Occupational exposure and consequent health impairments due to potential incidental nanoparticles in leather tanneries: An evidential appraisal of south Asian developing countries

Appraising the characteristics of particulate matter from leather tanning micro-environments, their respirational risks, and dysfunctions amid exposed working cohorts

Leather tanneries are known for chemical laden work environments and pulmonic complaints among workers. This study presents an analysis of tannery micro-environments emphasizing on size-based variation in composition of particulate matter and consequent respiratory dysfunctions. Qualitative (FTIR, SEM-EDX) and quantitative assessment (elemental composition, carbon forms) of PM10 and 2.5 has been employed. For lung function evaluation of workforce, spirometry with ATS proprieties was used. The peak concentrations of both PM10 and 2.5 have been found at PU, FU, and B&S. The LTCR for only Cr is high for both PM2.5 and PM10. HQ was high for Al, Cr, and Mn for both PM sizes. The maximum organic and secondary organic carbon in PM10 was found at FU and in PM2.5 at PU. The varied PM composition included carbohydrate (B&S, WMO), ether (S&S, P&S) and hydroxyl (B&S, S&S, P&S), proteins, polyenes, vinyl groups (S&S, P&S, FU), alcohols (PU and FU), and aldehyde present at PU. These results were armored by high organic and total carbon concentrations for the same sites. Therefore, PM are classified into biogenic (carbonaceous: microbial and animal remains) from PU and WMO, incidental (industrial, mixt physico-chemical character) from PU, FU, WMO, B&S and P&S, and geogenic (crustal mineral dust) from RHT, B&S, PU, and P&S. Furthermore, increase in metal concentrations in PM10 (Cr, Mn, Co, Ni, V, As, Be, Ba, and Cd) and PM2.5 (As, Pb) while TC, OC, and SOC in PM2.5 caused depreciation overall lung function. The exposure to biogenic and incidental PM nature are key cause of pulmonic dysfunction.

Solid waste collagen-associated fabrication of magnetic hematite nanoparticle@collagen nanobiocomposite for emission-adsorption of dyes

The strategic utilization of hazardous particulate waste in eliminating environmental pollution is an important research hotspot. Herein, abundantly available hazardous solid collagenic waste of leather industry is converted into stable hybrid nanobiocomposite (HNP@SWDC) comprising magnetic hematite nanoparticles (HNP) and solid waste derived collagen (SWDC) via co-precipitation method. The structural, spectroscopic, surface, thermal, and magnetic properties; fluorescence quenching; dye selectivity; and adsorption are explored via microstructural analyzes of HNP@SWDC and dye adsorbed-HNP@SWDC using ¹H nuclear magnetic resonance, Raman, ultraviolet-visible, Fourier-transform infrared (FTIR), X-ray photoelectron, and fluorescence spectroscopies; thermogravimetry; field-emission scanning electron microscopy; and vibrating-sample magnetometry (VSM). The intimate interaction of SWDC with HNP and elevated magnetic properties of HNP@SWDC are apprehended via amide-imidol tautomerism associated nonconventional hydrogen bondings, disappearance of goethite specific -OH def. in HNP@SWDC, and VSM. The as-fabricated reusable HNP@SWDC is employed for removing methylene blue (MB) and rhodamine B (RhB). Chemisorption of RhB/MB in HNP@SWDC via ionic, electrostatic, and hydrogen bonding interactions alongside dimerization of dyes are realized by ultraviolet-visible, FTIR, and fluorescence studies; pseudosecond order fitting; and activation energies. The adsorption capacity = 46.98-56.14/22.89-27.57 mg g^-1 for RhB/MB is noted using 0.01 g HNP@SWDC within 5-20 ppm dyes and 288-318 K.

The interaction of ZnO nanoparticles, Cr(VI), and microorganisms triggers a novel ROS scavenging strategy to inhibit microbial Cr(VI) reduction

Cr(VI) contaminated water usually contains other contaminants like engineered nanomaterials (ENMs). During the process of microbial treatment, the inevitable interaction of Cr(VI), ENMs, and microorganisms probably determines the efficiency of Cr(VI) biotransformation, however, the corresponding information remains elusive. This study investigated the interaction of ZnO nanoparticles (NPs), Cr(VI), and Pannonibacter phragmitetus BB (hereafter BB), which changed the process of microbial Cr(VI) reduction. ZnO NPs inhibited Cr(VI) reduction, but had no effect on bacterial viability. In particular, Cr(VI) induced BB to produce organic acids and to drive Zn²⁺ dissolution from ZnO NPs inside and outside of cells. The dissolved Zn²⁺ not only promoted Cr(VI) reduction to Cr(V)/Cr(IV) by strengthening sugar metabolism and inducing increase in NAD(P)H production, but also hindered Cr(V)/Cr(IV) transformation to Cr(III) through down-regulating Cr(VI) reductase genes. A novel bacterial driven ROS scavenging mechanism leading to the inhibition of Cr(VI) reduction was elucidated. Specifically, the accumulated Cr(VI) and Cr(V)/Cr(IV) formed a redox dynamic equilibrium, which triggered the disproportionation of superoxide radicals mimicking superoxide dismutase through the flip-flop of Cr(VI) and Cr(V)/Cr(IV) in bacterial cells. This study provided a realistic insight into design the applicability of biological remediation technology for Cr(VI) contaminant and evaluating environmental risks of ENMs.

Tanneries impact on groundwater quality: a case study of Kasur city in Pakistan

Leather industry is the second largest export-earning sector of Pakistan. However, because of poor waste management, this industry has been continuously polluting the environment. In this paper, the impact of tanneries on the groundwater quality of Kasur city (i.e., the second largest leather producing city) is examined. The study is conducted in the following three phases: (I) water samples collection, (II) determination of physio-chemical properties, and (III) application of data mining techniques. In phase I, groundwater samples were collected from various sources such as hand pumps, motor pumps, and tube wells. In phase II, several physio-chemical properties such as (i) total dissolved solids (TDS), (ii) pH, (iii) turbidity, (iv) electrical conductivity (EC), (v) total hardness (TH), (vi) total alkalinity (TA), (vii) nitrates, (viii) chromium, (ix) fluoride, and (x) chloride were estimated. The estimated values of all these foregoing parameters are then compared with the Punjab Environmental Quality Standards for Drinking Water (PEQSDW). In phase III, principle component analysis and cluster analysis of the estimated parameters were performed to elucidate the relation between various parameters and to highlight the highly vulnerable sites, respectively. The results exhibit that most of the sampling collections sites are at the threshold of losing quality water. Moreover, it is also found that Mangal Mandi carries the worst groundwater quality among all sampling locations. Overall, it is concluded that serious attention is due from the water and wastewater authorities to further investigate and monitor the groundwater quality of Kasur before the country strikes with another pandemic after COVID-19.

Redistribution of potentially toxic elements in the hydrosphere after the relocation of a group of tanneries

Simultaneous relocation of a group of pollutant sources in a heavily polluted area is a rare event. Such a relocation has been implemented in Hazaribagh, a tannery built-up area with heavy pollution, in Bangladesh. This provides a valuable opportunity to compare the changes in environmental conditions associated with the relocation of multiple putative sources. Our environmental monitoring for a period of 6 years at the stationary areas centered on Hazaribagh geographically revealed trivalent [Cr(III)], hexavalent [Cr(VI)] chromium, lead, iron, and manganese as tannery-related elements after the legal deadline for tannery relocation. The median Cr(III) level in canal water, into which wastewater from tanneries was directly discharged, after the relocation was 97% lower of that before the relocation, indicating a beneficial effect of the relocation. In contrast, the median Cr(VI) level in water samples just after the relocation and 2 years after the relocation were approximately 5-fold and 30-fold higher, respectively, than those before the relocation. These results indicate not only a harmful effect of the relocation but also the possibility of conversion from Cr(III) to Cr(VI) in nature. Although the health hazard indexes considering all of the tannery-related elements in all of the canal water samples before the relocation exceeded the safety thresholds, the percentages of samples in which the indexes exceeded their safety thresholds after the relocation decreased by 32.5%-45.0%. Treatment with our patented hydrotalcite-like compound consisting of magnesium and iron (MF-HT) resulted in decreases in the health hazard indexes in all of the water samples in which the indexes exceeded their safety thresholds to levels lower than their thresholds. Thus, this study shows the double-edged effects associated with the relocation and a potential solution.

Characterization of biofilm formation and reduction of hexavalent chromium by bacteria isolated from tannery sludge

Biofilm formation ability of bacteria makes them potential in the field of tannery effluent treatment. However, the hazardous nature of effluent and environmental conditions may disturb the biofilm formation ability of bacteria which ultimately affects their effluent treatment efficiency. Accordingly, we isolated and characterized biofilm-forming bacteria Bacillus vallismortis (MT027009), Bacillus haynesii (MT027008), and Alcaligenes aquatilis (MT027005) from tannery sludge and examined them for biofilm formation under variable environmental conditions. Biofilm formation in tryptic soy broth (TSB) at different incubation times (24-120 h) revealed that the biofilm formation activity of the strain B. haynesii was not affected by incubation time, whereas the increase in biofilm formation was observed in the case of B. vallismortis (28 %) and A. aquatilis (52 %) after 48 h. The medium pH (pH 5.0-9.0) had a limited effect on biofilm formation except in the case of A. aquatilis at pH 5.0 (94 %) and pH 9.0 (80 %). Furthermore, compared to the controls (only TSB), the strains B. vallismortis, B. haynesii, and A. aquatilis showed enhanced biofilm formation in undiluted tannery effluent (28, 33, and 21 %) and 25 mg L^-1 Cr(VI) (23 %, 48 % 32 %). The biofilm structure was influenced by Cr(VI) as revealed by scanning electron microscopy (SEM) analysis. The results of Cr(VI) bioreduction studies suggest that bacterial biofilm (60-99 %) has a greater potential to remove Cr(VI) than planktonic cells (43-94 %). The results of the study provide important data on biofilm formation by indigenous bacteria in effluent environment conditions, making them potential isolates for tannery effluent treatment.

Relationship between Indoor High Frequency Size Distribution of Ultrafine Particles and Their Metrics in a University Site

Exposure to ultrafine particles (UFPs size < 100 nm) in life and work environments can contribute to adverse health effects also in terms of health burden of related diseases over time. The choice of parameters which better characterize UFPs is challenging, due to their physical-chemical properties and their variable size. It is also strictly related to the availability of different instrumental techniques. In the present study we focus on real time high frequency (1 Hz) UFPs particle size distribution (PSD) and their relationship with total particle number concentration (TPNC) and mean particle diameter (Davg) as a contribution characterizing by size the human exposure to UFPs in an indoor site of the University of Rome “Sapienza” (Italy). Further considerations about UFPs contribution to nucleation mode (NM) and accumulation mode (AM) have been highlighted, also in order to investigate the contribution of polycyclic aromatic hydrocarbons (PAHs) surface-adsorbed on indoor air particles (pPAHs). High indoor TPNC values were registered during the rush hours (early morning and mid/late afternoon) according to the outdoor influences originated from anthropogenic activities. AM mainly contribute to the indoor TPNC during working days showing high correlation with pPAHs. These findings may provide useful indications in terms of occupational exposure to UFPs since there are many evidences that indoor exposures to such pollutants may be associated with adverse health effects also in working environments.

Nanomaterials in the environment, human exposure pathway, and health effects: A review

Nanomaterials (NMs), both natural and synthetic, are produced, transformed, and exported into our environment daily. Natural NMs annual flux to the environment is around 97% of the total and is significantly higher than synthetic NMs. However, synthetic NMs are considered to have a detrimental effect on the environment. The extensive usage of synthetic NMs in different fields, including chemical, engineering, electronics, and medicine, makes them susceptible to be discharged into the atmosphere, various water sources, soil, and landfill waste. As ever-larger quantities of NMs end up in our environment and start interacting with the biota, it is crucial to understand their behavior under various environmental conditions, their exposure pathway, and their health effects on human beings. This review paper comprises a large portion of the latest research on NMs and the environment. The article describes the natural and synthetic NMs, covering both incidental and engineered NMs and their behavior in the natural environment. The review includes a brief discussion on sampling strategies and various analytical tools to study NMs in complex environmental matrices. The interaction of NMs in natural environments and their pathway to human exposure has been summarized. The potential of NMs to impact human health has been elaborated. The nanotoxicological effect of NMs based on their inherent properties concerning to human health is also reviewed. The knowledge gaps and future research needs on NMs are reported. The findings in this paper will be a resource for researchers working on NMs all over the world to understand better the challenges associated with NMs in the natural environment and their human health effects.

Factors Associated With Health Complaints Among Leather Tannery Workers in Bangladesh

Background: Few studies have reported associations between occupational exposure to tannery chemicals with breathing difficulty and skin diseases and none have been conducted in Bangladesh. The aim of this study was to investigate the associations of health complaints with types of work and length of employment among tannery workers in Bangladesh, where occupational health and safety regulations are less restricted compared with the developed world. Methods: One hundred sixty-seven (n = 167) workers from 10 tanneries were interviewed using a questionnaire adapted from the European Community Respiratory Health Survey (ECRHS) and the Tasmanian Longitudinal Health Study (TAHS) to collect information on occupational exposures and health outcomes. Workers' length of employment was examined, as well as their areas of work including beamhouse, wet finishing, dry finishing, and miscellaneous. Univariate and multivariate logistic regressions were performed to investigate potential associations while controlling for confounders. Results: Length of employment was positively associated with breathing difficulty (odds ratio [OR]: 1.32, 95% confidence interval [CI]:1.07-1.64). Workers involved in the wet finishing (OR: 11.75, 95% CI: 2.12-65.10) and dry finishing (OR: 13.38, 95% CI: 1.00-181.70) had higher odds of breathing difficulty; while, working in the beamhouse was associated with an increased risk of developing skin diseases (OR: 4.36, 95% CI: 1.10-17.32). Conclusion/Application to Practice: Length of employment and types of work were associated with increased risk of health complaints, including breathing difficulty and skin disease among tannery workers. Stronger regulations with regular enforcement, regular health surveillance, and worker and employer education are necessary for reducing these exposures and improving the health outcomes of the tannery workers.