Chronic Kidney Disease persists!

The common viewpoint is that agrochemicals are the cause of CKDu, but is there tangible evidence for it? On the other hand, CKDu or not agrochemical pollution is a serious matter and the government’s concern and the public outcry against it is justifiable. However, all facets relating to agrochemicals, namely, their impact on food security, environmental pollution and people’s health should be examined in depth in making decisions. Highly prejudiced and emotional views on the subject presented by the mass media mislead both the public and politicians.

“Wasa visa krushikarmaya” was a term coined by the media to denote agrochemical pollution. Nalaka Gunawardene, science writer and columnist has in a presentation titled ‘Mass Media and Mass Kidney Failure’ elegantly dealt on the media ignorance and bias on the matter. A very vociferous and prominent minister of the previous government at a public meeting once uttered that “our farmers are being killed by agrochemical companies, selling glyphosate, a “toxic fertilizer”. Not to be outdone, another coined the catchy phrase “asenic karayo” for agrochemical companies to implicate that arsenic is the cause of CKDu and its source is arsenic-contaminated agrochemicals. Evidence from the WHO study, 2013, and several other publications did not support this contention. These only display the ignorance and emotional approach to national issues of our law makers! It is hence incumbent on the media to educate the public and politicians through balanced and evidence-based reporting.

The government’s policy concept of ‘a toxin free nation’ is laudable, but its recent pronouncements are strongly indicative of not only plans for agrochemical reduction, but also of valiant efforts to promote organic farming and traditional rice varieties. All this is purported to reduce chemical use in agriculture as a means of curbing CKDu. The world moved away from organic farming and traditional varieties because these technologies could not feed the ever increasing population locally or globally. Lowering agrochemical use should be via judicious use. The national food security – agrochemical risk equation has to be balanced wisely.

CKDu and agrochemicals

CKDu is an unprecedented health hazard of the Rajarata, and now spreading to the neighbouring areas. Although numerous hypotheses have been promulgated as to its aetiology including agrochemicals, none has been able to explain it with any degree of certainty. The aetiology may be multifactorial. If so, it would be hard, if not impossible to define the causality. However, because CKDU is associated with farming communities, there is a strong belief that agrochemicals are the cause. The WHO study (2013)on CKDu in Sri Lanka, hitherto the most comprehensive as regards agrochemicals, reports significantly high levels of cadmium(Cd) in the urine of CKDu patients compared to control subjects. Cd is a known nephrotoxin and hence is a risk factor in CKDu. This report also states that the contents of several commonly used pesticides in the urine of patients were above reference (safe) limits and concluded that some of the pesticides are nephrotoxic and may contribute to the progression of the disease. A serious lapse in the Report, however, was the failure to present the urine pesticide residue data for the control subjects (who were from the Hambantota District). Our recent analysis of raw data for urine pesticides levels from the WHO study has revealed far greater exposure of the control subjects to pesticide residues than the patients with nearly all the pesticide levels double or more in the former than in the latter (see Table). This data, therefore, raise serious doubts whether pesticides play a role in CKDU. On the other hand, the argument that exposure to nephrotoxic pesticides, although their levels were lower in the urine of patients than in that of control subjects, aggravating the disease triggered by a more potent aetiolating agent such as Cd can still be valid. More importantly, the data demonstrate the extent of pesticide contamination of people in farming communities.

It is noteworthy that the content of glyphosate, which was banned by the government some months backed on the premise that it had a role in CKDU, was double for the control subjects compared to the CKDU subjects! Therefore, can the government’s glyphosate be justified? The ban has a serious negative impact on the tea industry where large extents are now said to be abandoned because of the exorbitant cost of manual weeding and poor tea prices. In rice farming some 20% more water is supposedly needed for pre-planting weed control in the absence of glyphosate, which is a huge cost, and farmers also complain that cultivation of other seasonal crops such as maize, gingelly and kurakkan is heavily impeded because of their inability to control certain weeds manually such as cyperus (kalanduru) and cooch grass. A substantial drop in maize yields for the last Maha season from Anuradhapura, for example, has been reported sequel to the glyphosate ban. There is thus a compelling need for the government to review the ban given also the fact that the WHO-FAO Expert forum appointed at the behest of the EU Parliament to review glyphosate toxicity on account of the growing public concern about this herbicide has last month reported no tangible evidence of carcinogenic or genotoxic effects of glyphosate. In any case, there has been no acceptable scientific evidence to link glyphosate and CKDu, and all glyphosate measurements in soil, vegetable and water in Sri Lanka are far below safety limits established for EU and USA.

The WHO Report (2013) on CKDu also stated that Cd levels in some soils and vegetables from the CKDu endemic area are higher compared to those of the control area. This supports the contention of Cd possibly playing a role in the disease. There is evidence that, very likely the major source of Cd in the soil and eventually arable crops is the result of application of highly Cd - contaminated triple superphosphate (TSP) over the years. The maximum allowable limit of Cd in TSP Imposed in 1988 is 5 ppm, but the WHO study (2013) reports 30 ppm Cd in TSP from the disease endemic area. Other recent studies too have reported comparably high (30 – 40 ppm) Cd levels in TSP. It would appear that despite the limit of 5 ppm imposed, highly Cd -contaminated TSP has been illegally imported! There is published research revealing build up of Cd in both upcountry and low country vegetables and vegetable growing soils. Vegetable farmers, especially in the upcountry are reported to apply 5 to 10 times the Department of Agriculture recommended dose of fertilizer and it is likely that this has caused build up of Cd in the soils . It has been known for years that phosphorus levels in these soils have reached unprecedented levels: and downstream reservoirs in the NCP are often highly phosphate- polluted (eutrophication) leading to algal blooms. Some of these algae are known to secrete nephrotoxins which may play a role in CKDU. Phosphate pollution also leading to Cd pollution is a matter of concern whether or not they relate to CKDu.

Agrochemical quality and misuse

The foregoing information amply demonstrates that the issues that need addressing are control of agrochemical quality and misuse. Relevant institutions should be strengthened to stop import of contaminated agrochemicals above allowable limits, and for agrochemical residue analytical research in food, water and soil. The government and the public should be regularly informed of data on food and environmental contamination of agrochemicals . The Pesticides Act should be revised to give greater authority to relevant law enforcement officials to deal with pesticide misuse more effectively. Farmers should be made to compulsorily use protective clothing and gear when handling pesticides. Fertilizer should be issued to farmers based on soil and crop requirements to be determined through soil analysis, Most importantly, the deteriorated extension services of the Provinces should be greatly strengthened for effective farmer training and education on prudent agrochemical use.

It is the view of the Plant Protection Division of the Department of Agriculture that integrated pest management technologies that can substantially reduce pesticide use can be expanded if resources are available. Biological pest control and biopesticides can greatly mitigate chemical pesticide use. Agriculture in Cuba is substantially dependent on such technologies. There are many technologies to learn from Cuba. Pesticides are like drugs; both are essential but misuse can be disastrous!

Is there adequate organic matter for mass scale organic farming?

The government is promoting organic farming (OF) as a means of reducing chemical fertilizer use. This is welcome but the activity will be greatly constrained by the availability of organic matter (OM). Although it is argued that OF is not merely the use of organic matter but beneficial microbes/biofertilizers, no such technologies with substantial benefits are widely accessible to the farmer except that of Rhizobium in biological nitrogen fixation in legumes. Multinational agrochemical enterprises such as Monsanto, however, have launched extensive research in the generation of beneficial microbial technologies, but there is yet no evidence of breakthroughs that can reach the farmer.

 

Despite the attractive prices for organically grown food, the total extent under organic agriculture in the world remains less than 1% of the total cropland (0.98% to be exact in 2013) ; of which 65% are in pastures!(The World of Organic Agriculture Statistics & Emerging Trends, 2015)). This is clearly because of the limitations in availability of OM. The world turned away from organic farming to chemical farming with the discovery of fertilizers from the mid 1850s because the former could not produce adequate food to meet the growing world demand even then. Despite the hype over OF, Sri Lanka’s extent under it has in fact reduced from 20,260 ha in 2010 to 19,517 in 2013 (International Federation of Organic Agriculture).

More importantly, OF is not toxin-free. A very serious contaminant of organic fertilizer is heavy metals. For example, the amounts of Cd , the heavy metal implicated in CKDu, reported by the Department of Agriculture in some samples of organic matter and cow dung are 2.42 , and 0.4 ppm respectively. Given the fact that vegetable farmers in particular apply as much as 10-20t/ha of organic fertilizer per season, the quantities of heavy metals entering the soil and food chain from organic matter may well exceed that from recommended quantities of chemical (phosphate) fertilizers. The other problem with organic fertilizer is the inability to provide the exacting quantities of nutrients (N, P, K) as the crop demands. When adequate OM is added to meet the nitrogen demand , for example, too much phosphorus may be added. Crops vary in their demand for nutrients (N,P&K) and excess addition of OM as in the case of chemical fertilizers can lead to environmental pollution. There are examples of such situations. Finally, OM also emits greenhouse gases (carbon dioxide, methane etc) which cause global warming, a serious environmental hazard the whole world is now addressing.

Promoting traditional rice varieties

There should be no objection to the cultivation of limited extents with traditional varieties if farmers are to benefit economically but the concern is that cultivation of large extents could jeopardize national food security, given the average national yields of only about 1 - 2t/ha for traditional varieties (TVs) as against 4.-5 t/ha for new improved varieties (NIVs). In fact, the potential research yields of NIVs is now about 9-11/ha, and 6-7 t/ha are often achieved in the high potential rice growing areas. It is said that one reason for diversification to TVs is the current trend in production over the national requirement, and our NIVs have no demand in the world market. If this is the case, our policy should be to diversify arable lands, in particular, for pulses, coarse grains and other crops much of which are inadequately produced locally and hence largely imported; and also breed new rice varieties with attributes for international demand, if we do not already have such in our breeding pipeline. CIC, a private company has already bred new varieties (example, red basmathi) with good export demand, and are being cultivated by several thousand farmers, and 300-400 tons are already exported annually.

That the traditional rice varieties have higher nutritive value and are resistant to pests and diseases are myths. (Please see“Attributes of Traditional Varieties of Rice in Sri Lanka” ITI-DOA Publication, 2010)There are several NIVs of red rice which are in high demand with comparable nutritive attributes, in particular low glycemic index. NIVs also have built in resistance to many pests and diseases, and it is a well known fact that TVs are highly susceptible to many pests and diseases, in particular to the fungal disease blast and the bacterial wilt disease. Patchaperumal, a popular traditional variety is one of the most susceptible to these two diseases. It may be that TVs grown in isolated plots escape these diseases, but the problem arises when cultivated in large tracts.

In conclusion, any major changes in agriculture policy should be made in consultation with technical experts in the subject, namely, the Department of Agriculture. It would appear, that it has not happened in making decisions on expansion of organic farming and cultivation of traditional varieties. There is no alternative to conventional agriculture in feeding the nation for which agrochemicals are an obligatory component. Agrochemicals, undoubtedly, have risks but the government has hitherto failed to set in motion stringent rules, regulations and mechanisms to ensure judicious use. Profligate misuse is the issue! There is no tangible evidence yet to implicate agrochemicals in CKDu. Organic farming and traditional rice varieties are a mere ‘pillow change’ for the CKDu headache.


Add new comment

CAPTCHA
This question is for testing whether or not you are a human visitor and to prevent automated spam submissions.
Image CAPTCHA
Enter the characters shown in the image.

Or log in with...