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Surface sediment samples from three water reservoirs of Slovakia were analyzed for selected organochlorine pesticides (OCPs). Concentrations of total dichlorodiphenyltrichloroethanes (ΣDDTs) in the sediments from Velke Kozmalovce, Ruzin, and Zemplinska Sirava ranged from 12 to 24 ng g -1 , 5 to 28 ng g -1 , and 1 to 20 ng g -1 , respectively, with the exception of one sediment sample from Zemplinska Sirava, having anomalously high concentration of ΣDDTs (526 ng g -1 ). Concentrations of hexachlorobenzene (HCB) in the sediments from these water reservoirs were generally lower and ranged from 0.3 to 9 ng g -1 . Other organochlorine pesticides such as mirex, lindane and heptachlor were not detected in the surface sediments. Ratios of DDT/(DDE + DDD) were lower than 1.0 in majority of the sediment samples indicating that the degradation of the parent DDT occurred significantly and DDT in the sediments from the studied water reservoirs was derived mainly from the weathered agricultural soils. Moreover, ratios of DDD/DDE indicated that the parent DDT was degraded under aerobic conditions before depositing into the sediments of these water reservoirs. . Iné v sedimentoch sledované organochlórované pesticídy ako mirex, lindán a heptachlór neboli zistené. Vo väčšine vzoriek sedimentov boli hodnoty pomeru DDT/(DDE + DDD) nižšie ako 1, z čoho sa dá usúdiť, že väčšia časť pôvodne prítomného DDT sa rozložila na jeho hlavné metabolity a že DDT v sedimentoch vodných nádrží pochádza najmä z erodovaných poľnohospodárskych pôd. Hodnoty pomeru DDD/DDE ukázali, že predtým ako bol DDT deponovaný do sedimentov vodných nádrží, rozkladal sa najmä za aeróbnych podmienok.KĽÚČOVÉ SLOVÁ: organochlórované pesticídy, DDT, dnové sedimenty, vodná nádrž, organická hmota.

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Tatarková V., Hiller E., Halko R. (2014): Retention characteristics of acetochlor in soils collected from different depths in relation to soil properties (Žitný ostrov area, SW Slovakia). Soil & Water Res., 9: 58-65.Determination of the sorption-desorption of herbicides within soil profile is one of the first steps in predicting their leaching potential. Batch experiments were performed to evaluate the influence of soil properties on acetochlor retention. Soil samples were taken from horizons A, B, and C of three soil types representative of the Žitný ostrov area. The sorption and desorption isotherms were fitted to the Freundlich equation. The Freundlich sorption coefficient (K fs ) values ranged from 0.71 to 6.58 mg(1-1/n) .l (1/n) /kg and were correlated positively with soil organic carbon, humic and fulvic acid carbons, amorphous aluminum oxides, and negatively with soil pH. The Freundlich desorption coefficient (K fd ) values were greater than those for sorption, showing that not all acetochlor sorbed was desorbed after four washing steps. The percentage of acetochlor desorbed ranged from 7.80 to 54.5% with decreased desorption from soil horizons B and C. The higher sorption capacity of surficial soil horizons in the three soils may be a limiting factor for penetration of acetochlor through soil profiles into groundwater.