Contamination of public water supplies of nitrate of Natal - Rio Grande do Norte - Brazil

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During the last ten years 38 wells had to be disabled in Natal, due to the high nitrate concentration recorded in water taken from these sources. One of the solutions found by Caern to prevent the closure to reach the other 119, resulting in a shortage of drinking water for the population of the capital, was the construction of two pipelines: the Jiqui and Rio Doce. The first operates in the testing phase and the second should be ready in the second half. Its waters are used to dilute the wells and reduce the concentration of nitrate.

Elisa Elsie
San Valley is still the only source of area that was not polluted and so the prosecution seeks its preservation with urgênciaSan It is still the only source of area that was not polluted and so the prosecution seeks its preservation urgently
However, the promoter Defense of the Environment, Gilka da Mata, believes that the situation is still serious. "The evolution of the nitrate contamination in the water Christmas still growing and harms human supply," he said. She recalls that in 2005, the Caern had 134 wells in activity and, of those, 69 showed nitrate contamination. "The city is losing much of the water that was used for human consumption and that is defiled," recalls Gilka da Mata, considering that today are only 119 active stations.

It reveals that 2010 numbers, raised by the Regulatory Christmas Sanitation Agency (Arsban), recorded 15 wells with nitrate content above allowed for human consumption in the north of 22 analyzed, and another 26 in the south of 50 surveyed. The position of Caern is less incisive. By Press Office, the company ensured that the "current situation is controlled, from the dilution water with nitrate levels above 10 mg / l in water of the new pipeline, which has been operating gradually."

The adductor of Jiqui entered the test phase in late 2009 and depend, to work in its fullness, the construction of two subadutoras under the responsibility of the Christmas City Hall. Still, Caern ensures that the use of Jiqui pond water in diluting wells already has "significant results". The company admits "specific problems in some neighborhoods, while the pipeline does not operate fully" and cites Felipe Shrimp, Morro Branco, Pirangi and vicinity.

The list of the prosecution is much more extensive: Lagoa Seca, Dix-Sept Rosado, Thursday, Northeast Quarter of the Rosemary, Potilândia, New Discovery Morro Branco, Lagoa Nova, Nazareth, Good Shepherd, Felipe Shrimp, New Town, New Town , Pirangi, Jiqui, Gramoré and Pajuçara. "And the population has brought to the Prosecutor situations which show increasing values of contamination in other neighborhoods," added the prosecutor.

Gilka Mata stressed that the construction of water mains, by the Caern was a legal requirement as a result of a civil lawsuit filed by the prosecutor. "Iran improve the quality of water distributed to the population, but these measures are to solve the problem in emergency regime. The city grows, the population increases and the springs of Jiqui and Doce will not be sufficient for the supply of long-term population, "he warns.

The adductor Doce River is expected to start operating in the second half. The wells that meet the pipeline have been drilled and, according to Caern showed excellent quality water.

Sewage treatment part of the solutions

The Caern understands that the most important project for the reduction of nitrate levels is the investment being made in the collection and treatment of wastewater capital. The works will prevent waste leach into the soil using tanks, contaminating the water table. To Gilka da Mata, you need agility. She advocates the preservation of the wealth that has not been polluted, mostly in San Valley region, the completion of water mains and the full implementation of the sewage system.

"You can not equate Christmas to other cities that do not have sewage system because the situation here is atypical. The Christmas aquifer has no clayey protection that usually separate the water table of confined aquifer. Thus, everything that turns out underground ends up spreading throughout the aquifer and reaching the deeper layers where it draws water for human consumption, "he says.

The prosecutor questions the lack of a specific plan as a Master Plan for Water Supply, determining the most suitable sites for the extraction of liquid. The Caern, however, confirms at least one of the places where the water is still good quality: the San Valley. This same region, along with Ponta Negra, are those with lower levels of nitrate contamination, ranging from zero to a maximum of 4 mg / l.

In areas where the value exceeds the limit of 10 mg / l, however, the consumer is only required to pay 50% of the bill. The Public Ministry is evaluating they will ask in court a discount on sewer rate, given that the Caern charges for service, but does not perform the treatment of many waste collected in the city. "The Baldo station will solve a large part of the problem but not solve the problem in its entirety," said the promoter.


The prosecution launched on the last day 22, the campaign "Save the Christmas Drinking Water", which aims to mobilize society for the preservation of wealth located in the area of the protection zone of the San Valley. "It is a simple campaign and the person can participate with just the act of signing a petition electronically. The final effect will be crucial to show the government that the population aware of the problem and requires quick and effective solution to prevent nitrate contamination reaches the ZPA of San Valley, which supplies 16 neighborhoods. "

According to the promoter, the lack of sanitation in the region caused wells that had 1.0 mg / l nitrate in 2004, today register up to 5.4 mg / l. The undersigned has received almost 4000 accessions and is available at:

Population does not trust the measures

The nitrate concentration ratio registered in the last water accounts Pirangi together population, South Christmas area, was 7.8 mg / l. The value below 10 mg / l makes the water potable region, according to the criteria established by Decree 518/04, the Ministry of Health. The number does not convince those who drink the water. "You can not trust, when business is wrong to fix it is difficult," says the retired José Guilherme Son.

Pirangi Dweller 26 years ago, he recalls that adopted the consumption of mineral water for about three when water contamination suspected in the region began to be published in the press. "Everyone was amazed at this story and now only drink mineral water. To return to take tap water, needed to change a lot, "he says.

The opinion of José Guilherme is no exception. "I can not believe it (the nitrate concentration recorded in the account), here in my house is mineral water to drink and is also the one we use for cooking," says the stay-at-home Zelia Firmino. The practice was also adopted for about three years and is, today, an average of four containers per week, which equates to a higher monthly cost to $ 50 "We will continue using the mineral, because I do not believe that the water is clean, "he said.

Best for traders as Nubia Gomes, whose grocery store is practically all taken by bottles of mineral water. "I think seeing about 40 a day," he says. She admits that consumption has increased grid part because of the excessive heat, but remember that the locals continue to use only mineral water to drink and do not know anyone who "risk" in tap water.


The Nitrate is considered one of the most common occurrence of contaminants in groundwater. The water is only considered safe when the concentration of this substance is less than 10mg per liter. Nitrate comes to the wells and aquifers mainly due to the lack of sewers. The population uses septic tanks, where the substance is produced during the final stages of decomposition of biological material. Nitrate penetrates the soil and reaches the water table. There are suspicions that the accumulation of nitrate can cause cancer and other diseases in humans.