Presence of arsenic in Sri Lankan rice

Abstract

Background: Arsenic and heavy metals are implicated in causation of CKDu among farmers in dry zone of Sri Lanka. Rice has been identified as a major source of arsenic in research carried out in other countries. We analyzed 120 samples of new improved varieties (NIVs) and 50 samples of traditional varieties (TV) of rice for total arsenic content. Findings: Rice cultivated in Sri Lanka is contaminated with arsenic. Agrochemical dependent NIVs contain considerable amount (20.6-540.4 μg/Kg) of arsenic. There is no difference between the arsenic content in NIV rice samples from areas where there is high or low prevalence of CKDu. TVs that are cultivated without using agrochemicals contain significantly less arsenic (11.6-64.2 μg/Kg). However, it is evident that the TVs also contain toxic metals if they are grown with fertilizers and pesticides. Conclusion: A high proportion of arsenic in rice exists in the inorganic form. Sri Lanka is a nation with high per capita consumption of rice. Codex Alimentarius recommends the maximum allowable limit for inorganic arsenic in rice as 200 μg/kg. Assuming that 70% of the total arsenic content exists in the inorganic form, this corresponds to a level of about 286 μg/kg of total arsenic. As such, 11.6% of the samples of NIVs exceeded this maximum recommended level in polished rice. Inorganic arsenic is a non-threshold carcinogen. Research should be focused on developing rice varieties that do not retain arsenic within the rice grain.

Trace elements in native and improved paddy rice from different climatic regions of Sri Lanka: implications for public health

“…Williams et al (2007) reported that the baseline inorganic As levels in rice are tenfold higher compared to other cereals. Although the groundwater and surface water arsenic levels are insignificant in Sri Lanka (Chandrajith et al 2011; Nanayakkara et al 2014), some studies highlighted alarming higher levels (21–540 µg/kg) of As in rice from Sri Lanka (Jayasumana et al 2015). This enriched As in rice was attributed to the application of contaminated fertilizer and pesticides in paddy cultivation.…”

Toxicology of freshwater cyanobacteria

“…Ochratoxin A [225], aluminium, fluorine [226] heavy metals; iron and lead [227] and arsenic [228]. However, these findings were later challenged by other studies and the cause still remains unresolved.…”

Arsenic and cadmium concentrations in legumes and cereals grown in the North Central Province, Sri Lanka and assessment of their health risk

“…Scientific research has found a number of causes for CKDu, of which one was As and Cd contamination (Bandarage, 2013). Jayasumana et al (2015) reported considerable amount (20.6-540.4 μg/Kg) of arsenic in rice, which is depend on the fertilizers and pesticides used during the cultivation.…”