Che cos'è
L'arsenico (As) è un semimetallo presente generalmente nell'ambiente in forma inorganica (composti con ossigeno, cloro e solfuri) e in forma organica (composti con carbonio e idrogeno). La distinzione tra inorganico e organico è fondamentale in quanto le forme inorganiche sono molto più pericolose rispetto a quelle organiche. Sia i composti inorganici sia quelli organici si presentano sottoforma di polveri di colore bianco o neutro, inodori e insapori.

Le concentrazioni medie di arsenico in aria variano tra 1-3 ng/m³ nelle zone isolate e i 20-100 ng/m³ nelle aree urbane. Generalmente, i livelli di arsenico nelle acque si attestano intorno ai 2 µg/m³. La legislazione europea e italiana fissano a 10 µg/l il limite massimo di concentrazione di arsenico nelle acque destinate al consumo umano, sebbene in Italia, e in Toscana, siano attualmente in vigore delle deroghe (limite a 20 µg/l) nelle aree caratterizzate da alte concentrazioni di arsenico di origine naturale.

Vie di esposizione
La principale via di esposizione all'arsenico è quella orale, per ingestione di cibi e acqua contaminati da arsenico; meno rilevanti la via inalatoria e per contatto epidermico. Gli alimenti che normalmente contengono maggiori quantitativi di arsenico sono i frutti di mare, riso, cereali, funghi, pollame. I bambini possono essere esposti anche per ingestione di suolo contenente arsenico.

Effetti sulla salute umana
L'arsenico inorganico è stato classificato dall'Agenzia internazionale per la ricerca sul cancro (IARC) come cancerogeno certo per l'uomo. Le sedi tumorali maggiormente coinvolte sono la pelle, il fegato, la vescica, i reni, la prostata e i polmoni. Gli effetti non cancerogeni tipicamente associati a una esposizione cronica ad arsenico inorganico  riguardano danni alla pelle, quali iperpigmentazione, ipercheratosi, calli, verruche. Altri effetti sanitari sono a carico del sistema respiratorio e cardiovascolare, diabete mellito, effetti neurologici, problemi riproduttivi.

L'arsenico nelle acque potabili dell'area geotermica toscana
Le concentrazioni di arsenico nelle acque potabili dell'area geotermica toscana negli ultimi anni hanno raggiunto valori prossimi o superiori al limite normativo di 10 microg/l, tanto da indurre alcuni comuni a far ricorso con una certa sistematicità alla richiesta di deroga ai limiti normativi. Comunque, nel corso del 2010, grazie ai nuovi sistemi di abbattimento introdotti dagli enti gestori, i livelli di arsenico sono scesi a valori tali da non dover ricorrere più alle deroghe.

Documenti rilevanti
Studi su marcatori di esposizione ed effetto precoce in aree con inquinamento da arsenico: metodi e risultati del progetto SEpiAs. Epidemiologia & Prevenzione anno 38 (3-4) maggio-agosto 2014
Progetto SEpiAs CCM2010 - Sorveglianza epidemiologica in aree interessate da inquinamento ambientale da arsenico di origine naturale o antropica. Rapporto conclusivo - Ottobre 2013
Agency for Toxic Substances and Disease Registry (ATSDR). Toxicological profile for arsenic, 2007.
International Agency for Research on Cancer (IARC). Monographs on the Evaluation of Carcinogenic Risks to Humans Vol. 84. Some drinking-water disinfectants and contaminants, including arsenic, 2004.
International Agency for Research on Cancer (IARC). Monographs on the Evaluation of Carcinogenic Risks to Humans Vol. 100C. A review of human carcinogens: arsenic, metals, fibres, and dusts, 2011.
World Health Organization. Guidelines for drinking-water quality, fourth edition, 2011.
World Health Organization. Arsenic in drinking-water background document for development of WHO guidelines for drinking-water quality, 2011.
World Health Organization. Exposure to arsenic: A major public health concern, 2010.
European Food Safety Authority. Dietary exposure to inorganic arsenic in the European population. EFSA Journal 2014;12(3):3597, 68 pp.

Selezione articoli di particolare interesse
Moon K, Guallar E, Navas-Acien A. Arsenic exposure and cardiovascular disease:an updated systematic review. Curr Atheroscler Rep. 2012 Dec;14(6):542-55.
Bloom MS, Fitzgerald EF, Kim K, Neamtiu I, Gurzau ES. Spontaneous pregnancy loss in humans and exposure to arsenic in drinking water. Int J Hyg Environ Health. 2010 Nov; 213(6):401-13. Review.
Cantor KP. Carcinogensin drinking water: the epidemiologic evidence. Rev Environ Health. 2010 Jan-Mar; 25(1):9-16. Review.
Balakumar P, Kaur J. Arsenic exposure and cardiovascular disorders: an overview. Cardiovasc Toxicol. 2009 Dec; 9(4):169-76. Review.
Chen Y, Parvez F, Gamble M, Islam T, Ahmed A, Argos M, Graziano JH, Ahsan H. Arsenic exposure at low-to-moderate levels and skin lesions, arsenic metabolism, neurological functions, and biomarkers for respiratory and cardiovascular diseases: review of recent findings from the Health Effects of Arsenic Longitudinal Study (HEALS) in Bangladesh. Toxicol Appl Pharmacol. 2009 Sep 1; 239(2):184-92.
Celik I, Gallicchio L, Boyd K, Lam TK, Matanoski G, Tao X, Shiels M, Hammond E, Chen L, Robinson KA, Caulfield LE, Herman JG, Guallar E, Alberg AJ. Arsenic in drinking water and lung cancer: a systematic review. Environ Res. 2008 Sep; 108(1):48-55. Epub 2008 May 29. Review.
Mink PJ, Alexander DD, Barraj LM, Kelsh MA, Tsuji JS. Low-level arsenic exposure in drinking water and bladder cancer: a review and meta-analysis. Regul Toxicol Pharmacol. 2008 Dec; 52(3):299-310. Epub 2008 Aug 26. Review.
Cantor KP, Lubin JH. Arsenic, internal cancers, and issues in inference from studies of low-level exposures in human populations. Toxicol Appl Pharmacol. 2007 Aug 1; 222(3):252-7. Epub 2007 Feb 24. Review.

Selezione ultimi articoli pubblicati
Das D, Bindhani B, Mukherjee B, Saha H, Biswas P, Dutta K, Prasad P, Sinha D, Ray MR. Chronic low-level arsenic exposure reduces lung function in male population without skin lesions. Int J Public Health. 2014 May 31
Saint-Jacques N, Parker L, Brown P, Dummer TJ. Arsenic in drinking water and urinary tract cancers: a systematic review of 30 years of epidemiological evidence. Environ Health. 2014 Jun 2;13(1):44
Becker A, Axelrad D. Arsenic and type 2 diabetes: commentary on association of inorganic arsenic exposure with type 2 diabetes mellitus: a meta-analysis by Wang et al. J Epidemiol Community Health. 2014 May 1;68(5):393-5
Bustaffa E, Stoccoro A, Bianchi F, Migliore L. Genotoxic and epigenetic mechanisms in arsenic carcinogenicity. Arch Toxicol. 2014 Apr 2
Dauphiné DC, Smith AH, Yuan Y, Balmes JR, Bates MN, Steinmaus C. Case-control study of arsenic in drinking water and lung cancer in California and Nevada. Int J Environ Res Public Health. 2013 Aug 2;10(8):3310-24.
Christoforidou EP, Riza E, Kales SN, Hadjistavrou K, Stoltidi M, Kastania AN, Linos A. Bladder cancer and arsenic through drinking water: A systematic review of epidemiologic evidence. J Environ Sci Health A Tox Hazard Subst Environ Eng. 2013;48(14):1764-75.
Dangleben NL, Skibola CF, Smith MT. Arsenic immunotoxicity: a review. Environ Health. 2013 Sep 2;12(1):73.
Stea F, Bianchi F, Cori L, Sicari R. Cardiovascular effects of arsenic: clinical and epidemiological findings. Environ Sci Pollut Res Int. 2013 Sep 10.
Parvez F, Chen Y, Yunus M, Olopade C, Segers S, Slavkovich V, Argos M, Hasan R, Ahmed A, Islam T, Akter MM, Graziano JH, Ahsan H. Arsenic Exposure and Impaired Lung Function: Findings from a Large Population-based Prospective Cohort Study. Am J Respir Crit Care Med. 2013 Jul 12.
Osorio-Yáñez C, Ayllon-Vergara JC, Aguilar-Madrid G, Arreola-Mendoza L, Hernández-Castellanos E, Barrera-Hernández A, De Vizcaya-Ruiz A, Del Razo LM. Carotid intima-media thickness and plasma asymmetric dimethylarginine in Mexican children exposed to inorganic arsenic. Environ Health Perspect. 2013 Jun 11. [Epub ahead of print]
Naujokas MF, Anderson B, Ahsan H, Aposhian HV, Graziano JH, Thompson C, Suk WA. The broad scope of health effects from chronic arsenic exposure: update on a worldwide public health problem. Environ Health Perspect. 2013 Mar;121(3):295-302
Begum M, Horowitz J, Hossain MI. Low-dose risk assessment for arsenic: a meta-analysis approach. Asia Pac J Public Health. 2012 Nov 27. [Epub ahead of print]
Feki-Tounsi M, Olmedo P, Gil F, Khlifi R, Mhiri MN, Rebai A, Hamza-Chaffai A. Low-level arsenic exposure is associated with bladder cancer risk and cigarette smoking: a case-control study among men in Tunisia. Environ Sci Pollut Res Int. 2012 Nov 27. [Epub ahead of print]
Argos M, Ahsan H, Graziano JH. Arsenic and human health: epidemiologic progress and public health implications. Rev Environ Health. 2012 Sep 10;0(0):1-5. doi: 10.1515/reveh-2012-0021. [Epub ahead of print]
Gribble MO, Howard BV, Umans JG, Shara NM, Francesconi KA, Goessler W, Crainiceanu CM, Silbergeld EK, Guallar E, Navas-Acien A. Arsenic exposure, diabetes prevalence, and diabetes control in the Strong Heart Study. Am J Epidemiol. 2012 Nov 1. [Epub ahead of print]
Maull EA., Ahsan H, Edwards J, Longnecker MP, Navas-Acien A, Pi J, et al. Evaluation of the association between arsenic and diabetes: A national toxicology program workshop review. Environ Health Perspect 2012 Aug 10.
Abir T, Rahman B, D'Este C, A F, Milton AH. The association between chronic arsenic exposure and hypertension: A meta-analysis. J Toxicol. 2012;2012:198793.
Leonardi G, Vahter M, Clemens F, Goessler W, Gurzau E, Hemminki K, Hough R, Koppova K, Kumar R, Rudnai P, Surdu S, Fletcher T. Inorganic arsenic and basal cell carcinoma in areas of hungary, romania, and slovakia: a case-control study. Environ Health Perspect. 2012 May;120(5):721-6.
Jovanovic D, Rasic-Milutinovic Z, Paunovic K, Jakovljevic B, Plavsic S, Milosevic J. Low levels of arsenic in drinking water and type 2 diabetes in Middle Banat region, Serbia. Int J Hyg Environ Health. 2012 Feb 10.
Marchiset-Ferlay N, Savanovitch C, Sauvant-Rochat MP. What is the best biomarker to assess arsenic exposure via drinking water? Environ Int. 2012 Feb;39(1):150-71.
Abhyankar LN, Jones MR, Guallar E, Navas-Acien A. Arsenic exposure and hypertension: a systematic review. Environ Health Perspect. 2012 Apr;120(4):494-500.
Rivera-Núñez Z, Meliker JR, Meeker JD, Slotnick MJ, Nriagu JO. Urinary arsenic species, toenail arsenic, and arsenic intake estimates in a Michigan population with low levels of arsenic in drinking water. J Expo Sci Environ Epidemiol. 2012 Mar-Apr;22(2):182-90.
Chen Y, Parvez F, Liu M, Pesola GR, Gamble MV, Slavkovich V, Islam T, Ahmed A, Hasan R, Graziano JH, Ahsan H. Association between arsenic exposure from drinking water and proteinuria: results from the Health Effects of Arsenic Longitudinal Study. Int J Epidemiol. 2011 Jun;40(3):828-35.
Huang CF, Chen YW, Yang CY, Tsai KS, Yang RS, Liu SH. Arsenic and diabetes: current perspectives. Kaohsiung J Med Sci. 2011 Sep;27(9):402-10. Review.