High levels of arsenic in pesticides

By Lakna Paranamanna

The raid carried out by Sri Lanka Customs on a consignment of toxic substances last week triggered a controversial debate concerning certain discoveries made by a collaborative research carried out by the Universities of Kelaniya and Rajarata about high levels of arsenic and mercury found in pesticides available in the country.

The research which is currently debated on, had been initiated in 2010 November with the involvement of some 30 doctors and 10 academics on causes behind the chronic kidney disease prevalent in the North Central province. “We conducted post-mortem studies on patients who had died of the disease and discovered accumulations of arsenic unusually high to human bodies in the cadavers,” research team member – Rajarata University Medical Faculty lecturer, Dr. Channa Jayasumana said explaining the research details.

Among tests carried out to determine the source of arsenic, the soil profiles had indicated a high level of arsenic in the topmost layers of soil. “Since Sri Lanka does not have natural arsenic in the soil we determined that the arsenic source should be external.” This breakthrough had led the researchers to examine pesticide samples which led them to the discovery of hazardous arsenic levels contained in pesticides available in markets.

The samples had been tested repeatedly in several other labs and even before agrochemical company representatives. All tests had indicated high levels of arsenic that is deadly to human beings. “The results were compatible in all the tests and our figures were even compatible with the independent investigations carried out by the Sri Lanka Customs on the consignments of pesticides,” Dr. Jayasumana said. 

Another research team member – Kelaniya University Science faculty Dean Professor Nalin de Silva speaking to Daily Mirror said that the concentration of arsenic or mercury should be zero percent in any pesticide or any other agro-chemical as the accumulation of such compounds in the environment results in adverse impacts on the biological system as well as humans. “Even the smallest trace of arsenic is prohibited to be included in any substance. With strict regulations introduced both locally and internationally on the use of arsenic, who authorized such substances to be imported to Sri Lanka?” Professor de Silva questioned.

Research data

improbable – PRO 

The national authority responsible for regulating the pesticide trade – the Pesticide Registering Office (PRO) in Peradeniya dismisses data brought into light through exhaustive research carried out by academics on high levels of arsenic and mercury in pesticides claiming they are certain that none of the pesticides available in the market contain arsenic or mercury in a hazardous range.

“There might have been traces of mercury or arsenic in the pesticides but not in the unusually high levels as claimed by the researchers. Some 28 chemicals including arsenic and mercury contain sanctions in importation only if such compounds are ‘active ingredients’ in the pesticide,” Registrar of Pesticides Dr. Anura Wijesekara said.

The PRO has introduced a set of guidelines to be considered during the importation of pesticides. It is compulsory to obtain a registering certificate from the PRO prior to releasing any brand of pesticide into the market. “The application has to be submitted by the pesticide distributor inclusive of a report  on toxicological data of the pesticide’s composition. The quality certificate is issued only after the composition report is studied. It is vital for the report to be issued by an independent lab with a GLP (Good Laboratory Practice) rating,” Dr. Wijesekara explained.

Inconclusive enforcement mechanism? 

Environmentalists point out that although the existing legal framework is sufficient to effectively regulate the trade and minimize possible hazards that are caused through pesticides, it is the loopholes in the enforcement mechanism that has left scope for swindles to occur. “The consignment of banned toxic substances seized at the Customs cannot be an isolated incident. It is possible that numerous other consignments could have been brought into the country for use in the similar manner. That is why it is important for the trade to be constantly monitored,” senior environmentalist and environmental lawyer Jagath Gunawardena said.

Mr. Gunawardena further pointed out that the toxicology reports submitted by the distributors during the registration of the pesticide could contain inaccurate information. “It is vital for the regulating bodies to be re-checking the data submitted by the distributors. It is a big weakness of the only regulating authority to base their conclusions on biased reports,” he pointed out.

However, Pesticide Registrar Dr. Wijesekara says in order to monitor and regulate the trade; the registration certificate is issued to be valid only for three years. “The registration certificate has to be renewed by the distributor every three years and the distributor is not given provisions to import the pesticide from a company other than the initial supplier during the validity period of the registration,” he added.

Although the possibility of inaccuracies in the pesticide composition report is not completely overruled by Dr. Wijesekara, he seems to be of the opinion that it is highly improbable. “This is an international trade – therefore practices and regulations are strictly followed by the distributors and the companies. There have been no reports of such swindles so far,” he added while supporting his opinion.

Impacts of arsenic on humans and nature  

Rajarata medical faculty lecturer Dr. Jayasumana pointed out that WHO Recommended Classification of Pesticides very clearly states that even the smallest trace of arsenic or mercury is in an ‘active’ state in pesticides. “The agro-chemical companies might not declare the compounds such as mercury and arsenic to be active ingredients in the pesticide. But it is the duty of the regulating body to re-check the information submitted by the companies without being dependant on their biased reports to support their conclusions,” he pointed out.  

He pointed out that when arsenic contained pesticides are used, the compounds are accumulated in the biological system. “Apart from chronic cases of kidney diseases, the compound could result in cancers, skins diseases such as keratosis, heart attacks as well as diabetes,” Dr. Jayasumana added. He also added that since arsenic easily replaces the phosphate groups in the DNA structures, it results in adverse impacts mainly concerning virus and bacteria DNA structure changes. “The virus or the bacteria becomes virulent which could once again impact on humans negatively.” 

Arsenic not linked to NC kidney disease – IFS

Institute of Fundamental Studies (IFS) based on their research findings claim that they do not believe arsenic to be directly linked to the chronic kidney disease prevalent in the North Central province. “The World Health Organization and the U.S. Environmental Protection Agency (EPA) guidelines, sets a limit of 10 micrograms per liter for arsenic in drinking water. We have checked ground water samples in various provinces including Jaffna, Hambanthota and Batticaloa but we have not detected arsenic in hazardous levels in any of the tested water samples from those districts,” IFS Research Fellow Dr. Meththika Vithanage said speaking to Daily Mirror. She pointed out that even in districts such as Jaffna where a high amount of pesticides are used in comparison to other districts, they did not detect high arsenic levels and neither are any unusual numbers of kidney patients reported.

However, Kelaniya University Science faculty Dean Professor Nalin de Silva said that a special method was developed by the Kelaniya University to detect arsenic since conventional methods do not give accurate results due the composition of water in the North Central province. “Wells and rivers in those areas contain hard water (kivul) which contains of high mineral content. The minerals in the water prevent arsenic from being identified when it is tested in conventional methods,” he explained adding that several more researches were carried out on plant life as well.

Raid conducted by the Customs

Customs Bio Diversity and National Heritage Deputy Director Samantha Gunasekara speaking to Daily Mirror said that investigations are still being carried out in the consignments of pesticides which were seized last week on suspicion of containing banned chemicals.

The consignment had contained some 400 packages of toxic substances containing banned chemicals such as arsenic and mercury. The shipment had been imported as insecticides, herbicides, rodenticides, bacteriacides and fungicides by six multinational agrochemical companies operating in the country.

 “The importers have not included the banned chemicals in their declarations. The initial tests carried out indicate that several banned chemicals including arsenic and mercury were detected in the consignments. Some of the pesticides in the consignment are categorized under “restricted use” – meaning only authorized personnel may buy or use such pesticides,” Mr. Gunasekara added. The value of the pesticide consignment is yet to be established.

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