Drinking Water Quality and Occurrence of Giardia in Finnish Small Groundwater Supplies

Tarja Pitkänen,Ilkka Miettinen,Kirsti Lahti,Tiina Juselius,Eija Isomäki,Matti Valve,Anna-Liisa Kivimäki,Marja-Liisa Hänninen

doi:10.3390/resources4030637

Abstract

The microbiological and chemical drinking water quality of 20 vulnerable Finnish small groundwater supplies was studied in relation to environmental risk factors associated with potential sources of contamination. The microbiological parameters analyzed included the following enteric pathogens: Giardia and Cryptosporidium, Campylobacter species, noroviruses, as well as indicator microbes (Escherichia coli, intestinal enterococci, coliform bacteria, Clostridium perfringens, Aeromonas spp. and heterotrophic bacteria). Chemical analyses included the determination of pH, conductivity, TOC, color, turbidity, and phosphorus, nitrate and nitrite nitrogen, iron, and manganese concentrations. Giardia intestinalis was detected from four of the water supplies, all of which had wastewater treatment activities in the neighborhood. Mesophilic Aeromonas salmonicida, coliform bacteria and E. coli were also detected. None of the samples were positive for both coliforms and Giardia. Low pH and high iron and manganese concentrations in some samples compromised the water quality. Giardia intestinalis was isolated for the first time in Finland in groundwater wells of public water works. In Europe, small water supplies are of great importance since they serve a significant sector of the population. In our study, the presence of fecal indicator bacteria, Aeromonas and Giardia revealed surface water access to the wells and health risks associated with small water supplies.

Highlights

Small drinking water supplies that provide water to small communities are an important public health issue because they are often vulnerable and may cause microbiological or chemical quality-associated health risks to the water consumers [1,2]
The definition of a small drinking water supply varies in Europe and in the United States
Due to the lack of exact recovery rates of the method used, we cannot rule out the possibility of false negative results in the Giardia and Cryptosporidium analysis

Summary

Introduction

Small drinking water supplies that provide water to small communities are an important public health issue because they are often vulnerable and may cause microbiological or chemical quality-associated health risks to the water consumers [1,2]. Even if the number of users in a supply is low, the total number of these supplies is high, and they often constitute the major water supplies, especially in rural areas. Estimates indicate that approximately 500 of these supplies serve fewer than 500 consumers in their distribution area and are, defined as small water supplies [4]. Most small water supplies are owned by cooperatives with operators who are often community members who work part-time, usually with no required professional training in the management of a water supply. Small Finnish water supplies with fewer than 50 users (or with a water distribution of less than m3 per day) are controlled by local health authorities according to the Decree of the Finnish

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