Thallium is a fairly rare and scattered metal on our planet. But, despite this, cases of poisoning with this element are quite common. The course of intoxication with thallium is severe, and deaths occur quite often. Its toxicity is similar to arsenic and lead.
Below we will consider the physico-chemical properties of this metal, the field of application, the toxic effect on the human body, as well as signs and clinic of thallium poisoning, therapy and existing antidotes.
Physicochemical properties of thallium
The substance is a soft powder having different colors depending on the compound. Thallium in its pure form has a bluish tinge and belongs to the transition metals of group III of the periodic table. It is univalent and trivalent, and the compounds of monovalent thallium are more toxic.
This element exists in nature in a diffuse form (1 gram per 1 cubic cubic meter), so its extraction is carried out in the production or processing of salts of heavy metals (lead, zinc).
Thallium compounds are poorly soluble in water and fats. The element exists basically as:
- nitrous oxide;
- halide salts (iodide, bromide, chloride);
- Clerici solution.
Thallium refers to the elements found in the human body, but the significance of which is still unknown. Presumably thallium enters the human body with plant food.
In addition to plants, its sources are:
- tobacco smoke;
- industrial smoke;
- dust in the room.
In the human body, thallium is distributed evenly. It is found in fats in a poorly soluble form, in the muscles, the minimum amount is found in adipose and connective tissue, as well as in teeth, hair and the large intestine. Thallium is considered to be normal in the body of 0.1 mg, with a large muscle mass - 0.5 mg.
Application of thallium
Thallium and its compounds are used:
in infrared night vision devices;
- in optical glasses;
- at geological researches of ore and rocks;
- in low-temperature thermometers;
- in the counters of Cherenkov;
- in the composition of complex conductors;
- in the production of poison for rodents, insecticides and pesticides;
- in the composition of fluorescent paints;
- in the manufacture of artificial precious stones.
Workers of many industries have direct contact with this substance. Therefore, its toxic effect is of great interest.
Thallium poisonings are acute and chronic. Chronic poisoning occurs in production workers in contact with this metal. Acute poisonings constitute the largest percentage of the total number of intoxications. Children who accidentally swallowed pesticides, or insecticides, or agents for removing rodents suffer more often. Deadly poisoning with thallium may result from his deliberate admission for suicide or murder.
Symptoms of poisoning
Acute poisoning occurs more often in the case of taking a dose of thallium-containing drugs exceeding 1 gram. But the substance can enter the body through the skin and the respiratory tract. Absorbed element for almost an hour. It penetrates the bloodstream and spreads throughout the body. Deadly poisoning with thallium, perhaps from a dose of 600 mg.
A greater amount of waist is deposited in the kidneys, since this is the main organ of excretion. Salivary glands secrete more thallium, but together with saliva it is swallowed again and absorbed into the intestine. The liver and myocardium also determine its high content. Within thirty days, only half of the dose used is excreted from the body.
Acute and chronic poisonings with this metal vary in time, but have common clinical manifestations.
In the next 3-4 hours there are the first symptoms of thallium poisoning, characteristic of most intoxications:
- intestinal bleeding.
During the following week there are symptoms of damage to the nervous system:
- confusion of consciousness;
- paresthesia (numbness) of the limbs;
- pain in the muscles;
- ataxia (impaired coordination of movements);
- defeat of cranial nerves;
- loss of vision.
In addition to the above symptoms, later there are signs of poisoning with thallium from other body systems.
Respiratory system - cough, shortness of breath, possible pulmonary edema or paralysis of the respiratory muscles.
- Heart and blood vessels - pain in the heart, tachycardia, increased blood pressure.
- Skin - a rash, alopecia (baldness), dermatosis, white inclusions on the nail plates.
- Vision is retinal atrophy.
- Kidneys - perhaps, a decrease in the rate of glomerular filtration, an increase in the level of urea in the blood, a decrease in the amount of urine.
Deadly poisoning with thallium begins suddenly. Symptoms can appear simultaneously or sequentially with short intervals. Subfebrile or high fever, nausea, vomiting, diarrhea, intestinal bleeding may be supplemented with acute bronchitis, pulmonary edema, psychosis, loss of consciousness or even coma. Death in acute poisoning with a lethal dose occurs within 7-10 days.
With chronic thallium poisoning, the symptoms are erased, the latent period lasts longer, and the clinical picture is manifested only in the last stages. Signs of disruption of the gastrointestinal tract are practically absent.
The first manifestations can be:
- muscle weakness;
- loss of vision;
- development of impotence.
Diagnosis of poisoning
Diagnosis of thallium poisoning is very difficult, because tallotoxicosis is masked by extrinsic diseases. Especially carefully it is necessary to ask the patient about his work, about what he took in the last week, whether he was in contact with pesticides or insecticides.
All patients with suspicion of poisoning with thallium salts are taken urine tests, it can detect the derived element.
In addition, thallium is well detected by X-rays and X-ray can be used for diagnosis. On the x-ray you will see the substance eaten. By the level of its location in the lumen of the gastrointestinal tract, one can judge the duration of use.
The treatment of long-term thallium poisoning requires hospitalization. Therapy is based:
- on deducing in the unchanged form;
- on the binding of matter and its removal from the body;
- neutralization by means of antidotes.
In the case of acute intoxication, treatment should begin with gastric lavage. It is advisable to carry out this procedure still at home, because, until the patient goes to a medical institution, most of the thallium is already absorbed into the blood. Washing can be carried out with activated carbon, ipecacuana solution, sodium thiosulfate or potassium iodide. Simultaneously, even at home, you can drink magnesia, mannitol or English salt for a laxative effect and diuretics for enhancing urinary excretion.
In a hospital, repeated hemodialysis is performed.
It is recommended to take potassium chloride 3-9 grams per day intravenously or orally. It prevents the inverse absorption of thallium in the renal tubules.
If breathing is disturbed, lubeline hydrochloride should be administered, with tachycardia and arrhythmia - cardiac drugs.
B vitamins are recommended to alleviate the symptoms of the nervous system.
Antidote for thallium have been looking for a long time. A lot of research has been done with various substances and, in the end, the most suitable one has been found. This Prussian blue or as it is also called, the Berlin azure. She is known to many people since the school chemistry course. This substance contains potassium, which replaces thallium in the body. The most effective is the Berlin azure in the form of a solution. She displays thallium along with feces.
Prevention and consequences of poisoning
Workers who are in contact with thallium in production must:
use personal protective equipment (special shoes, clothes, gloves, respirators);
- take a shower immediately after work;
- do not eat food and any drinks in the workplace;
- regularly undergo preventive medical examinations;
- fully to eat.
The consequences of thallium poisoning depend on the dose, the duration of contact and the general resistance of the organism. Intoxication can threaten later with impotence, infertility, an increase in the number of congenital malformations, chronic diseases of the gastrointestinal tract and respiratory system, mental and hormonal disorders. Death can come from a heart attack and stroke.
If the treatment was started on time, the dose was small, then after a few months it will completely disappear from the body.
Let's sum up. Thallium is a highly toxic element. Poisoning often ends in death. Intoxication with this substance is possible both in everyday life and at work. All body systems, especially muscular and nervous, are affected. Medical measures should be started as early as possible. It is desirable to introduce an antidote - Prussian blue. Workers in contact with thallium in production should not ignore precautionary measures and should regularly take urine for analysis.