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Health Impact Assessment

The evaluation of a potential exposure to Mercury (Hg), as well as to another xenobiotic, is done using the reference value (RV). It defines the metal concentration occurring in biological matrices (human fluids and/or tissues) as resulting from statistical treatment of the its dosage in a population or in a reference group, no professionally exposed. We refer to these values in order to assess the level of a potential exposure of other groups or individuals. The RV is used, therefore, as a term of comparison for assessing the true extent of unknown exposure. There are only few studies – ranging from 1990 to 2009 - on Italy’s population mercury exposure; and the sample size is not representative.

In 2008 the Italian Ministry of Health commissioned and funded the PROBE (Programme for Biomonitoring general population Exposure), a project carried out by Italian National Institute for Health (ISS) representing the first attempt to estimate the internal dose of metals (Hg included) of the Italy’s population as a consequence of environmental exposure. The project developed harmonized procedures and validated protocols aimed at establishing reliable RVs of twenty toxic metals. The purpose was to make the results comparable with those of similar monitoring campaigns in Europe and, eventually, to generate reliable information to develop exposure restriction and prevention strategies.

Table 1 shows the PROBE’s results as well as other previous studies that follow quality criteria in the selection of the population, in the validation of the analyses of the samples and statistical data treatment. In the case of breast milk, there are no studies devoted to the definition of Italian RVs, and the values reported in the table 1 should be considered only indicative of the Hg content in this matrix, due to the small sample number. Other significant matrices for evaluating human Hg exposure, such as hair and nails, are not defined.



Reference values ​​for mercury in the Italian population from 1990.  
(modified from [10])

Blood (µg/L)

Serum (µg/L)

Urine (µg/L)

Cerebrospinal fluid (µg/L) Breast milk (µg/g)

 - - - -  ≤ 0,5** [1] 1982 
 - - - -  13,9±12,9** [2] 1989 
1,7-9,9    0,6-3,8   0,1-6,9   -   -  [3] 1990 
 -  -  -  0,15-2,2  -  [4] 1992 
 -  -  0,12-5,02 *   -   -  [5] 2002 
 -  -   0,21-3,20 *   -  [6] 2003 
1,97-14,5  0,32-2,75  -    -  [7] 2005 
 -  -   -    -  2,63-3,53 *** [8] 2008 
 0,35-5,16  0,13-1,89   -    -   -  [9] 2010 

* informational values only (average±DS)
** in μg/g of creatinine
*** minimum-maximum range of values of different pools (CV≈10%)


[1]   Clemente GF, Ingrao G, Santaroni GP. The concentration of some trace elements in human milk from Italy.  Sci Total Environ 1982;24:255-65.
[2]   Paccagnella B, Riolfatti M. Livelli di mercurio totale nel latte umano di madri italiane senza particolare esposizione al metal-mercurio. Ann Ig Med Prev Comun 1989;1:661-71.
[3]   Minoia C, Sabbioni E, Apostoli P, Pietra R, Pozzoli L, Gallorini M, Nicolaou G, Alessio L, Capodaglio E. Trace element reference values in tissues from inhabitants of the European Community. I. A study of 46 elements in urine, blood and serum of italian subjects. Sci Total Environ 1990;95:89-105.
[4]   Sabbioni E, Minoia C, Pietra R, Fortaner S, GalloriniM, Saltelli A. Trace element reference values in tissues from inhabitants of the European Community. II. Examples of strategy adopted and trace element analysis of blood, lymph nodes and cerebrospinal fluid of Italian subjects. Sci Total Environ 1992;120:39-62.
[5]   Apostoli P, Cortesi I, Mangili A, Elia G, Drago I, Gagliardi T, Soleo L, Valente T, Sciarra GF, Aprea C, Ronchi A, Minoia C. Assessment of reference valuesfor mercury in urine: the results of an Italian polycentric study. Sci Total Environ 2002-a;289(1-3):13-24.
[6]   Soleo L, Elia G, Russo A, Schiavulli N, Lasorsa G, Mangili A, Gilberti E, Ronchi A, Balducci C, Minoia C, Aprea C, Sciarra GF, Valente T, Fenga C. Valori di riferimento del mercurio urinario nella popolazione italiana. G Ital Med Lav Erg 2003;25(1):107-13.
[7]   Alimonti A, Bocca B, Mannella E, Petrucci F, ZennaroF, Cotichini R, D’Ippolito C, Agresti A, Caimi S, Forte G. Assessment of reference values for selected elements in a healthy urban population. Ann Ist Super Sanità 2005;41(2):181-7.
[8]   Abballe A, Ballard TJ, Dellatte E, di Domenico A, Ferri F, Fulgenzi AR, Grisanti G, Iacovella N, Ingelido AM, Malisch R, Miniero R, Porpora MG, Risica S, Ziemacki G, De Felip E. Persistent environmental contaminants in human milk: concentrations and time trends in Italy. Chemosphere Vol. 73, Issue 1, Supplement, August 2008, Pages S220–S227.


Alimonti A, Bocca B, Mattei D, Pino A. Programma per il biomonitoraggio dell’esposizione della popolazione italiana (PROBE): dose interna dei metalli. Rapporti ISTISAN 11/9, 1-83. Istituto superiore di sanità.



Alimonti A, Bocca B, Mattei D, Pino D. Biomonitoraggio della popolazione italiana per l’esposizione ai metalli: valori di riferimento 1990-2009. Rapporti ISTISAN 10/22, 1-59. Istituto superiore di sanità.