College Proceedings and Journals
College Journal of Environmental Toxicology (CJET)
The College Journal of Environmental Toxicology (CJET) offers diverse research opportunities in studying the harmful effects of chemicals, biological, and physical agents on living organisms.
Editorial Board
Dr. Suryakiran Navath, Ph.D.
Senior Editor and Advisor, USA
Dr. Partha Samadder, Ph.D.
Matinas Biopharma, New Jersey, USA
Dr. Amritlal Mandal, Ph.D.
The University of Arizona, Arizona, USA
Dr. Kajal Sankar Roy, Ph.D.
National Institute of Animal Nutrition and Physiology, INDIA
PreScientist24
A to Z Proceedings and Journals
Issue 1
Toxicological Effects of Arsenic Contamination on Rural Populations in Bangladesh
Uttam K. Chowdhury, Dipankar Chakraborti
Published Date: Nov - 29 - 2025
Over a six-year nationwide study (1995–2000), 33,092 hand tubewell water samples from all 64 districts of Bangladesh were analyzed to assess arsenic contamination and its associated health impacts. Arsenic concentrations exceeded the WHO guideline for drinking water (10 µg/L) in 60 districts and the Bangladesh national limit (50 µg/L) in 50 districts. Based on representative data from 43 districts, approximately 51.6 million people were exposed to arsenic levels above 10 µg/L and 25.04 million above 50 µg/L. Field surveys in 33 highly contaminated districts identified arsenicosis patients in 222 villages across 31 districts, with 3,725 individuals (19.77%) showing characteristic skin lesions among 18,841 examined. The most frequent dermatological manifestations were spotted and diffuse melanosis and keratosis of the palms and soles. Advanced cases showed nodular keratosis, gangrene, and skin cancers, with 25 carcinoma or gangrene patients confirmed during fieldwork. These findings highlight a severe and widespread public health crisis in Bangladesh. Although many people have begun using safer water sources for drinking and cooking, long-term health monitoring and community-based mitigation programs remain essential.
Assessment of Toxic Arsenic Levels in Human Biological Samples from Bangladesh
Uttam K. Chowdhury, Dipankar Chakraborti
Published Date: Jan - 01 - 2026
Arsenic contamination of groundwater is a major public health concern in Bangladesh. Over a six-year period (1995–2000), 33,092 hand-tubewell water samples from all 64 districts were analyzed. Arsenic concentrations exceeded the WHO guideline of 10 µg/L in 60 districts and the national standard of 50 µg/L in 50 districts. Based on representative samples from 43 districts, an estimated 51.6 million and 25.04 million people were exposed to arsenic levels above 10 µg/L and 50 µg/L, respectively. Dermatological surveys in 33 districts with groundwater arsenic above 50 µg/L identified 3,725 arsenicosis patients among 18,841 individuals examined, with pigmentation abnormalities and keratosis being the most common manifestations. To evaluate internal exposure, arsenic concentrations were measured in hair, nails, urine, and skin scales collected from affected villagers. Elevated arsenic levels were found in 95.11% of urine samples, 83.15% of hair samples, and 93.77% of nail samples. Urinary arsenic showed the strongest correlation with arsenic in drinking water (r = 0.547). Findings also indicate that individuals without visible symptoms can carry a high internal arsenic burden. A follow-up study demonstrated that villagers remained exposed despite access to low-arsenic water due to contaminated food and periodic use of unsafe water sources. These results highlight widespread exposure and the need for continued monitoring and community-level mitigation strategies.
Toxic Metal and Metalloids Burden in Biological Samples from Populations Exposed to Contaminated Environments in Bangladesh
Uttam K. Chowdhury, Hiroshi Tokunaga, Masanori Ando, Dipankar Chakraborti
Published Date: Jan - 01 - 2026
Groundwater arsenic contamination remains a major public health concern in Bangladesh. In this study, 33,092 hand-tubewell water samples collected from all 64 districts of Bangladesh were analyzed to assess the extent of arsenic exposure, and biological monitoring was conducted using hair and nail samples from exposed and control populations. Arsenic concentrations exceeded the World Health Organization guideline value of 10 µg/L in 60 districts and the national standard of 50 µg/L in 50 districts. Clinical field surveys in highly contaminated districts identified arsenicosis in 31 districts, with nearly 20% of examined individuals exhibiting characteristic skin lesions. Total arsenic and selected metals and metalloids (Se, Zn, Cu, Hg, Pb, and Sb) in hair and nail samples were quantified by inductively coupled plasma–mass spectrometry (ICP–MS) following microwave digestion. Exposed individuals showed markedly elevated arsenic concentrations in hair and nails compared with controls, accompanied by significantly lower selenium and zinc levels and higher mercury, lead, and antimony concentrations. Strong negative correlations were observed between arsenic and selenium and between arsenic and zinc, while positive correlations were found between arsenic and mercury, lead, and antimony in both hair and nail samples. Segmental hair analysis revealed decreasing arsenic concentrations from the root to the tip, indicating higher recent exposure. These findings highlight complex interactions between arsenic and essential and toxic elements and support the utility of hair and nail analysis as biomarkers of chronic inorganic arsenic exposure.
Non-Gradient Exposure to Chemotactic Agents (FMLP, Shigella dysenteriae Type 1 Toxin, and Bacterial Culture Supernatants) Induces Neutrophil Shape Change
Uttam K. Chowdhury
Published Date: Jan - 27 - 2026
Neutrophil polarization is an early morphological event associated with chemotactic responsiveness and cell locomotion. In this study, we investigated the ability of Shigella dysenteriae type 1–derived factors to induce shape change (polarization) in human neutrophils in suspension and compared these effects with those of the well-characterized chemotactic peptide N-formyl-methionyl-leucyl-phenylalanine (FMLP). Neutrophils isolated from healthy donors were incubated with uniform concentrations of FMLP, Shiga toxin extracted by polymyxin B or lysozyme–EDTA methods, or bacterial culture supernatants collected at different growth phases. Neutrophil polarization was assessed as a function of dose and incubation time. FMLP induced rapid, dose-dependent polarization, with maximal responses observed at 10?? M after 30 minutes of incubation. Both Shiga toxin preparations and culture supernatants from S. dysenteriae type 1 also elicited significant neutrophil polarization in a concentration- and time-dependent manner, with maximal responses occurring at intermediate concentrations and approximately 30 minutes of exposure. Prolonged incubation resulted in a decline in polarization, likely due to receptor desensitization, internalization, or toxin-mediated cytotoxicity. These findings demonstrate that Shiga toxin and soluble bacterial products from S. dysenteriae type 1 can directly induce early neutrophil morphological responses, suggesting a potential role for these factors in initiating neutrophil activation during infection.
Homogeneous Shigella dysenteriae Type 1 Toxin Enhances Neutrophil Chemokinesis across Cellulose Nitrate Filters
Uttam K. Chowdhury
Published Date: Jan - 28 - 2026
Neutrophil migration is a fundamental component of the innate immune response and is tightly regulated by microbial products encountered during infection. In this study, we investigated the effects of uniform concentrations of Shigella dysenteriae type 1 toxin (Shiga toxin extracted by lysozyme–EDTA method) on human neutrophil locomotion (migration) using a modified Boyden chamber assay with cellulose nitrate filters. Neutrophils were exposed to identical concentrations of Shiga toxin in both upper and lower compartments, thereby eliminating chemotactic gradients and allowing assessment of chemokinesis. Uniform concentrations of Shiga toxin significantly enhanced neutrophil migration compared with unstimulated controls, indicating increased random locomotion. A concentration-dependent, bell-shaped response was observed, with maximal migration occurring at 500 µg/ml, followed by reduced migration at higher toxin concentrations. The chemotactic peptide N-formyl-L-methionyl-L-leucyl-L-phenylalanine (FMLP) served as a positive control and elicited maximal migration at 10?? M. These findings demonstrate that Shiga toxin acts as a potent modulator of neutrophil chemokinesis and suggest that bacterial toxins can profoundly influence neutrophil migratory behavior independently of directional cues, with potential implications for inflammatory responses during shigellosis.