruptors (chemicals that may interfere with the hormone system), other persistent organic pollutants or the alteration of circadian rhythm because of night shift jobs, and others.

Regarding the concentration of pollutants in water, Antonio José Molina, researcher in the department of Gene-Environment -Health Interaction (Ibiomed) told us that 227 water samples from 67 municipalities and 9 samples of bottled water (leading brands) were analyzed. Among these municipalities are the city of León and 12 towns of the province of León (Spain), considered representative in terms of the number of cancer patients and controls part of the MCC project, and longer exposure of these patients to water.

“Our chief objective is to understand water exposure and products in it as potential carcinogens. We found exposure to water may be associated with certain potential carcinogenic compounds and it is important to study their levels in Spanish water, because little information is available. Our aim is to know how much a person is exposed, how much water is available in a place, how people use water and for how long; and, according to this information, we are to perform a model taking into account exposure time to nitrates or other components,” the researcher explains.

The samples, collected from running water in establishments in these localities, have been comprehensively analyzed in the Laboratorio de Salud Pública de Guipúzcoa (a public healthcare laboratory in Spain). “The first thing to be noticed regarding findings is that no problems were found in samples; contaminants are below legal levels, but variability was found depending on places”, the researcher states. In this regard, the origin of water must be taken into account. “In towns, water mostly comes from wells and springs, while in the city, it is surface water coming from reservoirs. In Barcelona, for instance, desalination is performed and contaminant levels may vary depending on the source”, he adds.

Regarding bottled water, in Spanish provinces such as Barcelona and Murcia, they found extensive consumption records. “A fact barely studied, so we analyzed the situation obtaining the same results: contaminants under legal levels”, the researcher concludes.

MCC-Spain

MCC-Spain was launched in 2008 and currently involves 17 groups from CIBERESP (a biomedical research network for epidemiology and public healthcare), including Ibiomed. Tumors chosen for the study were: colorectal cancer, breast cancer, stomach cancer, prostate cancer and, later, chronic lymphoid leukemia (CLL).

Colorectal cancer was chosen because of its importance in terms of incidence and mortality in both men and women. Breast cancer is a major public health issue in which the known risk factors account for only 50% of reported cases. Prostate cancer has been included because of its incidence and its hormonal nature, sharing with breast cancer some etiological hypotheses on endocrine disruption. Stomach cancer was chosen because of its characteristic geographic pattern and environmental hypotheses explaining it. Finally, CLL has been taken into account in conjunction with CLL sequencing studies by the International Cancer Genome Consortium.

The project involves the recruitment of patients of various types of cancer to be compared with a single control group.

Antonio José Molina explains that about 10,000 people have been recruited to answer a structured questionnaire including detailed information on sociodemographic factors, occupation, personal and family history, lifestyle and diet; and to collect various biological samples for the use of biomarkers. Population-based controls are randomly chosen from lists of people attending primary health care centers.

	References
	Herrera, N. E., Kogevinas, M., Vinyals, G. C., Aragonés, N., Boldo, E., Ardanaz, E. A., Azpiroz, L., Ulibarrena, E., Tardón, A., Molina, A.J., ... & Villanueva, C. M. (2013). "Nitrato y elementos traza en agua embotellada y municipal en España". Gaceta sanitaria: Organo oficial de la Sociedad Española de Salud Pública y Administración Sanitaria, 27(2), 156-160.