Fish pollution questions the regular consumption recommendation -
Everyday compounds affect cognitive development or reproductive system.
"Of all the animals, the one who now has more pollutants in the body is you," says Nicolás Olea, from the University of Granada, one of the pioneers in Spain to investigate the presence of pollutants in the body.The statement sounds effective, but the message is clear: during our long life humans accumulate persistent chemical compounds that dress our diet, pollutants that our own industrial activity has generated.And there they stay, in an organism that does not know how to eliminate them.Moreover, they have entered the human species to stay.Mothers transmit them through the placenta and breast milk, so babies incorporate them as standard.What effect do they have?There is more and more evidence that many affects cognitive development to fertility, even low doses.
The toxicity of many of these compounds is known for a long time, and for example in the case of dioxins, polychlorinated bipheniles (PCB) or heavy metals, their industrial use or their release in the environment have been regulated.But not for that reason they have disappeared from the environment.They are in the food chain, entrenched mainly in fatty tissues;The older the animals we eat, and more fatty, more contaminated.The predative fish, such as the shark or the emperor, can have been storing methylmercury for more than ten years, the most toxic form of mercury, before reaching the dish.
In addition there are more modern and very common use compounds in everyday life, such as phthalates -used in soft plastics, for example for childrenHealth effects worry.
Ecologist and expert organizations have been giving the alarm for some time, with some results.The European Commission announced a week ago that as of 2011, bisphenol to bottle is prohibited, a decision that the United States made a year ago.John Dalli, a European health commissioner, declared that "new studies showed that bisphenol A could affect the development, immune response and generation of tumors."In contact with hot liquids, this compound is separated from the plastic, especially if the bottles are not new.To Olea the prohibition "is a fantastic news, but why have they taken so long? We know how this compound acts since 1936".
How many pollutants do we eat?José Luis Domingo, from the Laboratory of Toxicology and Environmental Health of the University Rovira I Virgili, and Joan María Llobet, of the University of Barcelona, have been analyzing the foods of the average purchase basket in Catalonia since 2000.Your third report is almost about.They take the samples choosing how an average consumer would do, and they measure eight more heavy metals.Then they cross the data with those of consumption of the Catalans and obtain the intake of an average consumer.
There are some good news: "You can tell some pollutants in the environment, such as lead, which is no longer used in gasoline, or dioxins and PCBs," says Domingo.Llobet recalls that "what we emit to the environment returns to us; if the environment is cleaner, food too."
The black point is mostly in fish and seafood, food in which concentrations do not fall.In fact, although the average intake of all compounds is below the security levels established by the World Health Organization (WHO), the 2007 study published by the Catalan Food Security Agency (ACSA), revealsthat boys and girls exceed this level little, and womenThey practically reach it.The text is referred to the EU recommendations: young children, pregnant women or who wish to conceive and those who are breastfeeding should not eat more than 100 grams per week of sword or shark fish, doses that exclude more fish that week.Tuna, no more than twice a week.Europe is not the only one to issue these recommendations;The United States and Canada have given similar advice for years.
The data of the ACSA studies marry that most of the alerts issued by the Spanish Food Security Agency in 2009 were by high levels of mercury in fish.It has its logic.Once in the middle, Mercury does not disappear.And to the natural sources of Mercury, such as volcanic eruptions, we must add the activity of man, which has been using this metal for 3,500 years.It is estimated that we continue to release 50,000 tons of mercury every year.
"We will never remove the mercury of the trophic chain," says Bernardo Herradón, a chemist of the Higher Council for Scientific Research (CSIC)."It has been used a lot, and although it is now very restricted it is still in some types of batteries and in fluorescent tubes, for example."Mercury is on the ground and also passes to the atmosphere;The rain takes him to the rivers and from there to the sea, where microorganisms make him methylmercury, which is the way we eat with fish.The microorganisms are at the base of the marine food chain, and the big predative fish, and ourselves, we are on the cusp.
But, in addition to the diet, researchers are discovering -"surprised," says Olea -another source of chemical pollutants for the organism: cosmetics."The effect of cream and shampo components is now a booming research area. We have more and more evidence that compounds very common in cosmetics, such as parabnes, interfere with the action of hormones. They are easily absorbed byThe skin but its elimination is very difficult, "explains Olea.
Also UV filters, used in antisolar creams and recommended by dermatologists to prevent skin cancer, begin to be suspicious.If its toxic action is confirmed, the biomedical community would be faced with a risk-benefit dilemma.
However, researchers warn that it will not be easy to establish out of any doubt the link between exposure to pollutants in everyday life and diseases.First because the effects, having them, take decades to manifest.And also because the important thing, the researchers warn, is the 'cocktail' of chemicals, that is, its joint action.The compounds are many, and their possible interaction, a mystery.
"We don't know what will happen, but the data is there," says Olea."The exposure is real. Toxic are in the blood and in the placenta, they excrete in breast milk. Mothers pass them to their children. We have compounds that we had never had before," says Olea.
Epidemiologists, for the moment, investigate the relationship between exposure to pollutants and diseases such as cancer, diabetes, endometriosis, infertility, genitourinary malformations, immunological depression, asthma, Alzheimer's and Parkinson.
For this type of work, tissue banks and data are a treasure like the one with the Olea group in Granada: 6,000 mothers placentas from all over Spain obtained a decade ago, with monitoring information, during that time, of the mother-pair-corresponding son.This allows to investigate, for example, the relationship between pollutants in the placenta and development.One of the last scientific works published, in September, indicates that a greater concentration of chlorinated compounds could negatively affect cognitive function, and recommends more studies.Researchers are also observing in recent years that the low concentration of these compounds in the agency does not guarantee their safety.The so -called low dose myth is falling.
"Both in animals and humans adverse effects of pollutants have been seen at the doses traditionally called low," explains Miquel Porta, Professor of Epidemiology and Public Health at the University of Barcelona and researcher at the Municipal Institute of Medical Research (IMIM)."Strictly, these doses are not low: concentrations or levels in blood or amniotic fluid, for example, are as high as those of our own natural hormones, and often much more."Until now it was accepted that these compounds should be presented at higher doses to alter physiological functions in the body, "but that is in review," says Porta.
This expert does not reassure know that in most foods these compounds do not exceed the levels considered safe by food security agencies and WHO."Often legal levels are established simply so that food can reach our table," Porta says."But no one can assure us that the concentrations that an important part of the population has are safe; as a doctor, they seem very worrying."
In a recent study, his group measured the presence of pollutants in a sample of 919 people in Catalonia, considered representative of the general population.The results revealed that some people had amounts of DDE and hexaclorobenzene up to 6,000 times higher than others."A population minority has a scandalously superior internal contamination. Is that minority that then develops disease?" He asks.
It is one of the many issues still pending to study.Researchers wonder, for example, how environmental toxics interfere with the action of genes.Some data suggest that arsenic, cadmium and organochlorine pesticides could turn off tumor suppressor genes, and turn on genes with precisely the opposite action.
Proof that the problem matters is that the European Union allocates funds to investigate it.The Group of Olea and seven other European laboratories participate in the Contamed International Project, which studies the relationship of daily chemistry with reproductive system disorders.The incidence of these alterations - from a lower quality of semen to genital malformations - is increasing in Europe and the problem causes "considerable concern", it is said on the project website.
