Modifikacija metode ocene tveganja za zdravje ljudi na primeru mehčanja pitne vode
doktorska disertacija
Abstract
Uvod: V zadnjem desetletju se pojavlja čedalje več raziskav, katerih izsledki kažejo, da se dnevni vnos fosforja povečuje in da vrednosti precej presegajo priporočene prehranske potrebe. Kronično izpostavljenost visokim koncentracijam fosforja povezujejo s številnimi škodljivimi učinki na zdravje. Eden od t. i. skritih virov fosforja je tudi kemično mehčana pitna voda. Cilj raziskave: Cilj raziskave je bil izdelati oceno tveganja za zdravje ljudi zaradi izpostavljenosti kemičnim mehčalom (natrijev polifosfat) v pitni vodi. Metode: Raziskava je razdeljena na več faz. V prvi fazi je analiza vključevala preiskovanje koncentracij in pogostosti pojavljanja fosfatnih mehčal (kemična analiza vzorcev vroče pitne vode s spektrometrijsko metodo z amonijevim molibdatom) ter ugotavljanje zavedanja uporabnikov o mehčanju pitne vode (anketni vprašalnik). Ker so se vrednosti izmerjenih koncentracij fosfatov na posameznih odjemnih mestih močno razlikovale, je bila na izbranih mestih v nadaljevanju raziskave koncentracija fosfatov spremljana tudi v odvisnosti od časa. Izdelana je bila ocena dnevnega vnosa fosforja z uživanjem kemično mehčane pitne vode za različne scenarije izpostavljenosti. Drugo fazo raziskave prestavlja analiza jedilnikov v šestih različnih ustanovah, s katero je bil ocenjen dnevni vnos fosforja za različne starostne skupine. V tretji fazi je bila s testom na luminiscenčnih bakterijah Vibrio fischeri preverjena morebitna akutna strupenost na vodne mikroorganizme. Z namenom opozoriti na posredna tveganja, ki niso vključena v standardni nabor toksikoloških in ekotoksikoloških testov, je bil v četrti fazi raziskave določen tudi vpliv komercialnega pripravka (natrijev polifosfat) na rast bakterij Legionella pneumophila. Rezultati z diskusijo: Kemična analiza je pokazala, da je bila v skoraj polovici (45 %) odvzetih vzorcev pitne vode (N = 242) potrjena prisotnost fosfatov v koncentracijah od 0,2 do 24,6 mg PO4/L. Hkrati so izsledki analize anketnega vprašalnika pokazali, da večina (70 %) uporabnikov ni seznanjena z izvajanjem kemičnega mehčanja pitne vode, ki jo uživajo. Uživanje kemično mehčane pitne vode sicer predstavlja manjši delež dnevnega vnosa fosforja, vendar pa predvsem zaradi neustreznega deklariranja oziroma (ne)informiranja predstavlja skriti vir fosforja, ki kumulativno prispeva k (pre)visokemu dnevnemu vnosu. Precej večji dnevni vnos fosforja predstavlja vnos fosforja s hrano, pri čemer so priporočene prehranske potrebe precej presežene pri vseh starostnih skupinah. Ekotoksikološki testi so pokazali, da dodani fosfati (komercialni pripravek za mehčanje pitne vode v koncentraciji 3,6 in 39,5 mg PO4/L) precej vplivajo na rast bakterij L. pneumophila, zaznana je povišana rast za 1,28 oziroma 1,19 log CFU/mL. Na podlagi odziva bakterij L. pneumophila v poskusu in vitro je mogoče sklepati, da predstavlja dodani fosfat hranilo, ki pospešuje rast bakterij tudi v vodovodnem sistemu in tako posredno predstavlja dodatno tveganje za zdravje uporabnikov na ta način pripravljene pitne vode. Modificiran pristop ocene tveganja za zdravje na primeru kemičnega mehčanja pitne vode vključuje poleg (i) ocene izpostavljenosti ter (ii) ocene varnih dnevnih odmerkov, temelječih na toksikoloških študijah, tudi (iii) posredne učinke dodanih fosfatov na mikroorganizme, (iv) morebitne aditivne učinke različnih onesnažil v vodi, (v) vpliv fosfatov na absorpcijo hranil v gastrointestinalnem traktu ter (vi) upravljanje s tveganji. Na podlagi predstavljenih izsledkov raziskave je mogoče zaključiti, da tveganje za zdravje zaradi izpostavljenosti fosfatom v pitni vodi ni zanemarljivo.
Keywords
javno zdravje;Slovenia;Slovenija;
Data
| Language: | Slovenian |
|---|---|
| Year of publishing: | 2019 |
| Typology: | 2.08 - Doctoral Dissertation |
| Organization: | UL MF - Faculty of Medicine |
| Publisher: | [G. Jereb] |
| UDC: | 614 |
| COBISS: |
4015124
|
| Views: | 1054 |
| Downloads: | 364 |
| Average score: | 0 (0 votes) |
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Other data
| Secondary language: | English |
|---|---|
| Secondary title: | Modification of the risk assessment methodology in the case of drinking water softeners |
| Secondary abstract: | Introduction: In the last decade, the concerned researchers issued warnings related to high phosphorus daily intake, which significantly exceeds the recommended dietary allowance. Chronic exposure to high daily phosphorus intake is claimed to lead to adverse health effects. One of the so-called hidden sources of phosphorus is also chemically softened drinking water. Aim: The study purpose was to determine the health risk assessment resulting from exposure to chemical softeners (sodium polyphosphate) in the drinking water. Methods: The study is divided into several sections. The analysis was focused on concentrations and frequency of phosphate softeners (chemical analysis of hot water samples with the spectrometric method with ammonium molybdate) and the awareness of consumers about water softening (survey questionnaire). Since concentrations of phosphates at different sampling sites vary substantially, additional analysis was conducted to measure changes in concentration through time. Additionally, the exposure assessment for phosphate in case of consuming chemically softened drinking water was established. The next section of the research presents the analysis of daily menus in six different institutions providing the data on daily phosphorus intake by different age groups. The toxicity test on Vibro fisceri to determine any potential acute toxicity for water microorganisms was conducted. In order to highlight the indirect risks, which are not included in the standard list of toxicity and eco-toxicity tests, the impact of commercial product (sodium polyphosphate) on the growth of Legionella pneumophila was determined. Results and discussion: In nearly half (45 %) of the samples of the drinking water (N = 242), the presence of phosphates was confirmed in concentrations from 0.2 to 24.6 mg PO4/L. The majority of the consumers (70 %) were not aware of the chemical softening of their drinking water. The consumption of chemically softened drinking water presents a minor share of the daily phosphorus intake. However, it should be noted that chemically softened drinking water is one of the hidden sources of phosphorus, which cumulatively adds to its exceeded dietary intake. More important is the phosphorus intake through the consumed food, which significantly exceeds the recommended dietary allowance in nearly all participating groups. The phosphate additives (commercial product for drinking water softening in concentrations 3.6 and 39.5 mg PO4/L) enhance the growth of L. pneumophila by log 1.28 and log 1.19 CFU/mL, respectively. According to the response of the L. pneumophila in vitro, it can be inferred that the added phosphorus promotes the growth of bacteria also in water systems and thus indirectly presents additional threat to the health of consumers. The modified approach to the risk assessment in case of water softening includes (i) exposure assessment, (ii) assessment of safe daily intake, based on toxicity test and also on (iii) indirect impact of the added phosphates on microorganisms, (iv) potential additive effects of various pollutants in water, (v) the impact of phosphates on nutrient absorption in gastro–intestinal tract, and finally (vi) the risk management. The research findings indicate that the health risks deriving from phosphate exposure in drinking water are not negligible. |
| Secondary keywords: | Health knowledge, attitudes, practice;Risk assessment;Methods;Drinking water;Analysis;Microbiology;Water softening;Polyphosphates;Diet;Water pollutants, chemical;Zdravstveno znanje, odnos, praksa;Ocena tveganja;Metode;Pitna voda;Analiza;Mikrobiologija;Mehčanje vode;Polifosfati;Dieta;Kemični onesnaževalci vode; |
| Type (COBISS): | Dissertation |
| Study programme: | 0 |
| Embargo end date (OpenAIRE): | 1970-01-01 |
| Thesis comment: | Univ. Ljubljana, Medicinska fak. |
| Pages: | XVI, 126 str. |
| ID: | 11148146 |
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