Arsenicosis: the greatest public health disaster in history.

Abstract

Thanks to stories like the play Arsenic and Old Lace, familiarity with arsenic poisoning is widespread. Few have even heard of chronic arsenic toxicity or arsenicosis, which initially is a dermatological problem. Patients present with mottled hypopigmentation and hyperpigmentation, knownas “raindropson adusty road,” andpalmoplantar keratoses aswell asmultiple squamous cell andbasal cell carcinomas. Later, internal cancerscandevelop,mostoften involvingthe lungsandbladder.Only inorganic formsofarsenicare implicated inarsenicosis, andsystemic features vary with the arsenic salt; for example, in Taiwan, severe peripheral vascular disease knownas “black footdisease”develops.Noarsenicosis developed when organic arsenic compounds like Salvarsan were used to treat syphilis. Traditional sources of chronic exposure have been industrial, especially smelting zinc or copper ores. Arsenicwaswidely used as an insecticide, often as Paris green, so that agricultural workers and especially vintners who drank contaminated grappa were at risk. Arsenic tonics wereused to treatbothasthmaandpsoriasis; iatrogenic arsenicosiswas describedaround 1890bybothSir JonathanHutchinson inLondon,England, and James C. White in Boston, Massachusetts. Whilegroundwater contaminationwitharsenic and resultant arsenicosis has long been identified in many countries, such as China, Thailand, andArgentina, and in theGangesDelta, the situationhasdramatically changed in the past 4 decades. In the 1970s, UNICEF encouraged theboring of deep (20-80m) tubewells in Bangladesh to eliminate the health problems from drinking contaminated surface water. The first cases of arsenicosis were identified a decade later. By the time it was determined in the early 1990s that the well water was rich in arsenic, amajor public health disasterwas underway,whichhasbeen called the greatestmass poisoning in history. In 2000, at least 25%of thewells providedwater containingmore than5ppbof arsenic,meaning that 35 to 77million of Bangladesh’s 125million peoplewere drinking contaminatedwater. A later study did not shown any improvement. Efforts to solve the problem have included drilling still deeper wells into aquifers with lower arsenic levels, as well as relatively ineffective filters and ion exchange systems. Data from the epidemic indicate that cutaneous changes occur after about 10 years, while malignant neoplasms have a 20-year latency period. Only 20%of those exposed are estimated to develop arsenicosis, but the latency period makes such statements uncertain. Another alarming estimate is that 1 in 100peoplewho regularly drinkwater contaminatedwitharsenicwill die fromarsenic-inducedcancers.Today, concerted international actions are trying to reduce the burden of arsenicosis. Bothdermatologyorganizations and individual physicians should investigate ways in which they can support such activities.