Trihalomethanes in Lisbon indoor swimming pools: occurrence, determining factors, and health risk classification.
Characterization of water quality from indoor swimming pools, using chorine-based disinfection techniques, was performed during a 6-mo period to study the occurrence, distribution, and concentration factors of trihalomethanes (THM). Several parameters such as levels of water THM, water and air chloroform, water bromodichloromethane (BDCM), water dibromochloromethane (DBCM), water bromoform (BF), free residual chlorine (FrCl), pH, water and air temperature, and permanganate water oxidizability (PWO) were determined in each pool during that period. Chloroform (CF(W)) was the THM detected at higher concentrations in all pools, followed by BDCM, DBCM, and BF detected at 99, 34, and 6% of the samples, respectively. Water THM concentrations ranged from 10.1 to 155 μg/L, with 6.5% of the samples presenting values above 100 μg/L (parametric value established in Portuguese law DL 306/2007). In this study, air chloroform (CF(Air)) concentrations ranged from 45 to 373 μg/m³ with 24% of the samples presenting values above 136 μg/m³ (considered high exposure value). Several significant correlations were observed between total THM and other parameters, namely, CF(W), CF(Air), FrCl, water temperature (T(W)), and PWO. These correlations indicate that FrCl, T(W) and PWO are parameters that influence THM formation. The exposure criterion established for water THM enabled the inclusion of 67% of Lisbon pools in the high exposure group, which reinforces the need for an improvement in pool water quality.
Water and Soil Unit, Environmental Health Department, Portuguese National Health Institute Doutor Ricardo Jorge (INSA), Lisbon, Portugal.
Zelinda Isabel
ZI
Silva
Maria Helena
MH
Rebelo
Manuela Manso
MM
Silva
Ana Martins
AM
Alves
Maria da Conceição
Mda C
Cabral
Ana Cristina
AC
Almeida
Fátima Rôxo
FR
Aguiar
Anabela Lopes
AL
de Oliveira
Ana Cruz
AC
Nogueira
Hermínia Rodrigues
HR
Pinhal
Pedro Manuel
PM
Aguiar
Ana Sofia
AS
Cardoso
D000393:Air Pollutants / Q000032:analysis* / Q000633:toxicity; D016902:Air Pollution, Indoor; D002725:Chloroform / Q000032:analysis / Q000633:toxicity; D004202:Disinfectants / Q000737:chemistry; D006801:Humans; D006863:Hydrogen-Ion Concentration; D017953:Isocyanates / Q000737:chemistry; D010084:Oxidation-Reduction; D011174:Portugal; D018570:Risk Assessment; D012621:Seasons; D012973:Sodium Hypochlorite / Q000737:chemistry; D013551:Swimming Pools; D013696:Temperature; D022882:Trihalomethanes / Q000032:analysis* / Q000633:toxicity; D014504:Urban Health; D014874:Water Pollutants, Chemical / Q000032:analysis* / Q000633:toxicity; D060753:Water Quality
D000393:Air Pollutants; D004202:Disinfectants; D017953:Isocyanates; D022882:Trihalomethanes; D014874:Water Pollutants, Chemical; C032707:chlorodibromomethane; D002725:Chloroform; D012973:Sodium Hypochlorite; C015044:bromoform