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ARS Home » Southeast Area » Oxford, Mississippi » National Sedimentation Laboratory » Water Quality and Ecology Research » Research » Publications at this Location » Publication #155247
Title: PRESENCE OF ATRAZINE IN WATER IN A RECHARGE AREA OF GUARANY AQUIFER IN BRAZIL

Author
item CERDEIRA, ANTONIO - BRAZILIAN MINISTRY-AG
item SANTOS, N - SAO PAULO UNIVERSITY
item PESSOA, M - BRAZILIAN MINISTRY-AG
item Smith Jr, Sammie
item LANCHOTE, V - SAO PAULO UNIVERSITY

Submitted to: Mississippi Water Resources Research Conference Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: 2/15/2004
Publication Date: 4/22/2004
Citation: Cerdeira, A.L., Santos, N.A., Pessoa, M.C., Smith Jr., S., Lanchote, V.L. 2004. Presence of atrazine in water in a recharge area of guarany aquifer in brazil [abstract]. Mississippi Water Resources Research Conference. p. 30.

Interpretive Summary:

Technical Abstract: The region of Ribeirao Preto City located in Sao Paulo State, southeastern Brazil, is an important sugarcane, soybean and corn producing area. This region is also an important recharge area for groundwater of the Guarany aquifer, a water supply source of the city and region. It has an intercontinental extension that comprises areas of eight Brazilian states, as well as significant portions of other South American countries like Argentina, Uruguay, and Paraguay, with a total area of approximately 1,200,000 Km2. Due to the high permeability of some soils present in this region, the high mobility of the herbicides and fertilizers applied, and being a recharge area, it is important to investigate the potential transport of applied herbicides to underlying aquifer. The cultivation of grain and sugar cane in this area demands the frequent use of the herbicide atrazine (2-chloro-4- (ethylamino)-6-(isopropylamino)-S-triazine). This research was conducted to characterize the potential contamination of groundwater with atrazine. Nine surface water sample points were selected in the Espraiado stream in the watershed, during the years of 1995-1998. Samples were collected in the months of October, November, December, January, March, May, and July of each year. Four replications were collected at each site for a total of 252 surface water samples per year. Groundwater was also collected during the same months from county groundwater wells located at the edge of the watershed during the years of 1999 and 2002. The following seven wells were studied: Palmares, Sao Jose, Sao Sebastiao Velho, JP, Higienopolis, Schimidt, Jardim Recreio, and DAERP Central. The water samples were analyzed using an HPLC (High Performance Liquid Chromatography) procedure followed by GC-MS for confirmation. To predict the atrazine leaching in the area, the CMLS-94 (Chemical Movement Layered Soil) simulation model was also used. Only four atrazine detections in surface water were found in the year 1996, with residues varying from 0.02 to 0.09 ppb. However, none of them were confirmed with GC-MS. No atrazine was detected in groundwater samples. The results obtained by the CMLS-94 simulations predicted that atrazine, after four years from the application date, would not have reached the depth of the confined aquifer (40m), with no potential to reach groundwater when evaluated by the CMLS-94. This result agrees with the information obtained by means of monitoring wells located in the study area, where atrazine was not detected in the water.