The determination of heavy metal contamination in water, sediment and suspended solid matter in lake Bafa

The purpose of this dissertation is to determine potential pollution levels of 9 different metals (Al, Cr, Co, Ni, Zn, Cd, Pb, Fe and Mn) in an aquatic environment such as Lake Bafa which is idiosyncratic in terms of both its being influenced by anthropogenic factors (agricultural, domestic and industrial wastes) and its own geographical characteristics (its connections with the sea and underground waters) and to reveal the relationship between the factors affecting this pollution accumulation and different segments (water, sediment and suspended solid matter) in which pollutants accumulate spatially and temporally.The data revealed after the analyses were interpreted via statistical analyses. According to the findings obtained after the analyses, firstly the physico-chemical parameters of the lake water were determined. The temperature was found between 7,6-29,5 °C; dissolved oxygen was found between 1,84-17,46 mg L-1, oxygen saturation was found between 23,10-234,30, chlorophyll-a was found between 0,79-35,57 mg L-1, pH values were found between 7,56-9,76, salinity values were found between ‰ 10,55-11,88 and TDS were found between 11,34-20,88 g L-1. The values of nutrients were specified as follows: ammonium nitrogen was between LOD-1,598 mg L-1, nitrite nitrogen was between 0,001-0,187 mg L-1, nitrate nitrogen was between 0,078-15,800 mg L-1 and phosphate phosphorus was between 0,006-4,740 mg L-1. The amount of organic matter in the SSM varied between 0,0002-0,0309 g L-1, the amount of inorganic matter varied between 0,0002-0,0184 g L-1. The amounts of TOC detected in sediment samples were between 0,59-5,50 g kg-1. As a result of heavy metal analyses in water samples, it was detected that Al values varied between LOD-47,45 mg L-1, Mn values were between 1,00-37,65 mg L-1, Fe values varied between 1,00-79,61 mg L-1, Co values varied between LOD -0,007 mg L-1, Ni values were between LOD-20,24 mg L-1, Cd values varied between LOD -0,0197 mg L-1 and Zn values varied between LOD-5,19 mg L-1. In the samples of SSM the amounts of heavy metals were found as follows: Al values were between 72,87-3164,90 mg kg-1, Mn values were between 1,47-947,77 mg kg-1, Fe values were between LOD-1779,36 mg kg-1, Cr values were between LOD-18,48 mg kg-1, Co values were between LOD-0,733 mg kg-1, Ni values were between LOD-85,42 mg kg-1, Cd values were between LOD-2,3162 mg kg-1, Pb values were between 0,06-30,49 mg kg-1 and Zn values were between 0,55-14,48 mg kg-1. After the analyses of sediment samples, Al was found between 54,03-7251,38 mg kg-1, Mn was found between 197,05-1331,47 mg kg-1, Fe was found between 22308,95-41345,00 mg kg-1, Cr was found between LOD-284,50 mg kg-1, Co was found between LOD-0,73 mg kg-1, Ni was found between 106,92-373,48 mg kg-1, Cd was found between 0,02-0,20 mg kg-1, Pb was found between 11,02-27,57 mg kg-1 and Zn was found between the values of 22,03-87,17 mg kg-1. In terms of stations, mean heavy metal concentrations in the core samples, which were taken from 3 different stations, and the samples of surface sediment taken from 10 different stations were detected as "<1" according to NIgeo. Enrichment factors calculated via obtained data from sediment core samples were found as follows; EF(Al) between 0,4-2,0, EF(Cr) between 0,65-1,0, EF(Mn) between 0,62-1,38, EF(Pb) between 1,18-1,6, EF(Zn) between 0,8-1,18, EF(Co) between 0,6-1,1 and EF(Cd) between 0,37-1,13. When all the findings were interpreted, it was concluded that the highest level of Al concentration was detected at the station where Büyük Menderes River entered into the Lake Bafa; Mn was mostly accumulated at the station where olive oil factories were situated and Ni values were at the highest levels at the stations where olive oil factories and the hotel were located. As a conclusion, it is of prime importance in terms of the sustainability of lake ecosystem that this kind of exemplary studies through which the changes in water quality can be monitored; the changes in the levels of pollutants can be detected and ecological situation of the lake can be revealed are conducted periodically on the Lake Bafa, the most significant wetland in South Western Aegean Region.