Chemical risks in drinking water of inhabitants in the basin of the Tonle Sap Great Lake

The present study aimed to assess chemical risks in the drinking water of inhabitants in the basin of the Tonle Sap Great Lake. Water samples from tube wells (n = 52), dug wells (n = 13), stored rain water (n = 39), ponds/lakes (n = 19), canals/rivers (n = 24), and household pipe water (n = 45) were collected and analyzed for physicochemical properties, as well as microbial and chemical qualities using standard methods. Analytical results revealed that 42.1% of tube wells had As > 10 μg L−1 while 8.3% had Cr > 0.05 mg L−1. Concurrently, 55.2 and 11.8% of tube wells had Cd > 3.00 μg L–1 and Pb > 10 μg L−1, respectively. Moreover, 35.0% of pipe water had Fe > 0.3 mg L−1, whereas 85.7% of tube wells and 69.2% of dug wells had Mn > 0.1 mg L−1. All water sources including pipe water could pose risks of non-carcinogenic effects of chemical mixtures to all exposure groups through their drinking water pathway. Children were at a higher risk of chemical mixtures in their drinking water than adults. This study suggests that advanced treatment technologies should be applied to the current water treatment plants to provide inhabitants with safe drinking water. HIGHLIGHTS Analytical results revealed that Escherichia coli and coliform were detected in all water sources.; Elevated As, Ba, Cd, Cr, F−, NO3−, and Pb were detected in some water sources.; Inhabitants of the Tonle Sap Great Lake basin were exposed to chemicals in drinking water.; Children were at a higher risk of chemical mixtures in their drinking water than adults.

Assessing drinking water quality and health risks of contaminants in the coastal areas of Cambodia

Abstract The present study aimed to assess the health risks of chemical contaminants of residents in the coastal areas of Cambodia through their drinking water pathways. Water was sampled from tube wells (n= 22), dug wells (n= 31), ponds (n= 11), canals (n= 12) and lakes (n= 4) across the Cambodian coastal areas, and measured for the contaminants of health concern (As, Cu, Cr, Cd, F−, NO2-, NO3-, Pb, Escherichia coli and total coliform) and aesthetic quality following the United States Environmental Protection Agency (USEPA) and standard methods. Analytical results reveal that 9.1% of tube wells and 9.7% of dug wells contained As &amp;gt; 0.01 mg/L. Appropriately, 22.7% of tube wells and 32.3% of dug wells contained Fe &amp;gt; 0.3 mg/L while 100% of tube wells and 80.6% of dug wells contained Mn &amp;gt; 0.1 mg/L. Health risk assessment found that the hazard quotient (HQ) &amp;gt; 1 for children and women. Additionally, the lifetime cancer risk (LCR) was found &amp;gt;1 × 10−4 for As in Cambodian coastal areas. Therefore, a monitoring programme and appropriate treatment to remove contaminants like arsenic, cadmium and fluoride would be required to ensure a safe drinking water supply to Cambodian coastal residents.</jats:p

Optical phonons of SnSe(1−x)Sx layered semiconductor alloys

AbstractThe evolution of the optical phonons in layered semiconductor alloys SnSe(1–x)Sx is studied as a function of the composition by using polarized Raman spectroscopy with six different excitation wavelengths (784.8, 632.8, 532, 514.5, 488, and 441.6 nm). The polarization dependences of the phonon modes are compared with transmission electron diffraction measurements to determine the crystallographic orientation of the samples. Some of the Raman modes show significant variation in their polarization behavior depending on the excitation wavelengths. It is established that the maximum intensity direction of the Ag2 mode of SnSe(1−x)Sx (0 ≤ x ≤ 1) does not depend on the excitation wavelength and corresponds to the armchair direction. It is additionally found that the lower-frequency Raman modes of Ag1, Ag2 and B3g1 in the alloys show the typical one-mode behavior of optical phonons, whereas the higher-frequency modes of B3g2, Ag3 and Ag4 show two-mode behavior.</jats:p