Edson Aparecido dos Santos

Herbicide detection in groundwater in Córrego Rico-SP watershed

Due to the large amount of pesticides applied in agriculture, mainly herbicides, there is a growing concern about a possible environmental contamination with these products, including water bodies. Given the above, the aim of the present work was to detect and quantify herbicides through multiresidue analysis in water samples collected in semi-artesian wells and springs in a rural area of the city of Jaboticabal (SP). Samples were collected from 32 wells and 13 water springs, in three different seasons: October 2010, February 2011 and May 2011. Additionally, samples at a residence in the urban area were also collected. Analysis using high performance liquid chromatography coupled to mass spectrometry was performed and herbicides ametryn, amicarbazone, clomazone, diclosulan, diuron, hexazinone, imazapic, imazapyr, isoxaflutole, S-metolachlor, sulfentrazone, sulfometuron-methyl, and tebuthiuron were evaluated. In semi-artesian wells, an incresed quantity of herbicides was found in comparison with the water springs. Among the tested herbicides, hexazinone, imazapyr and sulfentrazone were detected in measurable amounts in accordance with the analytical method applied, while clomazone was the most common herbicide being detected in more than 60% of the samples. Ametryn, diuron and amicarbazone herbicides were also detected. Diclosulan, imazapic, isoxaflutole, S-metolachlor, sulfometuron-methyl, and tebuthiuron were not detected in any sample. Inappropriate use of these products without prior knowledge of the behavior of the soil can lead to groundwaters and water springs contamination, thus an ongoing monitoring of this resource becomes very important.

Atrazine levels in the Jaboticabal water stream (São Paulo State, Brazil) and its toxicological effects on the pacu fish Piaractus mesopotamicus / Razine atrazina u vodotoku Jaboticabal (São Paulo, Brazil) i njihovi toksikološki učinci na ribu Piaractus mesopotamicus

Abstract The aim of this study was to determine the environmental concentration of atrazine (ATZ) in five streams located in the north of São Paulo state (Brazil) and evaluate its toxicological impact on young specimens of the pacu fish Piaractus mesopotamicus. Samples of water were collected on three occasions between 2010 and 2011, corresponding to periods signifying the beginning, middle, and end of rain season. ATZ levels were estimated by a high-performance liquid chromatography coupled with a mass spectrometry (HPLC-MS/MS) triple quadrupole. Later, the quotient of environmental risk (QR) was determined based on the medium lethal concentration (LC50 48 h), non-observable effect concentration (NOEC), and the estimated environmental concentration (EEC) of ATZ detected in the environment. Histological changes in gills and liver were also studied, along with the brain activity of the enzyme acetylcholinesterase (AChE). The highest concentration of ATZ measured was 10.4 μg L-1. The ATZ LC50 (48 h) for young P. mesopotamicus was 24.46 mg L-1 and the QR was classified as “safe”. Although the QR indicated that ATZ could be safe for the tested species, it caused many histological alterations in the liver and gills of the exposed specimens, and an increase in the AChE levels. Predmet ovoga istraživanja bio je odrediti okolišne koncentracije atrazina u pet vodotoka na sjeveru brazilske savezne države São Paulo te ocijeniti njihove toksikološke učinke na ribu Piaractus mesopotamicus. Uzorci vode prikupljeni su u tri navrata između 2010. i 2011. godine, i to na početku, usred i pri kraju kišne sezone. Razine atrazina mjerene su trostrukim kvadrupolom s vezanim sustavom tekućinska kromatografija visoke djelotvornosti-spektrometrija mase (HPLCMS/ MS). Potom je izračunat kvocijent okolišnog rizika (QR) na temelju srednje smrtonosne koncentracije (LC50 48 h), maksimalne koncentracije bez učinka (NOEC) te procijenjene okolišne koncentracije (EEC) atrazina pronađenog u okolišu. Nadalje, istražene su histološke promjene u škrgama i jetri te izmjerena aktivnost enzima acetilkolinesteraze (AChE) u mozgu. Najviša izmjerena razina atrazina bila je 10.4 μg L-1. LC50 (48 h) atrazina za mlade jedinke P. mesopotamicus bio je 24.46 mg L-1, a QR je klasificiran kao „siguran“. Premda QR upućuje na to da bi se atrazin mogao okarakterizirati sigurnim za ispitanu vrstu, uzrokovao je ne samo brojne histološke promjene u jetri i škrgama izloženih jedinki, nego i porast razina AChE u mozgu.