02598naa a2200385 a 450000100080000000500110000800800410001910000200006024500990008026000090017952014730018865000110166165000150167265000130168765000250170065000220172565000130174765000210176065000140178165000100179565000260180565000240183165000090185565300130186465300230187765300200190065300240192065300130194465300150195770000210197270000240199370000200201770000200203777301550205710154452015-09-28       2005    bl uuuu     u00u1 u    #d1 aCERDEIRA, A. L.  aHerbicide leaching on a recharge area of the Guarany Aquifer in Brazil.h[electronic resource]  c2005  aThe region of Ribeirao Preto City, located in Southeast of Brazil, Sao Paulo State, is an important sugarcane, soybean, and corn producing area with a high level of pesticides utilization. This region is also an important recharge area for groundwater supply of the Guarany Aquifer. Since the past ten years atrazine, simazine, ametryn, tebuthiuron, diuron, 2,4-D, picloram, and hexazinone are the main herbicides used in this area. In order to study a possible leaching of some of these herbicides into the aquifer, surface, and groundwater samples were collected in a watershed during the years of 1996 to 2003, from different locations. To detect and quantify the herbicides a GC-MS (gas chromatograph/mass spectrometry) method was used. The response of the herbicides analyzed was linear over the concentration range of 0.02 to 2.0 microg/L. Analysis of groundwater revealed that the herbicides tebuthiuron, diuron, atrazine, simazine, and ametryn were not present in the samples. In the surface water collected in 1997, ametryn was present in two out of nine locations with concentrations ranging from 0.17 and 0.23 microg/L, which is above the allowable 0.1 microg/L according to the European safety level. The leaching potential of tebuthiuron, diuron, atrazine, simazine, 2,4-D, picloram, and hexazinone has been evaluated using CMLS-94, "Chemical Movement in Layered Soil," as simulation model. No leaching into the depth of the water table at 40 m was found.  adiuron  ahexazinone  apicloram  aÁguas subterrâneas  aAnálise química  aAtrazina  aCana de açúcar  aHerbicida  aMilho  aModelo de simulação  aPoluição da água  aSoja  aAmetrina  aAqüífero Guarani  aRibeirão Preto  aSão Paulo (estado)  aSimazina  aTebutiuron1 aSANTOS, N. A. G.1 aPESSOA, M. C. P. Y.1 aGOMES, M. A. F.1 aLANCHOTE, V. L.  tJournal of Environmental Science and Health. Part B, Pesticides, Food Contaminants, and Agricultural Wastes, New Yorkgv. B40, n. 1, p. 159-165, 2005.