Death in Small Doses: Arsenic Exposure in Cambodia

Cambodia Population around - 15 million Life expectancy - 57yr Infant mortality - 96 per 1000 births One of poorest countries in Asia – GDP $270 >35% below poverty line 32% no safe drinking water

Global problem of Arsenic Considered ‘worlds worst Considered ‘worlds worst environmental disaster’ WHO 2003, Zhu et.al Nº people at risk 1 US Unknown 8 India 1,000,000 2 Mexico 400,000 9 Bangladesh 50,000,000 3 Chile 437, Thailand 1,000 4 Bolivia 20, Vietnam Millions 5 Argentina 2,000, Taiwan 200,000 6 Hungary 20, China 720,000 7 Romania 36, Nepal Unknown

Toxicity of Arsenic Arsenobetaine (AB) Arsenic (As) Inorganic (As ¡ ) Organic (As o ) Arsenite (As III ) Arsenate (As V ) Methylarsonic acid (MA) Dimethylarsinic acid (DMA) Toxicity Highest Lowest

Impacts of arsenic Arsenicosis; hyperpigmentation, Keratosis Arsenicosis; hyperpigmentation, Keratosis Skin Cancers Skin Cancers Internal Cancers Internal Cancers Death Death Social stigma Social stigma Testing of exposure; Testing of exposure; –Blood2-3hr –Urine3-4days –Hair & NailsWeeks-months Once ingested cannot be removed Once ingested cannot be removed *As has no colour, smell or taste!

Cancer Risks Concentration Expected Death Rates Concentration Expected Death Rates 10 ug/L= 1 in ug/L= 1 in ug/L= 1 in 100 =Married to a smoker 50 ug/L= 1 in 100 =Married to a smoker 500 ug/L= 1 in 10 = Active Smoker 500 ug/L= 1 in 10 = Active Smoker 5000ug/L= all die EU recommended s Majority of Asian countries Excess Deaths Excess deaths due to Arsenic in Chile

Where does the Arsenic come from?

Groundwater Arsenic risk in Cambodia

How does it move through the environment?

Exposure Routes

As in drinking water regulations 0.01mg/l for total As – EU 0.01mg/l for total As – EU 0.01mg/l for inorganic As – WHO, USA 0.01mg/l for inorganic As – WHO, USA 0.05mg/l for total As – Bangladesh/India 0.05mg/l for total As – Bangladesh/India 100g of food containing 0.1mg/kg inorganic As in is equivalent to drinking 1L of 0.01mg/L As in water.

Mean Water Intakes and Percentage Contribution to MTDI at Various Contamination Levels – – Mean Consumption MTDI (n) (L per Day) 10 µg Lˉ¹ 50 µg Lˉ¹ 1000 µg Lˉ¹ 3500 µg Lˉ¹ Male (F) % 125% 2516% 8800% Male (H) % 60% 1208% 4229% Mean Male % 93% 1862% 6518% Female (F) % 77% 1541% 5395% Female (H) % 53% 1065% 3727% Mean Female % 65% 1303% 4561% Literature Standard 216% 83% 1666% 5833% MTDI calculated assuming a bodyweight of 60kg) (F) = Whilst working in the field, (H) = Whilst working around the house So how much arsenic are they drinking?

There is no regulatory limit for arsenic in foods No EU, US or WHO limits for either total As or inorganic As in food. No EU, US or WHO limits for either total As or inorganic As in food. Only China has MCLs of 0.15mg inorganic As/Kg rice. Only China has MCLs of 0.15mg inorganic As/Kg rice. Toxicology of arsenic is independent of source once arsenic crosses the gut. Toxicology of arsenic is independent of source once arsenic crosses the gut. Bioavailability of inorganic arsenic from rice is high (in the order of 90% (Ackerman et al., 2005; Juhasz et al., 2006). Bioavailability of inorganic arsenic from rice is high (in the order of 90% (Ackerman et al., 2005; Juhasz et al., 2006).

So how much arsenic are they eating? Summary of Total Arsenic Concentrations by Country and Province of Production Total arsenic (ppb) CountrynMean % of MTDI Cambodia Prey Veng % Kampot % Takeo % Kandal % Battam Bong % Kompong Thom % Kompong Speu % Cambodian Mean % China % Vietnam % Thailand % (MTDI calculated assuming a bodyweight of 60kg and 522g of rice consumption)

What can be done…. Identify risk zones for groundwater Identify risk zones for groundwater Identify risk zones for rice production Identify risk zones for rice production Mitigation or remediation Mitigation or remediation Education/awareness raising (people at risk, NGO’s, gov) Education/awareness raising (people at risk, NGO’s, gov)

An inspiration to us all…………. RDIC 2008 RDI Mickey Sampson Andrew Shantz

Education and awareness What is the impact of arsenic awareness raising programme (ARP) on the level of knowledge in 'mitigation' and 'comparison' villages What is the impact of arsenic awareness raising programme (ARP) on the level of knowledge in 'mitigation' and 'comparison' villages Ascertain how knowledge varies across the population (socio-economic factors affecting knowledge) Ascertain how knowledge varies across the population (socio-economic factors affecting knowledge) To examine the effect of arsenic knowledge on behaviour (choice of water sources) To examine the effect of arsenic knowledge on behaviour (choice of water sources)

Key Village Characteristics Preak Russei Roboah Angkhan Chrung Meas Mitigation Village Comparison Village 1 Comparison Village 2 n % female Average age Years of education Daily expenditure 2.5$3.7$3.1$ Land owned 0.68 ha 0.23 ha 0.74ha Number cattle/hh Number pigs/hh

Results: Differences in knowledge score between villages Significant differences in knowledge score between all villages (p=0.000) Significant differences in knowledge score between all villages (p=0.000) Variablen Knowledge Score (Mean) Mitigation Village Comparison V Comparison V

Conclusions Knowledge of the arsenic problem is very low in some areas Knowledge is likely to be influenced by distance from high risk areas and word of mouth, also group membership. ARPs can be more effective by taking this into account ARP seems to have removed the effect of education and wealth (expenditure) on arsenic knowledge, but may need to target older people more