Ingesting canned fish with excessive arsenic, a health hazard - Toxicologist | Sunday Observer
Medi Snips

Ingesting canned fish with excessive arsenic, a health hazard - Toxicologist

13 February, 2022

Officials of the Consumer Affairs Authority (CAA) in Puttalam recently said they would file legal action against producers of eight varieties of canned fish that exceeded the arsenic content allowable in production, after it was revealed that arsenic levels in canned fish seized during raids were high.

The Puttalam District Office of the CAA was also reported to have said that the high levels of arsenic were found in six types of canned fish imported into the country, and to types of canned fish produced from imported salmon.

The Sunday Observer spoke to Emeritus Professor of Forensic Medicine and Toxicology, University of Colombo and Senior Professor of Forensic Medicine, General Sir John Kotelawala Defence University Dr. Ravindra Fernando to find out what the levels of arsenic were allowable for fish production in general both here and abroad. The Sri Lanka Standards Institution (SLSI) has approved the composition of one milligram of arsenic per kilogram of fish in canned fish in accordance with the SLS 591 standards. Is it the same in other countries as well since most of the fish is imported, we asked.

In response to our query he said, “According to the European Food Safety Authority (EFSA), fish, seafood and seaweeds are foodstuffs that significantly contribute to dietary arsenic intake. With the exception of some algal species, the dominant compounds of arsenic in such food products are the less toxic organic forms. Both the Joint FAO/WHO Expert Committee on Food Additives (JECFA) and EFSA recommend that speciation studies be performed to determine the different chemical forms in which arsenic is present in food due to the differences in their toxicity. Knowing such compositions can thus enable a complete exposure assessment to be made.

We next inquired whether ingesting fish with high levels of arsenic if digested only for a short period could still affect our health.

He said, “Research results demonstrate that dietary arsenic intake from fish, seafood and seaweed along with all their products do not constitute a significant health threat to consumers apart from the seaweed species Hizikia fusiformis in which over 40 percent of all the inorganic arsenic compounds were found.

What about the long term effects when digested over a continuous period? We have been told that it could lead to cancer. Is this true? Has there been any evidence based studies on this? Who were those most at risk?

His reply was, “Chronic arsenic toxicity (arsenicosis) due to drinking of arsenic contaminated ground water is a major environmental health hazard throughout the world including India. A lot of new information is emerging from extensive research on health effects of chronic arsenic toxicity (CAT) in humans during the last two decades. Available literature has been reviewed to highlight the problem including cancers.

Skin pigmentation and keratosis are the specific skin lesions characteristics of CAT. CAT also produces various systemic manifestations over and above skin lesions, important ones being chronic lung disease like chronic bronchitis, chronic obstructive pulmonary disease and bronchiectasis, liver disease like non-cirrhotic portal fibrosis and other diseases like polyneuropathy, peripheral vascular disease, high blood pressure, and ischaemic heart disease, diabetes mellitus, non-pitting oedema of feet/hands, weakness and anaemia. Cancer of skin, lung and urinary bladder are important cancers associated with chronic arsenic toxicity. Stopping the drinking of arsenic contaminated water is the mainstay in the management of arsenicosis as specific chelation therapy to remove arsenic from the human body has limited value. Early skin cancer, detectable by regular active surveillance, is curable. In addition to dermatological features, Treatment of arsenic poisoning is unsatisfactory and is mostly symptomatic.

If a mother-to- be consumes this fish which is the cheapest in the market given the high cost of fresh fish, will it affect her foetus? How?

His response was, “In animal studies, arsenic exposure has caused offspring to be born with low birth weight, fetal malformation, and even fetal death. Arsenic can cross the placenta and has been found in fetal tissues

We further inquired that since most children are given sardine sandwiches for their lunch and even toddlers are given sardines meals, how it could affect them if they were to eat canned fish with high arsenic levels continuously?

His reply was, “It is not advisable to regularly eat canned fish with high arsenic levels.”

What the symptoms and signs to look out for in arsenic poisoning. In reply he listed the following “The immediate symptoms of acute arsenic poisoning include vomiting, abdominal pain and diarrhoea. These are followed by numbness and tingling of the extremities, muscle cramping and death, in extreme cases.”

Were they visible at an early stage? How long does it take for the signs to become visible?

His answer was, “It takes some time for the signs to become visible.”

As a veteran Toxicologist, do you have a viable solution to this problem, we asked. In reply he said, “Yes, avoid foods that can have high arsenic levels.”

Although this problem has only been reported in Puttalam so far, parents and the public in general are worried that some of these toxic tins of fish could have slipped illegally into other parts of the island. Did he have a message to allay these fears?

In reply he said, “Do not consume any food that you suspect has high arsenic levels.”