This cross-sectional study was carried out in some selected arsenic contaminated rural areas of Bangladesh to determine any clinical changes in oral cavity, among the arsenic exposed population through drinking water. Total 600 respondents (200 arsenicosis patients, 200 non-patients but having the history of taking arsenic contaminated water and another 200 arsenic non-exposed). 75.5% of arsenicosis patients had swelled vallate papillae whereas only 44.5% and 8.5% in case of arsenic exposure and non-exposure subjects respectively. The differences were found statistically significant (p<0.001). This study suggests that there is a tendency of developing swelled vallate papillae among the arsenic exposed population.

The aim of this study to development and validate an analytical method to determine the Azithromycin (AZN) residue in water approach to monitor the contamination level of river and fish farm water of Bangladesh. Azithromycin (AZN) was analyzed using liquid chromatography mass spectrometry (LC-ESI MS/MS). The chromatographic separations of analyte were performed using ZORBAX RRHD Eclipse Plus C18 (2.1×100 mm, particle size 1.8 µm) column and mobile phase was 0.1% formic acid in water and acetonitrile with 50:50. The analyte were detected in positive electron spray ionization mode with multiple reaction monitoring mode (MRM) with mass transition from 749.5 m/z to 591 m/z and 158 m/z as quantifier and qualifier ion respectively. Liquid-liquid extraction method was used for the extraction of AZN residues. The developed method was validated in terms of accuracy, precision, linearity and specificity. The analyte showed a good linear in the range of 0.1-100 µg/L. Three spiking levels (0.25, 0.5 and 1.25 µg/L) was performed for determining accuracy and precision. Recoveries and RSD were in the range of 96.6-101.5% and 3.5-6.3 respectively. The estimated limit of detection and limit of quantification was 0.017 and 0.05 µg/L respectively. Using the developed method, we analyzed 5 different rivers and 5 different fish farm samples. We found no azithromycin residue in rivers water, but we found in one fish farm water azithromycin residue 0.35±0.06 µg/L. The results indicate that we should be concern to use antibiotics in fish farm water in different ways.