Following a request from the European Commission, the risks to human health related to the presence of chlorate in food were assessed by the EFSA Panel on Contaminants in the Food Chain (CONTAM Panel). The presence of chlorate in food can arise from the use of chlorinated water for food processing and the disinfection of foodprocessing equipment. Inhibition of iodine uptake in humans was identified as the critical effect for chronic exposure to chlorate. A tolerable daily intake (TDI) of 3 μg chlorate/kg body weight (b.w.) was set by readacross from a TDI of 0.3 μg/kg b.w. derived for this effect for perchlorate, multiplied by a factor of 10 to account for the lower potency of chlorate. Formation of methaemoglobin was identified as the critical acute effect of chlorate. An acute reference dose (ARfD) of 36 μg chlorate/kg b.w. was derived from a no-observedeffect-level for chlorate in a controlled clinical study. Chronic exposure of adolescent and adult age classes did not exceed the TDI. However, at the 95th percentile the TDI was exceeded in all surveys in ‘Infants’ and ‘Toddlers’ and in some surveys in ‘Other children’. Chronic exposures are of concern in particular in younger age groups with mild or moderate iodine deficiency. Mean and 95th percentile acute exposures were below the ARfD for all age groups indicating no concern. Based on the current practices in food industry, application of a hypothetical maximum residue limit (MRL) of 0.7 mg/kg for all foodstuffs and drinking water would only minimally reduce acute/chronic exposures and related risks. Assuming chlorate concentrations of 0.7 mg/kg for all foods and drinking water consumed in a day, acute exposures would increase by up to about 5-fold and the ARfD be exceeded at mean estimates in ‘Infants’ and ‘Toddlers’ and at 95th percentile also in ‘Other children’and ‘Adults’. © European Food Safety Authority, 2015

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EFSA CONTAM Panel (EFSA Panel on Contaminants in the Food Chain), 2015. Scientific Opinion on risks for public health related to the presence of chlorate in food

A case of severe sodium chlorate poisoning was observed within 5 h after suicidal ingestion of 150–200 g of the herbicide. Methaemoglobinaemia was the early symptom of the intoxication. Treatment with methylene blue and ascorbic acid could not prevent a massive haemolysis with disseminated intravascular coagulation. Hypercoagulation and hyperfibrinolysis could be treated successfully with exchange transfusions, heparin and fresh plasma. During the first hours, 70 mmol chlorate were excreted before complete renal failure occurred which required haemodialysis for several weeks. Clinical observations and in vitro experiments provide evidence that methylene blue is effective only in the very early stages of chlorate poisoning. Consequently, the following treatment is suggested: gastric lavage, exchange transfusion, bicarbonate infusion, haemodialysis, anticoagulation with heparin and substitution of clotting factors if necessary.

Severe chlorate poisoning: report of a case.

Background Chlorate poisoning as a cause of methemoglobinemia is regarded in current literature to be resistant to treatment by methylene blue due to the oxidizing and denaturing properties of the chlorate anion, and often leads to severe renal and hematological complications with a high mortality rate. Recent case studies suggest practitioners have eschewed the use of methylene blue in such situations. Objectives This report describes a case of chlorate poisoning presenting as severe methemoglobinemia successfully treated with methylene blue alone, believed to be a first in reported literature. Case Report A 34-year-old male construction worker presented 4 h after accidental ingestion of an industrial chemical, with giddiness and breathlessness. Physical examination did not reveal any abnormal cardiorespiratory findings, although arterial blood gas analysis and pulse oximetry revealed an “oxygen saturation gap.” Methemoglobin levels were found to be severely elevated at 66.8% 6 h after ingestion, and the patient was promptly treated with methylene blue. Clinical examination and laboratory tests suggested the absence of hemolysis at the time of treatment. The patient was discharged after a brief and uneventful hospital stay. Subsequent tests revealed the chemical ingested to be sodium chlorate. Conclusion The successful outcome in our case suggests that a window of opportunity as long as 6 h may exist during which treatment of chlorate poisoning with methylene blue may be of clinical value. We postulate that the absence of significant hemolysis and hematological alterations at the time of antidote administration may be a necessary prerequisite for treatment success.

Severe Chlorate Poisoning Successfully Treated with Methylene Blue

Two cases of chlorate poisoning presenting as unexpected sudden deaths are described. Both cases had previous psychiatric histories but poisoning was not seriously considered as the cause of death prior to autopsy, when the finding of chocolate-coloured fluid blood alerted the pathologist to the cause of death.

Chlorate poisoning--two cases diagnosed at autopsy.

It may be helpful to outline the principal classes of pesticides according to their economic role: 

1.

Rodenticides are intended to kill rats, mice, moles, etc. (i.e. mammals).




2.

Insecticides are designed to kill insect and related species that prey on crops, farm stock, etc.




3.

Fungicides are agents intended to control moulds, fungi, etc., on crops, stored foods, timber.




4.

Herbicides are used to kill weeds.




5.

Plantgrowth controls are substances which modify the growth and form of the plants, usually hormon-ally, without actually killing them.

C. A. Bloxham

Papers

Self-Poisoning by Sodium Chlorate-Some Unusual Features