Ecology / 6. Ecological monitoring

PhD. Myslyuk O., PhD. Khomenko O., student Zinchenko M.

Cherkasy State Technological University, Ukraine

WATER QUALITY ASSESSMENT OF ZOLOTONOSHKA RIVER

Zolotonoshka river belongs to the Dnipro river basin and is its left first order stream. The complicated water and ecological situation on the river that led to the death of fish several times requires the detailed research, development and implementation of special measures directed at exploring the strength, the character, the sources and the factors of the process.

The purpose of this research is to assess the degree of contamination of water in Zolotonoshka river and the factors of the formation of its hydrochemical state. The assessment of water quality was based on the matching of some indicators of water quality to the normative requirements of maximum permissible concentrations for fishery (MPC_f) and on the contamination coefficient (CC) [1]. The quantitative and qualitative hydrochemical indicators were analyzed based on the results of systematic observations (in spring and autumn) during the period of 2008-2014 that are conducted by sanitary-epidemiological station of the Zolotonosha city on 2 controlled river stations - the river station, that is 1 km upstream Zolotonosha city and the river station, that is 0,5 km downstream Zolotonosha city.

The analysis and generalization of long-term data of monitoring observations showed that there is a systematic excess of the normative values for sulfate ions (1,2-3 MPC_f). The increase of the concentration on the river station located downstream the city is the evidence of anthropogenic impact [2].

The excess of MPC by the ammonium ions content (1,2-6,1 MPC_f) is permanently indicated and is particularly significant on the river station located downstream the city. The high content of ammonium indicates its poor water quality of Zolotonoshka river due to the arrival of insufficiently treated wastewater from sewage treatment plants of Zolotonosha city. The high concentrations of ammonium ion on river station located upstream of the city is probably the result of the land runoff and emission of untreated wastewaters in its upstream (in Drabiv region there are no treatment facilities).

Since 2009 there have been identified the systematic excesses of MPC_f (1,3-28,3 times) by nitrite ion, which is the most toxic of nitrogen compounds and can have detrimental effect on the life of living organisms. The level of water pollution by nitrogen ammonia is repeatedly assessed as unstable, but the high level of water contamination by nitrites is typical and high.

The level of dissolved oxygen, the content of which in the water characterizes the oxygen condition of the water reservoir and determines its ecological and sanitary condition, was found low both on river stations upstream and downstream the city. The oxygen concentration varied in the range of 3,6-4,1 mg/dm³. Biological consumption of oxygen (BOD₅) value exceeded the standard in 1,6-3,3 times.

The excess of MPC_f is also identified by heavy metals, in particular by manganese, iron and copper. Manganese concentration was much higher than the normative (3,5-8 MPC_f). The high concentrations of manganese both on the first and the second river stations are probably the results of the natural factors. The increased concentration of manganese in the water depends significantly on the content of dissolved oxygen. The reduction of the oxygen content in the water up to its complete deficiency leads to a significant increase in the concentration of manganese due to manganese coming from the bottom sediments [3]. The concentration of iron was significantly higher than standard (up to 12 MPC_f) and may be related to both - the natural content of this element in the surface waters, leaching of elements from soil and forest floor, and the anthropogenic influence. The concentration of copper exceeded the standards in 2-6,4 times.

The maximum concentration of oil products (16 MPC_f) was recorded in autumn 2009 on the river station located downstream Zolotonosha city. The water pollution on river stations I and II with oil products is caused by the land runoff and emission of waste waters of industrial facilities. The increase of the concentration of oil products (in 1,2-3,3 times) is observed on river station downstream Zolotonosha city, which is the evidence of the impact of urban agglomeration on water quality in the river.

According to the result of the calculation of the contamination coefficient, the water quality can be assessed as moderately polluted. The value of CC ranges from 2,7 to 4,6. The level of water pollution on the river station downstream Zolotonosha city is generally higher. In autumn, this coefficient increases slightly, that can be explained by natural factors impact such as high temperatures and water-short area in summer, resulting in the decrease of water content and water quality impairment. In 2012, the water content was 45-50% of the annual runoff, in 2013 - 44-47%, in the spring of 2014 - 39-42%. The tendency of CC growth is observed (Fig. 1).

Fig. 1 – The average annual value of contamination coefficient of Zolotonoshka river

The water of Zolotonoshka river is in critical state and loses its natural ability to cleanse itself under significant and growing anthropogenic impact, the level of which is close to the sustainability limit of the system. Taking into consideration the assessment of the formation conditions of the hydrochemical state of the river, we can speak about the significant impact of urban agglomeration.

References

1. Organization and implementation of observations of surface water pollution (in Ministry ecoresources system) КНД211.1.1.106 – Kiev, 2003. – 70 pp.

2. Khomenko O.M., Gajdar I.A. (2010). The analysis of the ecological state of small rivers of the Cherkassy region (on the example of river Zolotonoshka). Journal of Ecological Safety, (2), pp. 39-42.

3. Linnyk P.N., Zezerya V.A., Zubenko I.B., Zubko A.V. (2010). The content and form of the migration of metals in the water of Zaporizhia storage reservoir. Hydrobiological Journal, (4), pp. 97-116.