A comprehensive study was carried out from central part of Indo-Gangetic Plain (IGP; at Kanpur) to understand abundance, temporal variability, processes (secondary formation and fog-processing) and source-apportionment of PM₁-bound species (PM₁: particulate matter of aerodynamic diameter ≤ 1.0 μm) during wintertime. A total of 50 PM₁ samples were collected of which 33 samples represent submicron aerosol characteristics under non-foggy condition whereas 17 samples represent characteristics under thick foggy condition. PM₁ mass concentration during non-foggy episodes varied from 24–393 (Avg.: 247) μg m⁻³, whereas during foggy condition it ranged from 42–243 (Avg.: 107) μg m⁻³. With respect to non-foggy condition, the foggy conditions were associated with higher contribution of PM₁-bound organic matter (OM, by 23%). However, lower fractional contribution of SO₄²⁻, NO₃⁻ and NH₄⁺ during foggy conditions is attributable to wet-scavenging owing to their high affinity to water. Significant influence of fog-processing on organic aerosols composition is also reflected by co-enhancement in OC/EC and WSOC/OC ratio during foggy condition. A reduction by 5% in mineral dust fraction under foggy condition is associated with a parallel decrease in PM₁ mass concentration. However, mass fraction of elemental carbon (EC) looks quite similar (≈3% of PM₁) but the mass absorption efficiency (MAE) of EC is higher by 30% during foggy episodes. Thus, it is evident from this study that fog-processing leads to quite significant enhancement in OM (23%) contribution (and MAE of EC) with nearly equal and parallel decrease in SO₄²⁻, NO₃⁻ and NH₄⁺ and mineral dust fractions (totaling to 24%). Characteristic features of mineral dust remain similar under foggy and non-foggy conditions; inferred from similar ratios of Fe/Al (≈0.3), Ca/Al (0.35) and Mg/Al (0.22). Positive matrix factorization (PMF) resolves seven sources: biomass burning (19.4%), coal combustion (1.1%), vehicular emission (3%), industrial activities (6.1%), leather tanneries (4%), secondary transformations (46.2%) and mineral dust (20.2%).

Trivalent chromium [Cr(III)] and tannins serve as necessary substances in leather processing and coexist in tannery site, which lead to the chromium contamination in site soil when disposed improperly. However, coexisting tannins are very likely to complex with Cr(III) and affect its properties, ultimately changing the mobility of chromium in soil. In this study, tannic acid (TA) was selected to investigate the complexation with Cr(III) and the influence on the solubility and sorption of Cr(III) in soils. Then, the transport behavior and mechanism of Cr(III)-TA complexes in soil was clarified. Dialysis results showed that the increase of TA concentration and solution pH promoted the formation of complexed Cr(III). The results of UV–Vis absorption spectroscopy, X-ray photoelectron spectroscopy, and density functional theory calculations indicated that the adjacent ionized phenolic hydroxyls in TA functioned as the binding sites with Cr(III) to form the Cr–O bonds and the degree of complexation increased with pH. The Cr(III)-TA complexes had higher solubility than free Cr(III) at pH ≥ 6.0. Batch sorption experiments demonstrated that the sorption capacity of Cr(III)-TA to soils with different pH was always lower than that of free Cr(III). These reasons led to the stronger mobility of Cr(III)-TA in soil columns than Cr(III). Our research reveals that the enhanced mobility of Cr(III) in soils coexisting with TA.

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.

This study investigated the potential use of elemental S (S0) to convert Cr-VI to Cr-III which should decrease the bio-availability hence, toxicity of Cr-VI in soils. The bio-available fraction of Cr in soil was measured by phosphate buffer extraction (PBE) and the results showed that the fraction is about 10% of the total Cr-VI and varied from 12.8 to 42.5 mg kg−1. The addition of 4.0 mg g−1 S0 decreased PBE Cr-VI to <0.4 mg kg−1 limit established for Cr-VI toxicity in soils. Synchrotron-based X-ray absorption near-edge structure (XANES), X-ray fluorescence (XRF) and micro-XRD revealed that Cr-III was the dominant species (99% of total Cr) and Cr was retained by hematite and goethite in soil. Fe-containing minerals may have provided sufficient protection to render the dominant Cr-III species biochemically inert to redox processes in soils. It is concluded that S0amendment is a promising approach to remediate Cr-VI contaminated soils.

The Beibu Gulf is an important passageway between China and the Association of Southeast Asian Nations, where there has been an increase in pollution of heavy metals (HMs). High concentrations of Pb, Cr, Cd, Cu, Zn, As, and Hg in surface sediment were found in Qinzhou Bay, Fangchenggang, and other coastal areas. Stochastic geo-accumulation analyses identified the pollution to be “uncontaminated”; however, it had an 18% probability of deterioration. The Cd, Hg, and As pollution were relatively serious. Principal component analysis, positive matrix factor model, and mercury isotopes demonstrated that the HMs could mainly be attributed to industrial sources including petrochemical, coal-fired, metal and metalloid processing, leather tanning, and human activities: anthropogenic sources accounted for approximately 70% of all the contaminations. This study demonstrates the contribution of terrigenous input to HMs even at a low level and provides basic data for the coordinated development of land and marine resources.

This study assessed the concentrations of specific volatile organic compounds (VOCs) inside vehicle cabins under different practical vehicle driving conditions in China. The mean concentrations of the VOCs, including benzene, toluene, xylene, ethylbenzene, styrene, formaldehyde, acetaldehyde, acetone, and acrolein, were 16.73 μg/m3, 66.02 μg/m3, 14.20 μg/m3, 6.78 μg/m3, 28.09 μg/m3, 16.43 μg/m3, 12.47 μg/m3, and 20.65 μg/m3 (the sum of acetone and acrolein), respectively. All the specified VOCs inside vehicle cabins were not exceeded the limits of the national standard. The in-cabin VOCs concentrations were investigated for 16 private vehicles under three ventilation conditions: (i) fan off and recirculation (RC) off, (ii) fan on and RC off, and (iii) fan on and RC on. The VOCs concentrations increased 50.46% (mean of the measured VOCs) when the ventilation condition changed from (ii) to (i), and increased 51.38% (mean of the measured VOCs) when ventilation condition changed from (ii) to (iii). Two vehicle models (vehicle model A and vehicle model B) were tested in the study to investigate the influence on in-cabin VOCs concentrations of two typical interior trims (leather, fabric). The VOCs concentrations inside B vehicles (leather interiors) were averagely 1.42 times larger than the concentrations in A vehicles (fabric interiors). For new vehicles, the concentrations of benzene, toluene, xylene, ethylbenzene, formaldehyde, acetaldehyde, acetone and acrolein were larger than the concentrations inside old vehicles by 12.89%, 103.54%, 123.14%, 104.20%, 6.26%, 6.31%, and 10.67%, respectively. The VOCs concentrations significantly increased as the raise of ambient temperature. Toluene, styrene, ethylbenzene, and xylene were the most sensitive VOCs to temperature, which increased 513.6%, 544.8%, 767.0%, and 597.7% as the temperature increased from 11 °C to 25 °C.

Preservation or curing of hides/skins is performed as the primary step of leather processing to conserve them from putrefaction. Normally preservation is carried out using common salt (NaCl), which is discharged in the soak liquor contributing to ~ 70%, of total dissolved solids (TDS) load of entire leather manufacturing. In an attempt to reduce the TDS and chlorides, phyto-based preservation using garlic peel (Allium sativum) and white onion peel (Allium cepa) was carried out. Different concentrations of salt in combination with garlic peel and white onion peel were applied on freshly flayed goat skins based on its green weight and compared to control (40% salt). Sensory evaluation of the preserved skin was done by assessing different parameters like hair slip, putrefaction and odour. Estimation of hydroxyproline (HP) release, moisture content and microbial load were carried out at regular intervals. Skins that remained in good condition for 14 days were further processed into leather and properties were examined which were found comparable to the conventionally cured skins. Hence, this cleaner curing technique helps in reducing the TDS and chlorides in the effluent, thus controlling the pollution caused by tanneries through sustainable leather processing.

The idea of sustainable development and green supply chain management is considered at the underlying stage in the research and academic fields, particularly in the rising economies of Asia. This research investigates the persuasive force of the firm’s green supply chain management practices with the mediating part of the competitiveness and investment recovery. Data was collected from the 12 ISO 9001 and ISO 14001 leather industries based in Pakistan. We distributed the 350 questionnaires at 12 leather industries, and the questionnaire was also transferred on Google Forms, and 50 questionnaire mail to different individuals who work in leather industries of other cities of Pakistan; out of 350 questionnaires, 183 were filled, and the remaining questionnaires were incomplete, and out of 50 emails, we get the response of 33 emails, and evaluated the model of this study by using the partial least square structural equation modeling PLS-SEM. We interact with the employees of leather industries and try to understand how they are following the green practices in their firms. This research uses resource dependence theory as the theoretical base. This study elaborates how the organization’s behavior is affected by the external resources of the corporation. The actual outcomes uncover that green supply chain management activities positively impacting the firm’s performance, where competitiveness and investment recovery play a mediating role among intra-organizational green practices.

The wide availability of pollutant by-products from the leather industries has been a key factor in driving the research into converting these low-cost by-products into high value-added collagen-based products. In this study, collagen hydrolysate (CH) was extracted from hide trimming waste from the tanneries and used to prepare biodegradable films with chitosan nanoparticles (CNPs) with different concentrations to develop an alternative product to non-biodegradable plastics. The effects of CNPs concentration on the thickness, mechanical, water barrier, thermal, light transmittance, color properties, and opacity of CH-based films were investigated. The results clearly show that the tensile strength and elastic modulus values of CH/CNPs films increase significantly as the concentration of CNPs increases, while the elongation at break, water solubility, and water vapor permeability values decrease. In addition, scanning electron microscopy (SEM) showed uniform distributions of CNPs in the CH-based films. Based on the results obtained, the extraction of CH from hide trimming wastes and reuse in the production of biodegradable films will both prevent these valuable wastes from being dispose into the landfills and will be an alternative to fossil-derived plastics in the future.

As a common heavy metal, chromium and its compounds are widely used in industrial applications, e.g., leather tanning, electroplating, and in stainless steel, paints and fertilizers. Due to the strong toxicity of Cr(VI), chromium is regarded as a major source of pollution with a serious impact on the environment and biological systems. The disposal of Cr(VI) by biological treatment methods is more favorable than traditional treatment methods because the biological processes are environmentally friendly and cost-efficient. This review describes how bacteria tolerate and reduce Cr(VI) and the effects of some physical and chemical factors on the reduction of Cr(IV). The practical applications for Cr(VI) reduction of bacterial cells are also included in this review.