Revaluation of the health risk assessment associated with exposure to chloroform as a disinfection by-product in conventional freshwater indoor swimming pools

Uvod: Za uporabnike dvoranskih bazenov je kloroform zdravstveno problematičen saj ga mednarodna agencija za raziskovanje raka uvršča v skupino 2B, kot mogoče kancerogen za človeka. V dvoranskih bazenih obstajajo tri glavne poti izpostavljenosti kloroformu: (1) ingestija bazenske vode, (2) inhalacija zraku dvoranskega bazena in (3) dermalni kontakt z absorpcijo preko kože. Namen: Namen magistrskega dela je predstaviti oceno tveganja za zdravje zaradi dolgodobne izpostavljenosti kloroformu na primeru dvoranskih bazenov s sladko vodo, ki kot sredstvo za dezinfekcijo uporabljajo klorovo sredstvo in iz katerega se nato tvori kloroform. Metode dela: Izvedli smo oceno tveganja za kloroform na primeru dvoranskega bazena s sladko vodo, kjer se kot sredstvo za dezinfekcijo uporablja klorovo sredstvo. Na podlagi razpoložljivih podatkov smo ovrednotili vse 4 faze ocene tveganja: (1) identifikacijo dejavnika tveganja, (2) analiziali nevarnost kemikalije, (3) ocenili odziv na odmerek, (4) ocenili izpostavljenost ter določili tveganje ob različnih scenarijih izpostavljenosti po mednarodno uveljavljeni metodologiji, ki smo jo v določenih vsebinah smiselno modificirali. Rezultati: Ugotovili smo, da je tveganje pri vseh scenarijih inhalacijske izpostavljenosti kloroformu bistveno večje kot tveganje zaradi ingestije bazenske vode ali absorpcije kloroforma preko kože. Izračunana tveganja so bila pri vseh scenarijih za inhalacijsko izpostavljenost večja od sprejemljivega tveganja, kot to dopušča Svetovna zdravstvena organizacija (tveganje 1/100.000), izračunano tveganje je bilo najvišje pri tekmovalnih plavalcih. Kadar smo za izračun pri scenariju izpostavljenosti tekmovalnim plavalcem uporabili podatke realnih meritev koncentracij kloroforma v bazenski vodi in v zraku dvoranskega bazena tik nad vodno gladino smo ugotovili, da je bilo tveganje za več kot 1000x večje od še sprejemljivega tveganja. Razprava in zaključek: Rezultati izračunov tveganj zaradi izpostavljenosti kloroformu ob različnih scenarijih izpostavljenosti uporabnikov dvoranskih bazenov kažejo, da je tveganje zaradi inhalacije v slovenskih konvencionalnih dvoranskih bazenih s sladko vodo še posebej problematično. V bodoče bo potrebno bolje preučiti in nadzorovati kemična tveganja v dvoranskih bazenih, s poudarkom na zmanjševanju tveganj, povzročenih s kloroformom, trihalometani ali ostalimi stranskimi produkti kloriranja. To pa ne pomeni, da se lahko zanemari nadzor nad mikrobiološkimi in ostalimi tveganji v dvoranskih bazenih. Predlagamo, da se problematika kloroforma ne rešuje zgolj z nadzorom nad koncentracijo celokupnih trihalometanov v bazenski vodi, temveč naj se v bodoče opravlja tudi nadzor nad koncentracijami trihalometanov v zraku dvoranskih bazenov.Introduction: Human exposure to chloroform in indoor swimming pools has been recognized as a potential health concern by the International agency for research on cancer because it is classified into group 2B as possibly carcinogenic for humans. There are three main routes of exposure to chloroform in the indoor swimming pools: (1) ingestion of swimming pool water, (2) inhalation of the indoor pool air, and (3) dermal contact and absorption through the skin. Purpose: The purpose of the master\u27s thesis is to prepare a health risk assessment for long-term exposure to chloroform in freshwater indoor swimming pools which use chlorine as a disinfectant from which the chloroform is formed. Methods: We carried out a risk assessment for chloroform in the case of a freshwater indoor swimming pool where chlorine is used as a disinfectant. Based on the available data, we evaluated all 4 stages of the risk assessment: (1) hazard identification, (2) hazard characterization, (3) dose-response assessment, (4) exposure assessment and risk characterization under the different exposure scenarios according to the internationally established methodology, which was modified in certain contents in a meaningful way. Results: We found that the risk in all scenarios for inhalation exposure to chloroform is significantly higher than the risk due to water ingestion or absorption through the skin. In all scenarios for inhalation exposure, the calculated risks were greater than the acceptable risk, as suggested by the World health organization (1/100,000), the calculated risk was highest for competitive swimmers. When calculating the exposure scenario for competitive swimmers, when real-time measurements of chloroform concentrations in swimming pool water and in the air of the indoor swimming pool just above the water surface was used, we found that the risk was more than 1000x greater than the acceptable risk. Discussion and conclusion: The results of calculated risks due to exposure to chloroform under different exposure scenarios of indoor swimming pool users show that the inhalation risks in Slovenian conventional freshwater indoor swimming pools is particularly problematic. In the future, it will be necessary to better examine and control the chemical risks in the indoor swimming pools, with the focus on methods aimed to reduce the risks of exposure to chloroform, trihalomethanes or other chlorination by-products. This does not mean that control of microbiological and other health risks in the indoor swimming pools should be ignored. We suggest that the problem of chloroform is not solved solely by controlling the concentration of total trihalomethanes in swimming pool water, but in the future also the controlling of the trihlomethanes concentration in the indoor swimming pool air should be carried out by certified companies

Pollutants in air, water and food, oxidative stress and antioxidants

Prosti radikali oz. reaktivne kisikove zvrsti (RKZ) endogenega izvora so stranski produkt oksidativne fosforilacije, kjer se energija iz hrane in kisik pretvarjata v ogljikov dioksid, vodo in energijo. V mitohondrijih poteka redukcija molekule kisika v vodo v verigi prenosa štirih elektronov. Ta proces ni idealen, ker med procesom elektronskega verižnega transporta pri oksidativni fosforilaciji iz mitohondrijev “uhajajo” stranski produkti v citosol. Na ta proces žal nimamo vpliva. Drugi vzrok izpostavljenosti organizma RKZ pa je okolje v katerem živimo. Neprestano smo izpostavljeni oksidantom iz okolja, kot so: ozon, dušikovi oksidi, ionizirajoče in UV- sevanje, pesticidi, alkoholi, stranski produkti dezinfekcije vode s klorom, tobačni dim, itd. Na eksogeno izpostavljenost RKZ imamo delni vpliv: (i) lahko se umaknemo v okolje, kjer je manjša koncentracija okoljskih onesnažil, (ii) zaščitimo se lahko s povečanim vnosom antioksidantov. V prispevku bomo predstavili ali se je smiselno z antioksidanti zaščititi pred tistimi okoljskimi onesnažili, ki vplivajo na povečan oksidativni stres organizma.Free radicals and other reactive oxygen species (ROS) are manly formed endogenously during oxidative phosphorylation inside our cells. During this process, energy in the form of ATP is obtained from ingested food. Compounds from the food react with oxygen and carbon dioxide, water and energy are released. More precisely, each molecule of oxygen is reduced in 4 step reaction into water. However, the mentioned reaction is not 100 % efficient due partial reduction of oxygen which leads into formation ROS. Due to their reactivity ROS molecules cause damage to the cell macromolecules. Unfortunately, there is little we can do regarding the formation of ROS from the endogenous source. The second source of ROS-causing damage to human cells originates from the environment we are living. We are constantly exposed to diverse oxidizing products like: ozone, nitrogen oxides, ionizing and non-ionizing radiation (e.g., UVradiation), various pesticides, alcohol, disinfection by-products, cigarette smoke, etc. In the case of exogenous ROS exposure we have partial influence: we can either move to the environment with less ROS-sources or we can protect ourselves with ingestion of antioxidants. In the article, data will be discussed, whether it is reasonable to increase our defense against environmentaly-induced oxidative stress with antioxidants or not

Capillary wetting of profiled polyester fibres - a comparison between macroscopic and microscopic analysis

A comparative study between the standard Washburn macroscale method for determination of the capillary wetting rate in a nonwoven textile fibre mesh and the polarization optical video-microscopy-based microscale method for investigation of the wetting process in single fibres is reported. The study was performed with profiled polyester fibres associated with superior wicking performance. Both methods resulted in very similar values of the wetting rate, which confirms that for textile materials based on such type of fibres the microstructure of a single fibre dictates liquid transport properties on the micro- as well as on the macroscale. Consequently, for such materials the microscale method is fully competitive with the standard macroscopic approaches