Unlike the United States and the European Union, developing countries do not have sufficiently structured legal and institutional systems to apply certain environmental management tools such as ecological risk assessment. However, it is important for countries with valuable environmental and ecological resources to have appropriate tools and to strengthen their environmental management capabilities and capacities for the sake of those resources. The case study described in this paper attempts to be a case study towards developing environmental management plans, especially in developing countries. The problem formulation step of Ecological Risk Assessment applied in this study contributed to the basic elements of an environmental management plan including the following: the partnership-building process, prioritization of the problems and issues of the ecosystem, and development of the action plan. Based on the information provided by participants from a series of workshops held to develop an environmental management plan for Uluabat Lake, ecosystem risks were ranked and an action plan was formed. The results obtained with the aid of fuzzy set theory provided a base for identification of the action steps by allowing scientific information to be included in the process. The degree to which Uluabat Lake's problem formulation fits into the existing legal framework of Turkey is also analyzed in this paper.

To examine the status and risk of heavy metal pollution, the distribution of As, Cd, Cr, Ni, and Pb in the sediment of Lake Uluabat was characterized. The present study used a four-stage method to assess the ecotoxicological effects of the heavy metal and trace elements fractions in the sediment of Lake Uluabat. Total Cr and Ni concentrations in the sediment were determined to have exceeded the severe effect level (SEL) limit values. The percentages of the variable fractions of Cr and Ni were below 10%. Because of this reason, they were not defined to have a high risk. The relationships among the physicochemical parameters, heavy metals and trace elements in water and sediment were determined statistically. Pb, Cd, and As in the water were found in relation with some of the fractions. Moreover, it was thought that the amounts of the elements of As releasing into the water might be increased due to their relations with the physicochemical parameters.

A Neural Network (NN) modelling approach has been shown to be successful in calculating pseudo steady state time and space dependent Dissolved Oxygen (DO) concentrations in three separate reservoirs with different characteristics using limited number of input variables. The Levenberg-Marquardt algorithm was adopted during training. Pre-processing before training and post processing after simulation steps were the treatments applied to raw data and predictions respectively. Generalisation was improved and over-fitting problems were eliminated: Early stopping method was applied for improving generalisation. The correlation coefficients between neural network estimates and field measurements were as high as 0.98 for two of the reservoirs with experiments that involve double layer neural network structure with 30 neurons within each hidden layer. A simple one layer neural network structure with 11 neurons has yielded comparable and satisfactorily high correlation coefficients for complete data set, and training, validation and test sets of the third reservoir.

This article presents the results of an investigation carried out on the Nilüfer stream located in the southern part of Marmara region in Turkey 1999-2003. It evaluates water quality and proposes local requirements to prevent aquatic pollution problems. The study took into account the seasonal influences of point and non-point discharges on the organic pollution levels of the stream. The results indicated sub-standard water quality in most parts of the stream. Untreated domestic wastewaters, industrial discharges and agricultural activities contributed to the total annual organic loading. This study reveals the importance of construction, operation, maintenance and legislation of wastewater collection and treatment programmes, as well as the need for strict control of point and non-point nutrient loads for the preservation of the Nilüfer stream's water quality. Appropriate strategies for the control of point and non-point pollution sources, amendments and enforcement of legislation should be developed.

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.