In this study, the plant Polygonum amphibium, sediment samples surrounding it and water were collected from Kayseri-Sarimsakli, and their heavy metal contents (Ni, Cu, Zn, Cr, Pb and Cd), certain sediment characteristics and C and N contents in the plant organs were determined. The accumulation of heavy metals were ranked as Zn>Cu>Ni>Cr>Pb>Cd in the root and shoot of the plant; Ni>Cr>Zn>Cu>Pb>Cd in the sediment; and Cu>Zn>Ni in the water samples. Heavy metals accumulated in the root at a higher concentration than the shoot. The heavy metal concentrations in the water samples were determined to be below the criteria value. Threshold set by the National Oceanic and Atmospheric Administration (NOAA), the Ni content of the sediment was above the threshold concentration, the Cr was above the low concentration and the other metals were determined to be below the low concentration. It was found that the total organic carbon (TOC) contents of the sediment samples varied between 0.88-2.81%. According to the correlation analysis, there was a negative correlation between TOC and Ni, and no correlation was found with the other metals. Furthermore, a positive relationship was observed between Cr and silt as well as TOC and sand; whereas, a negative relationship was observed between clay and sand.