Scientists have discovered high levels of 11 pesticides in the water that supplies 127 grain-producing cities in western Paraná, where 5.5 million people live. According to the study, the problem is associated with at least 542 cases of cancer diagnosed in residents of the region in a period ranging from 2017 to 2019.
The work of researchers from Unioeste (Universidade do Oeste do Paraná) and the American university Harvard was recently published in Environment International, an international journal of scientific articles.
For the calculation, the average concentration levels of each pesticide in the water (ppb), the population exposed to them in each city and the cancer risk generated by the substances found were crossed, following the bases of the INCA (National Cancer Institute) and the IARC (International Agency for Research on Cancer).
That is, the scientists estimated how many cases of cancer each pesticide could cause from the population that was affected by each one. Then, they compared this number to the actual number of cases of the disease in the period analyzed in the region.
Thus, they concluded that in 542 patients it was possible to establish that exposure to pesticides was “significantly correlated with the sum of estimated cancer cases for all 11 pesticides detected in each city”. More than 80% of cases were linked to two substances, mancozeb-ETU and diuron.
“Of the 27 pesticides investigated in water, 11 are possibly, potentially or demonstrably carcinogenic, such as lindane,” says study coordinator, biochemist Carolina Panis — a columnist for Sheet Marcia Castro is also one of the authors.
Panis highlights the crossing of estimated cases with real cases, diagnosed in the same period by INCA. “We found a very large correlation in all municipalities, especially for breast cancer, which is very common in Paraná”, she says.
Cancer is a disease with many causes, but the researcher says there are studies that show how the effects of exposure to pesticides can contribute to the development of a tumor.
The reactions in the human body depend on a number of factors, such as the levels ingested, the exposure time and the susceptibility of each person, she says.
The study points out that the water contamination levels of the analyzed municipalities are above the limits of the European Union, which allows a total of 0.5 ppb (parts per billion) — in Paraná, the sum was 189.84 ppb. Brazilian legislation does not establish a general limit, only by substance, and the analyzed pesticides are within the permitted range.
The work used data from Sisagua (Water Quality Surveillance Information System for Human Consumption), of the federal government. Analyzes of water samples in the region also confirm the presence of pesticides.
Other side
When contacted, Sanepar (state responsible for basic sanitation in Paraná) said that at the time of the study, the Sisagua data were incomplete, with few options for registration, carried out directly by city halls.
“The presence of pesticides in the water was recorded, even if it was not detected, distorting the information. As of 2019, the data began to be sent by Sanepar’s management system directly to Sisagua, in order to avoid typing errors on the part of of the secretariats”, punctuates the note.
According to Sanepar, in the period referred to in the article, 27 types of pesticides were investigated and the results were below the permitted limits. “In other words, the presence of pesticides in the water distributed to the population was not detected.”
Panis says the Sisagua data were published in 2019, two years after the period studied. “Imagine the federal government’s irresponsibility for publishing an incomplete database. Why wasn’t the report corrected then? Was there never an errata?”, says the researcher.
In a note, the Ministry of Agriculture says that it created the National Program for the Qualification of Pesticides Applicators to register and train rural producers, which should reach two million by 2026.
He also said that Anvisa (National Health Surveillance Agency) and Ibama (Brazilian Institute for the Environment and Renewable Natural Resources) are responsible for analyzing the use of substances.
When contacted, the agency replied that “the specific topic addressed in the study, environmental contamination, is the responsibility of Ibama”.
The institute and Aprosoja (Brazilian Association of Soy Producers) did not respond to questions from the Sheet until the publication of this report.
