Child labor is a major challenge in the developing countries and comprehensive health hazard identification studies on this issue are still lacking. Therefore, the current study is an effort to highlight the health concerns of child labor exposed in the key small scale industries of Sialkot, Pakistan. Our findings revealed jolting levels of heavy metals in the urine, blood, serum, saliva, and hair samples collected from the exposed children. For example, in the urine samples, Cd, Cr, Ni, and Pb were measured at the respective concentrations of 39.17, 62.02, 11.94 and 10.53 μg/L in the surgical industries, and 2.10, 4.41, 1.04 and 5.35 μg/L in the leather industries. In addition, source apportionment revealed polishing, cutting, and welding sections in the surgical industries and surface coating, crusting, and stitching sections in the leather industries were the highest contributors of heavy metals in the bio-matrices of the exposed children, implying the dusty, unhygienic, and unhealthy indoor working conditions. Further, among all the bio-matrices, the hair samples expressed the highest bioaccumulation factor for heavy metals. In accordance with the heavy metal levels reported in the exposed children, higher oxidative stress was found in the children working in the surgical industries than those from the leather industries. Moreover, among heavy metals’ exposure pathways, inhalation of industrial dust was identified as the primary route of exposure followed by the ingestion and dermal contact. Consequently, chemical daily intake (CDI), carcinogenic and non-carcinogenic hazard quotients (HQs) of heavy metals were also reported higher in the exposed children and were also alarmingly higher than the corresponding US EPA threshold limits. Taken all together, children were facing serious health implications in these industries and need immediate protective measures to remediate the current situation.

With the signature of the free trade agreement, trade ties will develop rapidly between China and South Korea. Based on input–output model, this paper calculates and decomposes the embodied carbon emissions in the trade between China and South Korea from 2000 to 2010, analyses the reasons and gives some future advices. This paper suggests that the embodied carbon emissions surplus is not caused by trade surplus. It further points out that textile and leather industries, chemical manufacturing industries and metal manufacturing industries are three main sectors contributing to imported and exported embodied carbon emissions. In addition, the trade diversion between China and South Korea helps a lot in reducing the global carbon emissions and eases the pressure of carbon emissions in China. This paper also proposes that China should learn advanced technologies from South Korea and reduce carbon-intensive energy consumption in the future.

The leather industry converts the hide, a byproduct of slaughterhouses, into leather, a value-added product. This old industry generates wastes, causing environmental pollution. However, nanomaterials can help to decrease this problem. These tiny particles (1–100 nm) can replace chemicals in various steps of leather processing. This paper aims at giving an overview of the fundamentals of classical leather process and how nanomaterials can be applied in each step to obtain a more sustainable manufacturing. After a comprehensive literature review of journal articles, six steps were identified for potential for application of nanomaterials: unhairing, tanning, retanning, dyeing, fatliquoring, and finishing. With nano-oxides, polymers, and metals, it is feasible to reduce the amount of chemical products and also improve the properties of leather. Thus, it is possible to reach a more eco-friendly and effective process with the use of nanomaterials to turn hide/skins into finished leather.

Bioleaching of tannery sludge is an efficient and environmentally friendly way for chromium (Cr) removal, which supports the sustainable development of the leather industry. Acidithiobacillus thiooxidans has been reported effective in Cr bioleaching of tannery sludge. However, little is known about whether the presence of other benefiting species could further improve the Cr leaching efficiency of A. thiooxidans. Here, we studied the enhancing roles of four species namely Acidiphilium cryptum, Sulfobacillus acidophilus, Alicyclobacillus cycloheptanicus, and Rhodotorula mucilaginosa in chromium bioleaching of tannery sludge with A. thiooxidans by batch bioleaching experiments. We found that each of the four species facilitated the quick dominance of A. thiooxidans in the bioleaching process and significantly improved the bioleaching performance including bioleaching rate and efficiency. The bioleaching efficiency of Cr in the tannery sludge could reach 100% on the sixth day by co-inoculating A. thiooxidans and four auxiliary species. The achievements shed a light on the role of the community-level interactions on bioleaching and may also serve as guidance for managing bioleaching consortiums for better outcomes.

Salt-based preservation is practiced for decades in the leather industry because of its versatility, cost-effectiveness, and availability. The salt removed from the soaking process causes significant pollution including organic and elevated total dissolved solids (TDS). Hence, a low-salt skin preservation method using commercial sodium polyacrylate with a reduced quantity of sodium chloride aiming to retain leather properties and pollution reduction was the principal focus of the study. Commercial sodium polyacrylate initially characterized for water absorption capacity along with structural and functional properties is confirmed by NMR and IR spectroscopic techniques. In preliminary experiments, the process parameters attained optimized conditions of sodium polyacrylate (SPA) quantity (5%), a minimal amount of salt (15%), and contact time (4 h) required for skin preservation. Besides, reusability studies after SPA recovery (95%) were applied to skins with an optimized quantity of SPA and salt subsequently stored for 15 days along with control (40% salt). The results revealed that SPA with low salt aided an adequate curing efficiency with a substantial reduction (> 65%) of TDS and comparable physical and organoleptic properties on par with the conventional method. Overall, SPA supported low-salt skin preservation reduces pollutant load (TDS) caused due to using of 40% sodium chloride in the conventional curing process.

Raw hides/skins are considered to be the prime component for leather industry, which once flayed from animals, plummets to microbial attack. Their preservation combats putrefaction wherein curing using sodium chloride (NaCl) is by and large the most widely accepted method. However, there are few stumble blocks in using NaCl in terms of pollution load generated such as high total dissolved solids (TDS), total suspended solids (TSS), biological oxygen demand (BOD), chemical oxygen demand (COD) and chlorides (Cl⁻). Additionally, this effluent when discharged affects the quality of the water, soil and plants causing huge ecological damage. To evade these problems, researches are being carried out to explore alternative preservation techniques which are either salt free or with reduced amount of salt. Different methods were proposed time and again which remained unfeasible due to associated drawbacks like high cost, health hazards and environmental concerns. Therefore, finding cheaper, eco-friendly and sustainable method for preservation has become the need of the hour for this industry. This review meticulously summarizes the changing trends in preservation techniques for past few decades with special emphasis on bio-based preservation. The diversity of the natural preservatives explored for the said purpose has been systematically reviewed. The enormous environmental benefits that can be obtained by adopting bio-based preservation and future avenues of research have been discussed.

Leather manufacturing is the process of transforming animal skin into high value-added commodity. As a crucial step in the leather producing process, conventional chrome tanning could lead to discharge of chromium contaminant due to the low efficiency of chromium uptake. In this paper, a series of polyethylene glycol triazine derivatives’ tanning agent (PT) with different molecule weight was synthesized with one-step method and applied in the main tanning of hide. The chemical structure of the PT was detected by FT-IR and ¹H-NMR. The application experimental results indicated that after 16% of PT tanning at pH of 6, the wet-white was endowed with shrinkage temperature over 80°C and thickening rate over 108%. The experimental results indicated that the PT tanning leather not only have a better physical and mechanical properties than commercial triazine derivatives tanning agent, but also the leather is endowed with the effects of outstanding thermal properties. Considering that the pickling process became unnecessary, a large number of neutral salts could be avoided, the chromium load in spent liquor decreased from 1288 mg/L to 0, and the total dissolved chlorine in spent liquor decreased from 15,360 to 9581 mg/L; no toxic and harmful substances such as chromium and aldehyde are introduced into the tanning process. Compared with the leather tanned with commercial triazine derivatives’ tanning agent, the leather tanned with PT showed a similar overall tanning properties and better environmental friendliness, which makes PT matches the integral requirements of the modern sustainable leather industry.

Discharges of huge quantities of leather solid wastes by leather industries and the increased use of synthetic packaging films have raised serious concerns on account of their environmental impacts. The paper focuses on the development and characterization of potential environmentally friendly composite films using collagen hydrolysate (CH) extracted from leather solid wastes and chitosan (C) to assess the feasibility of producing polymeric materials suitable for applications in packaging and wrapping purposes. Solid collagen-based protein hydrolysate was extracted from chromium-tanned leather wastes and analyzed to determine its chemical properties. With the goal of improving the physico-chemical performance of CH, three types of composite films (CH75/C25, CH50/C50, CH25/C75) were prepared with increasing concentrations of C, and some of their physical and functional properties were characterized. The results indicated that the addition of C caused increase (p < 0.05) in the thickness, tensile strength (TS), elasticity modulus (EM), and water vapor permeability (WVP), leading to stronger films as compared with CH film, but significantly (p < 0.05) decreased the elongation at break (EAB) and solubility of films (p < 0.05). The light barrier measurements present low values of transparency at 600 nm of the CH/C films, indicating that the films are very transparent and they have excellent barrier properties against UV light. The structural properties investigated by FTIR and DSC showed total miscibility between both polymers. Scanning electron micrographs revealed that CH/C composite films showed a compact homogeneous structure. These results demonstrate the potential application of CH/C composite films in packaging industry.

Considerable tannery waste is generated by leather industry around the world. Recovery of the value-added products as natural fats from the solid wastes gained interest of many researchers. In this study, supercritical fluid separation method was applied for the fatty acid isolation from leather industry solid wastes. Pre-fleshing wastes of the double-face lambskins were used as natural fat source. Only supercritical CO₂ was used as process media without any solvent additive in high-pressure view cell equipment. The effect of different conditions was investigated for the best separation influence. The parameters of pressure (100 to 200 bar), temperature (40 to 80 °C), and time (1 to 3 h) were considered. Extraction yields and fat yields of the parameters were statistically evaluated after the processes. Maximum 78.57 wt% fat yield was obtained from leather industry fleshings in supercritical fluid CO₂ at 200 bar, 80 °C, and 2 h. Morever, conventional Soxhlet and supercritical CO₂ extracted fatty acids were characterized by using gas chromatography (GC) coupled with mass spectrometry (MS) and flame ionization detector (FID). Fourier transform infrared spectroscopy (FTIR) and differential scanning calorimetry (DSC) characterizations were also done. The results showed that supercritical fluid CO₂ extraction was highly effective for the fat separation as green solvent and leather industry tannery wastes could be used for the value-added products.

Raw hide/skins come to the tanners as a by-product of meat industry which is converted into value-added leather as product for fashion market. Leather manufacturing is a chemical process of natural biological matrix. It employs a huge quantity of water and inorganic and organic chemicals for processing and thereby discharges solid and liquid wastes into the environment. One of the potential solid wastes generated from leather industry is chrome-tanned leather shavings (CTLSs), and its disposal is increasingly becoming a huge challenge on disposal to tanners due to presence of heavy metal chromium. Hence, finding a sustainable solution to the CTLS disposal problem is a prime challenge for global tanners and researchers. This paper aims to the deeper review of various disposal methods on CTLS such as protein, chromium, and energy recovery processes and its utilization methodologies. Sustainable technologies have been developed to overcome CTLS solid wastes emanating from leather processing operations. Further, this review paper brings a broader classification of developed methodologies for treatment of CTLSs.