190 Annales Universitatis Paedagogicae Cracoviensis Studia Naturae, 1: 190–195, 2016, ISSN 2543-8832 Magdalena Greczek-Stachura*, Patrycja Zagata-Leśnicka, Mateusz Ślęczka Institute of Biology, Pedagogical University of Kraków, Podchorążych 2, 30-084 Kraków, Poland, *magresta@wp.pl Analysis of the coliform in the Wilga River (southern Poland) Introduction �e progressive development of industry, as well as the cities suburbanisation cause inevitable damages to the environment. �ese damages are related to water and soil pollution. Only 2% of surface waters in Poland belong to the �rst class purity. �e rest of water bodies is named as waters of poor quality. �e water pollution is caused usually by industrial wastewater and municipal sewage, which are directly discharged into rivers. Furthermore, pre-treated wastewater in industrial facilities is also the fac- tor leading to the environmental pollution (Rozporządzenie Ministra Środowiska…, 2004). �e pollutions of drinking water are caused by the occurrence of leaky septic tanks or by direct sewage discharging into watercourses and the surface areas. �e sewages seep through the ground and a�er that they are present in groundwater. �e ground- water should be pure, however, results of the monitoring carried out in the nineties of the twentieth century revealed, that water bodies are not included in the �rst class purity. �e microbiological contamination of the surface waters can cause food poi- soning of water consumers. Moreover, it is responsible for �sh diseases, which in result are not suitable for consumption. �us, the monitoring of drinking water intakes, as well as smaller watercourses is indispensable (George et al., 2002; Pant, Mittal, 2007; Hendricks, Pool, 2012; Budzińska et al., 2014). �e Wilga River is the right tributary of the Vistula River �owing through Kraków with the length of 11.5 km. �e total length of the river is 21.4 km and its spring is located in the north-eastern part of the Wieliczka Foothills in Pawlikowice (List of names…). �e middle course of the river is a part which strongly meanders and the �nal stretch has been dug up and straightened. In the part from Swoszowice to Kraków, Wilga �ows within the built-up area. �e catchment of the river is located in the rural area. �e banks in the upper and middle courses are covered with alluvial 191 A nalysis of the coliform in the W ilga R iver (southern P oland) forests. �ese forests give way to grassy �ora in Kraków. �e Wilga River is relative- ly short comparing to other rivers of Wieliczka Foothills, but it is characterised by trough characteristic to mountain rivers with swi� stream and rocky riverbed and by deep trough which occurs in lowland rivers with slow stream. Wilga belongs to the most polluted rivers in Kraków (Ocena jakości wód…, 2004). �e contaminations were mainly due to the occurrence of former industrial facilities in the IX district – Łagiewniki (Soda Solvay Factory). �e microbiological tests of wa- ter coliforms (the smallest volume of water with detected Escherichia coli T. Escherich) in di�erent locations along Wilga. �is test is a basic method to indicate the presence of sewage in watercourses based on the appearance of a bubble in Durham tube. �e bubble is the e�ect of the fermentation of lactose by E. coli. �e samples were collected from 16 locations along the Wilga River from the spring in Raciborsko up to Podgórze in Kraków (Fig. 1). In places of sampling we measured water parameters like temperature and pH. �e samples were initially diluted tenfold with physiological saline and a�er that the 1 cm3 of water was transferred to the test tube (with Durham tubes inside) with broth enriched with 1% lactose. Experiments were conducted for samples with di�er- ent water dilutions (1:10, 1:100, 1:1000, 1:10 000, 1:100 000). A�er 24 hours of incuba- Fig. 1. Map of sampling locations along the Wilga River 192 M ag da le na G re cz ek -S ta ch ur a, P at ry cj a Za ga ta -L eś ni ck a, M at eu sz Ś lę cz ka tion at the temperature of 37°C the occurrence of broth turbidity and the presence of bubble in Durham tubes were observed. Experiments were conducted during the hot summer of 2014. Air temperatures were above 30°C and water temperatures ranged from 15 to 21°C. �e temperature of upper river course reached 19°C. �e low temperature of water is usually due to the swi� stream in upper course. In the middle course, with slower stream, the temper- atures reached 20°C. �e highest temperature of water we measured in the mouth of the Wilga River was 21°C which was correlated to slow stream high exposure to solar radiation as well as Vistula backwaters. We detected the purest water in the middle course of the Wilga River (in Janowice and Sygneczów) (Fig. 2). �ere are no farm buildings near the river trough and river �ows fast. �e coliform was 1 which indicates that the water is not suitable to drink according to Whipple scale. Even at the spring of the Wilga River there was no microbiologically pure water. �e value of coliform reached 0.1 and the contamination is caused by the presence of public toilet for inhabitants of the neighbouring plot near the river. �e coliform of 0.1 was measured in 6 samples collected from: Pawlikowice, Raciborsko (ponds), Wrząsowice (near the bar “Wilga”), Swoszowice (near the boundaries of Kraków), Opatkowice and Łagiewniki (near the Sanctuary of Divine Mercy). �ere are courses of swi� stream in each of mentioned locations. �erefore, these courses should be well Fig. 2. �e values of coliform of water collected from di�erent locations: 1 – river spring, 2 – Raciborsko pounds, 3 – Raciborsko 2, 4 – Pawlikowice, 5 – Janowice, 6 – Sygneczów, 7 – Gołkowice, 8 – Wilga bar, 9 – Swoszowice G.M., 10 – Opatkowice, 11 – Swoszowice, 12 – Sanctuary of Divine Mercy, 13 – Zako- piańska street, 14 – Kopty forest, 15 – Mateczny roundabout, 16 – river mouth 193 A nalysis of the coliform in the W ilga R iver (southern P oland) oxygenated and relatively cool (even a few degrees colder) (Fig. 3). �ese locations are characterised by scattered buildings, the blanks are covered with meadows or even trees. �ere are neither farms near the river nor sewage discharge into the river. �us, the river reveals better microbiological parameters. �e Wilga River tends to self-clean. It can be observed at the stretch: Janowice – Sygneczów – Gołkowice as well as at the stretch: Swoszowice – Łagiewniki. We can suppose that if there were neither direct nor indirect discharges of the sewage into water, the river would reveal a signi�cant tendency to self-clean. �e rivers self-clean- ing process is long-term, therefore, if there is a large amount of sewage discharge, the process is inhibited and hard to observe. �e Wilga River is arti�cially regulated to avoid �ood of the river at the stretch from Kraków up to the river mouth. �e most polluted part of the Wilga River is located near to the Mateczny roundabout – coliform of 1:10 000. �e second most polluted area was located at the mouth of the river: 1:100. �ese two stretches are characterised by slow stream and high temperature of water reaching 21°C. �ere is a sewer pipe near to the Health Resort with residue of the sewage sludge deposited on the grid protecting the river banks against lateral erosion. We also observed a lot of water birds – mainly ducks looking for food. �e pH of water samples collected from the Wilga River is alkaline and it oscillates within 8.0–8.2, which is correlated with the type of substrate that river �ows through. Fig. 3. �e temperature of water [°C] measured in 16 locations of sampling along the Wilga River: 1 – river spring, 2 – Raciborsko pounds, 3 – Raciborsko 2, 4 – Pawlikowice, 5 – Janowice, 6 – Sygneczów, 7 – Gołkowice, 8 – Wilga bar, 9 – Swoszowice G.M., 10 – Opatkowice, 11 – Swoszowice, 12 – Sanctuary of Divine Mercy, 13 – Zakopiańska street, 14 – Kopty forest, 15 – Mateczny roundabout, 16 – river mouth 194 M ag da le na G re cz ek -S ta ch ur a, P at ry cj a Za ga ta -L eś ni ck a, M at eu sz Ś lę cz ka �e Wilga River valley is cut in Miocene schists and covered with quaternary sands (Łojan, 2008). Up to the mouth of the Krzywica stream in Swoszowice, the Wilga River catchment is covered with loess soil and the Tertiary �ysch layers beneath them consisting of shale, marl, sandstone and chalk layer. �e pH of water has an in�uence on water microorganism variety. �ese organ- isms require the water of neutral pH, but they also have an ability to adapt to the new environmental conditions, when water changes pH into weakly acid or alkaline (Pawlaczyk-Szpilowa, 1978). Rapid pH changes of surface waters are mainly due to discharge of some industrial sewage without their pre-neutralisation. �e main cause of high values of coliform is discharge of large amount of sewage into the river, as well as the fertilisation of farmlands with manure which get into the soil and are washed down by rain into the river. �e surface waters contaminations by pathogenic bacteria, originating from both the sewage discharge and the sewage in�ltration into the ground waters are serious problems. �e purity of surface waters should be considered as poor. �ere is only 2% of rivers and lakes waters that ful�l the requirements for the �rst class purity (Libud- zisz, Kowal, 2000). Microbiological quality of waters a�ects the quality of raw mate- rials and the food products with aquatic originating. Waters that are polluted by bac- teria belonging to the coli group are neither suitable to drink nor even to recreational purposes use. Even minor contaminations of water by coli bacteria poses a risk of causing illnesses or even epidemics among people (Langergraber, Muellegger, 2005). References Budzińska, K., Szejniuk, B., Jurek, A., Traczykowski, A., Michalska, M., Berleć, K. (2014). E�ectiveness of removing microbial pollutants from wastewater by the activated sludge method. Environment Protec- tion Engineering, 40, 53–67. DOI: 10.5277/epe140405 George, I., Crop, P., Servai, P. (2002). Faecal removal in wastewater treatment plants studied by plate counts and enzymatic methods. Water Research, 36, 2601–2617. DOI: 10.1016/S0043-1354(01)00475-4 Hendricks, R., Pool, E.J. (2012). �e e�ectiveness of sewage treatment processes to remove faecal path- ogens and antibiotic residues. Journal of Environmental Science and Health, 47, 289–297. DOI: 10.1080/10934529.2012.637432 Langergraber, G., Muellegger, E. (2005). Ecological Sanitation – a way to solve global sanitation prob- lems?, Evironmental International, 31, 433–444. DOI: 10,1016/j.envint.2004.08.006 Libudzisz, Z., Kowal, K. (2000). Mikrobiologia techniczna. Tom 1. Łódź: Wydawnictwo Politechniki Łódzkiej. [In Polish] List of names of �owing waters. Nazewnictwo geogra�czne Polski. Tom 1, Hydronimy. Część 1. Wody płynące, źródła, wodospady, Główny Urząd Geodezji i Kartogra�i. http://ksng.gugik.gov.pl/pliki/ hydronimy1.pdf. [In Polish] Łojan, E. (2000). Wpływ składników mineralnych na geochemię metali ciężkich w osadach dennych rzeki Wilgi. Kraków: Akademia Górniczo-Hutnicza im. Stanisława Staszica. [In Polish] Pant, A., Mittal, A.K. (2007). Disinfection of wastewater: Comparative evaluation of chlorination and DHS-biotower. Journal of Environmental Biology, 28(4), 717–722. 195 A nalysis of the coliform in the W ilga R iver (southern P oland) Pawlaczyk-Szpilowa, M. (1978). Mikrobiologia wody i ścieków. Warszawa: Wydawnictwo Naukowe PWN. [In Polish] Rozporządzenie Ministra Środowiska z dnia 11 lutego 2004 r. w sprawie klasy�kacji dla prezentowania stanu wód powierzchniowych i podziemnych, sposobu prowadzenia monitoringu oraz sposobu interpre- tacji wyników i prezentacji stanu tych wód. Dz. U. Z 2004 r. Nr 32, poz. 284. [In Polish] Wojewódzki Inspektorat Ochrony Środowiska w Krakowie. (2004) Ocena jakości wód powierzchniowych w województwie małopolskim w 2004 roku. [In Polish] Analiza form coli w rzece Wildze (południowa Polska) Streszczenie Rzeka Wilga należy do najbardziej zanieczyszczonych rzek w Krakowie. Zanieczyszczenie tej rzeki wynika głównie z obecności obiektów przemysłowych w jej pobliżu. Analizy miana coli w próbkach wody pobra- nych w 16 miejscach (począwszy od źródła rzeki w Raciborsku, aż do Podgórza w Krakowie) wzdłuż rzeki przeprowadzone zostały w 2014 roku. Analiza ta jest podstawową metodą służącą do wykazania obecności ścieków w ciekach wodnych i jest oparta na pojawieniu się pęcherzyka powietrza w rurce Durhama, co z kolei jest efektem fermentacji laktozy prowadzonej przez bakterie Escherichia coli. Wodę o największej czystości wykazano w środkowym biegu rzeki, gdzie zaobserwowano szybki nurt oraz brak zabudowań gospodarczych w pobliżu rzeki. Wodę złej jakości stwierdzono nawet przy źródle rzeki, gdzie miano coli wy- nosiło 0,1. Wilga wykazuje tendencję do samooczyszczania się, co można było zaobserwować na odcinkach: Janowice – Sygneczów – Gołkowice oraz Swoszowice – Łagiewniki. Rzeka ta wykazałaby sporą tendencję do samooczyszczania się w przypadku braku ścieków odprowadzanych w sposób pośredni i bezpośredni. Samooczyszczanie się rzek jest procesem długotrwałym, dlatego przy znacznym dopływie ścieków proces ten jest hamowany i przez to trudny do zaobserwowania. Key words: coliform, Escherichia coli, water contaminations, Wilga River Received: [2016.09.02] Accepted: [2016.10.25]