Spatial analysis of some important soil properties and heavy metal contents with determining of landuse types of the areas irrigated by the Nilufer stream

Consequently on going industrialization and urbanization in the last 30 years in Bursa province, the Nilufer creek water quality is reduced to class-4 from class-1-2. By long term use of this important water source for irrigation in the region, it is considered that the soil and plants may be contaminated in terms of heavy metals. In this research, six different research areas were created by interpreting the main tributaries and pollution sources of the Nilufer Creek. The research areas were determined considering where pollution factors (points of discharges of some industrial water treatment facilities) and irrigation were intense. Soil samples were collected in two different time series (May-October) representing the irrigation and non-irrigation period of the area. In the soil samples some soil fertility analysis were performed. Heavy metal (extracted by DTPA and total content) contents of the soil and sediment samples were also determined. The results were compared with international pollution limits. In addition, contamination indexes (contamination factor (CF), enrichment factor (EF), pollution load index (PLI) and geo-accumulation index (Igeo)) of the study areas were determined. All results obtained in this research were entered to a GIS database, which was created for the studied areas. Value results of all laboratory analysis were entered to the database and spatial distribution colour maps were created for each value and some statistical analysis were computed. As a result, the current state of pollution of the soils was established and mapped. In addition, actual land use/cover types based on digital satellite data were also identified and mapped. According to the results, because of use of Nilufer Creek as an irrigation source, heavy metal accumulation in soil was determined and it was significant for the available to plant forms (extracted by DTPA). In the study area contamination factor (CF) values were ranged between 0.31 and 6.31 while enrichment factor (EF) values were ranged between 0.19 and 5.54. The results obtained from this research can be used as a roadmap and data source for future research projects which will be related with the Nilüfer Creek, an important water source for Bursa which is in the process of urbanization and industrialization.