Groundwater chemistry in alluvia was investigated in a meander bend of the Biała Przemsza River in its middle course at Sławków in Upper Silesia, southern Poland. Pollution of groundwater induced by inflow of river water enabled recognition of relative differences in the amount of inflowing water. Biogeochemical zonation is a characteristic feature of the investigated groundwater. Inflow of river water is most intensive in the zone of about 1/3 of the bend width, parallel to the channel. It is characterized by macroions concentrations higher than that in the river. Outside, in the central part of the bend, concentrations of macroions significantly decrease. In this part of the bend, the largest head gradient also is observed. It increases toward the apex, and close to the river channel it equals about 40 cm. Groundwaters in the distal part of the bend are the least mineralized as a result of dilution by rain water. Investigations suggest a slow exchange of the hyporheic waters because of the prevalence of sandy-silty sediments. It favours transformation of nitrates, sulphates, and iron mobility in reducing conditions. Reducing their load in the river can be remarkable over the 30 km meandering reach of this river.