Thallium Contamination of Drinking Water: Health Implications in a Residential Cohort Study in Tuscany (Italy).

In 2014-2015, concentrations of thallium above the recommended reference value (EPA: 2 µg/L) were measured in some parts of the drinking water distribution system in the municipality of Pietrasanta (Tuscany, Italy). An extensive campaign of water samples and human biomonitoring surveys were implemented to quantify the exposure of population. A residential cohort epidemiological study was carried out on the population of the municipality of Pietrasanta, aimed at comparing the health status of residents in the areas affected by thallium contamination with residents living in the rest of the municipality. Cohort included people residing in the municipality of Pietrasanta from 1 January 2000 to 31 December 2015. Residence addresses were georeferenced and each subject living in one of the three contaminated areas were defined as exposed. Mortality, hospital discharge data and adverse pregnancy outcomes were taken from administrative health databases. Cox proportional hazard models and logistic models were used to test the association between thallium exposure and health outcome. This study did not show any excess of risk in terms of mortality and hospitalization in the population residing in the areas served by thallium-contaminated aqueduct branches, compared to the rest of the not contaminated area. Increased risks for low birth weight (OR = 1.43 95% CI 0.91-2.25) and pre-term birth (OR = 1.40 95% CI 0.82-2.37) were observed. In view of the paucity of epidemiological studies on thallium, this study is an important contribution to the state of knowledge of the health effects of chronic exposures to low concentrations of thallium.

Human biomonitoring to assess exposure to thallium following the contamination of drinking water.

In 2014, in some parts of the water distribution system of the municipality of Pietrasanta (Tuscany, Italy), thallium (Tl) levels above the recommended limits were measured and some restrictions to water usage for drinking and food preparation were imposed. The study aimed to assess Tl exposure and possible health effects by means of a human biomonitoring survey. In the 2014-2016 time frame, 2154 urine and 254 hair samples were taken from different population groups and from a control group. The levels of Tl found in urine and hair were statistically higher in exposed groups than in controls and compared to the reference values for the general population. Concentrations in urine were significantly associated with the geographical origin of the sample, the consumption of drinking water and food grown in local gardens. A significant association was found between urine and hair. No positive associations were found between the Tl levels in hair or urine and several self-reported symptoms and health effects, except for sleep disturbance. The study indicates that the concentration of Tl in drinking water can be traced by urine analysis. Urine and hair have proven to be biological matrices that can be effectively used for the evaluation of Tl exposure. To date, the study represents the most extensive human biomonitoring campaign for the evaluation of the Tl exposure available at international level.

[Epidemiological study on the population resident in the neighbourhood of an incinerator in Tuscany Region (Central Italy)]. / Indagine epidemiologica sulla popolazione residente nell'area circostante un impianto di combustione di rifiuti solidi in Toscana.

OBJECTIVES: to evaluate the health impact of the emissions of two waste incinerators located in the same area in Pietrasanta (Tuscany Region, Central Italy) at the border with the municipality of Camaiore, especially for diseases suggested in previous studies to be related to those emissions. DESIGN: epidemiological geographic study. SETTING AND PARTICIPANTS: the study population was defined on the basis of residence in the two municipalities and in the areas characterized by Particulate Matter with diameter equal or less than 2.5 µm (PM2.5) and poli-chloro-dibenzo-dioxin / poli-chloro-dibenzo-furans (PCDD/F) pollution defined with a dispersion model. From the resident population, for each cancer case it was sampled a control, matched to case by gender and age at case's diagnosis, and for each premature and low-weight newborn a control matched was sampled by year of birth, gender, and mother's residence. MAIN OUTCOME MEASURES: standardized (standard: European population) mortality and hospitalization rates in the residents of the two municipalities were calculated for liver, larynx, lung cancer, soft tissue sarcoma (STM), non-Hodgkin lymphoma (NHL), multiple myeloma, leukaemia, flu-excluded respiratory diseases, and circulatory diseases. The risk related to each PM2.5 and PCDD/F pollution level from the old incinerator for cancer and from the new plant for reproductive outcomes was analysed using logistic conditional regression model adjusted by gender and age. RESULTS: the mortality and hospitalization rates observed in the study area are similar to those calculated for the Versilia area excluded the two municipalities under study. There is a higher case distribution in the higher pollution levels, with significant increases in the highest level: • liver cancer: PM2.5 OR 2.3 (95%CI 1.5-3.6); PCDD/F OR 4.4 (95%CI 2.8-7.0); • larynx cancer: PCDD/F OR 3.2 (95%CI 1.5-6.7); • lung cancer: PCDD/F OR 1.5 (95%CI 1.1-2.0); • NHL: PCDD/F OR 8.5 (95%CI 3.1-23.5); • leukaemia: PCDD/F OR 4.1 (95%CI 1.8-9.3). The risks estimated for STM, although non significant, are consistent with those obtained in previous studies undertaken in areas characterized by dioxin pollution. There is a deficit of premature births in the area under study compared to the regional area, and no differences are observed among the different pollution areas. CONCLUSIONS: it cannot be excluded that the emissions from the old incinerator had a health impact on the population living in the neighbourhood. Nevertheless, it is possible that other risk factors (occupations and life styles) could have had a role on the obtained results. Better estimates could be obtained also taking into consideration the residential histories of the subjects under study.