INDOOR ENVIRONMENT QUALITY EVALUATION IN DWELLINGS: A POLISH CASE STUDY

S t r e s z c z e n i e Celem pracy jest przedstawienie problemu jakości wód podziemnych na obszarach wiejskich i jej wpływu na funkcjonowanie niewielkich systemów zaopatrzenia w wodę. W pracy obszernie przedstawiono czynniki, istotne dla jakości ujmowanych wód podziemnych na terenach wiejskich oraz ukazano specyfikę eksploatacji niewielkich systemów wodociągowych. Przedstawiono wyniki badań parametrów jakościowych wód podziemnych, uzyskane w latach 2012÷2016 dla wybranych ujęć wiejskich w północno-zachodniej Polsce. Jakość tych wód w analizowanych latach ulegała pogorszeniu, w szczególności stwierdzono wzrost stężeń związków żelaza i manganu, azotanów, jonu amonowego, a także obecność zanieczyszczeń bakteriologicznych. Z tych względów w opisywanych ujęciach odnotowano problemy z zapewnieniem odbiorcom wody o odpowiedniej jakości. W pracy podjęto próbę ukazania zależności między rodzajem i wielkością zmian jakości wody a skutecznością jej uzdatniania, ponadto odniesiono się do działań projakościowych, podejmowanych przez lokalne przedsiębiorstwa wodociągowe. K e y w o r d s : Drinking water; Groundwater quality; Rural areas; Water intakes; Water supply systems. 4/2017 A R C H I T E C T U R E C I V I L E N G I N E E R I N G E N V I R O N M E N T 153 A R C H I T E C T U R E C I V I L E N G I N E E R I N G E N V I R O N M E N T The Si les ian Univers i ty of Technology No. 4/2017 R . N o w a k , A . I m p e r o w i c z P a w l a c z y k 154 A R C H I T E C T U R E C I V I L E N G I N E E R I N G E N V I R O N M E N T 4/2017 amount of wastewater produced. Unfortunately, the construction of collective sewerage and treatment systems has not kept pace with the construction of water supply systems [2]. In rural areas, sewage is generally directed to cesspits, but also to rivers and ponds, often directly to the aerating zone. This results in contamination of the receiving water and land. Sometimes this contamination makes it impossible to use local water resources [3, 4]. Land use also affects the qualitative and quantitative status of groundwater resources. Point sources of hazardous chemicals are particularly important [5]. For these reasons, water management in rural areas should be related to the protection of the quality and quantity of water resources. In this area, there is a need for the development of scientific research. This research should aim to explain the impact of farming activities, biological progresses, agro-technical methods, land use, etc. on local groundwater and surface water resources. [6]. Intensive and long-term investment in the resources and protection of groundwater quality are also urgently needed [7]. In this work, attention has been paid to the problem of groundwater quality, which is the main source of supply of drinking water for rural inhabitants. The example of selected rural intakes shows the impact of the quality and quantity of available water resources on the functioning of small water supply systems. 2. FACTORS THAT SHAPE GROUNDWATER QUALITY IN RURAL AREAS In the case of residents of rural areas, the drinking water supply is most often provided through small systems, based on groundwater intakes. In such systems, cases of supplying water with unstable quality parameters are more frequently reported. These problems are often associated with the state of local groundwater resources. The deteriorating quality of groundwater may have natural causes, but there are mainly anthropogenic factors. The release and migration of pollutants from surface sources (in particular, cultivation and fertilization of soil and animal breeding) and on-farm activities in rural areas should be mentioned here [8]. For these reasons, aquifers are susceptible to landfill and waste water discharges due to the development of housing and the intensification of agriculture. Important factors for the quality of groundwater are considered: the management of organic and mineral fertilizers and compliance with sanitary regulations concerning the establishment of direct protection zones around water intakes. Problems in this area are present both in Poland and in many other regions of the world [9, 10, 11]. It should be noted that as a result of administrative decisions taken in Poland in 2010, zones of protection of groundwater intakes have been lost, resulting in the degradation of water resources [12]. The causes of deterioration of groundwater quality may be due to changes in the water circulation system, hydrogeochemical changes and the impact of pollutants. Increases in Fe and Mn concentrations may be due to changes in the water circulation system caused by the mixing of waters from various hydrogeochemical environments (often as well as Fe and Mn, ammonium nitrate levels, for example, may also increase). The greatest changes in water quality occur as a result of the lowering of the water table during the operation and activation of oxidation processes of sulfides and organic substances. Impacts of anthropogenic impurities are most likely to occur in open and poorly insulated aquifers [13]. An important factor influencing water quality in a given area can be hydrogeochemical changes in the conditions where water is abstracted. Under such conditions, increased levels of nitrates and sulphates can occur in water. Differentiated distribution of nitrate concentrations in the water from rural wells is a result of land development. Sometimes, as a result of hydrogeochemical changes, the chlorine concentration, which is an indicator of anthropogenic pollutants, may also increase [8]. Chloride concentration is highest in waters exposed to pollution from domestic sources. The lowest concentrations are recorded in water in the least populated and non-agricultural areas. Chlorides, by their conservative properties, allow the tracking of the speed and direction of movement of both the water and the substances present therein. However, in the studies on water quality in rural areas, chloride concentrations are often not taken into account. The potential of the data received to identify the sources and fates of substances that negatively affect water quality is also not used [14]. There may be significant degradation in the quality of groundwater due to the impact of pollutants, both large and small, linear and point. Potential foci of pollutants affecting the chemistry and quality of groundwater may be located in areas of intensive farming, in areas without collective sewerage and in the vicinity of waste water discharges. This is also true FACTORS AFFECTING GROUNDWATER QUALITY IN THE CONTEXT OF THE EXPLOITATION OF SMALL DRINKING WATER INTAKES E N V I R O N M E N T e 4/2017 A R C H I T E C T U R E C I V I L E N G I N E E R I N G E N V I R O N M E N T 155 in areas in which breeding farms, factories and petrol stations are situated. The quality of water can also be affected by industrial and municipal landfills [15]. Among the pollutants of groundwater, organic pollutants, including pesticides, should be mentioned. Groundwater susceptibility to these types of impurities depends on natural factors (soils, climate and the hydrology) and the properties of the pesticides [16]. Nitrogen compounds, in particular ammonium and nitrates, are basic indicators of the quality of groundwater. The origin of ammonium ions in water can be both natural and anthropogenic. The requirement for low concentrations of these ions in drinking water is primarily due to health reasons. It should be noted that excessive amounts thereof can also lead to secondary pollution of the water (through oxygen consumption and the development of anaerobic bacteria). Detection of ammonium ions in groundwater, where these ions have not previously been identified, most often means contamination of these waters with sewage. This applies particularly to areas of intensive livestock farming, agricultural crops or landfills. Counteracting and reducing the impact of point sources of pollution (mainly those associated with animal production) on rural areas must be associated with monitoring these contaminants [17]. It should be noted that increased concentrations of fertilizer components (nitrates or ammonium ions) can endure in contaminated water for a long time, even if commercial farming has been abandoned and farming or breeding is only carried out for personal use [18]. Near point contamination sources, there is a significant variation of the vertical water chemistry, especially in the first (subsurface) aquifer. Identification of processes that shape the subsurface aquifer chemistry may be based on multivariate analysis of the factor. The analysis should take into account a number of data: water chemistry, hydrogeological conditions and forms of land use [19]. In the migration of pollutants, the thickness of the soil layer and the thickness of the aeration zone play a significant role [20, 21]. The large vertical variation of the chemical composition of groundwater in the first aquifer has been demonstrated in hydrogeological research [22]. The removal of chemicals from the aeration zone has been observed, particularly with an increase in the depth of sampling the concentration of nitrates, nitrites, sodium and potassium has decreased. The inverse dependence was noted for the concentration of silica, iron and manganese, i.e., ions, penetrating into groundwater due to long-term interaction: the rock-groundwater. In water in rural areas, as opposed to sewerage areas, the concentration of nitrate nitrogen was higher than the concentration of nitrite nitrogen, which occurred in each aquifer. This relationship was observed in each aquifer and indicates that there are conditions that allow a faster transition of nitrogen compounds to oxidized forms (nitrate nitrogen). This occurrence may be augmented by other sources of pollution, for example, farming (agricultural fertilization, animal breeding) or poorly developed sewerage infrastructure [21]. Among the factors that a