An opposition member of parliament, Dr Harsha De Silva raised the issue of “contaminated” fertilizer stocks in the house. News reports and social media state that fertilizers “Laced with Unsafe Levels” of Lead and Cadmium have been released in Sri Lanka. Exposure to even small amounts of these heavy metals over time, mainly through the food chain, or by smoking, cause kidney, liver, bone and neurological damage in humans, leading to a variety of chronic diseases.
According to the news reports “The SLSI had suspended the release of the TSP consignment after it found that Lead and Cadmium in the imported fertilizer were higher than the maximum levels for toxic elements based on Sri Lanka standards specifications……However, following a meeting at the Presidential Secretariat, Director Siddika Senaratne authorized the release of the consignment into the market, on a strictly conditional basis, considering the food security of the country”.
Anyone reading the news would be justifiably alarmed, as both cadmium and lead are toxic substances that should not get into the food chain even in small concentrations. However, we point out here that the fault is not in the imported fertilizer, but in the ridiculous standards stipulated by those who wrote Sri Lanka’s standards for heavy metal residues in fertilizers. This is a topic that I have addressed in newspaper articles as well as in technical studies [e.g., Dharma-wardana, Environmental Geochemistry and Health volume 40, pages2739–2759 (2018) ].
This report must be taken in the backdrop of news about toxins in coconut oil, as well as the attempt of a TV-media host to make the SL Standards Institute (SLSI) Director Dr. Siddika Senaratne to reveal names of companies alleged to have imported contaminated coconut oil. She quite correctly stood her ground and declined to reveal names and make public accusations.
The Director of a scientific laboratory is not mandated to act as a public prosecutor. However, her answer showed that scientists lack media savvy and may give totally inappropriate answers that media outlets seek to create media hype. The fact that media hosts should try to destroy due process, and create “instant exposés” in an inappropriate manner show the extent of the decline in public standards of justice and fair play in the country.
However, let us use this opportunity to educate ourselves regarding toxic substances in general, and heavy meals in fertilizers, in particular. Due to lack of space, here we examine only the case of cadmium, whose Sri Lankan standards are stated in SLS-812-standard-1988, amended and re-approved in 2008. This says that a kilo of TPS fertilizer cannot contain more than 5 mg of cadmium (or 10.9 mg per kg of P2O5). This is an absurd specification which is impossibly LOW such that there are very few mineral sources that conform to such a specification.
Let us look at this in comparison with the standards required by other countries for cadmium in fertilizer.
Country mg of Cd per kg of phosphate.
Sri Lanka – 5
Canada – 889
Oregan, USA – 750
California – 400
Japan – 148
Australia – 131
Belgium – 90
Europen Union – 60 → 40 → 20 (future)
Each country, and some times each state or province of a country sets its standards based on the naturally existing cadmium levels in its soil. Most parts of UK have very high cadmium levels in its soil, and so inputs of Cd via fertilizers make ittle difference. Some parts of Western Europe (e.g, Brittany, in France, or parts of Holland) have low natural levels while Belgium is as contaminated as the UK. So the European union as a whole hopes to gradually tighten its standards and move to 20 mg/kg by 2040. But Sri Lanka has already, in 1988 itself, set its Cd limit at the impossibly low value of 5 mg/kg !
Was this very low limit set already in 1988 so as to disallow every imported batch of fertilizer, so that it can be allowed only when the right pockets are filled? Did the ring of racketeers with greased palms get broken, or did it not change with the change of government, and was this the reason why this matter had to go right up to the top for the “approval” of a perfectly safe and fine fertilizer? The fertilizer has been “condemned” as being “laced with cadmium” and other heavy metals using deliberately contrived specifications ?
How clean the food you eat depends fundamentally on the cleanliness and ecology of the soil to start with. It is only secondarily dependent on the purity of fertilizers in regard to trace metals, or the presence of traces of pesticides, even though a very different hype has been developed in the media for the consumption of a public frightened for its health and ready to even believe people like Dr. Mercola or even “Dr”. Dhammika Bandara inspired by Kaali Amma.
All soils have a certain amount of naturally occurring toxins, as well as toxins from human activity, e.g, earth works, mining, farming, burning of fossil fuels or forests that cause acid rain and noxious fumes, and poor disposal of garbage. Even organic farming, often believed to be clean and “natural”, produces toxins similar to those in mineral fertilizers, as composting plant matter leads to the cyclic accumulation of heavy metals like cadmium and lead found naturally in the soil, and re-concentrated in plant matter used for composting.
Mineral fertilizers like triphosphate (TPS) is mined from the ground, usually from desert locations (e.g., in Morocco, Nauri Islands in New Zealand). These mineral deposits are becoming increasingly scarce and phosphates are a threatened commodity. Mineral fertilizers applied to the soil also contribute some cadmium (and other trace metals) to the soil.
Let us take an “extremely polluted sample” of fertilizer by Sri Lanka’s specification, e.g. Nauru phosphate which has some 90 mg/kg of cadmium, i.e., 15 times more than that specified by the current absurd SL standard. We have shown (e.g., https://doi.org/10.1007/s10653-018-0140-x)
that it will still take a many centuries to modify the cadmium levels in, say, Sri Lankan soil significantly by such fertilizer additions. Hence even such a so-called “bad” fertilizer, but used in Australia and New Zealand, would be perfectly safe for use in Sri Lanka too.
Sri Lanka has a deposit of phosphate minerals at Eppawala. While it is quite high in its arsenic contamination, it has very low cadmium contamination. Some people have urged the government to exploit the Eppawala deposits. I have opposed this as the conversion of the rock phosphate to usable TPS etc., is a highly polluting process that is best done far away from human habitations – i.e., unsuitable for Sri Lanka. In any case, a local production will also cost three to ten times more than what is available in the international market. Given the increasing scarcity of phosphate, the local deposit should be regarded as a national treasure that must be conserved for future use, until cleaner nano-technological methods for mineral exploitation become available.
Hence I urge the government to change the cadmium and other heavy metal specifications used in Sri Lanka to conform to modern scientific knowledge and align its standards with values used internationally. Having looked at the level of cadmium in Sri Lankan soils, I believe that an appropriate standard for Sri Lanka is to set its upper level for cadmium to be about 100-150 mg per kg of Phosphate, instead the current absurdly low value.
*The author is currently affiliated with the National Research Council of Canada, Ottawa, and the University of Montreal. He was a past VC and Professor of Chemistry at Vidyodya/SJP university.