Temporal variations analyses and predictive modeling of microbiological seawater quality

Darija Vukić Lušić; Lado Kranjčević; Senka Maćešić; Dražen Lušić; Slaven Jozić; Željko Linšak; Lovorka Bilajac; Luka Grbčić; Neiro Bilajac

doi:10.1016/j.watres.2017.04.046

Temporal variations analyses and predictive modeling of microbiological seawater quality

Water Res. 2017 Aug 1:119:160-170. doi: 10.1016/j.watres.2017.04.046. Epub 2017 Apr 21.

Authors

Darija Vukić Lušić¹, Lado Kranjčević², Senka Maćešić³, Dražen Lušić⁴, Slaven Jozić⁵, Željko Linšak⁶, Lovorka Bilajac⁷, Luka Grbčić⁸, Neiro Bilajac⁹

Affiliations

¹ Teaching Institute of Public Health of Primorje-Gorski Kotar County, Department of Environmental Health, Krešimirova 52a, 51 000, Rijeka, Croatia; University of Rijeka, Faculty of Medicine, Department of Environmental Health, Braće Branchetta 20, 51000, Rijeka, Croatia. Electronic address: darija@zzjzpgz.hr.
² University of Rijeka, Faculty of Engineering, Department of Fluid Mechanics and Computational Engineering, Vukovarska 58, 51 000, Rijeka, Croatia. Electronic address: lado.kranjcevic@riteh.hr.
³ University of Rijeka, Faculty of Engineering, Departments of Mathematics, Physics, Foreign Languages and Kinesiology, Vukovarska 58, 51 000, Rijeka, Croatia. Electronic address: senka.macesic@riteh.hr.
⁴ University of Rijeka, Faculty of Medicine, Department of Environmental Health, Braće Branchetta 20, 51000, Rijeka, Croatia. Electronic address: drazen.lusic@medri.uniri.hr.
⁵ Institute of Oceanography and Fisheries, POB 500, 21000, Split, Croatia. Electronic address: sjozic@izor.hr.
⁶ Teaching Institute of Public Health of Primorje-Gorski Kotar County, Krešimirova 52a, 51 000, Rijeka, Croatia; University of Rijeka, Faculty of Medicine, Department of Environmental Health, Braće Branchetta 20, 51000, Rijeka, Croatia. Electronic address: zeljko.linsak@zzjzpgz.hr.
⁷ University of Rijeka, Faculty of Medicine, Department of Social Medicine and Epidemiology, Braće Branchetta 20, 51000, Rijeka, Croatia; Teaching Institute of Public Health of Primorje-Gorski Kotar County, Branch Office Opatija, Stube dr. V. Ekl 1, 51 410, Opatija, Croatia. Electronic address: lovorka.bilajac@medri.uniri.hr.
⁸ University of Rijeka, Faculty of Engineering, Department of Fluid Mechanics and Computational Engineering, Vukovarska 58, 51 000, Rijeka, Croatia. Electronic address: luka.grbcic@riteh.hr.
⁹ University of Rijeka, Faculty of Medicine, Department of Environmental Health, Braće Branchetta 20, 51000, Rijeka, Croatia. Electronic address: neiro.bilajac23@gmail.com.

PMID: 28456079
DOI: 10.1016/j.watres.2017.04.046

Abstract

Bathing water quality is a major public health issue, especially for tourism-oriented regions. Currently used methods within EU allow at least a 2.2 day period for obtaining the analytical results, making outdated the information forwarded to the public. Obtained results and beach assessment are influenced by the temporal and spatial characteristics of sample collection, and numerous environmental parameters, as well as by differences of official water standards. This paper examines the temporal variation of microbiological parameters during the day, as well as the influence of the sampling hour, on decision processes in the management of the beach. Apart from the fecal indicators stipulated by the EU Bathing Water Directive (E. coli and enterococci), additional fecal (C. perfringens) and non-fecal (S. aureus and P. aeriginosa) parameters were analyzed. Moreover, the effects of applying different evaluation criteria (national, EU and U.S. EPA) to beach ranking were studied, and the most common reasons for exceeding water-quality standards were investigated. In order to upgrade routine monitoring, a predictive statistical model was developed. The highest concentrations of fecal indicators were recorded early in the morning (6 AM) due to the lack of solar radiation during the night period. When compared to enterococci, E. coli criteria appears to be more stringent for the detection of fecal pollution. In comparison to EU and U.S. EPA criteria, Croatian national evaluation criteria provide stricter public health standards. Solar radiation and precipitation were the predominant environmental parameters affecting beach water quality, and these parameters were included in the predictive model setup. Predictive models revealed great potential for the monitoring of recreational water bodies, and with further development can become a useful tool for the improvement of public health protection.

Keywords: Bathing water quality; E. coli; Evaluation criteria; Microbiological parameters; Predictive models; Temporal variations.

MeSH terms

Bathing Beaches*
Environmental Monitoring
Escherichia coli*
Humans
Seawater
Staphylococcus aureus
Time Factors
Water Microbiology
Water Quality*