1971 Iraq poison grain disaster
The 1971 Iraq poison grain disaster was a mass methylmercury poisoning incident that began in late 1971. Grain treated with a methylmercury fungicide and never intended for human consumption was imported into Iraq as seed grain from Mexico and the United States. Due to a number of factors, including foreign-language labelling and late distribution within the growing cycle, this toxic grain was consumed as food by Iraqi residents in rural areas. People suffered from paresthesia (numbness of skin), ataxia (lack of coordination of muscle movements) and vision loss, symptoms similar to those seen when Minamata disease affected Japan. The recorded death toll was 459 people, but figures at least ten times greater have been suggested. The 1971 poisoning was the largest mercury poisoning disaster when it occurred,[1] with cases peaking in January and February 1972 and stopping by the end of March.
Reports after the disaster recommended tighter regulation, better labelling and handling of mercury-treated grain, and wider involvement of the World Health Organization in monitoring and preventing poisoning incidents. Investigation confirmed the particular danger posed to fetuses and young children.
Context
The properties of
Causes
Some 95,000 tonnes (93,000 long tons; 105,000 short tons) of grain (73,201 tonnes of wheat grain and 22,262 tonnes of barley), coloured a pink-orange hue, were shipped to Iraq from the United States and Mexico. The wheat arrived in Basra on SS Trade Carrier between 16 September and 15 October, barley between 22 October and 24 November 1971. Iraq's government chose Mexipak, a high-yield wheat seed developed in Mexico by Norman Borlaug. The seeds contained an average of 7.9 μg/g of mercury, with some samples containing up to nearly twice that. The decision to use mercury-coated grain has been reported as made by the Iraqi government, rather than the supplier, Cargill.[6] The three northern governorates of Nineveh, Kirkuk and Erbil together received more than half the shipments. Contributing factors to the epidemic included the fact that distribution started late, and much grain arrived after the October–November planting season.
Farmers were supposed to plant the poisoned grain, but many instead offered it to their families as food, since their own planting had been completed. Distribution was hurried and open, with grain being distributed free of charge or with payment in kind. Some farmers even sold off their own grain, lest this new grain's harvest devalue their old varieties. This left them dependent on tainted grain for the winter. Many Iraqis were either unaware of the significant health risk posed, or chose to ignore the warnings.
Mercury was ingested through the consumption of homemade bread, meat and other animal products obtained from livestock given treated barley, vegetables grown from soil contaminated with mercury, game birds that had fed on the grain and fish caught in rivers, canals, and lakes into which treated grain had been dumped by the farmers. Ground seed dust inhalation was a contributing factor in farmers during sowing and grinding. Consumption of ground grain in homemade bread is thought to have been the major source of toxicity,[8] since no cases were reported in urban areas, where government flour supplies were commercially regulated.[1]
Symptoms, outbreak and treatment
The effect of mercury took some time – the latent period between ingestion and the first symptoms (typically paresthesia – numbness in the extremities) was between 16 and 38 days. Paresthesia was the predominant symptom in less serious cases. Worse cases included ataxia (typically loss of balance), blindness or reduced vision, and death resulting from central nervous system failure. Anywhere between 20 and 40 mg of mercury has been suggested as sufficient for paresthesia (between 0.5 and 0.8 mg/kg of body weight[8]). On average, individuals affected consumed 20 kg or so of bread; the 73,000 tonnes provided would have been sufficient for over 3 million cases.[1]
The hospital in
The
Effects
6,530 patients were admitted to hospitals with poisoning, and 459 deaths reported.[1] Cases reached a peak of hundreds per day in January, and had largely subsided by the beginning of March. The last admittance was on 27 March; admissions represented every age and gender stratum, although those under the age of ten represented a third of admitted cases. This number is "certainly an underestimate",[8] because of the availability of hospital treatment, hospital overcrowding and lack of faith in treatment. In the most severely affected areas, prevalence was 28% and mortality was 21% of the cases.[8] Some Iraqi doctors believe both the number of cases and fatalities are at least ten times too low,[6] with perhaps 100,000 cases of brain damage. One suggested reason for the vast discrepancy between reported and estimated numbers of deaths is the Iraqi custom, common to large parts of the Middle East, for a person to die at home when possible. Home deaths would not have been recorded.[9]
A large number of patients with minor symptoms recovered completely; those with more serious symptoms improved. This was in contrast to expected outcomes, largely based on analysis of
In 1974, a joint Food and Agriculture Organization (FAO) and World Health Organization (WHO) meeting made several recommendations to prevent a similar outbreak. These included stressing the importance of labelling bags in the local language and with locally understood warning symbols. The possibility of an additive creating a strong bitter taste was studied.[8] The meeting urged governments to strictly regulate methyl- and ethylmercury use in their respective countries, including limiting use to where no other reasonable alternative was available. It also recommended the involvement of the FAO and WHO in assisting national governments in regulation and enforcement, and the setting up of national poison control centres. Over 9–13 November, a Conference on Intoxication due to Alkylmercury-Treated Seed was held in Baghdad. It supported the recommendations of the FAO/WHO report and further suggested that local and national media should publicise outbreaks, including size and symptoms; it considered the distribution of this information crucial. It also laid out a general plan as to the collection of relevant information from the field and potential analysis for further investigation. It called on national governments to make use of WHO involvement whenever feasible, and absolved world governments in clear terms, saying that "No country should ever feel that any blame will attach to it for allowing an outbreak to occur".[8]
See also
References
- ^ PMID 4719063. Retrieved 11 June 2010.
- ISBN 978-0-444-98903-1.
- ^ United Kingdom Health and Safety Executive. Banned and Non-Authorised Pesticides in the United Kingdom. Retrieved on 13 June 2010.
- ^ PMID 788949.
- ^ Goodyear, EJ (2009). "The State of Disaster Risk Reduction in Iraq" (PDF). UN Inter-Agency Information and Analysis Unit: Iraq. p. 12. Archived from the original (PDF) on 2011-07-26. Retrieved 18 July 2010.
- ^ ISBN 978-1-59726-395-5.
- ^ ISBN 978-0-7637-5280-4. Retrieved 24 July 2010.
- ^ PMID 1087584.
- ^ a b Jernelov, Arne (2003-09-09). "Iraq's Secret Environmental Disasters". Project Syndicate. Archived from the original on 15 June 2010. Retrieved 10 June 2010.
- University of Maryland. Archivedfrom the original on 28 May 2010. Retrieved 14 June 2010.