Poison on a platter | Daily News

Poison on a platter

Cadmium is not very widely distributed in nature but that relative scarcity is offset by its high toxicity. It is found mainly as the oxide, sulphate, sulphide and chloride. Fine particles of Cd compounds can be found in the air either alone or attached to other particles. Soils and rocks contain small varying amounts. Some other substances like fossil fuels and phosphate fertilizers and phosphate ores contain higher amounts. Cd minerals or ores are scarce and contain very little Cd making it uneconomical to refine them to obtain Cd. Therefore it is extracted as a by-product from ores of other metals – mostly of Zinc and less of Copper and Lead.

Cadmium is very toxic. The Nordic countries called on the WHO to consider Cd as a substance as toxic as mercury. Due to this high toxicity and the established fact that human activities greatly increase cadmium in the soil, air and water, the WHO recognized the need for action on a national and international scale to reduce cadmium in the environment. Action so taken includes;

* Increased recycling of cadmium.

* Minimizing emissions and discharges from mining, waste management and similar activities.

* Promoting safe working conditions for workers handling cadmium.

* Stopping tobacco smoking.

Also, in 2010 the World Health Organization recommended a provisional tolerable monthly intake for cadmium as 25 micrograms/kg of body weight, for drinking water as 3micrograms/litre and for air as 5 nanograms/cubic metre (annual average). In addition, the International Agency for Research on Cancer (IARC) declared cadmium and cadmium compounds as a Group 1 (highest level) carcinogen to humans. This means that there is sufficient evidence for their carcinogenicity in humans.

Mobilization of Cadmium

Considering that consumers hardly come across cadmium in the products they buy, it is interesting to learn as to how it comes to be present in our micro environment and how it gets mobilized.

Cadmium enters the environment naturally due to volcanic action – both on land and undersea, due to the weathering of rocks and as dust therefrom. Volcanic action is intermittent and varies in frequency; in general, the release of Cd from volcanic action may not exceed 2000 tons/year. Weathering of rocks, in contrast, takes place all over the globe and this output is a major input in the global cadmium cycle; however, it rarely has raised cadmium levels to dangerous levels in any locality. Small amounts of dissolved cadmium compounds are found in both freshwater and seawater.

Human activity produces Cd as a by-product of mining, smelting and refining ores mainly of zinc, and of lead and copper to a lesser degree. Fossil fuel combustion is a major contributor, especially the combustion of coal. A small amount is produced from the recycling of iron and steel scrap.

Another strongly established cause of mobilization of Cd due to human activity is in agriculture.

The use of low-quality phosphate fertilizers in previous decades have polluted our waterways. An extensive study by Bandara et al has shown that in all upper catchment tributaries of the Mahaweli River, except one, Cd pollution is disturbingly high. They have also shown that the high pollution is due to the use of imported phosphate fertilizers with a high Cd content – in tea plantations and in vegetable cultivation – and that the highest Cd pollution is from vegetable cultivation. Though it seems that action has been taken to ensure that only better quality phosphate fertilizers are imported, consumers might as well make a note of this fact from the point of view of healthcare.

Sri Lankan farmers, both in vegetable and rice culture, use the highest amount of fertilizer per unit area of land in this region of the world. This is probably because fertilizer is given to them at a huge subsidy. Overuse of low quality fertilizer tends to cause excessive Cd absorption by plants and seeds as well as Cd pollution of farmland, and water – both surface and underground. Cadmium is moved far away from its point of emission too by wind, storms and cloud movement.

Global production and uses

Global annual Cd production increased from about 5,000 tons in 1950 to about 19,600 tons in 2000 and total reserves then stood at 600,000 tons. This is not much in terms of quantity but lethal in terms of toxicity. Production decreased in the next decade. However increased use is inevitable since Cd is now used in batteries and solar PV panels. Other uses, such as in making pigments, as a PVC stabilizer, and in electroplating, are on the decline due to substitutions. Even so, since some countries still use Cd for such purposes, it is of high interest to find out whether the PVC imported to Sri Lanka for the extrusion of water pipes and fittings come from countries that still use Cd as a PVC stabilizer. Apparently there are no country studies that quantify these exposures.

Adverse health effects of Cadmium

Cd easily accumulates in organisms such as molluscs (includes squids – Della in Sinhala) and crustaceans (includes shrimps, prawns, crabs and lobsters) as well as in fish – both freshwater and seawater fish. Vegetables, cereals and starchy roots have smaller amounts. Danger to humans comes from Cd contaminated food, direct and indirect inhalation of tobacco smoke, and inhalation – especially for workers in the non-ferrous metal industries. Other dangers are Cd particles from coal power generation and from vehicle exhausts – in air, soil and water.

Cd accumulates in the body and remains for years – especially in the kidneys, liver and bones. The kidneys are the specific target organs, with Cd accumulating in them over its biological half-life in humans of 10-35 years, leading to the dysfunction of the filtering tubules of the kidneys. The result is the increased excretion of low molecular weight proteins in the urine – a generally irreversible stage of damage. This can happen with low-level accumulation of Cd.

Such accumulation of Cd in the body can cause kidney stones and damage the cardiovascular (CV) system. Disruption of calcium metabolism is one such damage to the CV system. Both sight and hearing can be damaged too. Higher exposure can lead to softening of bones and osteoporosis. Disruption of calcium metabolism leads to the calcification of arteries and valves of the blood circulation system and cataracts in eyes. Calcification of arteries – leading to the need for stents – seems to be increasingly encountered in Sri Lanka, but unfortunately attributed to deposition of cholesterol.

Simultaneously the liver too is seriously affected and results in fibrosis as found in cases of Itai Itai disease in Japan where there still are incurable survivors, mainly women. Exposure to Cd can cause cancers of the lung, breast, prostate, pancreas, urinary bladder, and nasopharynx too (nasal cavity above the soft palate).

It is medically advised that disrupted calcium metabolism can be countered by taking vitamin D3 with vitamin K 2-7 because this combination is supposed to work together to put back calcium in its due places in the body – in the bones and teeth. However, it might be necessary to reduce the Cd load too. Please note well that this is given as information and not as medical advice.

The best way to reduce your Cd intake is to be mindful and careful. Steps you can take are;

* Prepare rice in the same way as suggested to get rid of arsenic (previous article)

* Reduce rice intake. Replace one daily rice meal with an all vegetable meal (cooked and raw)

* Do not give up rice and change over to bread. That can worsen your condition because most wheat flours contain a poisonous herbicide used as a desiccant to aid wheat harvesting.

* For the same reason avoid legumes (chickpeas, dhals and mung) from the USA and Canada. Ask your grocer the country of origin of the legumes he sells; he should know

* Try to get truly organically grown rice and vegetables. An alternative is to grow your own food by means of a CSA arrangement if you have to. A CSA will be described later.

* Detoxify your body regularly. There are suggested methods for removal of heavy metals which can reduce the toxic load if not deliver total removal.

Disasters due to Cadmium

There are two notable incidents of Cd poisoning. The first was due to industrial action and the other was due to agriculture.

The first episode took place in Japan. A strange disease came to be observed in a few locations beside the Jinzu River in the early 1950s. The people called it Itai Itai disease which translates into English as “ouch ouch disease” and into Sinhala as “ooi ooi leday” – referring to the pain. Belated investigations started only after serious public disturbances; it was formally established in 1968 after legal proceedings that the cause was cadmium pollution arising from the discharge into the river of waste water from an ore mining and refining industry processing ores of zinc and lead.

The legal proceedings ended with a simple and clear court decision that the disease was due to Cd pollution, based purely on epidemiological evidence that only cadmium can explain the limited development of Itai-Itai disease in a specific area around parts of the Jinzu River.

I have included this paragraph for our scientists, science writers and critics of the ban on glyphosate to take note well.

The second episode occurred in Sri Lanka – the epidemic of the Chronic Kidney Disease of Unknown Origin. This can be linked to low quality fertilizer with high Cd content, excessive use of same, and a herbicide – also used where inappropriate – in plantations, and in food cultivation

This is a much more serious disaster than the Minamata (mercury) and the Itai Itai disasters in Japan. Each of them affected about 20,000 people or less. Some survivors of both disasters are still alive though seriously affected in health. In contrast, the CKDu disaster is much more massive with over 20,000 already dead and about a further 400,000 afflicted, some dying. The government is providing free medical attention with foreign assistance largely from China but the CKDu disaster did not get the same global attention and support as the two disasters in Japan did.

The “unknown” part needs to be removed from CKDu label now. It is being abused by regulators, other officers and even commercial interests stating there is no proof of a link between CKDu and glyphosate formulations. There is, without any doubt.

It is proven that Cd damages the filtration tubules of the kidneys (WHO). There is also highly acceptable evidence that the same damage is caused by herbicides containing glyphosate, as provided by a high-level research team led by the famous Professor Michael Antoniou who showed that glyphosate formulations first attacked and destroyed the liver and kidneys of lab rats. There was no report of a determination of the Cd content in the tested herbicides. Another famous researcher, Professor Seralini, also reported glyphosate damage to kidney tubules and a high content of arsenic. Above all, the manufacturer Monsanto’s own studies submitted in 1974 to the USEPA (Environmental Protection Authority, USA), along with their first application for the license to market glyphosate formulations, showed the same kidney damage plus the formation of growths that could develop into cancer. That was a short-term study. It showed very quick damage in a matter of 90 days or so. EPA scientists strongly objected to issuing the marketing license, but due to influence and pressure exerted by Monsanto and support for Monsanto from politically appointed high level administrators at the EPA, EPA’s scientists were silenced and Monsanto’s tailor-made repeat research was accepted as proof of safety. Influence, pressure and partisanship of the EPA were the only reasons for approval, not the proven safety of the herbicide.

The evidence of harm is much more than the epidemiological evidence accepted in Japan – but still our critics of the glyphosate ban were very vocal until recently. There is a deafening silence now after the science was proved in three court cases and the award of high damages running into billions of dollars. Monsanto are now privately negotiating settlements to avoid facing bankruptcy. It is quite probable that the slow kidney damage caused by Cd in the environment was accelerated by more Cd from imported fertilizers and further accelerated in a matter of months by glyphosate formulations. Another factor could be fluoride – a disruptor of the hormone system. Fluoride could very well disrupt the functions of the hormones regulating the kidneys. Fluorides are highly soluble and can leach from the Eppawala deposit since it is virtually immersed in underground water retained by the Jaya Ganga and fresh surface breaks are made in daily mining. The Cd, the glyphosate and the fluoride were absent up to 50 years ago. Hence there was no reported CKDu.

We need not go so far as to include fluoride in the equation even though fluoride could be a cause of damage. Effects of Cd and glyphosate only were enough to arrive at a firm positive decision. A firm decision was taken in regard to low quality phosphate fertilizers; so why object to the same decision on glyphosate formulations? The evidence here was more substantial than that of the epidemiological variety that was accepted in Japan; and Sri Lanka had ratified the Precautionary Principle too, and was committed to public safety over and above availability of scientific proof.


 

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