Assessment of the macrophyte flora, ecological quality, heavy metal risks and phytoremediation potential of the Isikli (Ci̇vri̇l) and Gökgöl Wetlands (Deni̇zli̇)

This thesis study was carried out in 2 different periods. In the first period of the study, it was aimed to determine the water quality by collecting water and macrophyte samples seasonally from 12 stations selected between October 2020 and August 2021 in Işıklı and Gökgöl Wetland (Çivril/Denizli). In the second period of the study, in order to determine the heavy metal pollution of Işıklı and Gökgöl Wetland using some heavy metal indices, water, sediment and some macrophyte samples were collected from 6 stations determined between June 2024 (Rainy period) and October 2024 (Dry period) twice. In the first period of the study, 77 genera and 113 macrophyte species belonging to 45 families from the phylums Spermatophyta (106), Charophyta (2), Chlorophyta (1), Pteridophyta (2), Marchantiophyta (1) and Bryophyta (1) were identified in the wetland. Among macrophytes, Poaceae (13), Potamogetonaceae (10), Cyperaceae (9) and Asteraceae (8) are the families with the most species, respectively. The percentage overlap and abundance categories of the determined taxa were determined, and frequency, dominance and similarity analyses were performed. According to the frequency analysis, P. australis, Cladophora sp., C. demersum, L. trisulca, M. spicatum and P. pectinatus species were frequently observed. According to the dominance analysis, the most dominant taxa were P. australis, L. trisulca, C. demersum, L. gibba, Cladophora sp., P. pectinatus and M. spicatum. According to Sorensen similarity analysis, the highest similarity was detected between the 2nd (GG-1) and 3rd (GG-2), and the lowest similarity was detected between the 4th (SK) and 6th (IG-2) stations. To determine water quality according to macrophytes, macrophyte index (MI) was used at still water stations (GG-1, GG-2, IG-1, IG-2, IG-3, IG-4, IG-5 and IG-6), while biological macrophyte index for rivers (IBMR) and mean trophic rank (MTR) were used at stream stations (DS, SK, BMN and KÇ). Macrophytes were also evaluated according to the macrophyte index scheme (MIS). According to the general means of macrophyte indices, Gökgöl (GG-1 and GG-2) with a value of 3.90, Işıklı Lake (IG-1, IG-2, IG-3, IG-4, IG-5 and IG-6) with a value of 3.79 were determined as polluted water (5th quality) in terms of MI, streams were determined as poor water (4th quality class) in terms of IBMR and eutrophic water (2b quality class) in terms of MTR. During this period, water temperature, electrical conductivity, pH, dissolved oxygen and oxygen saturation,biochemical oxygen demand, nitrate nitrogen, ammonium nitrogen, ortho-phosphate phosphorus, chloride ion, calcium ion, magnesium ion, bicarbonate, total water hardness and turbidity were measured. The measured parameters were evaluated according to the Surface Water Quality Regulation (YSKY), Water Pollution Control Regulation (SKKY), World Health Organization (WHO), European Union (EU), US Environmental Protection Agency (EPA) and Turkish Standards Institute (TS 266) criteria and water quality index (WQI). In addition, the relationships between the parameters were evaluated according to Pearson correlation analysis. According to the evaluation results, the water quality was in compliance with YSKY and SKKY standards, the average pH values were determined to be in accordance with all criteria at GG-1, GG-2 and IG-5 stations, and in IG-3 station, except for WHO and EPA criteria, other parameters were within the reference value range. According to WQI, the wetland was identified as having excellent water quality. In the second period of the study, water, sediment and some macrophytes (Phragmites australis, Myriophyllum spicatum, Ceratophylum demersum) samples were collected from Gökgöl and Işıklı Lake. Temperature, electrical conductivity, pH, dissolved oxygen, oxygen saturation and biochemical oxygen demand values were determined in water. Al, As, Cu, Cr, Fe, Mn, Pb and Zn levels were measured in water, sediment, roots, stems and leaves of P. australis and M. spicatum and in whole C. demersum. The water quality of the wetland was evaluated both by comparing it to national and international standards, including Surface Water Quality Regulation (SWQR), Water Pollution Control Regulation (WPCR), WHO, EU, EPA, and TS 266 criteria, and by employing various indices such as the Water Quality Index (WQI), Heavy Metal Pollution Index (HPI), and Heavy Metal Evaluation Index (HEI). The quality and pollution level of the sediment were assessed by calculating a range of indices, including the Contamination Factor (CF), Contamination Degree (Cd), Modified Contamination Degree (mCd), Enrichment Factor (EF), Geoaccumulation Index (Igeo), Pollution Load Index (PLI), Sediment Quality Guidelines (SQG), Toxic Risk Index (TRI), mean Effect Range Median Quotient (mERM-Q), mean Probable Effect Level Quotient (mPER-Q), Hazard Quotient (HQ), Hazard Index (HI), and Lifetime Cancer Risk (LCR). Additionally, relationships among the parameters measured in water and sediment were analyzed using Pearson correlation analysis. To evaluate the phytoremediation potential of the macrophytes, bioaccumulation factor (BF) and translocation factor (TF) values were calculated. Furthermore, variations in metal concentrations were examined both across plant tissues and among different plant species. The physicochemical parameters and metal concentrations in the wetland water were found to comply with SWQR and WPCR standards; however, levels of Al, As, and Fe in Işıklı Lake exceeded the limits set by other international standards. Based on the WQI, HPI and HEI, the water quality of Gökgöl was classified as low, and Işıklı Lake was deemed unsuitable for drinking purposes. In both lakes, the indices Cd, mCd, Igeo, PLI, TRI, mPER, HI, and LCR were recorded at minimal levels, indicating no significant environmental or health risk. According to EF values, As, Cu, and Zn showed significant enrichment. The SQG suggested that particular attention should be paid to As and Cu levels. Based on the CF moderate contamination with Zn was detected in Işıklı Lake, and mER values indicated a moderate ecological risk associated with As. Phragmites australis was found to accumulate metals primarily in its roots, while Myriophyllum spicatum showed a tendency to translocate metals to its leaves. Ceratophyllum demersum proved effective in directly accumulating metals from the water column. Across all three macrophyte species, Fe and Mn were found at the highest concentrations, whereas Cr and Pb were consistently present at the lowest levels.