Assessment of coastal river water quality in Bangladesh: Implications for drinking and irrigation purposes.

Saltwater intrusion in the coastal areas of Bangladesh is a prevalent phenomenon. However, it is not conducive to activities such as irrigation, navigation, fish spawning and shelter, and industrial usage. The present study analyzed 45 water samples collected from 15 locations in coastal areas during three seasons: monsoon, pre-monsoon, and post-monsoon. The aim was to comprehend the seasonal variation in physicochemical parameters, including water temperature, pH, electrical conductivity (EC), salinity, total dissolved solids (TDS), hardness, and concentrations of Na+, K+, Mg2+, Ca2+, Fe2+, HCO3-, PO43-, SO42-, and Cl-. Additionally, parameters essential for agriculture, such as soluble sodium percentage (SSP), sodium absorption ratio (SAR), magnesium absorption ratio (MAR), residual sodium carbonate (RSC), Kelly's ratio (KR), and permeability index (PI), were examined. Their respective values were found to be 63%, 16.83 mg/L, 34.92 mg/L, 145.44 mg/L, 1.28 mg/L, and 89.29%. The integrated water quality index was determined using entropy theory and principal component analysis (PCA). The resulting entropy water quality index (EWQI) and SAR of 49.56% and 63%, respectively, indicated that the samples are suitable for drinking but unsuitable for irrigation. These findings can assist policymakers in implementing the Bangladesh Deltaplan-2100, focusing on sustainable land management, fish cultivation, agricultural production, environmental preservation, water resource management, and environmental protection in the deltaic areas of Bangladesh. This research contributes to a deeper understanding of seasonal variations in the hydrochemistry and water quality of coastal rivers, aiding in the comprehension of salinity intrusion origins, mechanisms, and causes.

Chromium and arsenic bioaccumulation and biomass potential of pink morning glory (Ipomoea carnea Jacq.).

Soil contamination with heavy metals and metalloids is a global concern nowadays. Phytoremediation is an eco-friendly, cost-effective, and sustainable way of mitigating such contamination by utilizing the plants' ability to accumulate, sequester, and stabilize elements. Biomass-producing plants may outperform hyperaccumulators in terms of total elemental removal and offer more cost-effectiveness through their usable biomass. Ipomoea carnea is a wild plant in the Asian region. It is resilient, spreads rapidly in a wide range of soil conditions, and has a high potential for biomass feedstock. In this work, we have tested this plant species for its growth performance and accumulation characteristics of Cr and As. In a pot experiment, the plants could easily grow from rootless stem segments in 2 weeks when garden soils are treated with 100-500 ppm of Cr and 20-300 ppm of As. Plant growth reduction was little at the moderate level of these elements, with a significant accumulation of elements in 45 days. Within this time, in the stems and leaves, the Cr concentrations were found to be 49 and 39 ppm, respectively, when treated with 500 ppm of Cr, whereas the As concentrations were obtained as 83 and 28 ppm, respectively, for the treatment with 300 ppm of As. To estimate the biomass production potential, the plant was grown with a density of 80,000 per ha under normal field conditions (without metal stress). At the harvest, the plants consisted of 80% stems, 11% leaves, and 9% belowground portions on a dry weight basis. The dry weight of stems, leaves, and belowground parts was 31.3%, 17.9%, and 23.7%, respectively. Overall, the estimated biomass was 25.8 Mg/ha/year from three harvests. The ability to regrow from the basal part makes it useful for continuous sequestration of toxic elements over multiple harvests. Our results show that I. carnea could lower Cr and As from contaminated soils and potentially a phytoremediation candidate considering accumulation rate and high amount of usable biomass production.

Medicinal plants used by the Mandais--a little known tribe of Bangladesh.

The Mandais are a little known tribe of Bangladesh inhabiting the north central regions, particularly Tangail district of Bangladesh. Their population has been estimated to be less than 10,000 people. Although the tribe has for the most part assimilated with the mainstream Bengali-speaking population, they to some extent still retain their original tribal customs, including their traditional medicinal practices. Since this practice is also on the verge of disappearance, the objective of the present study was to conduct an ethnomedicinal survey among Mandai tribal practitioners to document their use of medicinal plants for treatment of various ailments. Four traditional practitioners were found in the exclusive Mandai-inhabited village of Chokchokia in Tangail district. Information was collected from the practitioners with the help of a semi-structured questionnaire and guided field-walk method. It was observed that the four traditional practitioners used a total of 31 plants distributed into 23 families for treatment. The various ailments treated included diabetes, low semen density, jaundice, gastrointestinal tract disorders (stomach ache, indigestion, dysentery, and diarrhea), leucorrhea, pain (rheumatic pain, joint pain), skin disorders, respiratory tract disorders (coughs, mucus, and allergy), debility, fever, and helminthiasis. From the number of plants used (seven), it appeared that gastrointestinal tract disorders formed the most common ailment among the Mandai community, possibly brought about by the low income status of the people coupled with unhygienic conditions of living.