Toxicity risks associated with heavy metals to fish species in the Transboundary River - Linked Ramsar Conservation Site of Tanguar Haor, Bangladesh.

The presence of trace metals in aquatic ecosystems can have detrimental effects on fish survival. The Tanguar haor, a Ramsar conservation wetland, receives sediment and water from multiple transboundary rivers. However, there have been limited studies on the metal concentrations in fish species in this sediment-rich wetland. This study aimed to analyze the concentrations of iron (Fe), manganese (Mn), chromium (Cr), copper (Cu), zinc (Zn), cadmium (Cd), and lead (Pb) in water, sediment, and fish tissues. Higher concentrations of Cd and Pb were found in the water and sediment. All these metals were detected in eight fish species, including benthic and pelagic species. Among them, Systomus sarana, a pelagic fish that also consumes benthic organisms, exhibited a higher metal pollution index than other fish, particularly benthic species. The release of higher metal concentrations from sediment into the water has the potential to impact the accumulation of metals in fish. SYNOPSIS: This study on metal concentrations in fish species will aid policymaking on ecotoxicology research for transboundary river-connected wetlands.

Isolation and characterization of chromium(VI)-reducing bacteria from tannery effluents and solid wastes.

In the present investigation, five novel Cr(VI) reducing bacteria were isolated from tannery effluents and solid wastes and identified as Kosakonia cowanii MKPF2, Klebsiella pneumonia MKPF5, Acinetobacter gerneri MKPF7, Klebsiella variicola MKPF8 and Serratia marcescens MKPF12 by 16S rDNA gene sequence analysis. The maximum tolerance concentration of Cr(VI) as K2Cr2O7 of the bacterial isolates was varying up to 2000 mg/L. Among the investigated bacterial isolates, A. gerneri MKPF7 was best in terms of reduction rate. The optimum temperatures for growth and Cr(VI) reduction by the bacterial isolates were 35 and 40 °C, respectively except A. gerneri MKPF7 which grew and reduced Cr(VI) optimally at 40 °C. The optimum pH for growth and Cr(VI) reduction by K. cowanii MKPF2, A. gerneri MKPF7 and S. marcescens MKPF12 was 7.0 whereas the optimum pH for growth and Cr(VI) reduction by K. pneumoniae MKPF5 and K. variicola MKPF8 were 7.0, 8.0 and 6.0, 7.0, respectively. All the bacterial isolates showed maximum tolerance against Ni2+ and Zn2+ whereas minimum tolerance was observed against Hg2+ and Cd2+. The bacteria isolated in the present study thus can be used as eco-friendly biological expedients for the remediation and detoxification of Cr(VI) from the contaminated environments.

Pesticide residues in tobacco leaves from the Kushtia district in Bangladesh.

In this study, tobacco leaf samples (n = 26) were collected from different areas in Kushtia to determine the presence of residues of cypermethrin, diazinon, heptachlor, methoxychlor dichlorodiphenyltrichloroethane (DDT), dichlorodiphenyldichloroethan (DDD) and dichlorodiphenyldichloroethylene (DDE). The analysis was conducted by a High Performance Liquid Chromatography (HPLC) system that was equipped with a photodiode array detector. Both cypermethrin and diazinon were detected in tobacco samples from six districts, namely, Mirzapur, Shahebnagar, Kodalipara, Pragpur, Farakpur and Taragunia. The highest concentration of cypermethrin was found in Kodalipara (2.00 ppm) while the highest concentration of diazinon was detected in a sample from Pragpur (0.15 ppm). The pesticide DDT was only detected in the sample from Pragpur at 4.00 ppm. This is the first study in Bangladesh that reports pesticide residue concentrations in tobacco leaf samples.

Alterations of serum trace elements and other biochemical parameters are correlated with the pathogenesis of systemic lupus erythematosus: A preliminary study on Bangladeshi population.

BACKGROUND: Systemic lupus erythematosus (SLE) is an autoimmune disorder in which the body's defense system wrongly attacks healthy body tissues. The objective of this current setup was to quantify and compare the serum concentration of ascorbic acid (Vit-C), malondialdehyde (MDA), c-reactive protein (CRP) and trace elements (Cu, Fe, Mn and Zn) in SLE and normal subjects. METHODS: The proposed case-control study was performed with 25 SLE patients and 25 healthy subjects as case and control, respectively. The serum level of malondialdehyde (MDA) and vitamin C was evaluated by UV spectrophotometric method. For the determination of CRP, the latex agglutination method was used, whereas serum trace elements were estimated by atomic absorption spectroscopy (AAS). RESULTS: This analysis demonstrated that patients with SLE possessed a significant (p < 0.001) higher level of MDA and lower level of vitamin C compared to control subjects. Pearson's correlation analysis found negative correlation between the serum level of MDA and vitamin C (r= -0.023, p = 0.887) for patients while control group also possessed similar result (r= -0.157, p = 0.453). The current findings have also revealed that serum level of Zn and Cu in SLE patients was significantly (p < 0.05) lowered to that of the control group, while serum level of Mn also showed a similar scenario. During Pearson's correlation analysis a significantly (p < 0.05) negative correlation was found between Zn and Mn (r= -0.410, p = 0.042) in patients' group. CONCLUSION: Although our study was limited to a small sample size and confined to a particular area of the country, the study results support a significant role of antioxidants, CRP, and trace elements in the generation of SLE and, therefore, recommends a large spectrum study of the associations between SLE and these biochemical parameters.

Reduced High-Dose Radiation-Induced Residual Genotoxic Damage by Induction of Radioadaptive Response and Prophylactic Mild Dietary Restriction in Mice.

Radioadaptive response (RAR) describes a phenomenon in a variety of in vitro and in vivo systems that a low-dose of priming ionizing radiation (IR) reduces detrimental effects of a subsequent challenge IR at higher doses. Among in vivo investigations, studies using the mouse RAR model (Yonezawa Effect) showed that RAR could significantly extenuate high-dose IR-induced detrimental effects such as decrease of hematopoietic stem cells and progenitor cells, acute radiation hematopoietic syndrome, genotoxicity and genomic instability. Meanwhile, it has been demonstrated that diet intervention has a great impact on health, and dietary restriction shows beneficial effects on numerous diseases in animal models. In this work, by using the mouse RAR model and mild dietary restriction (MDR), we confirmed that combination of RAR and MDR could more efficiently reduce radiogenotoxic damage without significant change of the RAR phenotype. These findings suggested that MDR may share some common pathways with RAR to activate mechanisms consequently resulting in suppression of genotoxicity. As MDR could also increase resistance to chemotherapy and radiotherapy in normal cells, we propose that combination of MDR, RAR, and other cancer treatments (i.e., chemotherapy and radiotherapy) represent a potential strategy to increase the treatment efficacy and prevent IR risk in humans.

Serum CRP, MDA, Vitamin C, and Trace Elements in Bangladeshi Patients with Rheumatoid Arthritis.

Rheumatoid arthritis (RA) is an autoimmune disorder that is a painful health crisis. This study aimed to assess the serum C-reactive protein (CRP), malondialdehyde (MDA), non-enzymatic antioxidant (vitamin C), and trace elements (Zn, Cu, Mn, and Fe) in RA patients, and thereby correlate these parameters with the association of RA. This study included 20 Bangladeshi RA patients and 20 normal healthy volunteers as control subjects. CRP level was determined using a laboratory-based latex agglutination-enhanced immunoassay. The lipid peroxidation level was determined by measurement of the serum level of MDA. Non-enzymatic antioxidant vitamin C was assessed by UV spectrophotometric method. Trace elements were determined by atomic absorption spectroscopy (AAS). Our study observed significantly higher concentrations of CRP (p < 0.001) and MDA (p < 0.001), and significantly lower concentrations of vitamin C (p < 0.001) in the RA patient. The mean values of Zn, Cu, Mn, and Fe were 6.62 ± 0.34, 1.42 ± 0.17, 7.51 ± 0.23, and 29.25 ± 0.41 ppm for the RA patients respectively and 13.57 ± 9.13, 1.15 ± 0.17, 1.59 ± 0.18, and 62.47 ± 5.25 ppm for the control subjects, consequently. There was a significant difference (p < 0.05) in the trace element levels between the RA patients and control subjects. Our study suggests that a higher concentration of CRP and MDA, lower levels of vitamin C, and altered trace elements may be linked to RA.

Citrulline, A Potential Biomarker of Radiation-Induced Small Intestine Damage.

Radiation damage assessment of the small intestine is important in nuclear accidents or routine radiotherapy of abdominal tumors. This article reviews the clinical symptoms and molecular mechanisms of radiation-induced small intestinal damage and summarizes recent research on biomarkers of such damage. Citrulline is the most promising biomarker for the evaluation of radiation-induced small intestinal damage caused by radiotherapy and nuclear accidents. This article also summarizes the factors influencing plasma citrulline measurement investigated in the latest research, as well as new findings on the concentration of citrulline in saliva and urine after different types of radiation.

Altered Response to Total Body Irradiation of C57BL/6-Tg (CAG-EGFP) Mice.

Application of green fluorescent protein (GFP) in a variety of biosystems as a unique bioindicator or biomarker has revolutionized biological research and made groundbreaking achievements, while increasing evidence has shown alterations in biological properties and physiological functions of the cells and animals overexpressing transgenic GFP. In this work, response to total body irradiation (TBI) was comparatively studied in GFP transgenic C57BL/6-Tg (CAG-EGFP) mice and C57BL/6 N wild type mice. It was demonstrated that GFP transgenic mice were more sensitive to radiation-induced bone marrow death, and no adaptive response could be induced. In the nucleated bone marrow cells of GFP transgenic mice exposed to a middle dose, there was a significant increase in both the percentage of cells expressing pro-apoptotic gene Bax and apoptotic cell death. While in wild type cells, lower expression of pro-apoptotic gene Bax and higher expression of anti-apoptotic gene Bcl-2, and significant lower induction of apoptosis were observed compared to GFP transgenic cells. Results suggest that presence of GFP could alter response to TBI at whole body, cellular and molecular levels in mice. These findings indicate that there could be a major influence on the interpretation of the results obtained in GFP transgenic mice.

Retracted Human Health Risk of Chromium Intake From Consumption of Poultry Meat and Eggs in Dhaka, Bangladesh.

BACKGROUND: Heavy metals contamination of food is a serious threat. Long term exposure may lead to human health risks. Poultry and eggs are a major source of protein, but if contaminated by heavy metals, have the potential to lead to detrimental effects on human health. OBJECTIVES: The objective of this study is to determine chromium concentrations in poultry meat (flesh and liver) and eggs collected from poultry farms in Dhaka, Bangladesh, to calculate the daily intake of chromium from the consumption of poultry meat and eggs for adults, and to evaluate their potential health risk by calculating the target hazard quotients (THQ). METHODS: All samples of poultry feed, meat (flesh and liver) and eggs were analyzed by a graphite furnace atomic absorption spectrometer (AAS) (GFA- EX- 7i Shimadju, Japan). RESULTS: Chromium concentrations were recorded in the range of not detected (ND) to 1.3926±0.0010 mg kg-1 and 0.0678±0.0001 mg kg-1 to 1.3764±0.0009 mg kg-1 in the liver of broiler and layer chickens, respectively. Chromium concentrations were determined in the range of 0.069±1.0004 mgkg-1 to 2.0746±0.0021 mg kg-1 and 0.0362±0.0002 mg kg-1 to 1.2752±0.0014 mg kg-1 in the flesh of broiler and layer chicken, respectively. The mean concentration of chromium in eggs was 0.2174-1.08 mg kg.-1 The highest concentration of chromium 2.4196±0.0019 mg kg-1 was found in egg yolk. Target hazard quotients values in all poultry flesh, liver and eggs samples were less than one, indicating no potential health risks to consumers. CONCLUSIONS: The estimated daily intake values of chromium were below the threshold limit. Thus, our results indicate that no adverse health effects are expected as a resultof ingestion of chicken fed with tannery waste. ETHICS APPROVAL: This study was approved by the Biosafety, Biosecurity & Ethical Committee of Jahangirnagar University.

Determination of heavy metals in the soils of tea plantations and in fresh and processed tea leaves: an evaluation of six digestion methods.

BACKGROUND: The aim of this study was to determine the levels of cadmium (Cd), chromium (Cr), lead (Pb), arsenic (As) and selenium (Se) in (1) fresh tea leaves, (2) processed (black) tea leaves and (3) soils from tea plantations originating from Bangladesh. METHODS: Graphite furnace atomic absorption spectrometry (GF-AAS) was used to evaluate six digestion methods, (1) nitric acid, (2) nitric acid overnight, (3) nitric acid-hydrogen peroxide, (4) nitric-perchloric acid, (5) sulfuric acid, and (6) dry ashing, to determine the most suitable digestion method for the determination of heavy metals in the samples. RESULTS: The concentration ranges of Cd, Pb, As and Se in fresh tea leaves were from 0.03-0.13, 0.19-2.06 and 0.47-1.31 µg/g, respectively while processed tea contained heavy metals at different concentrations: Cd (0.04-0.16 µg/g), Cr (0.45-10.73 µg/g), Pb (0.07-1.03 µg/g), As (0.89-1.90 µg/g) and Se (0.21-10.79 µg/g). Moreover, the soil samples of tea plantations also showed a wide range of concentrations: Cd (0.11-0.45 µg/g), Pb (2.80-66.54 µg/g), As (0.78-4.49 µg/g), and Se content (0.03-0.99 µg/g). Method no. 2 provided sufficient time to digest the tea matrix and was the most efficient method for recovering Cd, Cr, Pb, As and Se. Methods 1 and 3 were also acceptable and can be relatively inexpensive, easy and fast. The heavy metal transfer factors in the investigated soil/tea samples decreased as follows: Cd > As > Se > Pb. CONCLUSION: Overall, the present study gives current insights into the heavy metal levels both in soils and teas commonly consumed in Bangladesh.

Heavy Metal Contents and Physical Parameters of Aegiceras corniculatum, Brassica juncea, and Litchi chinensis Honeys from Bangladesh.

The present study was undertaken to determine the heavy metal levels and the physicochemical parameters (pH, electrical conductivity (EC), and ash, moisture, and total sugar content) of honeys from Bangladesh. Three different floral honeys were investigated, namely, khalsi (Aegiceras corniculatum), mustard (Brassica juncea), and litchi (Litchi chinensis) honeys. The heavy metals in the honeys were determined by using a High Temperature Dry Oxidation method followed by Atomic Absorption Spectroscopy. The mean pH, EC, and ash, moisture, and total sugar contents of the investigated honeys were 3.6, 0.51 mS/cm, 0.18%, 18.83%, and 68.30%, respectively. Iron was the most abundant among all the investigated heavy metals, ranging from 13.51 to 15.44 mg/kg. The mean concentrations of Mn and Zn in the investigated honeys were 0.28 mg/kg and 2.99 mg/kg, respectively. Cd was below the detection limit, and lead was found in some honey samples, but their contents were below the recommended Maximum Acceptable Level. Cr was also found in all of the samples, but its concentration was within the limit. The physicochemical analysis of the honey samples yielded levels within the limits set by the international honey legislation, indicating that the honey samples were of good quality and had acceptable values for maturity, purity, and freshness.