Chapter 10
MANY KINGS AND QUEENS employed royal tasters to sample their food for them, as this was such a favourite method of poisoning in the past. Simon, a monk at the court of King John, committed suicide in 1216 by deliberately drinking some wine that he knew to be poisoned, to try to get the King to drink it as well. He failed!
Boiled to death
King Henry VIII may be best known for his six wives, but he was also a bloodthirsty tyrant. He had more than 70,000 people executed during the 38 years he reigned – more than five every day.
In 1531, King Henry VIII was especially harsh. A man named John Roose was convicted of poisoning 17 people in the Bishop of Rochester’s house; he had poisoned the broth served to both the Bishop’s family and the poor of the parish and two people died as a result. The King wanted a particularly nasty punishment for John Roose, to deter others from food tampering. He passed a very special law: felons would be boiled to death and would be denied the last rites before their punishment. And so John Roose was boiled to death. This special law was in force for 16 years, and during this time a woman called Margaret Davey met the same fate. She was found guilty of tampering with foodstuffs at Smithfield, the famous meat market outside the London city walls at that time. Although Edward VI ‘downgraded’ the punishment for deliberate poisoning to the same as for murder, this law was not formally removed until 1863.
Unexpected additives
Food has often been adulterated so that cheaper produce can be passed off as being of a better quality than it really is. This was so rife in the early years of the nineteenth century that a German chemist, Friedrich Accum, who had lived in Britain for over 30 years, published his ‘Treatise on the Adulteration of Food and Culinary Poisons’ in London in 1820.
In one example, he revealed some Gloucestershire cheese to which some red lead had been added. This cheese was usually coloured with annatto, a natural colouring derived from a plant. A trader had used an additive to improve the colour of his poor quality annatto before selling it on to an unsuspecting farmer, who made the cheese. Unfortunately, the vermilion pigment used (which contains mercury) had itself already been adulterated with red lead by the druggist who supplied it. This druggist had thought it would only be used for house painting, and adulterated it to increase his own profit.
Herr Accum also exposed other doubtful practices, such as how flour was ‘improved’ when the harvest was poor, being mixed with potato flour, barley bran and other similar substances. This produced a rather dark coloured flour, which was then ‘whitened’ by the addition of alum. There was no limit to products being adulterated: milk was watered down, with chalk added to whiten it; copperas was added to beer, and capsicum to mustard; artificial tea was made from blackthorn leaves; and ‘coffee’ was made from horse beans, wheat or rye, which were first partially burnt and then ground down. Much of the wine at that time was made from spoiled cider.
In 1875, the Foods and Drugs Act said that ‘no person shall mix any article of food with any ingredient or material to render it injurious to health’. But that didn’t stop the watering down of milk and the continuation of other dubious practices. It would be many years later that legislation to protect the public from such food adulteration would be introduced and enforced. Even today there are dubious practices, such as adding water to chicken meat, changing sell-by dates, and selling pet food for human consumption.
Naturally occurring toxins can sometimes be found in foodstuffs. This may be due to an error in the preparation, or to a poisonous part (such as rhubarb leaves – read on below) being used instead of being discarded. And the spoilage of food may occur during storage, if either the temperature and/or humidity are unsuitable, which may lead to bacterial or fungal growth and spoilage. In the time of Herr Accum, most of the butter was rancid, the meat tainted and the fish stinking, because in those far-off days refrigeration had not yet been invented.
Rhubarb, sorrel soup, rabbits, trees and ragwort
Rhubarb and custard is a traditional pudding in Britain. The young stems are boiled gently until tender, with a little sugar and ginger added to taste. The rhubarb leaves are always discarded as they contain poisonous oxalic acid crystals. Many accidental poisonings have occurred over the years, when small children have eaten bits of these leaves. Immediate first aid in such a case is to give the child a big drink of milk and then take him or her to the nearest hospital accident and emergency department. The calcium in the milk will combine with the oxalic acid to form calcium oxalate, an insoluble substance that cannot then be absorbed from the stomach.
Other plants also contain oxalic acid. Sorrel, a wildflower whose stems and leaves contain oxalic acid, is used, sparingly, in salads and soups. But, in 1989, there was a fatal case of oxalic acid poisoning caused by eating sorrel soup.
In 1921, The Lancet carried an unusual report of belladonna poisoning, which was caused by eating a rabbit! The rabbit had eaten some deadly nightshade shortly before it was killed for the pot, and this remained in the meat. Fortunately, the poisoning was not too severe in those who ate the rabbit meat, but it did cause dilated pupils, a dry mouth, giddiness and a rapid pulse.
If you take a holiday in Jamaica, then beware of a small fruit tree called the Akee. The seed covering, or arillus, of the unripe fruit of the akee contains a toxic substance called hypoglycin A, which is responsible for the so-called Jamaican vomiting sickness. The symptoms are acute and severe vomiting, low blood sugar, muscular weakness, central nervous system depression and convulsions leading to coma – such poisoning is frequently fatal.
Common ragwort, an abundant weed in Britain, is poisonous to livestock if eaten in quantity, and even a single ragwort leaf can damage a horse’s liver. Dried ragwort is even more poisonous than the fresh plant, so great care must be taken during haymaking to ensure that no ragwort is contained in the hay bales, especially if it is intended to be fed to horses over the following winter. Ragwort should only be handled when wearing gloves, to avoid any risk of skin absorption. There is risk of chronic poisoning from both the common species here in Britain, and from the golden ragwort found in the USA. Both species have been used in the past in the herbal treatment of menstrual complaints. In Arizona, USA, in the 1970s, there were reports of liver damage and death following consumption of a herbal tea, called Gordolobos, made from yet another species of ragwort. The widespread use of such herbal teas in the traditional medicine of the West Indies is a continuing problem, as chronic exposure to low doses of pyrrolizidine alkaloids, found in these plants, can lead to liver cirrhosis.
Poisonous plankton
In the Philippines, paralytic poisoning is caused by eating certain shellfish. And in Australia and the Pacific Islands there are more than 20,000 cases every year of food poisoning due to people eating coral reef fish. The cause of poisoning is the same for both shellfish and coral reef fish: the plankton these sea creatures eat produce saxitoxin, a nerve poison that does not affect them at all, but has dire effects on the humans who like eating seafood.
Toxic fungi
Aflatoxins are fungal poisons produced by the Aspergillus fungus, which grows on many vegetables, but particularly on peanuts. Aflatoxins cause liver damage and liver cancer in animals, and there is a similar link to liver cancer in humans. In 1978, a report in The Lancet told of two children who developed Reye’s syndrome. This condition is usually associated with the use of aspirin in children, and will be described in detail in Chapter 18, Malevolent Medicines. These children were both found to have aflatoxin in their blood during the acute phase of the illness. In October 2004, there was a health scare in Hungary, when it was discovered that supplies of the national spice, paprika – the mainstay of Hungarian cuisine, made by grinding down dried red peppers – were adulterated with some very inferior paprika from Latin America, which was heavily contaminated with aflatoxin.
Many outbreaks of ergotism, due to the ergot fungal infection of rye, have occurred throughout history, particularly in those parts of Europe and Russia, where rye bread is a staple part of the peasant diet. There was a major outbreak near the Urals in 1926-7, when over 11,000 people were affected. Russia suffered again in 1942-3 when Fusarium, another fungal infection, affected the grain in parts of Siberia resulting in thousands of people dying within two weeks of eating the affected bread. In 1979 The Lancet carried a report of an outbreak of ergotism, attributed to the ingestion of infected wild oats, in Wollo, Ethiopia.
Poisoned porridge and other contaminated foods
Sometimes foodstuffs are found to contain a toxic substance in error or a permitted substance in a vastly increased amount.
In 1950, the British Medical Journal reported a case of poisoned porridge. Two people were taken ill within ten minutes of eating their bowls of porridge at breakfast one morning. The porridge oats used were found to be contaminated with potassium bichromate to the extent of one part in 400. How it got there was never discovered, but the symptoms included severe abdominal pain and vomiting. Fortunately, there was no lasting damage in this case, but there have been a number of fatal poisonings due to potassium bichromate in the past.
During the Prohibition Era (1919-1933), when alcoholic drinks were banned in the USA, there was an epidemic of progressive paralysis in the south and mid-west of the country. It started with aching muscles, then numbness, followed by loss of sensation, weakness and eventually paralysis. Some 20,000 cases were diagnosed, affecting both the arms and legs of the patients. The cause was traced to drinking an imitation ginger extract. This was a medicinal product with a high alcoholic content that had escaped the Prohibition ban. Investigations eventually traced the problem to a contaminant in the product, which affected the nervous system. Very few deaths occurred, but most of the people affected only made a partial recovery after some months, and in many cases the paralysis seemed permanent.
Potassium bromate is a chemical added to flour to improve or mature it, only in a very small quantity. However, in South Africa in the late 1960s, nearly a thousand people were poisoned by eating bread prepared from dough containing too much potassium bromate. On analysis the poisoned bread was found to contain almost 300 times too much.
In early 1981, a mass poisoning began in Spain, particularly affecting those living in Madrid and the northwest regions of the country. This was traced to contaminated cooking oil, and by June 1981 the Spanish government had begun to remove it from the market. The last new case was found in September of that year. About 25,000 people were affected and more than 600 eventually died. Severe respiratory illness, with fever, rash and weak, painful muscles led on to long-term neuromuscular damage in about 20 per cent of those who survived.
The cooking oil was mainly rapeseed oil, but also contained a little aniline, as required by Spanish law for all imported rapeseed oil – to prevent it from being used for cooking. It had been imported into Spain for industrial use only, but someone decided to sell it and make a lot of extra profit. After treatment, which was supposed to remove the aniline, it was sold, house to house, and at street markets – and people bought it because it was very cheap. Too cheap! The cooking oil, when analysed, was found to contain rapeseed oil, other seed oil – including olive oil – but also liquefied pork fat, together with traces of aniline and fatty acid anilides.
Sensitive to preservatives
In Europe, every food additive is given an E number. This includes not just colouring agents like tartrazine (E102), but preservatives, anti-oxidants, emulsifiers, stabilisers and thickeners, flavours and flavour enhancers, artificial sweeteners, nutrients and many others such as anti-foaming and anti-caking agents. The USA has a similar – though different – system of codes for food additives.
Chinese Restaurant Syndrome appeared in the 1970s with the increase in the number of Chinese restaurants at that time. Some customers suffered tingling and weakness of the face and upper body, and flushing of the skin. They had palpitations and felt anxious, nauseous and thirsty after eating their Chinese meal. These symptoms were partly due to a deficiency in vitamin B6 (pyridoxine), which was needed to safely eat the Chinese food: a flavour enhancer called monosodium glutamate is used in cooking Chinese food and pyridoxine is needed to metabolise and so remove the glutamate. The symptoms were due to the toxic effects caused by the glutamate.
The food industry uses preservatives to prevent spoilage of foodstuffs, but these can sometimes cause problems. Sodium nitrate and potassium nitrate are both used as preservatives in the food industry, particularly for meat products. Sodium nitrite is also used, but in much smaller quantities, as this is the dangerous one.
In 1997, there was a report of three people who became ill after eating sausages that had been preserved with a mixture of sodium nitrate and sodium nitrite, rather than sodium nitrate and potassium nitrate. As a result of the incorrect sodium nitrite content, the sausage eaters became cyanosed (turned blue), and developed methaemoglobinaemia, a condition in which the haemoglobin in the blood is changed so that it can no longer carry oxygen.
Over 70 years ago, in 1936, three members of a Middlesborough family died within two hours of consuming some sodium nitrite, taken in error for salt (sodium chloride). These were the first known fatalities due to nitrite poisoning in Great Britain at that time.
Some people seem to be particularly sensitive to sodium nitrite when it is used as a preservative in food or drink. One person developed headaches after eating cured meat products, and also when given a weak solution of the suspected preservative in water to drink. Another had recurrent attacks of muscle pain when he drank beer that contained sodium nitrite as a preservative. Sodium nitrite is not allowed at all in foodstuffs intended for small babies due to the high risk of methaemoglobinaemia.
In Australia in the 1970s, because of the hot weather, a 36-year-old man accidentally took sodium nitrite tablets (1g daily) for several weeks, thinking that they were salt tablets. One particularly hot day, after taking double the usual dose, he became ill. He became obviously cyanosed, was perspiring and was quite distressed but recovered after receiving treatment, which included the administration of oxygen.
Sulphur dioxide and various sulphites are also used as food preservatives. Sodium, potassium and calcium sulphites are all used because, when in aqueous solution, they form sulphur dioxide, which kills bacteria. And because it is also an anti-oxidant, it prevents food from going brown. It is widely used with both fruit and vegetables because it preserves the natural colour. When grapes are crushed, the juice will start to ferment naturally, due to wild yeasts present on the skin of the fruit. This natural fermentation can be prevented by as little as 10 parts per million of sulphur dioxide. When making wine, specially cultured yeasts, which can survive sulphur dioxide, can then be added to produce wine of the desired quality. Just before bottling the wine, the sulphite is added to prevent any further fermentation. This sulphite will react with other components in the wine, dissipating as it matures during storage. However, young wines, lacking the all-important storage stage, often contain noticeable amounts of sulphur dioxide.
Salt substitutes
Sodium chloride is the chemical name for ordinary salt, which we add to our food during cooking, or at the table. Because a low sodium diet is helpful for those with high blood pressure, many chemicals have been marketed as salt substitutes over the last century. In America, there were a number of poisonings, including some fatalities, from the use of table salt substitutes containing lithium chloride, by people on just such a low sodium diet. The early symptoms included drowsiness, weakness, loss of appetite and nausea; later victims experienced tremors and blurring of vision, followed by confusion, before falling into a coma and death. If the salt substitute was discontinued at an early stage of poisoning, then the symptoms faded away over the next three to four days.
The other chemical widely used as a salt substitute was potassium chloride. This substance was also used medicinally at that time in the 1930s and 1940s as a diuretic, to prevent kidney stones. A fatal case of poisoning happened in Canada in 1940, connected to this very chemical. A man had taken between 30g and 35g of potassium chlorate over a period of three days in mistake for potassium chloride, which he used instead of salt. The poor man died five days after the last dose. Potassium chlorate was widely used at that time as a mouthwash and gargle and also in toothpowders, but was not supposed to be swallowed.
Sweeter than sugar
Artificial sweeteners such as saccharin, cyclamate and aspartame are used by manufacturers as a cheap alternative to sugar. Saccharin is 300 times sweeter than sugar and aspartame is about 200 times as sweet, while cyclamate is about 30 times as sweet as sugar. Many people use these sweeteners as a means of reducing calorie intake while weight watching.
Saccharin was found by chance, a happy accident, discovered by a chemist at Johns Hopkins University in the USA in 1879. Graduate student, Constantin Fahlberg, was attempting to make some toluene derivatives and got one of them on his hands. He went to lunch and noticed that his bread tasted sweet, then realised he had not washed his hands before lunch and that the sweet taste must have come from the chemical he had made that morning. It was widely used until safety testing in 1977, when it was banned in the USA for a time due to cancer concerns, but only for extreme and unrealistic doses. There was such a public outcry that it was allowed again while further testing was carried out, and only in the year 2000 were official concerns dropped.
A similar problem occurred with cyclamate, a sweetener preferred by many since it did not have the bitter aftertaste of saccharin. Cyclamic acid and its calcium and sodium salts were intense sweetening agents used in soft drinks, foods and sweetening tablets. They too were banned for a time, but now have official backing once again.
Aspartame is another sweetening agent, which is widely used in the food industry and can be bought by the public to use in place of sugar. However, it must be used with care by those who suffer from PKU (mentioned in Chapter 5) because one of its breakdown products is phenylalanine.
A sticky honey situation
Since 2006, bees have been a cause of concern, because of a phenomenon called colony collapse disorder, which has massively reduced the bee population in the USA. No cause has yet been found, but production of honey there has halved and more honey has been imported, but not without problems. A similar decline has recently occurred among European bees due to the spread of the parasitic mites – Varroa – which decimate hives.
Imported honey has been found, in many cases, to have come from China, but by devious routes, involving repackaging and re-exporting, to hide its true origin. This is referred to as ‘honey laundering’ and is an attempt to avoid health and safety checks, import fees and other tariffs imposed to prevent ‘dumping’ of tainted foodstuffs on to world markets, at below the cost of production.
Chinese honey has been and still is tainted, because back in 1997 bees were nearly wiped out by a bacterial epidemic. The beekeepers, instead of burning the hives to remove the infection, chose to treat them with chloramphenicol, an antibiotic that can cause aplastic anaemia, a serious blood disorder. Although this practice was outlawed, some honey is still tainted, not only with chloramphenicol but also with other antibiotics, such as ciprofloxacin.
Adam’s ale
A safe and adequate water supply is vital for a healthy life. Typhoid and cholera are just two of the diseases that may result from foul water supplies. The antibacterial properties of silver were known thousands of years ago, and silver has been used since ancient times to sterilise water. The Greek historian, Heroditus (485-425 BC), reported that the Persian King Cyrus the Great, who died in about 530BC, used silver for this purpose. Drinking water and swimming pools can be made safe by as little as 10 parts per billion of silver – although this is too expensive to put into action these days.
Any one visiting a local swimming pool knows that chlorine is another substance used to disinfect the water. It was first used in 1897 during a typhoid epidemic in Maidstone, Kent. It then became the main means of disinfecting drinking water both in Britain and throughout the developed world, preventing further outbreaks of water-born diseases such as typhoid, cholera and meningitis.
In Peru in 1991, the authorities stopped using chlorine to purify drinking water, following a campaign by environmentalists about the health threat of organochlorine compounds. The result was a massive outbreak of cholera: over a million cases were reported and 10,000 people died. Needless to say, the authorities started to chlorinate the water again as soon as they realised their mistake, although it took some time to bring the disease under control. This is a prime example of how risks and benefits must both be considered. In this case the benefits of chlorinated water to prevent cholera far outweighed the risks that worried the environmentalists.
Unfortunately, even in the developed world, water contamination can get the better of us. Babies have been poisoned by contaminated water mainly in the rural areas of Britain, such as Lincolnshire and East Anglia. This poisoning is usually a result of the baby being given feeds made with water from wells that have become contaminated, with nitrates, for example, in groundwater run-off from the fertilisers used on the fields.
In 1988, a lorry-load of aluminium sulphate was emptied, by mistake, into a reservoir near Camelford, in Cornwall. This chemical contaminated the local water supply, causing diarrhoea, mouth ulcers and blisters, malaise, joint symptoms and memory defects in the local population of some 20,000 people who drank the water. The memory problems did not appear until some months later. Even six months later, aluminium deposits were still found in the bones of those affected. A report issued in 2005, following a four-year study into Britain’s worst water poisoning incident, found evidence of long-term health problems, including asthma and arthritis, suffered by the victims of 1988, some of whom have since died.
Even bottled water has problems
Bottled water is marketed as pure, from a spring or similar. But even this form of water can be dangerous.
In the early 1990s, miniscule traces of benzene were discovered in Perrier water, forcing the French company to withdraw 160 million bottles worldwide. Analysis of a number of the drinks showed the benzene was caused by a reaction of the preservative, sodium benzoate, and the antioxidant, vitamin C. Then in 2005 and 2006, tests on some 230 drinks on sale in Britain and France again showed high levels of benzene – eight times the level permitted in drinking water. Benzene is an aggressive carcinogen and may lead to leukaemia and other cancers of the blood. There is currently no known safe level for benzene. Part of the problem is that benzene is present in the air already, and we breathe in more than 200 micrograms of it every day.
In 1995, Scottish biochemistry lecturer, Paul Agutter, was tried in the High Court in Edinburgh for attempting to murder his wife. On a Sunday evening in August 1994, he gave his wife, Alexandra, a gin and tonic to which he had added poison. He used atropine, the poison found in the plant Deadly Nightshade. His wife noticed that it didn’t taste right and stopped drinking after a few sips. But later that evening, she became ill and was admitted to hospital. She was treated for acute poisoning and fortunately made a complete recovery. The remaining undrunk gin and tonic was analysed and was found to contain a large amount of atropine. Agutter tried to blame the tonic water, which had come from Safeway.
The supermarket was forced to issue a nationwide recall on some 55,000 two-litre bottles of tonic water after seven more cases of poisoning came to light. He had posed as a victim, but the supermarket CCTV showed Agutter placing more poisoned bottles on the shelf in an Edinburgh store, and he was then arrested. He wanted to kill his wife so that he could then be free to marry his lover. But this lady deserted him as soon as he was charged, and although his wife stood by him throughout his trial, she divorced him as soon as he was imprisoned. Found guilty, he was sentenced to serve 12 years in jail.
Contaminated foodstuffs
Insecticides of the organophosphate type are very good at killing insects, but they can cause great problems if they contaminate foodstuffs, which happened in India in July 1997.
A group of 60 fit and healthy young men, aged 20-30 years old, ate their midday meal in a works canteen. The meal included chapatis, cooked vegetables, beans and halva. Over the next three hours, all 60 became ill, suffering nausea, vomiting and abdominal pains. They were treated at the local healthcare centre, but four of the men needed hospital treatment and one of them died a few days later. The doctors initially assumed it was caused by some sort of food poisoning, such as botulism. Blood tests, however, revealed the presence of the insecticide malathion, and this was traced to the chapatis, which were found to be heavily contaminated.
A few years ago, a nationwide food alert came about because of a very unusual contaminant: a large-animal tranquilliser.
In 2003, a Cumbrian manufacturer of game pies and sausages unwittingly bought some deer meat that was contaminated with Immobilon, a strong tranquilliser used by veterinary surgeons to sedate large animals such as lions and elephants. Immobilon was many times stronger than the more usual sedatives, and many deaths, both accidental and deliberate, resulted from its use, before it was banned in the 1990s. But in 2003 it was still being used, illegally, to kill red deer, and this is how it got into the pies and sausages. A nationwide alert had to be issued by the Food Standards Agency warning people not to eat the affected food.
Alcohol poisoning
Alcohol presents growing problems and few people realise how dangerous it can be. Even ordinary beer, wines and spirits can kill. The current craze for binge drinking can be particularly dangerous. People who are drunk should be placed in the recovery position and watched carefully for several hours in case they vomit or their condition deteriorates, in which case they should be taken to hospital. If vomiting is excessive, it can lead to a massive drop in the blood glucose level, which may need intravenous fluids to correct. And apart from the risk of vomiting and the dehydration it can cause, there is also the risk of choking to death on the vomit too.
While alcohol is a poison itself, it can also be adulterated by the addition of other poisonous substances, which may be cheaper or easier to obtain. In America in the early 1950s, some 23 people were poisoned by drinking Korean saké which contained 16 per cent methanol. Five of them died of respiratory arrest after several hours of coma, and another one died four hours after admission to hospital. The post-mortems showed swelling of both the brain and lungs, with inflammation of the stomach and fatty livers. The other 17 saké drinkers were all treated, and unfortunately one more died, but the rest recovered.
Unappetising arsenic
There have been many poisonings of food with arsenic over the years (as you’ve likely already discovered with the numerous arsenic anecdotes sprinkled throughout this book), for an amazing variety of reasons. One of these is because of its use as a pesticide. Apple orchards used to be sprayed with the pesticides Bordeaux Mixture (copper sulphate and slaked lime), and Paris Green (copper arsenate). Unfortunately, poisonous incrustations were left on the fruit as it ripened, only to poison the unwary.
Cocoa was also poisoned in the 1930s, when it was treated with impure potassium carbonate contaminated with arsenic. The potassium carbonate was used to make cocoa soluble, but the new ‘chocolate with arsenic’ flavour wasn’t the plan!
Interestingly, in very small doses, arsenic seems to boost the metabolism and increase the formation of red blood cells. Vichy water contains about two parts per million of arsenic, which may account for its supposed tonic effect.
A famous case of mass arsenic poisoning in Britain happened in 1900: over 6,000 people were affected and 70 died. The cause was found to be contamination of the invert sugar used to brew beer. Invert sugar is a mixture of glucose and fructose which has been treated for use in brewing or confectionery. This particular invert sugar had become contaminated with arsenic during its manufacture. The poisoned beer was found to contain enough arsenic that a night’s drinking contained a dangerously high dose. At first some of the victims were thought to be suffering from the effects of too much alcohol, but one doctor realised that their symptoms could also be caused by arsenic poisoning.
Even today, arsenic poisoning can occur. In the summer of 2008, Cornish health officials had to warn people not to eat a sea plant called marsh samphire (glasswort). The plant had been picked illegally on mudflats in the Hayle Estuary in Cornwall and was sold for use as a garnish on seafood dishes in local restaurants. These mudflats were known to be contaminated with high levels of arsenic from past tin mining in the area. Even a small quantity of the plant could cause problems with swallowing and salivation.
Various third world countries continue to be at risk of arsenic poisoning. The surface water in countries such as India, Bangladesh and Thailand is often heavily contaminated with sewage and should not be used. This polluted water causes diarrhoea, which kills some 20,000 people each year in Bangladesh alone. In the 1960s, a UN project encouraged and even paid for tube wells to be dug in such countries to provide clean water both for people to drink and for the irrigation of rice crops. Although done with the best of intentions, the tube wells were sunk down to the depth of arsenic-containing rock strata. This was not known at the time, but the water from the wells then contained high levels of arsenic, leached from the underlying rocks. Over a period of time, this has resulted in the slow poisoning of many millions of people, including about 40 million in West Bengal and Bangladesh. This arsenic poisoning causes, among other things, disfiguring leprosy-like skin eruptions, particularly on the hands and feet, which make walking and working both difficult and painful. After many years of continual exposure, cancerous growths also develop.
Once the problem and its cause were realised, the Indian government began to issue chlorination tablets to add to the water. These react with the arsenic, oxidising it to an insoluble form which then combines with iron, also present in the water, making the water safe to drink.
Recently it has been discovered that the powdered dried roots of the water hyacinth plant can rapidly reduce the arsenic levels of contaminated water from 200 micrograms per litre to below the World Health Organization (WHO) guideline of ten micrograms per litre within an hour. It is hoped that a filtration system incorporating the powdered roots can be developed to purify drinking water and irrigation supplies. The water hyacinth plant thrives in arsenic-rich landscapes, such as Bangladesh, and has until now been regarded as a troublesome weed in water courses. Further research into this interesting possible solution continues.
Heavy as lead
Many countries have taken action to reduce lead exposure from environmental sources, by limiting or banning its use in food, paint, petrol and other sources. In Great Britain, the amount of lead present in food is carefully regulated and must be less than one part per million. If the food is for babies and small children, it must contain less than 0.2 parts per million of lead. In 1995, WHO reduced the recommended upper limit for lead in water supplies to ten parts per billion.
Even ordinary household dust can contain lead, although the amount will depend on how near the home is to major roads or industrial sources. The soil contains a certain level of lead, both from its natural mineral content and from airborne particulates deposited on it.
Vegetables and fruit grown near busy roads or in urban areas may contain excess lead, which has been absorbed by the plants. This is now less of a problem, since lead-free petrol has been introduced, and many more diesel-powered cars have become available. But though picking blackberries from hedgerows at the roadside may seem like a good idea, no matter how carefully the fruit has been washed to remove the surface dust, there will still be lead content: lead from the soil, and dissolved in the ground water, is taken up by the roots of plants.
When preparing food, leafy produce should always have the outer leaves removed, other produce should be peeled and then all should be well washed before eating. Most lead passes through the body without being digested and any that is absorbed tends to be deposited in bone, hair and teeth.
In the past, many people accumulated lead, largely as lead phosphate in their bones, from their lead-glazed cooking utensils. The risk was found to be particularly high where acid foods, such as beers and wines, or pickles and preserves, were stored for a long period of time in lead-glazed containers. This could happen when a large batch of a homemade produce was made, and was then stored away for future use. Lead poisoning has occurred with home-brewed cider, moonshine liquor, apple juice and barley water, all of which were stored in earthenware jars and resulted in poisoning due to lead from the glaze being leached into the drink during storage.
Old pewterware dishes, mugs and plates, which were in everyday use centuries ago, have been found to have a very high lead content, as have lead crystal decanters, so any food or drinks stored in them pose a threat. Even today, new cooking, drinking and storage containers have been found to release lead into the food placed in them. The glazes used in the manufacture of pottery and earthenware, especially the handmade variety, may contain lead. Enamelled cookware from Asia, and particularly China, may also have a very high lead content.
Lead was used in the early days of the canning industry to solder the seams of cans. This lead affected the food and resulted in poisoning when the canned food was eaten. In 1848, Sir John Franklin led an expedition to find the fabled North-West sea passage to the Orient. The ship became stuck in pack ice and all 129 members of the expedition were dependent on tinned food, regardless of its lead contamination, for their survival.
In 1988, the bodies of some members from this ill-fated expedition were found. Tests showed high lead levels in their tissues, consistent with acute lead poisoning, which, no doubt, dulled their senses and hastened their demise.
More than 60 years after Franklin’s fateful expedition, in World War I (1914-18), trench neuritis was the name given to symptoms suffered by the troops. Trench neuritis was really a sign of lead poisoning, caused by the contaminated canned food the soldiers were eating in the trenches.
Lead-lined containers were used by the Romans when making wine, which must have resulted in it being heavily laced with lead. Even cider makers in Devon used lead pipes to draw their cider from the cask to the pump. The cider, being more acidic than beer, dissolved some of the lead from the pipes, and the resulting drink gave the cider drinkers lead colic. In 1922, some 93 people were affected by lead poisoning of beer in Isleworth in West London, but this was caused by the lead glaze enamel on the iron-brewing vessels.
Lead acetate, known as Sugar of Lead, has been used to sweeten wine for thousands of years. This substance caused a form of colic in those who drank too much, with stomach cramps, constipation, tiredness and anaemia, ultimately leading to insanity and a lingering death. The practice of adding lead to wine to ‘improve its flavour and keep quality’ continued well into the nineteenth century, a piece of lead shot being deliberately added to each bottle, where it would slowly dissolve.
In the past, many babies and young children accumulated lead simply by chewing painted surfaces. All paint once contained lead, and this included painted nursery furniture, the children’s painted toys and, of course, lead soldiers too. All the household woodwork, if painted, was a hazard, and still is, if removed by sanding or a blowtorch. We will return to this topic in the next chapter.
Despite legislation, lead salts continue to be deliberately used to adulterate food. In 1969 there was even a case of both lead, and chromium, poisoning caused by the use of chilli powder that had been deliberately adulterated with lead chromate. Medical literature is littered with hundreds of such cases of lead poisoning.
Problems in Japan
Mercury is a heavy metal, and a cumulative poison, widely distributed in nature. Some fish, plants and plankton have developed the ability to concentrate it, without it harming them, as in the example below. But this concentration moves up the food chain, leading to increasing levels of poisoning of the fish in contaminated areas, which may contain up to ten times as much mercury as the normal level found in fish elsewhere.
During the 1950s, one of the worst examples of environmental mercury pollution occurred in Minamata Bay, Japan. The local chemical company had been discharging mercury compounds into the bay for over 30 years, at a rate of about 100 tons a year. Over the years the mercury had built up, in the form of organomercury compounds, made by the micro-organisms that lived in the sediment of the bay. These then poisoned the fish, which the local people had always eaten. Over the years the villagers slowly became crippled by ‘Minamata disease’. This was caused by organomercury poisoning of the central nervous system. Some of those affected eventually died as a result.
In recent years, the Food and Drug Administration (FDA) in the USA has been concerned about the high mercury levels found in tuna sushi, so beloved of New Yorkers. Most of the sushi tested was from bluefin tuna, which generally has higher mercury levels than other species such as yellowfin and albacore tuna. As an occasional treat, it’s fine, but eaten every day it could cause neurological symptoms and increase the risk of cardiovascular disease too.
Another metal that has plagued Japan is cadmium, a metal with a number of uses, including batteries. Cadmium is found associated with zinc-containing minerals, and the ore is extracted by mining. But there is always the problem of waste, with spoil tips, which can become environmental hazards.
In Japan, long-term exposure to cadmium resulted in the development of a ‘new’ disease they call Itai-Itai, meaning ‘It hurts’. Coming to light over 25 years ago, the cause was traced to eating rice grown on contaminated land. The rice fields had been watered from a source polluted by waste, containing cadmium, from a zinc mine nearby. Itai-Itai was the result of chronic cadmium exposure, which had weakened bones and joints, making movement both difficult and painful. The rice, which the sufferers had been eating, contained ten times the cadmium level of normal rice. An additional factor to the disease was found to be the low vitamin D levels of the sufferers. vitamin D is essential for the normal turnover of calcium in the bones.
Thallium for tea
Thallium and its salts have been used to kill rodents and insects for many years. Thallium was the poison of choice for a number of murderers, as we shall see in a couple of Australian examples. Being tasteless and colourless, thallium salts are easy to disguise in foodstuffs by those with murder in mind.
Caroline Grills lived in Sydney, Australia. She married Mr Grills in the early years of the twentieth century. Nearly 40 years later, when she was 63 years old, she nursed her stepmother-in-law, Mary Ann Mickelson, through her final illness.
A number of elderly relatives all died in fairly quick succession at about the same time: 87-year-old Christina Mickelson died in 1947; then a family friend, Angeline Thomas, who was also in her eighties, died. However, when the rather younger 60-year-old, John Lundberg, died the following year after his hair had fallen out, and then a short while later, when his relative and Caroline’s stepmother-in-law Mary Ann Mickelson died, with similar symptoms, people, not surprisingly, grew suspicious.
The mysterious illness had also begun to affect John Lundberg’s widow and her daughter. Their hair started falling out, they both felt very tired and they both had difficulty moving about. Eventually, a suspicious relative contacted the police. The common factor in all four deaths was Caroline, always there helping to care for the victims, and always making them endless cups of tea. The tea was sent for analysis. Thallium was found, and its discovery was just in time to save the lives of Mrs Lundberg and her daughter, although Mrs Lundberg lost her sight as a result of the poisoning. Caroline Grills was tried for the murders and found guilty. She was sentenced to life imprisonment.
In another Australian case of poisoning a few years later, no doubt copying Caroline Grills’ ‘modus operandi’, a woman in New South Wales used thallium to kill off two husbands. This lady used a rat poison, a paste containing two per cent thallium sulphate, to poison her second husband, Mr Fletcher, in 1953. She gave him several doses mixed in his food, causing his hair to fall out, giving him pains in his hands and feet and making him feel nervous and cry. The cause of his condition was not diagnosed, and after 11 days of increasingly severe illness, he died. At the post-mortem, thallium was found in his body tissues. The police then remembered that four years previously the widow’s first husband, Mr Butler, had died of similar undiagnosed symptoms. They exhumed Butler’s body and found thallium in his tissues as well. Like Caroline Grills, the woman was tried, found guilty and sentenced to life imprisonment.
Thallium is no longer used as a rat poison, but accidental poisoning with thallium has still occurred. In Guyana in 1987, hundreds of people were poisoned and 44 died after drinking contaminated milk. This milk had been produced by some cows that had eaten molasses laced with thallium sulphate. The molasses was poisoned bait intended to kill rats, but unfortunately the cows found it first. They liked the taste and ate it, with fatal consequences to the dairy customers.
Galvanised into action
Fifty years ago, the Ministry of Health issued advice that galvanised iron vessels should not be used for the soaking, cooking or storing of acid fruits. Such containers were in common use until new plastics became available for household purposes in the 1960s. Today, nearly all bowls and buckets are made of polypropylene (polythene) and are safe to use for foodstuffs of every type.
Galvanisation is a process where a layer of zinc is deposited onto steel to protect it from corrosion. The zinc layer on the surface is quickly oxidised by oxygen in the air, and it is this zinc oxide layer that prevents further corrosion of the steel from the air or from water – but not from acidic foods. Corrosion can occur if acidic foodstuffs are left in contact with the galvanised surface, and this can cause zinc poisoning when the food is eaten.
Storage of acidic fruit juices in galvanised containers has caused many mass poisonings, resulting in vomiting, stomach cramps, diarrhoea and fever. Out of eight outbreaks of food poisoning attributed to zinc in the past, seven were found to be due to the use of a galvanised container in which fruit had been soaked, cooked or stored after cooking. The acidity of the fruit, or its juice, had dissolved the zinc, leading to symptoms. Only a short time elapsed between eating the poisoned fruit and the onset of symptoms, which luckily were mild, only nausea and vomiting. Fortunately, the symptoms were followed by a rapid recovery period.
Infamous botulism
Food poisoning is usually a brief, self-limiting form of gastro-enteritis, although more serious outbreaks of food-borne illness have been associated with certain bacteria, such as Salmonella and Escherichia coli, which both produce exotoxins.
Botulism is a very serious form of food poisoning that comes about from the exotoxin produced by the bacterium Clostridium botulinum. This is the same toxin as in the anti-wrinkle treatment Botox. Botulism has been responsible for many deaths over the years, from undercooked meat and particularly from canned meat that has not been sterilised properly.
This form of food poisoning was first described in 1895 by Van Emermengem. It was discovered that the bacterium responsible is an anaerobe, meaning it can live and grow without oxygen. The botulinum toxin it produces is a virulent poison, but it can easily be destroyed by heat, as normally happens during cooking, or during the sterilisation process which follows the canning of the food.
Unfortunately, in the early days of the food canning industry, failures occurred for a variety of reasons. Some were due to incomplete sterilisation, some to poor sealing of tin lids and some to poor soldering of the seam down the side of the can. In the United Kingdom during the years 1882 to 1919, there were no less than 51 outbreaks of food poisoning, and all but one of these cases involved canned meats. In the years 1919 to 1922, there were a further 14 outbreaks in Great Britain, of which ten were caused by tins of canned meat which had been imported from South America. Other outbreaks were traced to potted meat prepared from wild duck in Loch Maree, Scotland, in 1922, and ‘vegetable brawn’ in London in 1935.
Botulism was also common in the United States and Canada, and there were 84 outbreaks in the years 1906 to 1920, resulting in a total of 206 deaths. These were all traced to tins of fruit or vegetables, where botulinum spores naturally present in the soil were also on the fruit and vegetables. Adequate sterilisation was needed as the spores are highly resistant to heat. If any spores did survive the sterilisation, they would not produce sufficient changes to cause rejection of the tin, in the short time until it was inspected on the production line. However, with the passage of time, eventually such tins could become ‘blown’ due to germination of the spores and subsequent growth of the bacteria. The contents would then have an offensive odour when the tin was opened.
And finally, typhoid
In 1963 there was a major outbreak of typhoid in Aberdeen, and smaller outbreaks elsewhere in the UK, including the South Shields area on Tyneside and Bedford. These outbreaks resulted in hundreds of people being hospitalised, some for as long as three months, and many deaths. The cause was eventually traced to some South American corned beef. The large tins (the size of catering packs), which each contained six pounds in weight of corned beef, had been produced and canned in Argentina. They were used in shops where customers could buy a few slices at a time of an array of different cooked meats.
The tins of corned beef had been contaminated because of poor sterilisation in the factories in Argentina, and this problem was compounded by the use of the local river (which contained sewage) as the place to cool the tins after sterilisation. Some of the tins had weak seams, which burst during the sterilisation process. The cooling of the tins in the river water thus allowed contamination of the meat by the typhoid bacteria from the sewage.
The infection spread because the slicing machines in the shops and supermarkets became contaminated when slicing the corned beef, passing the bacteria on to other cooked meats that were sliced on the same machine. This cross-contamination caused many more cases of typhoid. Because some patients had not eaten any corned beef at all – only another sliced cooked meat – the investigation of the outbreaks was initially very confusing.