Swimming pool water disinfection by-products profiles and association patterns.

The aim of this work was to determine and study the concentration of different groups of disinfection by-products (DBPs): trihalomethanes, haloacetic acids, haloacetonitriles, haloacetones and combined chlorine (as an indicator of chloramine levels), in the water of 175 public swimming pools in Gipuzkoa (Basque Country, Spain). The study included chlorinated and brominated pools, indoor and outdoor, used for recreational and sports purposes, and filled with water from calcareous and siliceous soils. The most abundant were haloacetic acids, followed by trihalomethanes, with chlorinated or brominated forms predominating depending on whether the pools were disinfected by chlorination or bromination, respectively. All the 75th percentiles of DBPs were below the limits established by the European Chemical Agency (ECHA), although the maximum values of trihalomethanes exceeded them. The same was true for dichloroacetonitrile in chlorinated pools and dibromoacetonitrile in brominated pools. All families of DBPs showed positive associations with each other, all being significant except for combined chlorine. Their mean levels were higher in outdoor pools than in indoor pools, significantly so in all except combined chlorine. Recreational pools showed higher levels of haloacetic acids and combined chlorine than sports pools. The concentrations of the different groups of DBPs were higher in the pools than in the mains water that fed them. This increase, especially that of the haloacetonitriles, as well as the high concentrations of brominated forms in the pools disinfected by bromination, make it necessary to focus on their toxicological implication. The differences in the DBP profiles of the filling network water were not transferred to the pool water.

Serum metal levels in a population of Spanish pregnant women / Niveles de metales en suero en una población de mujeres embarazadas españolas

Objective: To describe serum levels of calcium, copper, selenium, magnesium, iron and zinc and evaluate their relationship with maternal socio-demographic characteristics and dietary variables in women in the first trimester of pregnancy. Method: Cross-sectional study with 1279 participants from the INMA cohorts. Results: The concentrations of the elements analyzed were within the normal range. Associations with higher levels of these metals were found for calcium with white meat intake (p = 0.026), for copper with excess body weight (p < 0.01), low social class (p = 0.03) and being multipara (p < 0.01), for magnesium with being over 35 years old (p = 0.001), high social class (p = 0.044), primiparous status (p = 0.002) and low daily intake of bread (p = 0.009) and legumes (p = 0.020); for zinc with university education (p = 0.039) and residence in Gipuzkoa (p < 0.01), and for selenium with residence in Valencia (p < 0.01), university education (p = 0.001), vitamin B6 supplementation (p = 0.006), fish intake (> 71 g/day) (p = 0.014) and having been born in Spain (p = 0.001). Further, lower iron levels were associated with being overweight (p = 0.021) or obese (p < 0.001) and vitamin B12 supplementation (p = 0.006). Conclusions: Our results suggest that trace elements in the analyzed cohorts are adequate for this stage of pregnancy. The variability in these elements is mainly linked to socio-demographic and anthropometric variables. (AU)

Objetivo: Describir las concentraciones de calcio, cobre, selenio, magnesio, hierro y zinc en muestras de suero de gestantes en el primer trimestre y evaluar la relación con las características sociodemográficas maternas y las variables de dieta. Método: Estudio transversal con 1279 participantes de las cohortes INMA. Resultados: Las concentraciones de los elementos analizados estuvieron dentro de los límites de referencia. El calcio se asoció con el consumo de carne blanca (p = 0,026). Los valores elevados de cobre se asociaron con tener exceso de peso (p < 0,01), clase social baja (p = 0.03) y ser multípara (p < 0,01). Los valores más elevados de magnesio se asociaron con tener más de 35 años (p = 0,001), clase social alta (p = 0,044), ser primípara (p = 0,002) y bajo consumo diario de pan (p = 0,009) y legumbres (p = 0,020). El zinc se asoció con tener estudios universitarios (p = 0,039) y con la cohorte de Gipuzkoa (p < 0,01). Los valores más altos de selenio se asociaron con la cohorte de Valencia (p < 0,01), tener estudios universitarios (p = 0,001), tomar suplementos de vitamina B6 (p = 0,006), consumo de pescado >71 g/día (p = 0,014) y ser española (p = 0,001). Los valores más bajos de hierro se asociaron con tener exceso de peso (p = 0,021) u obesidad (p < 0,001) y con tomar suplementos de vitamina B12 (p = 0,006). Conclusiones: Nuestros resultados sugieren que los oligoelementos en las cohortes analizadas son adecuados para esta etapa del embarazo. La variabilidad de estos elementos está asociada principalmente a las variables sociodemográficas y antropométricas. (AU)

Serum metal levels in a population of Spanish pregnant women.

OBJECTIVE: To describe serum levels of calcium, copper, selenium, magnesium, iron and zinc and evaluate their relationship with maternal socio-demographic characteristics and dietary variables in women in the first trimester of pregnancy. METHOD: Cross-sectional study with 1279 participants from the INMA cohorts. RESULTS: The concentrations of the elements analyzed were within the normal range. Associations with higher levels of these metals were found for calcium with white meat intake (p=0.026), for copper with excess body weight (p <0.01), low social class (p=0.03) and being multipara (p <0.01), for magnesium with being over 35 years old (p=0.001), high social class (p=0.044), primiparous status (p=0.002) and low daily intake of bread (p=0.009) and legumes (p=0.020); for zinc with university education (p=0.039) and residence in Gipuzkoa (p <0.01), and for selenium with residence in Valencia (p <0.01), university education (p=0.001), vitamin B6 supplementation (p=0.006), fish intake (> 71g/day) (p=0.014) and having been born in Spain (p=0.001). Further, lower iron levels were associated with being overweight (p=0.021) or obese (p <0.001) and vitamin B12 supplementation (p=0.006). CONCLUSIONS: Our results suggest that trace elements in the analyzed cohorts are adequate for this stage of pregnancy. The variability in these elements is mainly linked to socio-demographic and anthropometric variables.

Prenatal exposure to PM2.5 and NO2 and sex-dependent infant cognitive and motor development.

BACKGROUND: Prenatal exposure to air pollutants including particulate matter (<2.5 µm of diameter,PM2.5)and nitrogen dioxide (NO2) has been identified as a potential risk factor for neuropsychological developmental and mental health disorders. OBJECTIVE: This study aimed to analyze the associations between prenatal PM2.5 and NO2 exposure and cognitive functions in children at 4-6 years of age, including sex differences, and the modification effect of the duration predominant breastfeeding these associations. DESIGN: This study was conducted as part of the INMA project, a population-based birth cohort study in Spain (n = 1119). Each of the pregnant mothers was assigned a prenatal exposure to PM2.5 and NO2 for their whole pregnancy based on their place of residence. At the 4-6 year-old follow-up, infants' neuropsychological development was assessed using McCarthy scales: Verbal, Perceptive-Manipulative, Numeric, General Cognitive, Memory and Motor (gross and fine). Between 6 and 14 months of age, information concerning breastfeeding was gathered with a questionnaire. Regression analyses were performed to estimate the associations between exposure and outcomes, accounting for potential confounders. The analyses were stratified by child sex and breastfeeding duration. RESULTS: The majority of coefficients for the different cognitive domains were negative either for PM2.5 and NO2, though none was statistically significant. After stratifying by sex, the associations become even more negative for boys, with some of the associations becoming statistically significant (memory both for PM2.5 and NO2), and global cognition and verbal for NO2. Duration of predominant breastfeeding was not found to have a modifying effect. CONCLUSIONS: These findings suggest a sex-dependent effects on neuropsychological development at 4-6 years of age, with a greater vulnerability in boys, specifically in domains related to memory, verbal and general cognition. No modifying effect was observed for duration of predominant breastfeeding.

Ingesta de flúor a través del consumo de agua de abastecimiento público en la cohorte INMA-Gipuzkoa / Fluoride intake through consumption of water from municipal network in the INMA-Gipuzkoa cohort

Objetivo: Estimar la ingesta de flúor en mujeres embarazadas y sus hijos/as de la cohorte INMA-Gipuzkoa a través del consumo de agua de la red municipal y comparar estas ingestas con los valores recomendados. En Euskadi, la fluoración del agua de consumo es obligatoria en abastecimientos de más de 30.000 habitantes. Método: Se han incluido 575 mujeres embarazadas (reclutamiento en 2006-2008) y 424 niños/as de 4 años (seguimiento en 2010-2012). Las concentraciones de fluoruros en el agua se obtuvieron del sistema de información de aguas de consumo de Euskadi (EKUIS). Los hábitos de consumo de agua y las variables socioeconómicas se obtuvieron mediante cuestionario. Resultados: El 74,9% de las mujeres y el 87,7% de los/las niños/as consumían agua de red municipal. En agua fluorada, el valor medio de fluoruro fue de 0,805mg/l (desviación estándar [DE]: 0,194) durante el periodo de reclutamiento, y de 0,843mg/l (DE: 0,080) durante el seguimiento de los/las niños/as. La ingesta media de flúor y el percentil 95 en las zonas fluoradas fueron de 0,015 y 0,026mg/kg al día en las mujeres y de 0,033 y 0,059mg/kg al día en los/las niños/as. Considerando solo el flúor aportado por el agua, el 8,71% de los/las niños/as residentes en zonas con fluoración superaban la ingesta de 0,05mg/kg al día recomendada por la European Food Safety Authority. Conclusión: Los resultados obtenidos muestran que las ingestas de flúor a través del agua de consumo pueden superar lo recomendado en población infantil, y propician futuros estudios que aporten evidencias que puedan ayudar en las políticas de fluoración de las aguas de consumo público

Objective: To estimate fluoride intake through consumption of water from the municipal network in pregnant women and their children from the INMA-Gipuzkoa cohort and to compare these intakes with recommended levels. In Euskadi (Spain), fluoridation of drinking water is compulsory in water supplies for more than 30,000 inhabitants. Method: 575 pregnant women (recruitment, 2006-2008) and 424 4-year-old children (follow-up, 2010-2012) have been included. Fluoride levels in drinking water were obtained from the water consumption information system of the Basque Country (EKUIS). Water consumption habits and socioeconomic variables were obtained by questionnaire. Results: 74.9% and 87.7% of women and children consumed water from the municipal network. Average fluoride levels in fluoridated water were 0.805 (SD: 0.194) mg/L during baseline recruitment and 0.843 (SD: 0.080) mg/L during follow up, at 4 years old of the children. Average and 95th percentile of fluoride intake were 0.015 and 0.026mg/kg per day in women and 0.033 and 0.059mg/kg per day in children. Considering only fluoride provided by drinking water, 8.71% of children living in fluoridated areas exceeded intake level recommended by the European Food Safety Authority, consisting in 0.05mg/kg per day. Conclusion: The results show that ingested levels of fluoride through consumption of municipal water can exceed the recommended levels in children and encourages further studies that will help in fluoridation policies of drinking water in the future

[Fluoride intake through consumption of water from municipal network in the INMA-Gipuzkoa cohort]. / Ingesta de flúor a través del consumo de agua de abastecimiento público en la cohorte INMA-Gipuzkoa.

OBJECTIVE: To estimate fluoride intake through consumption of water from the municipal network in pregnant women and their children from the INMA-Gipuzkoa cohort and to compare these intakes with recommended levels. In Euskadi (Spain), fluoridation of drinking water is compulsory in water supplies for more than 30,000 inhabitants. METHOD: 575 pregnant women (recruitment, 2006-2008) and 424 4-year-old children (follow-up, 2010-2012) have been included. Fluoride levels in drinking water were obtained from the water consumption information system of the Basque Country (EKUIS). Water consumption habits and socioeconomic variables were obtained by questionnaire. RESULTS: 74.9% and 87.7% of women and children consumed water from the municipal network. Average fluoride levels in fluoridated water were 0.805 (SD: 0.194) mg/L during baseline recruitment and 0.843 (SD: 0.080) mg/L during follow up, at 4 years old of the children. Average and 95th percentile of fluoride intake were 0.015 and 0.026mg/kg per day in women and 0.033 and 0.059mg/kg per day in children. Considering only fluoride provided by drinking water, 8.71% of children living in fluoridated areas exceeded intake level recommended by the European Food Safety Authority, consisting in 0.05mg/kg per day. CONCLUSION: The results show that ingested levels of fluoride through consumption of municipal water can exceed the recommended levels in children and encourages further studies that will help in fluoridation policies of drinking water in the future.

Exposure to extremely low and intermediate-frequency magnetic and electric fields among children from the INMA-Gipuzkoa cohort.

Detailed assessment of exposure to extremely low frequency (ELF) and intermediate frequency (IF) fields is essential in order to conduct informative epidemiological studies of the health effects from exposure to these fields. There is limited information available regarding ELF electric fields and on both magnetic and electric field exposures of children in the IF range. The aim of this study was to characterize ELF and IF exposure of children in the Spanish INMA cohort. A combination of spot and fixed measurements was carried out in 104 homes, 26 schools and their playgrounds and 105 parks. Low levels of ELF magnetic fields (ELF-MF) were observed (with the highest 24-h time-weighted average (TWA) exposure being 0.15µT in one home). The interquartile range (IQR) of ELF electric fields (ELF-EF) ranged from 1 to 15V/m indoors and from 0.3 to 1.1V/m outdoors and a maximum value observed was 55.5V/m in one school playground. IQR ranges for IF magnetic and electric fields were between 0.02 and 0.23µT and 0.2 and 0.5V/m respectively and maximum values were 0.03µT and 1.51V/m in homes. Correlations between magnetic and electric fields were weak for ELF (Spearman 0.04-0.36 in different settings) and moderate for IF (between 0.28 and 0.75). Children of INMA-Gipuzkoa cohort were exposed to very low levels of ELF-MF in all settings and to similar levels of ELF-EF compared to the range of previously reported levels, although somewhat higher exposures occurred at home. Children enrolled to our study were similarly exposed to IF in all settings.

Exposure to fine particle matter, nitrogen dioxide and benzene during pregnancy and cognitive and psychomotor developments in children at 15 months of age.

BACKGROUND: Prenatal exposure to air pollutants has recently been identified as a potential risk factor for neuropsychological impairment. OBJECTIVES: To assess whether prenatal exposure to fine particulate matter (PM2.5), nitrogen dioxide (NO2) and benzene were associated with impaired development in infants during their second year of life. METHODS: Regression analyses, based on 438 mother-child pairs, were performed to estimate the association between mother exposure to air pollutants during pregnancy and neurodevelopment of the child. The average exposure to PM2.5, NO2 and benzene over the whole pregnancy was calculated for each woman. During the second year of life, infant neuropsychological development was assessed using the Bayley Scales of Infant Development. Regression analyses were performed to estimate the association between exposure and outcomes, accounting for potential confounders. RESULTS: We estimated that a 1 µg/m(3) increase during pregnancy in the average levels of PM2.5 was associated with a -1.14 point decrease in motor score (90% CI: -1.75; -0.53) and that a 1 µg/m(3) increase of NO2 exposure was associated with a -0.29 point decrease in mental score (90% CI: -0.47; -0.11). Benzene did not show any significant association with development. Considering women living closer (≤ 100 m) to metal processing activities, we found that motor scores decreased by -3.20 (90% CI: -5.18; -1.21) for PM2.5 and -0.51 (-0.89; -0.13) for NO2, while mental score decreased by -2.71 (90% CI: -4.69; -0.74) for PM2.5, and -0.41 (9% CI: -0.76; -0.06) for NO2. CONCLUSIONS: Our findings suggest that prenatal residential exposure to PM2.5 and NO2 adversely affects infant motor and cognitive developments. This negative effect could be higher in the proximity of metal processing plants.

[Trend in lead exposure in the Spanish child population in the last 20 years. An unrecognized example of health in all policies?]. / Estudio de la evolución de la exposición a plomo en la población infantil española en los últimos 20 años. ¿Un ejemplo no reconocido de "salud en todas las políticas"?

OBJECTIVE: To describe the time trend in atmospheric lead concentrations in Spain, from before lead was banned as a gasoline additive to the present, and to determine the trend in lead body burden in the Spanish child population. METHODS: We obtained the annual average for atmospheric lead levels in several Spanish cities from the 1980s to the present. A literature search was conducted to identify published studies on lead concentrations in populations of Spanish children. RESULTS: Overall, atmospheric lead levels decreased, particularly between 1991 and 1999. This downward trend was related to a decrease in lead concentrations in Spanish children from 1989, the year in which the first study of childhood lead exposure was published, until the present. The decreased concentrations in both air and in children was most probably a result of legislative measures regulating the maximum amount of lead in gasoline in 1987 until a complete ban in August 2001. CONCLUSIONS: From a public health point of view, the banning of leaded gasoline has significantly increased health protection in the Spanish population.

Concentración de trihalometanos y de ácidos haloacéticos en el agua de consumo y estimación de su ingesta durante el embarazo en la cohorte INMA-Guipúzcoa (España) / Trihalomethane and haloacetic acid concentrations in drinking water and their estimated intake during pregnancy in the INMA cohort (Guipúzcoa, Spain)

ObjetivosDescribir la concentración de trihalometanos (THM) y ácidos haloacéticos (AHA) del agua de consumo, valorar su variación espacio-temporal y estimar las ingestas individuales en el embarazo.MétodosEn los años 2006–2008 se analizó el agua en 33 puntos representativos de las redes de abastecimiento de los 25 municipios del área de estudio. Los hábitos de consumo de agua se obtuvieron mediante cuestionario.ResultadosLa media (desviación estándar) fue de 16,9μg/l (7,9) para el total de THM y de 10,9μg/l (4,9) para la suma de las concentraciones de cinco: monocloroacético, dicloroacético, tricloroacético, monobromoacético y dibromoacético (AHA5). Las concentraciones fueron menores en las aguas de manantial, sólo cloradas, que en las de embalse, sometidas a tratamiento completo de potabilización: 8,8μg/l frente a 19,1μg/l (p<0,01) y 8,2μg/l frente a 11,7μg/l (p<0,01). Los valores aumentan significativamente con el número de depósitos de la red y con la recloración, y son mayores en verano y en otoño. La ingesta media del total de THM y de AHA5 es menor en las mujeres que se abastecen de agua de manantial. Hay diferencias en la ingesta según el embalse de abastecimiento.ConclusionesEl origen del agua, la estructura de la red de distribución y la estación del año condicionan la cantidad de productos derivados de la desinfección en el agua. Las ingestas medias varían según el origen del agua, y para todos los productos están muy por debajo de los valores establecidos por la OMS (AU)

ObjectivesTo report trihalomethane (THM) and haloacetic acid (HAA) concentrations in drinking water, assess variations in these concentrations depending on source and over time, and estimate individual intake during pregnancy.MethodsWater taken from 33 representative points of the water supply network of the 25 municipalities in the study area was analyzed from 2006–2008. Water drinking habits were recorded using a questionnaire.ResultsMean total THM concentrations were 16.9μg/L (standard deviation, 7.9), while the mean value for the sum of concentrations of five HAA (monochloroacetic, dichloroacetic, tricholoroacetic, monobromoacetic, and dicromoacetic acids) was 10.9μg/L (standard deviation, 4.9). Concentrations were lower in spring waters, which were only chlorinated, compared with dam waters, which were subject to a complete purification treatment: 8.8μg/L vs 19.1μg/L (p<0.01) and 8.2μg/L vs 11.7μg/L (p<0.01). Concentrations significantly increased with the number of deposits in the network and with their rechlorination and were higher in the summer and fall. Mean intakes of total THM and of the five HAA were lower in women supplied with spring water. Intakes differed depending on supply reservoir.ConclusionsDisinfection by-products in water are affected by water source, supply network structure, and annual season. The mean intake of these products varies depending on the source of drinking water. Mean intakes of all products were much lower than values recommended by the World Health Organization (AU)

Air quality assessment in urban areas of Gipuzkoa (Spain)

Objetivo. El objetivo del estudio es evaluar la calidad del aire a la que esta expuesta una poblacion de 90.000 habitantes de Gipuzkoa que residen en un entorno periurbano, donde las actividades industriales (11 industrias siderometalurgicas) se entremezclan con zonas residenciales en la propia trama urbana. Métodos. Se cuantificaron las concentraciones de particulas de 2,5mm de diametro (PM2.5) y se analizaron los elementos traza asociados a PM2.5: cadmio (Cd), arsenico (As), manganeso (Mn), cobre (Cu), cromo (Cr), niquel (Ni), hierro (Fe), plomo (Pb), mercurio (Hg) y zinc (Zn) a lo largo de 2006 y 2007. Las muestras se recogieron a partir de 3 captadores de alto volumen DIGITEL Modelo DAH 80 en 7 puntos de muestreo. Se analiza la variabilidad anual asi como la variabilidad estacional de los diferentes contaminantes en cada valle. Asimismo, se recogieron muestras de PM10 y PM2.5 con equipos similares durante un mes y en el mismo sitio para analizar la composicion de los elementos traza en las diferentes fracciones PM10 y PM2.5. Por ultimo, los resultados fueron comparados con los de los equipos de la Red de Calidad del Aire del Gobierno Vasco ubicados en la misma area de estudio. Resultados. Las concentraciones de PM2.5 observadas (12.2¨C28.9¦Ìg/m3) fueron similares a las descritas en entornos urbanos de grandes ciudades europeas. Las concentraciones medias de elementos traza, en cambio, superaron con gran diferencia a las de las ciudades europeas. Las concentraciones de Mn encontradas en los tres valles indican la influencia de la industria siderometalurgica en la calidad del aire.ConclusionLos resultados de particulas y elementos traza encontrados en el area de estudio presentan valores similares o superiores a las areas metropolitanas, lo cual tiene implicaciones en la valoracion del riesgo en la salud de entornos apartados de los grandes nucleos de poblacion(AU)

Objectives. To evaluate the air quality to which a population of 90,000 inhabitants in the province of Gipuzkoa (Basque Country, Spain) is exposed. The population resides in a periurban environment, where industrial activity (11 iron and steel foundries) is scattered among residential areas.MethodsThroughout 2006 and 2007, levels of particulate matter less than 2.5mm in diameter (PM2.5) were quantified and levels of trace elements in PM2.5 fraction [cadmium (Cd), arsenic (As), manganese (Mn), copper (Cu), chromium (Cr), nickel (Ni), iron (Fe), lead (Pb), mercury (Hg) and zinc (Zn)] were analyzed. The samples were gathered in seven sampling sites using three high-volume Digitel DAH 80 samplers. Annual and seasonal variability were evaluated for the various contaminants in each valley and PM10 and PM2.5 samples were also gathered at the same site for a month, with the goal of analyzing the composition of trace elements in each particle size. Finally, the results were compared with those obtained from the same study area by the Basque Government Air Quality Network equipment.ResultsThe observed PM2.5 concentrations (12.2¨C28.9¦Ìg/m3) were similar to those described in urban environments in large European cities, while mean trace element concentrations were significantly higher. The Mn levels observed in all three valleys indicated the influence of the steel and metal industries on air quality.ConclusionThe finding that levels of particulate matter and trace elements in the study area were similar to or higher than those found in metropolitan areas has implications for the evaluation of health risks in populations far from large population centers(AU)

[Trihalomethane and haloacetic acid concentrations in drinking water and their estimated intake during pregnancy in the INMA cohort (Guipúzcoa, Spain)]. / Concentración de trihalometanos y de ácidos haloacéticos en el agua de consumo y estimación de su ingesta durante el embarazo en la cohorte INMA-Guipúzcoa (España).

OBJECTIVES: To report trihalomethane (THM) and haloacetic acid (HAA) concentrations in drinking water, assess variations in these concentrations depending on source and over time, and estimate individual intake during pregnancy. METHODS: Water taken from 33 representative points of the water supply network of the 25 municipalities in the study area was analyzed from 2006-2008. Water drinking habits were recorded using a questionnaire. RESULTS: Mean total THM concentrations were 16.9 µg/L (standard deviation, 7.9), while the mean value for the sum of concentrations of five HAA (monochloroacetic, dichloroacetic, tricholoroacetic, monobromoacetic, and dicromoacetic acids) was 10.9 µg/L (standard deviation, 4.9). Concentrations were lower in spring waters, which were only chlorinated, compared with dam waters, which were subject to a complete purification treatment: 8.8 µg/L vs 19.1 µg/L (p<0.01) and 8.2 µg/L vs 11.7 µg/L (p<0.01). Concentrations significantly increased with the number of deposits in the network and with their rechlorination and were higher in the summer and fall. Mean intakes of total THM and of the five HAA were lower in women supplied with spring water. Intakes differed depending on supply reservoir. CONCLUSIONS: Disinfection by-products in water are affected by water source, supply network structure, and annual season. The mean intake of these products varies depending on the source of drinking water. Mean intakes of all products were much lower than values recommended by the World Health Organization.

Air quality assessment in urban areas of Gipuzkoa (Spain).

OBJECTIVES: To evaluate the air quality to which a population of 90,000 inhabitants in the province of Gipuzkoa (Basque Country, Spain) is exposed. The population resides in a periurban environment, where industrial activity (11 iron and steel foundries) is scattered among residential areas. METHODS: Throughout 2006 and 2007, levels of particulate matter less than 2.5mm in diameter (PM(2.5)) were quantified and levels of trace elements in PM(2.5) fraction [cadmium (Cd), arsenic (As), manganese (Mn), copper (Cu), chromium (Cr), nickel (Ni), iron (Fe), lead (Pb), mercury (Hg) and zinc (Zn)] were analyzed. The samples were gathered in seven sampling sites using three high-volume Digitel DAH 80 samplers. Annual and seasonal variability were evaluated for the various contaminants in each valley and PM(10) and PM(2.5) samples were also gathered at the same site for a month, with the goal of analyzing the composition of trace elements in each particle size. Finally, the results were compared with those obtained from the same study area by the Basque Government Air Quality Network equipment. RESULTS: The observed PM(2.5) concentrations (12.2-28.9 microg/m(3)) were similar to those described in urban environments in large European cities, while mean trace element concentrations were significantly higher. The Mn levels observed in all three valleys indicated the influence of the steel and metal industries on air quality. CONCLUSION: The finding that levels of particulate matter and trace elements in the study area were similar to or higher than those found in metropolitan areas has implications for the evaluation of health risks in populations far from large population centers.