THE FOLLOWING ARTICLE APPEARED IN THE

MARCH 1998 ISSUE

THE POISON SLEUTHS

DEATH BY COMMON SALT

-Dr. Anil Aggrawal

"Good morning doctor. Oh, my God, what are you doing today? You have the dead body of a very young female infant today. What happened to her? Please tell me."

"Good morning Tarun. The name of this 6 month old tiny girl is Babli. When she was born, her mother died due to some obstetric complication. Her father Ramdev soon remarried a nubile young girl Rekha. Before marriage she had promised that she would look after Babli well, but after marriage she often showed frank animosity towards this girl. She would not look after her well and would often not even feed her properly.."

"Oh, so she probably starved her to death?"

"Don't jump to conclusions Tarun. Look at her body. She doesn't look starved. An infant who dies of starvation looks just like a bag of bones. There is no fat in his or her body. But this girl is looking fairly well fed. What I was going to tell you is that Babli's grandmother Shanti Devi, i.e. Ramdev's mother, is still alive. She was not in favor of Ramdev getting married to Rekha in the first place. She probably knew that Rekha was not of good nature. Rekha was undoubtedly not feeding her well, but Shanti would always make up for her, giving her feeds in time. In fact that is why starvation was never a problem for Babli."

"Then how did Babli die?"

"Babli died of some respiratory disorder. At least that is what her physician told me just now. I will tell you what happened yesterday. Till yesterday morning, Babli was fine. Ramdev left for work in the morning at 8. As usual Rekha started seeing TV just after that, completely ignoring Babli. Seeing that it was her feeding time, Shanti prepared her feed, and filled her milk bottle with that. Just then a neighbor came to meet her, and she went to the drawing room to attend her, leaving the bottle in the kitchen. For half an hour they discussed about some religious programme they were going to attend that evening. After the guest left, Shanti went back to the kitchen, picked up the bottle and gave the feed to Babli. About half an hour later, Babli, who had consumed only about half the bottle by that time, started showing some strange symptoms. She started crying. It appeared as if she was irritable. She vomited twice. Shanti tells me that she had convulsions and muscular twitchings, fluttering of eyelids and of facial muscles. She displayed avid thirst. Shanti knows this because when she gave her water, she would feel a little relaxed, but after some time she would start crying again. But what was most prominent was that she was not breathing well. She had extreme difficulty in respiration. Shanti called Rekha for help, but she kept on seeing TV. Then Shanti phoned her son Ramdev, who immediately got in touch with their family doctor on phone. Dr. Saxena, the family doctor, arrived within 15 minutes, and found that the child was in real bad shape. Ramdev also reached home soon after. Dr. Saxena injected some medicines for respiratory distress, but although the injections seemed to help initially, they weren't of any lasting help. The doctor couldn't really understand what had happened to her. He thought that probably it was an attack of asthma. But what was most confusing was that Babli never displayed this symptom before. They were preparing to shift her to some big hospital for diagnosis and treatment, but before arrangements could be made, Babli died."

"Oh, I see. So Babli's body has been brought to you to let them know how she really died?"

"Yes, that's right. Actually Dr. Saxena was quite prepared to give the cause of death as asthma, but Shanti Devi immediately raised doubts. She has alleged that while her guest came to meet her, Rekha went to kitchen and mixed some poison in her feed. That is why Babli started having those strange symptoms immediately after having that feed. Rekha, of course, vehemently denied this, and Ramdev too refused to believe her mother, but she wouldn't listen to anyone. She phoned police immediately and called them to their house. The police ransacked the whole house and even searched all Rekha's belongings, but they couldn't find any poison anywhere in the house. That is what is lending weight to Dr. Saxena's theory that Babli indeed died of asthma. Every one including the police is thinking that Shanti Devi is making all this fuss, because she didn't like Rekha in the first place."

"Yeah, that looks likely to me as well. So what are you going to do now?"

"Tarun, since the matter has reached the police, Dr. Saxena preferred not to give cause of death and leave that to me. The body has been brought to me for post-mortem so that I could comment upon the cause of death."

"How do you think Babli died?"

"Tarun, the symptoms that Babli displayed surely point towards some respiratory trouble. But the symptoms also point towards a very unusual poison, a poison no one can ever think of. And that is why I have to be extra careful. You have got to remember, that I have a reputation as a poison sleuth, and so I can not afford to leave out even a remote possibility as far as administration of poison is concerned.

"Come on doctor. No poison was ever found in the possession of Rekha. Not even that, there was no poison in the whole house. How could anyone administer any poison to Babli?"

"Yeah, that sounds very convincing to the police, and that's why they think Shanti Devi is a nut. But I don't think so. I know of a poison which produces exactly the same symptoms as displayed by Babli..."

"Please don't talk in riddles doctor. Explain everything to me in clear terms."

"Yeah sure. To test my theory, I took some of the stomach contents of Babli and subjected them to chemical analysis. Not to my great surprise, they have shown very high concentrations of salt. Then I took Babli's blood and examined it chemically too. And again it showed very high levels of sodium. I am inclined to think that Babli has been killed with ...."

"With what?"

"With common salt!"

"Common salt? You must be joking doctor. How can anyone be killed with common salt. This is what all of us take daily in our food. Well my father is so fond of common salt he always puts an extra teaspoonful of common salt in his dal."

"Yeah, this is what is not known to most people. Common salt is a deadly poison. The only difference between this and other commonly known poisons is that one has to administer rather large quantities to kill with it. One or two teaspoonfuls of salt would not kill an adult but can easily kill a 6 month old baby. Come to think of it, even an adult can be killed with common salt. Only he would have to be fed larger quantities. About 40 teaspoons of common salt would kill an adult human being too."

"Well the information is getting interesting. Why don't we begin from the beginning doctor?"

"Tarun, before you start visualizing it as a villain, I must hasten to add that there is no doubt that common salt or sodium chloride (NaCl) is indeed essential to all life. It is the basic milieu of mammals. It occurs as colorless cubic crystals or as white crystalline powder. When salt is administered in larger quantities than required, it can cause death too. One teaspoonful of salt weighs about 5 gms. Normal uptake by adults is about 5 to 15 g daily or about 1-3 teaspoonfuls. Children consume less. Salt is even necessary for normal growth in children. The sodium needed for growth is 0.5 mEq/kg from birth to 3 months of age, which decreases to 0.1 mEq/kg at 6 months. The average content of sodium in human milk is 7 mEq/L and that in cow milk is 21 mEq/L ..."

"Doctor, you started your answer telling me weights in grams, but suddely you have switched to milliEquivalents. I don't really understand the concept of milliEquivalent so well. And why should we talk in milliEquivalents, when we can talk equally well in grams?"

"Tarun, in ordinary day-to-day life, it is useful and convenient to talk in grams and kilograms, but chemists and biochemists often find it easier to talk in terms of equivalent weights because of several reasons. You would surely agree that chemists are mainly interested in chemical combinations, and Equivalent weights are actually measures of the characteristic proportions in which given elements combine. For this reason, this term is also often known as Combining weight. Equivalent weights can be used for elements as well as for compounds. In plain and simple words, they are the measure of the combining capacity of a substance with other chemical substances. Well, even if after this, you are feeling inconvenient with equivalent weights, let me add that 1 mEq of sodium equals 23 mg and that of salt equals 58.5 mg. I would also like to tell you that 1 milliequivalent would be equal to 1/1000 Equivalent weight. Now when I say that the sodium needed for growth is 0.5 mEq/kg from birth to 3 months of age, I simply mean that for every kg of baby's weight, 0.5 mEq of sodium is needed. Thus if the infant weighed, say, 4 kg, he would need 4x0.5 or about 2 mEq of sodium. Since 1 mEq of sodium is 23 mg, it would mean that the infant would need about 46 mg of sodium daily. This much sodium would be available from about 117 mg of salt. Thus in effect, a baby from birth to 3 months needs about 117 mg of salt. Similarly you can convert other values which I told you earlier in grams. I told you the sodium contents of human milk, because this is the only food available to young babies."

"Oh, I see. Doctor, you were saying that 40 teaspoons of salt would kill even an adult?"

"Yes Tarun. The toxic oral dose of salt is 0.5 to 1.0 gm/kg. For a 70 kg man this amounts to about 35-70 gm. That means that if an adult consumes about 70 g of salt (or about 14 teaspoons), he would be severely poisoned. The estimated fatal amount, i.e. one that would kill is about 1 to 3 gm/kg. This amounts to about 70-210 gm (or about 40 teaspoonfuls) of salt for a 70 kg man."

"Oh, that is interesting. Has salt been used to kill people before?"

"Tarun, interestingly the Chinese used saturated salt solution for suicide. Salt intoxication and death have occurred when it is used to induce vomiting."

"Why would one want to vomit anyway?"

"When somebody has consumed some poison, it is imperative to remove as much poison from his stomach as possible. One of the best ways to do this is to make the person vomit. It has been known from ancient times, that a strong solution of common salt induces vomiting, and that is why for centuries, it was a favorite method of doctors to induce vomiting in poisoned patients. But it is known now that saturated solution of salt itself can cause salt poisoning, so it is rarely used these days."

"Oh, I see. So you are suggesting that Rekha mixed salt in Babli's feed when Shanti was talking to her neighbor in the drawing room."

"Babli's stomach contents, and her blood analysis definitely tells me that salt has been administered to her. I have examined her brain tissue under the microscope too, and I have found that the capillaries of her brain are damaged. They are full of blood, and there are innumerable bleeding points - technically known as hemorrhages- in her brain. There is bleeding underneath one of the coverings of the brain. We call it subarachnoid bleeding, because it occurs underneath the covering known as arachnoid mater. Many venous channels of her brain - technically known as dural sinuses- are blocked. All these findings are strongly in favor of salt poisoning. I have no doubt that someone had indeed mixed salt in her feed. To tell you the truth now, I surreptitiously picked up the milk bottle from Ramdev's house and have analyzed it for salt. It showed as much as 11 g of salt and it was only half full. It means that the full bottle must have contained about 22 g of salt. In other words, Rekha must have put about 4 teaspoonfuls of salt in Babli's bottle when Shanti was talking to her neighbor. There was no other person in the house at that time, and no one except Rekha could have done that."

"Rekha indeed is a wicked woman. It is surprising she knew that salt can kill."

"I have enquired about Rekha's background. She studied biochemistry in college, although she dropped out of college later. Surely when she was studying biochemistry she must have learnt that salt is a poison and can be used to kill infants. It is indeed a rather safe poison, because you don't need to buy anything. It is available right at everyone's home. And the police won't suspect you either, because they won't find any poison....any traditional poison, I mean. Come let us tell the police that Babli didn't die of asthma. It is Rekha who has added salt to Babli's feed to kill her."

"Oh, how very clever of you doctor. This was a most interesting discussion. Tell me what are you going to tell me the next time?"

"Tarun, next time, I would tell you about a very interesting poison- iodine"