Dejavniki, ki vplivajo na preživetje Escherichie coli v morskem okolju

diplomska naloga

Gala Jarc (Author), Dušan Žagar (Mentor), Suzana Žižek (Co-mentor)

Abstract

E. coli je termotolerantna koliformna bakterija iz družine Enterobacteriaceae in je vedno prisotna v iztrebkih sesalcev in ptičev. Večina sevov je prisotna tudi v prebavnem traktu ljudi in predstavlja pomemben del naše črevesne flore. E. coli skoraj nikoli ne najdemo v vodi ali tleh, ki niso fekalno onesnažena. V izogib okužbam v morskem okolju oziroma z morsko hrano je potrebno poskrbeti, da oboje ustreza zahtevam - kopalne vode morajo zadostiti minimalnim higienskim zahtevam, v školjkah iz školjčišč pa je določeno najvišje dovoljeno število E. coli. V diplomski nalogi smo se osredotočili na pregled dejavnikov, ki vplivajo na odmiranje E. coli v morski vodi. Za račun spreminjanja koncentracije bakterij s časom je v uporabi Chickov zakon, kjer se koncentracija računa s pomočjo eksponentne stopnje odmiranja. V literaturi smo poiskali enačbo, ki zajema kar največ dejavnikov, vendar pa so ti, zaradi svoje kompleksnosti, omejeni na merljive fizikalne dejavnike. V obravnavanih izvedenkah Mancinijeve enačbe so to intenzivnost sončnega sevanja ter globina, temperatura in slanost vode. Z značilnimi podatki za Tržaški zaliv smo najprej opravili občutljivostno analizo, nato pa z enačbo izračunali stopnjo umrljivosti tudi za realne merjene podatke, ki jih je posredovalo podjetje Harpha Sea d.o.o. Enačba je primerna za vgradnjo v numerične modele, ki so v uporabi na UL FGG. Z izboljšanimi modeli bo mogoče oceniti, kakšna je v slovenskem morju verjetnost onesnaženja kopalnih voda in školjčišč z E. coli.

Keywords

gradbeništvo;diplomska naloga;UNI;B-VOI;Escherichia coli;odmiranje;Mancinijeva enačba;morska voda;Tržaški zaliv;

Data

Language:	Slovenian
Year of publishing:	2014
Typology:	2.11 - Undergraduate Thesis
Organization:	UL FGG - Faculty of Civil and Geodetic Engineering
Publisher:	G. Jarc
UDC:	579.8:628.3(497.4)(043.2)
COBISS:	6782561
Views:	2835
Downloads:	676
Average score:	0 (0 votes)
Metadata:

Other data

Secondary language:	English
Secondary title:	Factors affecting Escherichia coli decay in the marine environment
Secondary abstract:	E. coli is a thermo-tolerant coliform bacterium from the family Enterobacteriaceae present in the faeces of mammals and birds. Most strains can also be found in the human gastrointestinal tract and represent an important part of our intestinal flora. E. coli is rarely found in water or soil without faecal contamination, making it suitable for detecting faecal contamination. To avoid infection in the marine environment or with seafood it is important to ensure that both meet the requirements - bathing water must meet minimum hygiene requirements while shell farms must not surpass the highest allowed number of E. coli in seashells. In this thesis we examined the factors affecting E. coli decay rate in seawater. Chick's law is used to calculate the changes in concentration of bacteria with time, where concentration is calculated using the exponential decay rate. We identified the equation that includes most of the impacts; however, due to the complexity of factors influencing the decay, they are limited to measurable physical factors. In Mancini's equation these are the intensity of solar radiation, water depth, temperature and salinity. With characteristic data for the Gulf of Trieste we first performed a sensitivity analysis, then calculated the decay rate also for the data obtained from the company Harpha Sea d.o.o. The equation is suitable for implementation in numeric models used at UL FGG. With the improved models it will be possible to evaluate the likelihood of pollution in bathing waters and seashell farms in Slovenian waters.
Secondary keywords:	Escherichia coli;decay rate;Mancini's equation;seawater;Gulf of Trieste;
File type:	application/pdf
Type (COBISS):	Bachelor thesis/paper
Thesis comment:	Univ. v Ljubljani, Fak. za gradbeništvo in geodezijo
Pages:	X, 38 str., 2 pril.
ID:	8708243