Chronic kidney disease of unknown etiology (CKDu) is spreading gradually in Sri Lanka. In the current research, 1,435 well water samples from all 25 districts of Sri Lanka, 91 rice samples, and 84 human urine samples from both CKDu-endemic and non-endemic areas in Sri Lanka were analyzed for arsenic, cadmium, lead, and chromium to detect whether toxic elements could be a cause of CKDu. The liver-type fatty acid binding protein (L-FABP) concentration and arsenic, cadmium, lead, and chromium concentrations of the urine samples were analyzed to determine the relation of L-FABP with arsenic, cadmium, lead, and chromium. High concentrations of arsenic, cadmium, lead, and chromium were not detected in the well water samples from CKDu-endemic areas. Arsenic, cadmium, and lead contents in the rice samples from both CKDu-endemic and non-endemic areas were well below the Codex standard. There were no relationships between the L-FABP concentration and concentrations of arsenic, cadmium, lead, and chromium in urine. In addition, arsenic, cadmium, lead, and chromium concentrations in human urine samples from CKDu-endemic areas were not significantly different from those from non-endemic areas. These findings indicated that arsenic, cadmium, lead, and chromium could not cause CKDu.

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The ingestion of fluoride-contaminated water causes serious health issues in people all over the world. In the current study, the adsorption of fluoride onto chicken bone char (CBC) was investigated as a defluoridation technique. Finer-sized CBC with a diameter of 106–212 µm was used to investigate the fluoride adsorption capacity onto CBC. Results revealed that finer-sized CBC yielded an unusually high fluoride adsorption capacity of 11.2 mg/g at the equilibrium fluoride concentration of 10 mg/L. The study shows that CBC can be utilized in the defluoridation of drinking water and that finer-sized CBC enhances ion exchange to perform a higher adsorption capacity.

Ab s trac t Polpala (Aeroa lanata) is a medicinal plant that is extensively used fo r the treatment of renal disease in Ayurvedic medicine. This preliminary investigation was carried out to evaluate the diuretic effect of the crude aqueous plant extract and high and low molecular mass fractions of this herb, using the hydrated rat assay technique. Possible toxicological effects on renal structure and function , mediated by long term administration of aqueous plant extract was also studied using two concentrations of both fresh and dried plant material , made according to A yurvedic system of medicine in Sri Lanka. Urine output, osmolality and electrolyte excretion were measured to evaluate diuretic activity. Creatinine clearance and histopathological studies were done to evaluate toxicological effects on renal structure and function. Crude aqueous plant extract showed a diuretic activity with marked increase in urine output, urine osmolality and urinary potassium excretion. Low molecular mass fraction of dried plant material showed a Significant diuretic effect while the high molecular fraction did not have the same effect. Investigations also showed that long term administration of the aqueous extract of this plant had no toxicological effects on renal structure and function of rats.

Neonicotinoids are systemic insecticides used since the 1990’s , that possess renal tubular toxicity. We conducted a field-based descriptive study in the North Central Dry-zone of Sri Lanka, where chronic kidney disease (CKD) of unknown etiology has been increasing since the 1990’s. To elucidate the relationship between renal tubular dysfunctions and urinary neonicotinoids concentrations, we collected spot urine samples from15 CKD patients, 15 family members, and 62 neighbors in 2015, analyzed two renal tubular biomarkers, Cystatin-C and L-FABP, quantified seven neonicotinoids and a metabolite N-desmethyl-acetamiprid by LC–MS/MS; and we investigated their symptoms using a questionnaire. Cystatin-C and L-FABP had a positive correlation (p < 0.001). N-Desmethyl-acetamiprid was detected in 92.4% of the urine samples, followed by dinotefuran (17.4%), thiamethoxam (17.4%), clothianidin (9.8%), thiacloprid and imidacloprid. Dinotefuran and thiacloprid have never been registered in Sri Lanka. In High Cystatin-C group (> 70 μg/gCre, n = 7), higher urinary concentration of dinotefuran (p = 0.009), and in Zero Cystatin-C group (< LOQ, n = 7), higher N-desmethyl-acetamiprid (p = 0.013), dinotefuran (p = 0.049), and thiacloprid (p = 0.035), and more complaints of chest pains, stomachache, skin eruption and diarrhea (p < 0.05) were found than in Normal Cystatin-C group (n = 78). Urinary neonicotinoids may be one of the potential risk factors for renal tubular dysfunction in this area.

The effectiveness of regenerated chicken bone char (CBC) in fluoride removal was investigated in the present study. Heat treatment was studied as the regeneration method. Results revealed that the CBC regenerated at 673 K yielded the highest fluoride adsorption capacity, hence, 673 K was the best regenerating temperature. The study continued up to five regeneration cycles at the best regenerating temperature; 673 K. The CBC accounted to 16.1 mg F/g CBC as the total adsorption capacity after five regeneration cycles. The recovery percentage of CBC reduced from 79% at the first regeneration to 4% after five regeneration cycles. The hydroxyapatite structure of CBC was not changed during the fluoride adsorption by five regeneration cycles. The ion exchange incorporated with the chemical precipitation occurred during the fluoride adsorption. The repeated regeneration of CBC is possible and it could be used as a low cost defluoridation technique to minimize the wastage of bone char.

The growing worldwide prevalence of chronic kidney disease of unknown etiology (CKDu) has been reported since the 1990’s. Neonicotinoids are systemic insecticides used since 1990’s, which may cause renal dysfunction, but the effect on the urinary concentration was unknown. We conducted a field-based case-control study in the North Central Dry-zone of Sri Lanka where CKDu was prevailing. We collected spot urine samples from15 CKD patients, 15 CKD family members, and 62 neighbors in May and December 2015, analyzed seven neonicotinoids and a metabolite by LC-ESI/MS/MS, in addition to two biomarkers of renal tubule activity, Cystatin-C and L-FABP. We also investigated their symptoms using a questionnaire. In CKD patients, urine Cystatin-C and L-FABP were significantly higher compared to non-CKD participants; and they complained of finger tremor, fever, and abnormal behavior more. Among neonicotinoids, N-desmethyl-acetamiprid was detected at the highest rate in 92.4 %, followed by thiamethoxam in 17.4%. Dinotefuran and thiacloprid that was not registered since 2015 in Sri Lanka were detected in 17.4%, 3.3%, respectively. In the participants whose urine Cystatin-C was in higher half, N-desmethyl-acetamiprid was significantly less than others. The urine neonicotinoid levels in CKD patients with compromised tubular function doesn’t seem to reflect their level of exposure.

Experimental studies were carried out in two phases to evaluate diuretic effect of the herb using hydrated rat assay technique and to determine possible toxic effects of prolonged use of Aerva lanata on the urinary tract of rats. Phase I – Two different concentrations of extract prepared using fresh and dried forms Aerva lanata was administered orally to 24 healthy rats. Findings of test groups were compared with those from rats administered water (negative control) and frusemide (positive control). Phase II – Two different concentrations of dried infusion of Aerva lanata was administered orally to 40 healthy rats for 30 days as per the WHO guidelines. Control group of rats were given water. Creatinine clearance (Ccr) and urine flow rate (UFR) were calculated to determine the effect of the herb on renal function. Kidneys, bladders and ureters were harvested for light (LM) and electron microscopic (EM) studies. Crude aqueous plant extract showed a diuretic activity. Ccr and UFR of test groups were not statistically different when compared with that of control group. LM of kidneys, ureters and bladders were negative for toxic changes. EM of kidneys showed significant changes in proximal convoluted tubular epithelial cells of rats in test groups. EM changes indicate that long term use produces structural changes.