Nanocrystal-induced chronic tubular-nephropathy in tropical countries: diagnosis, mitigation, and eradication.

In tropical countries, a mysterious tubulo-interstitial chronic renal disease (CKD), unrelated to diabetes, hypertension, and immunological causes, manifested four decades ago. Approximately 25,000 primarily middle-aged male farmers succumb annually to this crystal-tubular nephropathy (CTN). Without any known causative factors, it was identified as CKD of unknown aetiology (CKDu). Because multiple factors contribute to causing it later, was changed to CKD of multi-factorial (CKDmfo). Despite no evidence, it was hypothesised to cause by agrochemicals or heavy metals in food or drinking contaminated water. However, current data suggest that the CKD-CTN is due to natural geogenic water contamination. Consumption of concentrated stagnant groundwater from deep-dug wells and tube wells containing hard water and fluoride, overdecades is necessary for its clinical manifestations. In all affected countries have prolonged annual dry seasons that led to the evopo-concentration of ions and minerals in groundwater, making hard water even more unpalatable, thus, peasants consume lesser amounts of water. They develop chronic dehydration from daily exposure to hot climatic conditions aggravated by regular alcohol intake. These conditions provide a highly conducive environment-a perfect storm for calcium phosphate (CaPO4) crystal formation in renal tissues. Our recent histological and preliminary electron microscopic data reveal deposition of CaPO4 crystals and nano-tubes in kidneys. While CaPO4 nano-minerals are unstable, the presence of fluoride ions stabilises and allows their growth. This new concept paves the path for highly cost-effective, straightforward local solutions to protect farm workers and eliminate the disease, without embarking on expensive medications, interventions, or building hospitals. Chronic dehydration-associated CKD-CTN is preventable by increased consumption of potable water. Increasing clean water consumption reduces CKD-CTN incidence, and associated morbidities and premature deaths. However, the damage becomes irreversible when the disease advances beyond CKD stage IIIB. The incidence of this deadly renal failure can be prevented by its education, lifestyle changes, and increased water consumption, not by treating the renal disease or expanding dialysis centres/hospitals, or transplantation services. Eradication of CKD-CTN cost significantly less than the current approach of treating affected persons and unnecessarily expanding health infrastructure. Since the manifestation of CKD-CTN is due to consuming naturally contaminated drinking water (with calcium containing hard water and fluoride), it is not difficult to remove these to prevent CKD-CTN: thus, international assistance is unwarranted for its eradication. The straightforward approaches described here will prevent CKD-CTN and save thousands of lives in affected farming communities.

Geochemistry of trace elements in paddy (rice) soils of Sri Lanka--implications for iodine deficiency disorders (IDD).

Iodine Deficiency Disorders (IDD) are a common health problem prevalent in the wet zone of Sri Lanka with a prevalence of >25% of the population. In comparison, in the dry zone of Sri Lanka IDD occurs in <10% of the population. Seventy soil samples from 14 villages selected on the basis of the incidence of goitre, were collected and analysed for 13 trace elements using ICP-MS. In order to identify any prevailing differences in antecedent chemical environments, soil samples from each pre-selected village were classified into three groups in terms of their geographical location. Among the elements investigated, the total soil concentrations of Rb, Sr, Ba, Mn and Co are lower in the wet zone of Kalutara. In contrast, total soil Rb, Sr, Ba and Mn contents are higher in the dry zone of Anuradhapura. Further soil total Mo and Nb levels are relatively similar in all pre-selected study locations. The high endemic goitre regions (IDD >25% of the population) show low levels of Rb, Sr, Ba, and Mn and higher levels of V, Cr, Co, Ni, Cu, Zn and Pb as compared with moderate and non-goitre areas. Factor analysis was used to exploit the correlation structure present in data and yielded three groups in all cases. This indicated that most transition group elements and iodine are associated with the Mn phase in the low IDD areas whereas iodine shows a high affinity for the organic phase in high IDD regions. The variable distribution of trace elements, therefore, must be due to differences in mobility and capacity for incorporation into the structure of secondary minerals or organic phases.

The abundances of rarer trace elements in paddy (rice) soils of Sri Lanka.

Concentrations of Ti, Ga, As, Sc, Zr, Sn, Hf, Th, U and Y have been determined for 70 paddy soils from 14 villages, selected throughout Sri Lanka by means of ICP-MS. The mean elemental contents of all paddy soil samples were 6120 Ti, 14.1 Ga, 0.84 As, 7.26 Sc, 129 Zr, 2.27 Sn, 3.64 Hf, 12.71 Th, 1.53 U, and 13.35 Y (all data in microg/g). Paddy soils were classified into groups based on morphology and climate. Higher contents of Th and U were found in the wet zone lowland soils whereas the higher Ti contents were observed in dry zone soils. Arsenic, Zr and Hf contents were comparatively similar in all regions. Factor analysis was used to identify the relationships between the contents of elements.