DSA - Apresentações orais em encontros internacionais
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- Analysis and Identification of Trihalomethanes in Lisbon Indoor Swimming Pools: Distribution, Determinants and Human ExposurePublication . Silva, Z.; Rebelo, H.; Silva, M.M.; Alves, A.; Cabral, C.; Almeida, A.C.; Aguiar, F.; Oliveira, A.; Nogueira, A.; Pinhal, H.; Matos, A.; Ramos, C.D.; Pacheco, P.; Aguiar, P.; Cardoso, A.S.Water disinfection methods are used in swimming pools to ensure an effective protection of users against microbiological pathogens, being chlorination the most common disinfection method used worldwide. The use of chlorine based treatment techniques has one strong drawback, which is the generation of disinfection by-products (DBPs), potentially harmful products that have been associated with respiratory and ocular symptoms, bladder cancer and adverse reproductive effects. Amongst DBPs, the most better characterized are trihalomethanes (THMs): chloroform (CF), bromoform (BF), bromodichloromethane (BDCM), and chlorodibromomethane (DBCM). In Portugal a specific legislation to assess the quality of swimming pools is inexistent. The guideline value used to evaluate total THMs in water (TTHMsW) is the one established in the Law 306/2007 - 100 μg/L. Some other water/air parameters were assessed by Law 5/97, WHO guidelines for safe recreational water environments (2006) and Standard 62.1 (2006) from American Society of Heating, Refrigerating, and Air-Conditioning Engineers (ASRHAE). The main goal of this investigation was to study the occurrence, distribution and determinants of THMs in indoor swimming pools. This will also enable an evaluation of the exposure of users to THMs. In order to achieve this goals, the characterization of water quality in 30 Lisbon indoor swimming pools, using chorine based treatment techniques, was made during a six month period. Several parameters such as TTHMs, CF, BDCM, DBCM, BF levels in water, free residual chlorine (FrCl), pH, TW, Tair, Hu, chemical oxygen demand (COD), and other, were determined in each pool, once a month. Statistical analysis was performed using the SPSS 17.0 software. Descriptive analysis was applied to all variables. Student’s t-test, Mann-Whitney tests and Spearman’s rank correlation coefficient were also used. Large variation in TTHMs and CF water levels between the pools was obtained, being CF the THM obtained in higher concentrations, with sporadic higher values than the allowed. In air, CF level (CFair) also presented occasional higher levels. There was a clear positive linear correlation between CFW and TTHMsW (R>0.95, p<0.01), CFW and CFair (R> 0.5; p<0.05), CFW and FrCl (R>0.2; p<0.05) and, CFw and Tw (R>0.2; p<0.05). Good correlations were also obtained between other THMs: BDCM and DBCM (R>0.5, p<0.01) and BF and DBCM (R>0.6; p<0.05). The strong positive correlation obtained between CFW and TTHMsW was expected, since, usually, CFW has the higher contribution to TTHMsW. CFW is often considered as a good indicator of TTHMs concentration in water. Therefore correlations between TTHMs and CFair, FrCl, and Tw were expected and observed: TTHMsW vs CFair (R>0.5; p<0.05), TTHMsW vs FrCl (R>0.2; p<0.05) and TTHMsW vs TW (R>0.2; p<0.01). In conclusion, reasonable water and air quality was obtained in the studied Lisbon swimming pools, although some pools presented high TTHMsW, CFW and CFair. These results clearly demonstrate that THMs monitoring is particularly important and that, in a near future, this should be extended to other DBPs. Furthermore, for conscious use of swimming pools, appropriate and targeted information about safe practices should be provided to pool users.
- Assessment of indoor environmental quality in elderly care centersPublication . Cano, M.; Nogueira, S.; Alves, M.; Papoila, A.L.; Aguiar, F.; Rosa, N.; Brás, M.C.; Quintas, M.C.; Pinhal, H.; Nogueira, Ana; Proença, C.; Teixeira, J.P.The aim of this study was to characterize indoor environmental quality in a representative sample of Elderly Care Centers (ECC) in order to associate it with ventilation, health and comfort of elderly people. Indoor air quality (IAQ) parameters and thermal comfort were measured twice, during winter and spring/summer seasons, from 18 Elderly Care Centers (ECC) located in Lisbon, with a total of 116 rooms evaluated.
- Preliminary results on indoor environmental quality in day care centers located in LisbonPublication . Cano, M.; Azevedo, S.; Aguiar, F.; Almeida, G.; Brás, C.; Pinhal, H.; Nogueira, A.; Proença, M.C.The growing concern about indoor air quality results from the knowledge that exposure to indoor air pollutants may be higher than the exposure to outdoor air pollutants and from the evidence that in most developed countries day care centers are places where children spend most of their time. How environmental factors affect children respiratory health is still controversial and unclear. This paper describes the results from field measurements of physical parameters, chemical and biological indoor contaminants, to investigate indoor environmental quality, in 70 classrooms of 10 Children Day Care Centers (CDCC), located in Lisbon. Objective The aim of this study is to gather information on indoor environment of CDCC in order to correlate it with both ventilation and children’s health. Material and Methods Chemical contaminants (carbon dioxide, carbon monoxide, formaldehyde, total volatile organic compounds and PM10), biological contaminants (bacteria, fungi and house-dust mites) and thermal comfort parameters were monitored. Formaldehyde was analyzed according to NIOSH 3500 method using a visible absorption spectrometry with air samples taken on impingers by active sampling. Total volatile organic compounds were analyzed by gas chromatography according to the ISO 16000, part 6, with air samples taken on Tenax TA sorbent by active sampling. Carbon monoxide and carbon dioxide measurements were made using a Photoacoustic Multi- Gas Monitor INNOVA. Samples of viable microorganisms were collected using a MAS-100 sampler with Malt Extract Agar plates, Trypticase Soy Agar and MacConkey agar as collecting media for fungi, total bacteria and gram-negative bacteria. Dust samples were collected on filters using a vacuum cleaner with a DustreamTM collector and determined using an ELISA test to quantify mite antigens. PM10 were collected using PTFE filters on Personal Environmental Monitors attached to personal pumps and the filters were analyzed gravimetrically for particle mass. Thermal comfort was evaluated according to the ISO 7730 International Standard using a 1213 Bruel & Kjaer analyzer. Results The reported preliminary results only represent a small part of a larger study under development in 20 CDCC located on Lisbon and Porto. The mean CO2 concentration indoors exceeded the recommended level of 1800 mg/m3 in 54% of the 70 studied rooms, with a maximum concentration of 5630 mg/m3 and an outdoor average of 839 mg/m3. The majority of the studied rooms had suspended particulate matter, TVOC’s and formaldehyde concentrations under the recommended limits. In 51% of the rooms the bacterial concentrations exceed 500 ufc/m3 (recommended limit), being also observed predominance gram-positive bacteria. In 50% of the studied rooms fungal concentrations were above 500 ufc/m3, however the mean outdoor concentration was 560 ufc/m3. Conclusion The preliminary results provide evidence that ventilation is insufficient, resulting in the accumulation of human source contaminants, such as bacteria and CO2. Taking into consideration that the results correspond to the Spring period, when occupants maintain windows and doors open, we expect worse results in the Winter period.
- Trihalomethanes in Lisbon Indoor Swimming Pools: Occurrence and Determining FactorsPublication . Silva, Z.; Rebelo, H.; Silva, M.M.; Alves, A.; Cabral, C.; Almeida, A.C.; Aguiar, F.; Oliveira, A.; Nogueira, A.; Pinhal, H.; Matos, A.; Ramos, C.D.; Pacheco, P.; Aguiar, P.; Cardoso, A.S.The presence of water disinfection by-products (DBPs) in swimming pools constitutes today a public health concern, particularly because swimming is an activity used by a high percentage of the population, namely elderly and young children. Moreover, several adverse short-term and long-term health effects have been associated with these compounds (Lakind et al., 2010; Zwiener et al., 2007). Water disinfection methods are used in all swimming pools, namely in public pools, to ensure an adequate and effective protection of users against microbiological pathogens. Chlorination is the most common disinfection method used worldwide, because it is low cost, easy to use, efficient against a broad spectrum of microorganisms, and enables the maintenance of a residual protection. The use of chlorine based treatment techniques has one strong drawback, which is the generation of several DBPs, potentially harmful products, that can be absorbed by ingestion, inhalation and absorption through the skin (Nieuwenhuijsen et al., 2009; Caro and Gallego, 2007). DBPs comprise several compounds that are formed through the reaction of chlorine with organic matter present in water. Amongst DBPs, the most relevant and better characterized are trihalomethanes (THMs): chloroform (CF), bromoform (BF), bromodichloromethane (BDCM), and chlorodibromomethane (DBCM). These compounds have been associated with health effects such as respiratory, ocular and cutaneous symptoms and also with some long-term health effects such as bladder cancer and adverse reproductive outcomes (Lee et al., 2009; Zwiener et al., 2007). Accurate exposure assessments to THMs in indoor pool environment is particularly difficult because their formation depends on many factors such as water and air temperature (Tw and Tair), humidity (Hu), pH, free residual chlorine (FrCl), total organic content and number of pool users (Lee et al., 2009). In Portugal a specific legislation to assess the quality of swimming pool waters is inexistent. The guideline value used in this study for total THMs (TTHMs) was the one established in the Portuguese Law 306/2007, for drinking water quality - 100 μg/L. Some other water parameters determined in swimming pools such as Tw turbidity (Turb), pH, FrCl, total residual chlorine, conductivity (Cond), permanganate index (COD) and isocyanuric acid were assessed by Portuguese Law 5/97, regarding technical and safety conditions of closed environments with water diversions. WHO guidelines for safe recreational water environments (2006) were also used to assess some water and air parameters in pools. Standard 62.1 (2006) from American Society of Heating, Refrigerating, and Air-Conditioning Engineers (ASRHAE) was also used to assess pool air parameters. The main goal of this investigation project was to study the occurrence, distribution and determinants of THMs in indoor swimming pools. This will enable an evaluation of swimming pool users’ exposure to THMs. In order to achieve this goal, the characterization of water quality of 30 Lisbon indoor swimming pools, using chorine based treatment techniques, was made during a six month period. Because of laboratory working restrictions, CF concentration in pool air was studied only in 6 swimming pools, at the same period. Several parameters such as TTHMs concentration, CF, BDCM, DBCM, BF concentration in water, FrCl, combined residual chlorine (CrCl), pH, Tw and Tair, Hu, COD, Cond, Turb and chloride (Cl) were determined in each pool, once a month. THMs water sampling was made in duplicates in two pool water spots, physicochemical parameters were determined in one of the THMs water sampling spots and THMs air sampling was made in two pool spots, considered to be representative of the swimming pool air. All sampling procedures were performed by specialized sampling technicians from Lisbon Health Centres Group (ACES). Statistical analysis was performed using the SPSS 17.0 software. Descriptive analysis was applied to all variables in order to determine mean, median, standard deviation, minimum and maximum. Student’s t-test and Mann-Whitney tests were used to compare numerical variables and Spearman’s rank correlation coefficient were used to examine correlation between all environmental parameters. TTHMs water level ranged from 10 to 160 μg/L, while CF water level typically ranged from 5 to 150 μg/L, with occasional higher levels detected. Regarding other THMs levels in pool water, BDCM ranged from 0.5 to 15 μg/L, DBCM from 0.4 to 10 μg/L and BF was obtained in concentrations less than 2 μg/L. Moreover, in some pools, DBCM and BF were not detected. From these results, it can be concluded that there was a large variation in TTHMs and CF water levels between the pools and that CF was the THM obtained in higher concentrations. These results are in agreement with studies presented by other authors (Lee et al., 2009; Chu and Nieuwenhuijsen, 2002). In air, CF level ranged from 40 to 200 μg/m3, with occasional higher levels detected. Tw presented less variation (27 to 31 ºC) than Tair (21 to 33 ºC), although sporadic higher values were found. FrCl and Cond presented higher values than the guidelines from DR 5/97 only in a small number of pools. Turb and COD values were within the guidelines from DR 5/97. pH varied from 7 to 8.5, with only a small number of pools having values higher than 7.8. As referred in WHO guidelines, pH should be maintained between 7.2 and 7.8 for chlorine disinfectants to ensure efficient disinfection. Using the statistical tests mentioned before, it was possible to obtain some interesting results. There was a clear positive linear correlation between CF water concentration (CFW) and TTHMs water concentration (R>0.98, p<0.01), good correlation other THMs, there was a clear positive linear correlation between BDCM and DBCM water concentration (R>0.78, p<0.01) and good correlation between TTHMs water concentration and Tw (R>0.45, p<0.05). These results are in agreement with Lee et al. (2009) which obtained positive linear correlations between CFW and COD and with Chu and Nieuwenhuijsen (2002) which also obtained correlations between TTHMs water concentration and Tw. In conclusion, there appears to be good water and air quality in the studied Lisbon swimming pools. Regarding THMs levels in water, some pools presented high TTHMs and CF concentrations. Moreover, CF air concentrations were also high in some swimming pools. These results clearly demonstrate that THMs monitoring is particularly important and that, in a near future, this should be extended to other DBPs. Furthermore, for a correct and conscious use of swimming pools, appropriate and targeted information about safe practices should be provided to pool users.