Evidential role of municipal solid waste and liquid effluent on environment and public health

Cities in Bangladesh produce large amounts of solid waste (SW) through various human activities which severely pollutes our native environment. As a result, SW pollutes the three basic environmental elements (air, water, and soil) by increasing pathogenic microbial load, which might be hazardous to public health directly or indirectly. In this study, we conducted 30 samples (i.e., soil, water, and air) collected from areas where municipal solid wastes are dumped (Tangail Sadar Upazila, Bangladesh). All the samples were analyzed to assess bacteriological quality for presumptive viable and coliform count using different agar media. We performed serial dilution 10⁻³–10⁻¹⁰ times for soil and water samples, and the diluted samples were spread on Mac-Conkey agar and nutrient agar plates. For the air sample, the sterile media containing petri-dish was placed adjacent to the dumpsite of the municipal waste and kept for an hour. Then all the samples were incubated at 37°C overnight for total viable count (TVC) and total coliform count (TCC). Biochemical tests and PCR were performed for the identification of these microorganisms. The antibiogram study was performed to reveal their (identified bacteria) susceptibility against clinically used antibiotics according to the standard disk diffusion technique. The highest bacterial loads were found in the air: TVC 3.273 × 10³ and TCC 1.059 × 10³ CFU/plate; tube-well water: TVC 8.609 × 10³, and TCC 8.317 × 10³ CFU/mL; in surface water: TVC 6.24 × 10¹³ CFU/mL and TCC 2.2 × 10¹² CFU/mL; in soil: TVC 2.88 × 10¹¹ and TCC 1.02 × 10¹¹ CFU/g, respectively. Microbes from SW can be transmitted through air, dust particles, or flies, and here we found an average of 1120 microbes spread over 63.61 cm² area per hour. Eight bacterial isolates (Pseudomonas spp., Klebsiella spp., E. coli, Proteus spp., V. cholera, Salmonella spp., Shigella spp., and Vibrio spp.) were identified by the biochemical test. Among them, E. coli and Shigella spp. were further ensured by PCR targeting bfpA and ipaH genes. Antibiotic susceptibility test results showed that E. coli isolates were highly resistant to erythromycin (80%); Shigella spp. were resistant to nalidixic acid (90%), whereas Salmonella spp. was found resistant to kanamycin (90%). Vibrio spp. were also resistant to azithromycin (80%) and erythromycin (80%), which should be a great concern for us. A semi-structured survey revealed that 63% of respondents suffered from different clinical conditions (intestinal diseases) due to SW pollution. So, steps should be taken to improve the proper management and disposal of solid waste and liquid effluent to save our environment and public health.     

Arsenic in the food chain and assessment of population health risks in Bangladesh

The most consumed food samples of cereals (rice, maize and wheat), vegetables (lentil, brinjal, carrot, bean, potato, tomato, onion and chili), fruits (banana, mango and jackfruit), fish (taki, rui, pangas and tilapia), egg (chicken and duck), milk (cow) and meat (chicken, duck, beef and mutton) were collected from some markets of Bogra district northern part of Bangladesh to evaluate the levels of arsenic (As) and associated health risk to the adult’s and child inhabitants. Arsenic is a highly toxic element, and its presence in food composites is a matter of concern to the world scientists. Target hazard quotients (THQs) and target carcinogenic risk were calculated to evaluate the non-carcinogenic and carcinogenic health risk from ingested arsenic. The highest and the lowest mean concentrations of arsenic were noted in the Tilapia fish [(0.94 mg/kg, wet weight (ww)] and beef (0.012 mg/kg, ww). The daily intakes of arsenic via foodstuffs were 1.92 and 3.30 µg/kg-bw/day for rural adults and children and 1.69 and 3.04 µg/kg-bw/day for urban adults and children, respectively. The result shows the highest THQs of arsenic in cereals and vegetables for both the rural and urban inhabitants which exceed the safe limit (>1) indicating that cereals and vegetables are the main food items contributing to the potential health risk. The estimated target cancer risks from ingesting dietary arsenic all exceeded 10^?6, indicating increased risk of cancer for adults and children in the study area.     

Physicochemical characterization of hydroxyapatite and its application towards removal of nitrate from water

A laboratory study was conducted to investigate the efficiency of hydroxyapatite (HAP) towards removal of nitrate from synthetic nitrate solution. In the present research HAP synthesized from egg-shell was characterized using SEM, XRD, FTIR and TGA–DSC. The removal of nitrate was 96% under neutral conditions, using 0.3 g of adsorbent in 100 mL of nitrate solution having an initial concentration of 100 mg/L. An adsorption kinetic study revealed that the adsorption process followed first order kinetics. Adsorption data were fitted to a linearly transformed Langmuir isotherm with correlation coefficient (R²) > 0.98. Thermodynamic parameters were also calculated to study the effect of temperature on the removal process. In order to understand the adsorption type, equilibrium data were tested with the Dubinin–Radushkevich isotherm. The process was rapid and equilibrium was established within the first 40 min.     

Modeling mitigation strategies for toxic cyanobacteria blooms in shallow and eutrophic Lake Kasumigaura, Japan

This paper explores mitigation scenarios for toxic cyanobacteria blooms in Lake Kasumigaura is located about 60–90 km northeast of Tokyo, in the southeast of Ibaraki Prefecture, Japan. Dominant species of cyanobacteria (Microcystis aeruginosa, Microcystis viridis and Microcystis ichthyoblabe) produce highly potent toxins as (Microcystin-(Leucine + Arginine, MC-LR), Microcystin-(Arginine + Arginine, MC-RR) and Microcystin-(Tyrosine + Arginine, MC-YR) in the Lake. Toxin production is generally the result of two major factors-natural processes and human interferences. Both factors have an extreme influence on the generation of cyanobacteria toxins within lake ecosystems. To address these factors, we propose two concepts for mitigation. The first concept is intended for examining the natural process of toxin production behavior within the lake and the second concept is used for evaluating inflow of wastes and nutrients from human activities that form toxins. Our research aims to combine both strategies to mitigate impacts of toxins, by examining trends of cyanobacteria nutrient sources, buoyancy regulations that influence bloom formation, and the environmental conditions that spur blooms. This study proposes a simple IMPACT (Integrating Mitigation Policies for Aquatic Cyanobacteria Toxin) model for diminution strategies of harmful algal blooms and their toxins. A mixed-methods approach is employed, nested within the Environmental Systems Analysis (ESA) tools e.g. scenario analysis and stakeholder analysis. The quality of the lake is assessed through a combination of observation and field study analysis. The findings suggest that successful mitigation of cyanobacteria toxins is highly dependent on multi-functional, multi-stakeholder involvement, and relevant intergovernmental policy. Without integrating approaches among different stakeholders, diverse socioeconomic activists, local-national policymakers and effective policy measures, prevention of cyanobacteria toxin production within lakes becomes extremely complex and difficult. The proposed IMPACT model could be a decision framework for identifying suitable policies that mitigate cyanobacteria impacts.     

Genetic damage induced by lead chloride in different tissues of fresh water climbing perch Anabas testudineus (Bloch)

The present investigation was undertaken to study the induction of DNA damage by lead chloride (PbCl(2)) in freshwater climbing perch Anabas testudineus using alkaline single cell gel electrophoresis (comet assay). Based on the LC(50) values of lead chloride of A. testudineus three different concentrations viz., 0.1, 1.0 and 2.0 mg/L were selected to expose fish. The DNA damage was observed in the gill, kidney and liver tissue as the percentage of DNA in comet tails and comet heads in the tissue of the exposed fish. DNA damage at different concentrations showed sensitivity to particular tissue. The liver tissue exhibited significantly (p < 0.01) higher DNA damage, followed by kidney and gill. However, the DNA damage was found to be dose dependent; at 2 mg/L of PbCl(2) the tail and head DNA of liver tissue were 57.84% and 39.49%, in kidney tissue the values were 52.36% and 44.97% whereas in gill tissue the values were 48.86% and 48.96% respectively. The current study explored the utility of the comet assay for in vivo laboratory studies using A. testudineus species for screening the genotoxic potential of lead chloride.     

Modeling of freshwater wetland management strategies for building the public awareness at local level in Bangladesh

Bangladesh has a large aerial extent of freshwater wetlands for her deltaic characteristics. In 1970, the total area of wetlands in Bangladesh is estimated to be 70000–80000 km², approximately, i.e., 50 % of total national land area. In the recent years, most of these wetlands are being lost and degraded primarily because of flood control projects, irrigation and agricultural activities and others human interference. Unfortunately, over the last three decades in the name of wetland development, local habitats were not taken care of. In this paper, the stakeholder and scenario analyses are employed for measuring public views towards wetlands degradation in Bangladesh. Involvement of stakeholders helps reconcile their different conflicting interests in wetlands, hence creating a common understanding about the problem under study. An exploratory scenario analysis illustrates different themes fulfilled by the wetlands and their associated services in case study Chalan Beel. The Chalan Beel once covered an area of approximately 651,230 acres in 1967. Currently, the permanent flooded area of the Chalan Beel has been reduced to about 18,120 acres. The scenarios show that most of the wetlands in Bangladesh are converted into agricultural lands, settlements, roads, and highways. Aquatic plants and animals are lost and endangered due to human interference and natural disturbance. The government, policymakers and some private organizations are trying to design suitable policy for wetland management but they are not able to reach this goal. It is observed that the local and national policies are facing complexities to create an effective regime to set aside the wetlands management policy in Bangladesh. In this context, this paper proposed an Increased Public Awareness (IPA) policy model that could be pathways for both short and long-term solutions of wetlands degradation in developing nations like Bangladesh.     

Novel Silica Functionalized Monosodium Glutamate/PVA Cross-Linked Membranes for Alkali Recovery by Diffusion Dialysis

Journal of Polymers and the Environment - In this work, two types of silica functionalized monosodium glutamate (GMSG and VMSG)/poly(vinyl alcohol) (PVA) were cross-linked by sol–gel process...     

Water quality index modeling using random forest and improved SMO algorithm for support vector machine in Saf-Saf river basin

Environmental Science and Pollution Research - The water quality index is one of the prominent general indicators to assess and classify surface water quality, which plays a critical role in river...     

In-silico screening of naturally derived phytochemicals against SARS-CoV Main protease

Environmental Science and Pollution Research - Coronavirus disease 2019 (COVID-19) is a rapidly growing pandemic that requires urgent therapeutic intervention. Finding potential anti COVID-19 drugs...