Atta-ur-Rahman FRS,
N.I., H.I., S.I., T.I.
Front Page Article
Last week fourteen persons died and 350 were hospitalised when a ship MV Hercules carrying a large cargo of soya bean of US origin was being unloaded at berth 12 of the Karachi Port. The report by Pakistan’s premier research Institute, the International Center for Chemical and Biological Sciences at University of Karachi, suggested that the probable cause of death and illness was exposure to certain toxic materials present in soya bean dust. “The symptoms due to exposure to soybean dust (aeroallergens) may be considered as the possible cause,” the report stated, and it recommended bronchodilator and anti-histamine treatment for the patients and extreme care while uploading soybean containers.
There were all sorts of other rumours flying around, including exposure to nuclear waste, exposure to methyl bromide that may have been sprayed on containers containing old clothing, leakage of cylinders containing some toxic gases etc. It was also reported that MV Hercules was fumigated on Jan. 8 at Cargill grain reserve Los Angeles, US after loading onboard with 56 degree aluminum phosphide. It was stated in a report that the “the breathing of aluminum phosphide can irritate the nose, throat and lungs causing coughing, wheezing or shortness of breath whereas repeated exposure may damage the lungs, kidneys and liver.” So aluminum phosphide exposure was also considered as a possible cause of the unfortunate incident.
So what really happened and how can it be prevented in the future? A puzzling feature of the incident was that the workers unloading the soya bean consignment at the docks were not affected. A valid question that had to be answered was why was it that the workers nearest to the claimed toxic materials remained unaffected while those in farther places suffered severely and many died.
The first real clue regarding the cause of illness and deaths was obtained by the team led by Prof. Iqbal Choudhary at the International Center of Chemical and Biological Sciences at University of Karachi when they carried out a careful analysis of the blood and urine of affected patients. It was discovered that the Immunoglobin E (IgE) levels in most samples of affected patients were up to 10 fold higher than normal. IgE antibodies are normally found in small amounts in the blood, but higher amounts can be a sign that the body overreacts to certain materials that can cause severe allergies (allergens). The allergic reactions can cause inflammation of the throat and lungs, leading to difficulties in breathing, asphyxiation and even death.Diseases which cause the elevation of serum IgE levels include asthma, and allergic rhinitis. Allergy symptoms can range from sneezing and a stuffy nose to a life-threatening condition called “anaphylactic shock”. Not all persons affected need have higher IgE levels as the immune reactions of individuals vary. However about 70% of persons affected show higher levels of IgE which establishes without doubt that the substance causing the toxic affect was an allergen.
The discovery of much higher IgE levels in blood and urine samples of about 70% affected patients established that the cause was the breathing of some aeroallergens —— allergic materials carried by the wind— by susceptible persons. Why were not all persons exposed, particularly the dock workers affected? The reason is simple. Most persons are not allergic to soya bean dust. Only those allergic to it would show symptoms, and those severely allergic to it could die. This is similar to the pollen allergies encountered in March or April in Islamabad when not all persons are affected but only those allergic to pollen suffer.
A study of the literature shows that such incidents have been reported in other countries in the past associated with soya bean dust. The first such epidemics from soya bean dust were observed in Barcelona, Spain in 1981 and in subsequent 5 years, 26 such outbreaks of asthma were reported in Barcelona alone leading to the hospitalization of over a thousand patients and 20 deaths. .These epidemics corresponded with the unloading of soya beans in the Barcelona harbor. Similar incidents have previously been reported in Naples (Italy), New Orleans (USA), France and in other countries.
The incidents stopped when safety measures were introduced involving fitting of filters in the silos that were used in the unloading process. This filtration protocol is now standard the world over but was apparently ignored at the Keamari harbor.
A certain element of uncertainty remains as there are two landfill sites near the place where the asthma epidemics occurred. They need to be checked before reaching the final conclusion about this unfortunate incident. However one needs to ensure that future unloading of soya bean cargo should be carried out according to internationally prescribed procedures as such asthma epidemics and deaths due to toxic allergens are well established in many countries of the world.
The writer is the Chairman of the Prime Minister’s Task Force on Science & Technology, former Federal Minister of Science & Technology & former Chairman of Higher Education Commission.
