Search

Owing to the extensive use of antibiotics in hospitals, animal husbandry, and various human activities, antibiotic contamination is becoming an increasing global concern, including in Bangladesh. In Bangladesh, the Buriganga River is heavily polluted with multiple antibiotics, which can lead to antibiotic resistance in bacteria. In this study, we performed the first investigation of seasonal variations in the occurrence and spatial distribution of 29 antibiotics in the Buriganga River, Bangladesh, from wet season (August 2019) and dry season (February 2020). We also evaluate the potential environmental and resistance risks related to antibiotic contamination. The concentrations of metronidazole (9.1-970 ng L -1 ), sulfadiazine (below the limit of detection (-1 ), and levofloxacin (-1 ) were the highest, and metronidazole, amoxicillin, and doxycycline were detected in all samples during both seasons. The number of antibiotics detected, and their overall concentrations were higher during the dry season (February) than during the wet season (August). Ecological risk assessment using risk quotients (RQs) indicated that levofloxacin (maximum RQ = 90), amoxicillin (58), and ciprofloxacin (21) could pose a high risk to aquatic organisms, whereas sulfamethazine, trimethoprim, doxycycline, and lincomycin pose a medium risk. The levels of seven antibiotics, trimethoprim, ciprofloxacin, levofloxacin, amoxicillin, ampicillin, cefotaxime, and metronidazole exceeded the antibiotic resistance thresholds. In conclusion, this study highlights the urgent need for further research with improved wastewater management practices and implement stricter regulations on antibiotic use to protect aquatic ecosystems and public health in Bangladesh., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Masahiro Tokumura reports financial support was provided by Ministry of the Environment. Masahiro Tokumura reports financial support was provided by Kurita Water and Environment Foundation. Masahiro Tokumura reports financial support was provided by Steel Foundation for Environmental Protection Technology. If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

The consumption of arsenic and trace-metal-contaminated rice is a human health concern worldwide, particularly in Bangladesh. In this study, the effects of rice varieties and water management practices on the concentrations of arsenic and trace metals in rice grains were investigated to reduce human health risks related to rice consumption. In addition, the performance of risk reduction using the optimum combination of rice variety and water management practices was quantitatively assessed using Monte Carlo simulation, in which non-carcinogenic and carcinogenic risk distributions under the status quo and the optimum combination were compared. The experimental results revealed that Dular and BRRI dhan45 (rice varieties) cultivated under alternate wetting and drying (AWD) and continuous flooding (CF) conditions showed the lowest hazard quotient (HQ) values for copper, cadmium, and arsenic and the lowest target cancer risk (TR) for arsenic. In Dular and BRRI dhan45 (AWD and CF) varieties, the proportion of the population for which HQs exceeded 1.0 (the reference value) tended to decrease (except for arsenic), compared with populations for which the rice varieties and water management practices were not specified. These results suggest that the use of optimum combinations of rice varieties and water management practices could reduce non-carcinogenic and carcinogenic risks associated with arsenic and trace metals uptake via rice grain consumption by the Bangladeshi people., Competing Interests: Declaration of competing interest This study was supported by the Mitsui Bussan Environmental Fund (grant number: R18-2009), Japan. The authors declare no competing financial interest., (Copyright © 2024 Elsevier B.V. All rights reserved.)

The Buriganga River plays a key role in the socioeconomic structure of Dhaka, the capital of Bangladesh. However, this river is severely polluted and is considered one of the most polluted in the world. Therefore, this study aimed to assess the concentrations of various metals in the Buriganga River. A study was conducted from August 2019 to February 2020 to determine the concentrations of 16 metals in water samples (n = 210) collected from 10 distinct sites in the Buriganga River. The mean values for the concentrations of Cr, Mn, Ni, Zn, As, Se, Cd, Sb, and Pb in river water were above the guideline values prescribed by the WHO, Japan, and Bangladesh. Moreover, the fraction ratios of Be, Cr, Co, Ni, Cu, Zn, Se, Mo, Ag, Cd, Sb, and Pb were high (>0.85); consequently, these metals could accumulate at high concentrations in river sediments. Assessment using the single-factor pollution index allowed the classification of the pollution level as 'serious pollution' for Sb and 'heavy pollution' for Cd, Ni, and Pb. The trace metal concentrations in this river imply that crops cultivated along the river using river water may also be contaminated with trace metals.

Because of their unintentional formation and low vapor pressure, polycyclic aromatic hydrocarbons (PAHs) and their halogenated derivatives (XPAHs) in the atmosphere are distributed primarily to aerosolized particles with an aerodynamic diameter less than 2.5 μm (PM 2.5 ). However, no information is available regarding the occurrence of PM 2.5 -bound PAHs and XPAHs in Bangladesh, one of the most highly PM 2.5 -polluted regions worldwide. In this study, we investigated the occurrence of PM 2.5 -bound PAHs and XPAHs in the atmospheres of Dhaka in Bangladesh and Shizuoka in Japan (as a reference) and estimated their incremental lifetime cancer risks (ILCRs). In addition, we statistically estimated the potential sources of PM 2.5 -bound PAHs and XPAHs by using principal component analysis and positive matrix factorization. The median concentration of total PM 2.5 -bound PAHs and XPAHs in Bangladesh was 24.2 times that in Japan. The estimated potential sources of PAHs clearly differed between Japan and Bangladesh, whereas those of XPAHs were largely (>80%) unknown in both countries. The median ILCR in Bangladesh was 2.81 × 10 -3 , which greatly exceeded the upper limit of acceptable risk (10 -4 ). These results indicate that comprehensive monitoring and control of atmospheric PM 2.5 -bound PAHs and XPAHs are needed urgently, especially in highly polluted countries., (Copyright © 2021 Elsevier Inc. All rights reserved.)