This study was conducted on a storage reservoir situated in a valley, in the lower course of the Sz¹bruk stream in north-eastern Poland, the Olsztyn Lakeland mesoregion. The catchment area of the Sz¹bruk stream consists of an agricultural and an afforested part. A storage reservoir is found in the lower part of the Sz¹bruk stream valley. The reservoir was built 25 years ago. It is enclosed by a dike and equipped with an outlet box. Outflows from the reservoir pass through the terminal segment of the Sz¹bruk stream to Lake Wulpiñskie.The results of the experiment indicate that the calcium content of water evacuated from the catchment was determined by the type and intensity of catchment use, ranging from 22.3 mg Ca⋅dm -3 to 178 mg Ca⋅dm -3 . The highest calcium concentrations, 113 mg Ca⋅dm -3 on average, were noted in the agricultural catchment connected to a drainage network; lower levels, 78.7 mg Ca⋅dm -3 , were found in farming areas drained via ditches, while the lowest Ca content in water, 38.7 mg Ca⋅dm -3 on average, was determined in outflows from afforested catchments. Calcium concentrations were lower during the growing season in all studied catchment types. The calcium load discharged from the catchment dependnded on the catchment management. The highest calcium loss per area unit was observed in the drained agricultural catchment (76.6 kg Ca⋅ha -1 ⋅year -1 ), followed by the catchment drained via ditches (56.3 Ca⋅ha -1 ⋅year -1 ) and the afforested catchment (31.8 Ca⋅ha -1 ⋅year -1 ). Despite the inflow of calcium-rich drainage water, calcium concentrations decreased by 11%, from 56.8 mg Ca⋅dm -3 to 50.3 mg Ca⋅dm -3 , after the stream's waters passed through the storage reservoir. An increase in Ca levels was noted in the girdling ditch. The flow of water through the ditch minimizes sedimentation, and higher quantities of Ca were supplied with drainage water. The reservoir accumulated 242.4 kg Ca per ha in the course of one year, mostly in the growing season (83%). The above indicates high involvement of biological processes. The reservoir fulfilled the role of a barrier inhibiting calcium loss from the catchment. ZNACZENIE ZBIORNIKA RETENCYJNEGO W OGRANICZENIU MIGRACJI WAPNIA ZE ZLEWNI ROLNICZEJ AbstraktBadania prowadzono na zbiorniku retencyjnym po³o¿onym w dolinie koñcowego biegu strugi Sz¹bruk po³o¿onej w pó³nocno-wschodniej Polsce, w mezoregionie Pojezierza Olsztyñskiego. Zlewnia strugi Sz¹bruk sk³ada siê z czêoeci leoenej i rolniczej. W dolnej czêoeci doliny strugi Sz¹bruk jest po³o¿ony zbiornik retencyjny wykonany przed 25 laty, zamkniêty grobl¹ i mnichem. Odp³ywy ze zbiornika kierowane s¹ koñcowym odcinkiem strugi Sz¹bruk do Jeziora Wulpiñskiego. W wyniku badañ stwierdzono, ¿e stê¿enie wapnia w wodzie odp³ywaj¹cej ze zlewni zale¿alo od sposobu i intensyfikacji u¿ytkowania i mieoeci³o siê w granicach od 22,3 mg Ca⋅dm -3 do 178 mg Ca⋅dm -3 . Najwy¿sze stê¿enie, oerednio 113 mg Ca⋅dm -3 , wyst¹pi³o w wodach zlewni rolniczych odwadnianych sieci¹ drenarsk¹, ni¿sze, oerednio 78,7 mg Ca⋅dm -3 , w wodac...

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The examination of total amounts of heavy metals (Hg, Cd, Cu, Pb, Cr, Ni, Zn) was conducted in the outflow from a sewage treatment plant and in the waters and sediments of ponds supplied with them. As the water passed through the pond system, a decrease of heavy metal concentrations in the post-treatment sewage water supplying the ponds was observed. The highest concentrations of heavy metals were found in the outflow from the sewage treatment plant and lower concentrations were observed in the water of pond 1 (except for Zn), which was the direct receiver of post-treatment sewage, while the lowest values were noted in the final pond. The concentration of heavy metals in the sediments decreased in consecutive ponds. The highest concentrations were determined in the sediment of pond 1 that received the post-treatment sewage * Corresponding author: katemel@uwm.edu.pl DOI 10.2478/v10009-009-0051-3Original research paper directly from the sewage treatment outflow, whereas the lowest values were estimated in the sediments of pond number 4, which was the final pond in the system.