Expanding urban populations, traditional and developing technologies, and intensive agricultural production have greatly increased the amount of wastewater generated in Turkey and many other countries. Levels of contaminants have also grown, including both organic (e.g., pesticides, petroleum hydrocarbons) and inorganic (e.g., metals) chemicals. The wastewater treatment capacity of the region has fallen far short of the level needed to meet the demand of multiple sectors. As a result, untreated and undertreated wastewater enters many streams and rivers, eventually finding its way to a lake [1]. Lake sediment Pol. J. Environ. Stud. Vol. 25, No. 5 (2016), 1937-1946 Original Research Relationships of Heavy Metals in AbstractLake Uluabat is dependent on the RAMSAR Convention (the Convention on Wetlands of International Importance, especially as waterfowl habitat) which was accepted in Iran in 1971 as a member of Living Lakes network carried out by the Global Nature Fund. The lake is very important in terms of biodiversity. Relationships of physicochemical parameters of lakewater and sediment with chemical fractions of heavy metals (chrome and nickel) in lake sediments were investigated in Lake Uluabat in Bursa, Turkey. The concentrations of Cr and Ni forms (dissolved, particulate, total sediment, sediment fractions) and other water and sediment quality parameters were assessed monthly at 10 sampling points between August 2013 and July 2014. The results demonstrate that the concentrations of water and sediment quality parameters undergo monthly changes. The geoaccumulation (Igeo) index has been widely applied to the assessment of sediment contamination. According to this index, Lake Uluabat has moderately polluted sediment. Cr and Ni concentrations in sediment have been determined to be higher than the upper effect threshold according to international standards. Variations of the fractions of Cr and Ni bound to organic matter (F4), residual, and bound to Fe-oxide fractions (F5) were found to be the most dominant forms. Mostly, all forms of Cr and Ni were significantly and positively correlated with pH, electrical conductivity, and suspended solids. The results revealed the importance and the need for strict control of point and non-point pollution loads for the preservation of Lake Uluabat's water and sediment quality.

Lake Uluabat is one of the most important wetlands in Turkey because of its rich biodiversity, lying on a migratory bird route with almost all its shores being covered by submerged plants. The lake has been protected by the Ramsar Convention since 1998. However, the Lake is threatened by natural and anthropogenic stressors as a consequence of its location. Geographic Information System (GIS) analysis is a tool that has been widely used, especially for water quality management in recent years. This study aimed to investigate the water quality and determined most polluted points using GIS analysis of the lake. Temperature, pH, dissolved oxygen, chemical oxygen demand, Kjeldahl nitrogen, total phosphorus, chlorophyll-a, arsenic, boron, iron, and manganese were monitored monthly from June 2008 to May 2009, with the samples taken from 8 points in the lake. Effect of pH, relation of temperature, and Chl-a with other water quality parameters and metals are designated as statistically significant. Data were mapped using ArcGIS 9.1 software and were assessed according to the Turkish Water Pollution Control Regulations (TWPCR). The research also focused on classifying and mapping the water quality in the lake by using the spatial analysis functions of GIS. As a result, it was determined that Lake Uluabat belonged to the 4th class, i.e., highly polluted water, including any water of lower quality. A remarkable portion of the pollution in the water basin was attributed to domestic wastewater discharges, industrial and agricultural activities, and mining.

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The concentrations of Cu, Zn, Pb, Cr, Fe, Mn, and Ni and other sediment quality parameters (percentage of organic matter, calcium carbonate, total carbon, total nitrogen, and total phosphorus) were investigated seasonally in Lake Uluabat (Turkey) sediments (to reveal the sources of biological material and to determine the effect of the settling particle compositions on heavy metal transport. Examination of seasonal variations and correlation coefficients calculated among the parameters showed that settling biological material was an important carrier phase, especially for Cr, Cu, Pb, Fe, and Mn. The metals and nutrients in the lake could come from the same pollution sources. According to the C:N:P ratios of the sediments, it was discovered that biologic materials originated from algae population and domestic and industrial wastewaters. Iron and manganese cycling was also a contributor to trace element transport, while calcium carbonate formations were determined to be inefficient carrier material.

Bu çalışma, kırsal alanlarda potansiyel su ihtiyacının karşılanması maksadı ile yağmur sularının toplanması ve miktarının hesaplanması amacıyla yürütülmüştür. Bu amaçla, Bursa’nın Karacabey İlçesi, Akçasusurluk Köyü’nde bulunan 2000 m2’lik kırsal bir alanda, 300 m2 çatı alanına sahip (200m2 konut+100 m2 otopark) bir konutun çatısından toplanacak yağmur suyu miktarı hesaplanmıştır. Ayrıca, bu yağmur sularının depolanması için gerekli depo hacmi, tarımsal sulamada, toplanan yağmur sularının kullanılması ile gerçekleştirilecek su tasarrufu miktarları hesaplanmıştır. Hesaplamalarda, Bursa’nın uzun yıllar (1928-2020) aylık yağış verileri kullanılmıştır. Sonuç olarak çalışma alanında, yıllık 170,1 m3 su hasadı yapıldığı, alanda tarımsal sulama amacı için ihtiyaç duyulan su miktarının yıllık 109,5 m3, evsel kullanım amacı için ihtiyaç duyulan su miktarının ise 86,4 m3 olduğu tespit edilmiştir. Çalışma alanında ihtiyaç duyulan suyun % 87’si yapılan tarımsal maksatlı su hasadı ile sağlanabilmektedir. Sahip olduğumuz tatlı su kaynaklarının kalite, miktar ve maliyetleri göz önüne alındığında, bu tür alternatif su temin sistemlerinin yaygın kullanımı, su kaynaklarının sürdürülebilirliği açısından büyük önem taşımaktadır.