We studied the rate and environmental risks associated with sediment and water stream pollution by excessive nutrient concentrations caused by runoff and leachate from the municipal solid waste composting plant of Sanandaj (Kurdistan, Iran). Sediment and water samples were analyzed for physico-chemical parameters including: sediment particle size distribution, pH, electrical conductivity (EC), water total dissolved solids (TDS), water total hardness (TH), total organic carbon (TOC), total Kjeldahl nitrogen (TKNS), inorganic nitrogen (NO3- and NH4+), phosphorus (P), calcium (Ca), magnesium (Mg) and potassium (K). The results showed that the water was unfit for irrigation and drinking purposes, and threatened the aquatic life, and that the quality of the sediments was degraded, as the physico-chemical parameters had higher values than those of quality guideline values for nutrient elements. Furthermore, in comparison with previous studies, in most cases the concentration of the surveyed parameters in the studied stream water and bed sediments was higher. Overall, the stream water and sediment pollution clearly reflected the impact caused by the runoff and leachate from the composting site, and posed risks for the surrounding ecosystems. Therefore, technologies for preventing emission from the composting plant and remediation actions on the contaminated area are recommended.
