Tannery Effluent Research Articles

EVALUATION OF HEMATOLOGICAL PARAMETERS IN ALBINO RATS EXPOSED DERMALLY TO TANNERY EFFLUENT FROM CHALLAWA INDUSTRIAL ESTATE KANO, NIGERIA.

The effects on haematological parameters of albino rats were evaluated to assess possible toxicity of tannery effluent. The study was carried out for 28 days. Forty (40) matured albino rats of both sexes were divided into four groups of 10 rats each. Group 1 is the control group, which were exposed dermally with normal water. Groups 2, 3 and 4 were exposed dermally at different concentrations of 100%, 50% and 25% of the effluent respectively. The result of the physicochemical analysis of the effluent shows that the physicochemical parameters were above the standard limit. Rats exposed to different percentages of the effluent showed significant decrease in the level of haemoglobin and packed cells volume. Red blood cell, white blood cell, mean corpuscular volume, mean corpuscular haemoglobin, mean corpuscular haemoglobin concentration, platelet and lymphocytes do not significantly decrease or increase.

A Review on Tannase and its Applications

of tannin and is converted to gallic acid and glucose. Natural tannins occur in various parts of plants such as leaves, roots, bark and fruits. Tannins are distributed in animals, insects and microorganisms. However, microbial tannase is one of the great attention in many industries. Gallic acid is one of the industrial and therapeutic molecules that is widely used in various applications. Tannase is also applicable in feed, pharmaceutical, brewing, chemical and beverage industries. Furthermore, tannase plays a significantly important role in biodegradation or reduction of tannin from the tannery effluent. The present review apprises a brief description of tannase and its industrial applications.

Small scale photo bioreactor treatment of tannery wastewater, heavy metal biosorption and CO2 sequestration using microalga Chlorella sp.: a biodegradation approach

Recently, mass production of lipid along with heavy metal reduction is gaining momentum due to their cost-effective and greener approach towards waste water treatment. The purpose of this study is to investigate the small scale photo bioreactor treatment of tannery effluent using Chlorella sp. isolated form Yercaud lake, Tamil Nadu, India. The results showed a significant decrease in the heavy metals content in the tannery effluent after the treatment. Maximum reduction of the heavy metal Chromium (Cr) of 10.92 mg L−1 was recorded, followed by Cobalt (Co)-7.37 mg L−1, Nickel (Ni)-9.15 mg L−1, Cadmium (Cd)-8.48 mg L−1, Lead (Pb)-12.54 mg L−1, Zinc (Zn)-11.56 mg L−1 and Copper (Cu)-10.71 mg L−1 at the end of the 20th day of treatment. The microalgae, Chlorella sp. was analyzed for their biosorption ability and the maximum biosorption capacity (qmax) rate against heavy metals was 81.36, 70.53, 82.15, 63.29, 58.92, 83.43, 64.83 µg L−1 for Cr, Pb, Ni, Cd, Co, Zn, and Cu respectively. It matched with the Langmuir and Freundlich kinetics models. The maximum CO2 utilization was found to be 60.50% and maximum concentration of lipid, carbohydrate and protein was found to be 0.95 g L−1, 250 µg mL−1 and 160 µg mL−1, respectively. The presence of various groups such as hydroxyl, alkyl, carbonyl and carboxylic acids was confirmed using Fourier transform infrared analysis. Thus, the isolated microalgae showed good biosorption ability towards the various heavy metal pollutants from tannery waste water.

REMEDIATION OF HEAVY METALS FROM TANNERY EFFLUENTS AND ITS EFFECTS ON ENZYMATIC AND NON-ENZYMATIC ANTIOXIDANTS OF CYANOBACTERIA

Cyanobacteria account for most of the biologically sequestered heavy metals in terrestrial as well as aquatic environments. Based on previous research of our lab and prevailing literature, Cyanobacteria’s ability to absorb and metabolize heavy metals can be associated with the presence of high-affinity metal binding groups on the cell surface and efficient metal uptake and storage systems. Our study dealt with the uptake of heavy metals dissolved in Tannery effluent by freshwater Cyanobacteria. Various microscopic and viability studies were performed along with studies on the effects of respective heavy metals on the non-enzymatic anti-oxidative pigments and anti-oxidative enzymes of Cyanobacteria. Maximum metal uptake was observed in case of Fe and Cr compared to Cd or Pb at different concentrati ons and conditions. The given study shows how freshwater Cyanobacteria are an economical, productive alternative of the prevailing remediation techniques for the remediation of heavy metals.

Assessment of DNA Damage and Apoptosis in the Brain of Freshwater Fish <i>Oreochromis mossambicus</i> Exposed to Tannery Effluent Wastewater

The present study was designed to evaluate the effect of tannery effluent on the fingerlings of freshwater fish Oreochromis mossambicus. The fishes were maintained at 10% concentration of tannery effluent for a period of 30 days. Apoptosis was studied by activity of caspases. Caspase 3 and 9 activity showed significant alteration. DNA seperation by agarose gel electrophoresis shows difference in intensity of genomic DNA between 750-1000 bp in fishes exposed to tannery effluent. DNA damage was also confirmed by Comet assay which showed an increase in DNA damage and tail migration was indicated by increase in percentage of mean DNA comet tail length formation.

Spatiotemporal variations in the composition of algal mats in wastewater treatment ponds of tannery industry.

Wastewater Treatment Pond (WTP) is an effective remediation technology for economically developing nations. Although it's excessive organic and nutrient loads with higher water logging time triggers mixed and unprofitable microalgal mats. This may serve as a seeding source for Cyanobacterial bloom in receiving waterbodies. Since,to maintain the growth of desirable algal species in WTPs, understanding towards environmental regulation and algal mat composition is important, especially for tropical countries, like India. In this study, biological treatment pond (BTP) and outlet pond (OP), of a tannery effluent treatment plant in eastern coast of India, were chosen for surveying the algal community composition concerning ecological parameters. Nearly, both the ponds were polluted, but the diversity was lower in BTP due to its elevated nutrient content (Ammonia 173mg L-1) and higher persistent organic matters (COD 301.7mg L-1) than OP. Using canonical correspondence analysis, seasonal variations showed higher species abundance during early summer compared to other seasons. A total of 37 taxa forming thick algal mats were recorded. The matrix of mats was mainly composed of Cyanobacterial members such as Phormidium, Leptolyngbya, Spirulina, and Pseudanabaena, followed by diatoms, especially Amphora and Nitzschia. Diatoms commonly occurred as embedded component in the entangled matrix of blue-green algal filaments. Hierarchical cluster analysis was employed to group all these taxa based on their seasonal appearance and abundance. This year-long intensive study revealing seasonal algal mat composition patterns in these WTPs will ultimately safeguard the livelihood and security of adjoining localities through proper site-specific pollution control.

Environmental impact and diversity of protease-producing bacteria in areas of leather tannery effluents of Sialkot, Pakistan.

Massive discharge of wastes produced by the processing of leather so far confers the most important environmental challenge facing the tanneries worldwide. Waste material from tanneries mostly consists of skin remnants and proteinaceous substances as by-products of leather processing. In these conditions, protease-producing bacteria play a vital role in degrading wastes in this sludge. Therefore, an investigation was made to study the effect of long-term tannery sludge contamination on the diversity of both protease-producing microbes and of bacterial extracellular proteases near tanneries of Sambrial and Sialkot. The high amount of carbon and nitrogen in the soil samples reflected their effect on the diversity of the microbial communities in these areas. Phylogenetic analysis based on 16S rRNA gene sequences suggest that the isolated proteolytic bacteria belonged to 9 different genera including Pseudomonas (26.19%), Proteus (19.04%), Serratia (16.66%), Klebsiella (14.28%), Providencia (9.52%), Achromobacter (7.14%), Enterobacter (2.38%), Myroides (2.38%), and Acinetobacter (2.38%). Enzyme activity showed that among all Pseudomonas and Proteus showed relatively high protease production, and inhibition studies revealed that proteases produced by all isolates were strongly inhibited by serine and/or metalloprotease inhibitors, and a smaller proportion was inhibited by inhibitors of cysteine and/or aspartic proteases. Furthermore, isolated bacteria revealed promising degradation activities against casein and/or gelatin with only a few that could hydrolyze elastin, suggesting proteases produced by these isolated bacteria belong to different classes of proteases, i.e., serine and metalloproteases. This study provided new insights on the community structure of cultivable protease-producing bacteria near tannery sludge of Sambrial and Sialkot. This study would be beneficial not only for establishing the way for effective degradation of tannery slugs but also for questing the novel properties of proteases for a future technological application.

Rhizopus oryzae-Mediated Green Synthesis of Magnesium Oxide Nanoparticles (MgO-NPs): A Promising Tool for Antimicrobial, Mosquitocidal Action, and Tanning Effluent Treatment.

The metabolites of the fungal strain Rhizopus oryaze were used as a biocatalyst for the green-synthesis of magnesium oxide nanoparticles (MgO-NPs). The production methodology was optimized to attain the maximum productivity as follows: 4 mM of precursor, at pH 8, incubation temperature of 35 °C, and reaction time of 36 h between metabolites and precursor. The as-formed MgO-NPs were characterized by UV-Vis spectroscopy, TEM, SEM-EDX, XRD, DLS, FT-IR, and XPS analyses. These analytical techniques proved to gain crystalline, homogenous, and well-dispersed spherical MgO-NPs with an average size of 20.38 ± 9.9 nm. The potentiality of MgO-NPs was dose- and time-dependent. The biogenic MgO-NPs was found to be a promising antimicrobial agent against the pathogens including Staphylococcus aureus, Bacillus subtilis, Pseudomonas aeruginosa, Escherichia coli, and Candida albicans with inhibition zones of 10.6 ± 0.4, 11.5 ± 0.5, 13.7 ± 0.5, 14.3 ± 0.7, and 14.7 ± 0.6 mm, respectively, at 200 μg mL–1. Moreover, MgO-NPs manifested larvicidal and adult repellence activity against Culex pipiens at very low concentrations. The highest decolorization percentages of tanning effluents were 95.6 ± 1.6% at 100 µg/ 100 mL after 180 min. At this condition, the physicochemical parameters of tannery effluents, including TSS, TDS, BOD, COD, and conductivity were reduced with percentages of 97.9%, 98.2%, 87.8%, 95.9%, and 97.3%, respectively. Moreover, the chromium ion was adsorbed with percentages of 98.2% at optimum experimental conditions.

Insights into the influence of CO2 supplement on phycoremediation and lipid accumulation potential of microalgae: An exploration for biodiesel production

An economic and environmentally friendly approach for sustainable wastewater treatment, CO 2 abatement, and resource recovery via assimilation into biomass would be — Phycoremediation. Thus an attempt was made to investigate the effect of CO 2 gas supplement on an ozone pre-treated tannery effluent (OPTE) accustomed microalgae Nannochloropsis oculata , Chlorella vulgaris, and Chlorella sorokiniana for their nutrient removal efficiency, biomass productivity, CO 2 fixing rate, lipid content, and fatty acid composition in OPTE. The experiments were conducted in a glass reactor maintained at optimized cultivation conditions within the algal chamber. In which, the CO 2 gas was supplied intermittently through a glass tube immersed in the reactor. Among the species studied, C.sorokiniana has revealed its better performance towards nutrient removal i.e. NH 4 + -N (96%) and o-PO 4 3 − (100%) with the maximum biomass yield and CO 2 fixation rate of 2.1 ± 0.15 g/L and 0.48 g CO 2 / L/d respectively. While the results recommended the N. oculata for biodiesel production owing to its maximum lipid accumulation potential (51%) and lipid yield (703 ± 2.8 mg/L). Further, the predicted biodiesel properties of N. oculata were good associations with the standard biodiesel quality. Thus, the phycoremediation of OPTE with the supplement of CO 2 can be considered as a sustainable treatment method owing to the recovery of value-added biomass for biodiesel production. • CO 2 supplement has a significant influence on phycoremediation and lipid content. • C.sorokiniana revealed better performance towards nutrient removal — C, N & P. • The maximum biomass yield and CO 2 fixation rate were attained with C.sorokiniana . • FAME profile suggested N. oculata — a suitable feedstock for biodiesel production. • The predicted biodiesel properties were in line with the standard biodiesel quality.

Pseudomonas putida APRRJVITS11 as a potent tool in chromium (VI) removal from effluent wastewater

Bioremediation is an essential feature of microorganisms concerning contaminations in soil and water. The use of microorganisms has been proved to be an effective treatment of industrially released effluents comprising of heavy metals, such as chromium (VI). In the current study, seasonal variations were observed in the concentrations of chromium(VI) as the samples from selected locations showed an increase in mean concentration during the summer compared to the low mean during winter, suggesting excessive evaporation in the summer leading to the heavy metal accumulation. Among the 35 isolates obtained from tannery effluent contaminated wastewater sources the 3 unique strains identified as Streptococcus pyogenes strain APRRJVITS10, Pseudomonas putida strain APRRJVITS11, and Bacillus thuringiensis strain APRRJVITS15, showed tolerance toward chromium(VI) and the maximum tolerance for each strain was 1250 ppm. The media optimization through shake flask methods showed chromium(VI) (in 100 ml LB broth) removal of 47.82%, 48.11%, and 49.93% by S. pyogenes, P. putida, and B. thuringiensis respectively. Further, Pseudomonas putida showed chromium(VI) (in 1500 ml LB broth) removal of 50.48% in optimized conditions, proving to be highly potential for treating effluent wastewater for chromium(VI) removal.

Highly Cr(vi)-tolerant Staphylococcus simulans assisting chromate evacuation from tannery effluent

Abstract Chromium(vi) contaminated sites have been targeted for studying highly chromate-resistant bacteria. From a total of 23 Cr(vi)-resistant bacteria isolated on Luria-Bertani agar medium supplemented with K2CrO4 (1,500 μg/mL), only one strain UT8 (Staphylococcus simulans) was able to tolerate high concentration of chromate, i.e., up to 200 mg/mL in agar medium from tannery effluent. In acetate minimal medium (AMM), it showed maximum tolerance of up to 2,500 μg/mL. Cr(vi) removal potential was 94.6% after 24 h (K2CrO4 1,500 μg/mL). Parametric conditions were optimized in AMM to attain maximum chromate removal. Exopolysaccharides extracted from bacterial cells exposed to chromate exhibited major absorption shifts from 2,500 to 500 cm−1 revealed by Fourier transform infrared spectroscopy. Energy-disperse X-ray spectroscopy further confirmed the adsorption of oxyanions to the bacterial cells. Surface topography of the Cr(vi) treated cells showed transformation into concave shape by scanning electron microscopy. The presence of resistance genes, i.e., chromate reductase (chrR) and class I integrase (intI1), further confirmed tolerance toward chromate. Microarray data analysis of transcriptional gene expression suggested upregulation of cys gene cluster under chromate exposure. Concisely, the present investigations revealed the potential of S. simulans to be an effective candidate for chromate reclamation of wastewater.

Biological treatment of hazardous heavy metals by Streptomyces rochei ANH for sustainable water management in agriculture

Microbial bioremediation of heavy metals-polluted industrial effluents has been adopted as one of the most effective eco-friendly tool to cope up with the harmful effects of metals. This study was designed to investigate the biosorption potential of marine actinomycetes isolated from the Alexandrian Mediterranean Seacoast, Egypt, with their potential use in metal remediation of industrial effluents. Among the nine marine actinomycetes isolates, Streptomyces rochei ANH showed the highest versatile metal resistance capability with MIC values of 125 mg/l for Cr6+ and 60 mg/l for both Cd2+ and Pb2+. Additionally, scanning electron micrographs showed complete disintegration of Cr6+-treated biomass compared with the control ones where spores remained intact and connected in long chains. The study also aimed to improve the percentage of Cr6+ biosorption by S. rochei ANH biomass using the statistical designs of Plackett–Burman and Box-Behnken where up to 85% of Cr6+ removal was recorded under the following conditions: pH (5), incubation temperature (30 °C), contact time (3 h), agitation speed (90 rpm), initial Cr6+ concentration (50 mg/l) and living biomass concentration (10 mg/ml). The results also showed that the percentage of Cr6+ biosorption by S. rochei ANH decreased gradually beyond these values. Moreover, the results revealed that the use of the biomass of S. rochei ANH is an effective biotechnological agent for the biological treatment of heavy metal-contaminated tannery effluent where the percentages of metal removal were in the following order: Ni2+ (100%) ≥ Cu2+ ≥ Mn2+ ≥ Fe2+ > Pb2+ (95%) ≥ Cd2+ > Cr6+ (86%). Furthermore, the treated effluent exhibited a stimulating effect on the germination process of Lepidium sativum seeds. Therefore, the present study implies that S. rochei ANH can be considered a powerful candidate to mitigate hazardous heavy metals pollution from industrial effluents and improve the water quality for agricultural purposes.

Anaerobic Co-Digestion of Tannery and Slaughterhouse Wastewater for Solids Reduction and Resource Recovery: Effect of Sulfate Concentration and Inoculum to Substrate Ratio

Anaerobic digestion is considered unsuitable for the bioremediation of tannery effluent due to process inhibition, mainly due to high concentrations of sulfur species, and the accumulation of H2S and/or NH3. This study using the standardized biochemical methane potential protocol showed that efficient processing is possible with slaughterhouse wastewater, provided sufficient functional biomass is present at the start of the process and the SO42− concentration is below inhibition threshold. Methanogenic activity (K = 13.4–17.5 and µm = 0.15–0.27) and CH4 yields were high when reactors were operated ISR ≥ 3 and/or lower SO42− ≤ 710 mg/L while high SO42− ≥ 1960 mg/L and ISR < 3.0 caused almost complete inhibition regardless of corresponding ISR and SO42−. The theoretical optimum operating conditions (922 mg/L SO42−, ISR = 3.72) are expected to generate 361 mL biogas/gVS, 235 mL CH4/gVS with reduction efficiencies of 27.5% VS, 27.4% TS, 75.1% TOC, 75.6% SO42−, and 41.1% COD. This implies that tannery sludge will be reduced by about 27% (dry mass) and SO42− by 76%, with a fraction of it recovered as S0. The models displayed a perfect fit to the cumulative CH4 yields with high precision in the order Logistic > Cone > modified Gompertz > first order.

Microbial fuel cell for harvesting bio-energy from tannery effluent using metal mixed biochar electrodes

The present study aims on the ways and means of reducing the cost of electrodes and decreasing environment pollution using waste materials. For example, Coconut Shell (CS) materials were used for synthesizing electrodes through carbonization and testing it as the anode in the Microbial Fuel Cell (MFC) utilizing tannery effluent. The electrodes were synthesized by using activated coconut shell wastes blended with various metals such as Silicon (Si0.2), Zinc (Zn0.2), and Copper (Cu0.2) with 20%. The specific surface area of CS-Si0.2 (0.1825 m2 g−1), CS-Zn0.2 (0.1900 m2 g−1), and CS-Cu0.2 (0.2162 m2 g−1) is greater than Graphite Particle (GP) (0.1890 m2 g−1). Power output of electrodes were CS-Si0.2 ((16.8 ± 0.5) mW m−2), CS-Zn0.2 ((22.96 ± 0.6) mW m−2), and CS-Cu0.2 ((38.72 ± 0.5) mW m−2) similar to GP ((30.42 ± 0.5) mW m−2). Our outcomes exhibit that the activated coconut shell with CS-Cu0.2 metal electrode gives the maximum power output. Therefore, CS-Cu0.2 electrodes are progressively viable, have greater biocompatibility, effective and adaptable for application in the microbial fuel cell. Among these three proposed electrodes, CS-Cu0.2 electrode has a huge potential for maximum performance and developing a cost-effective sustainable MFC.

Decoration of serpentine with iron ore as an efficient low-cost magnetic adsorbent for Cr (VI) removal from tannery wastewater

In this paper, a dry particle-particle coating technique was implemented to develop magnetic adsorbent from natural mineral constituents. Iron ore, specifically banded iron formation (BIF), was used as guest magnetic particles while serpentine (Serp) was used as host adsorptive material. Surface characterizations for the synthesized composite were investigated. The results confirmed the formation of a composite that combines both magnetic and adsorptive properties. The capability of the composite for hexavalent chromium Cr(VI) removal was investigated under different conditions. A maximum adsorption capacity of 138 mg/g was achieved. The adsorption of Cr(VI) onto the magnetic composite (BIF@Serp) was further thermodynamically and kinetically investigated. The results indicated that the adsorption follows 1.2-order kinetics and occurs spontaneously with an exothermic nature. Application of BIF@Serp for the treatment of real tannery effluent was conducted, the composite showed an excellent removal performance not only with Cr(VI) but also with other heavy metals and organic contaminants.

MIL-53(FE) / COW BONE CHAR COMPOSITE FOR CHROMIUM REMOVAL FROM TANNERY WASTEWATER

MIL-53(Fe)/Cow bone char composite, prepared via the sol-gel method was used for the removal of chromium from real tannery effluent having an initial concentration of 40mg/l. The characteristics of MIL-53(Fe)/Cow bone char were studied using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), thermo gravimetric analysis (TGA) Boehm titration and scanning electron microscopy (SEM-EDX). Adsorption capacity of MIL-53(Fe)/Cow bone char composite for chromium was 19.61 mg/g with a removal efficiency of 87.8% at an optimal bed height of 2.4cm (2.0g) for MIL-53(Fe)/Cow bone char composite, time of 2 minutes and pHpzc=5.4.The kinetic studies showed that the adsorption data were well fitted to the pseudo second-order model with high correlation coefficient R2=0.9911. Furthermore, the adsorption isotherm equilibrium studies confirmed that the Langmuir model best described the adsorption process of chromium onto MIL-53(Fe)/Cow bone char composite. Analysis of data with Dubinin–Radushkevich and Temkin isotherms showed that adsorption of chromium onto MIL-53(Fe)/Cow bone char composite is physical in nature.

Analysis of Chromate Transporters in Bacterial Species for Cr(VI) Reduction Isolated from Tannery Effluent Contaminated Site of Dindigul District, Tamil Nadu, India

Leather industries are well-known causative for hexavalent chromium [Cr(VI)] pollution in the environment. This possess a greater risk to human survival and disruption of ecological balance. Conventional methods to manage chromium through physical and chemical processes are mostly expensive and generate subsequent solid wastes which are cumbersome to treat. Hence, biological treatment is often regarded as the alternative method employing microorganisms for detoxification of Cr(VI). In this investigation, almost 32 bacterial strains were isolated from Dindigul district of Tamil Nadu, India. Among them, five isolates showed exceptional Cr(VI) reduction within 48 h upon aerobic cultivation. Bacteria confers chromium resistance through Chr transporters which involve metabolic reduction of toxic Cr(VI) to nontoxic Cr(III) through reductase enzyme. Activity by this enzyme are often associated with soluble proteins located in cytosol of the cell. Existence of chromate (Chr) transporters in identified isolates were confirmed in their genome through bioinformatics tools, where their structures were predicted based on Protter, a web-based tool. Conclusively, bacterial strains that could evolve as potential ones to reduce toxic Cr(VI) to its nontoxic Cr(III) form in chromium contaminated sites.

Reduction of pollution load of tannery effluent by cell immobilization approach using Ochrobactrum intermedium

The purpose of this present study was to reduce the pollution load of the tannery effluent through a cell immobilization approach using chromium tolerant bacteria isolated from tannery sludge. Among various initially isolated bacteria, strain IITR002 exhibited the highest pollution load reduction was characterized as Ochrobactrum intermedium by 16S rDNA sequencing. The bacterium was successfully immobilized with 10 % polyvinyl alcohol (PVA) and 1% sodium alginate (SA) and tannery effluent treatment were carried out using both free and immobilized cells of O. intermedium. Preliminary chemical oxygen demand (COD) reduction studies demonstrated 85 % and 54 % COD reductions by immobilized and free cells, respectively as compared to blank PVA beads (10 % COD). Both free and immobilized cells were able to degrade tannery effluent after 48 h but the reduction of total dissolved solids-TDS (56 %), COD (85 %), biochemical oxygen demand-BOD (68 %), and total chromium-TC (95 %) were higher with immobilized cells. The reduction of pollutants in tannery effluent was established by GC–MS analysis in which degradation of organic pollutants after treating with free and immobilized cells was observed. Phytotoxicity investigation of tannery effluents on Vigna radiata L seed showed that bacterial treatment not only allowed seeds germination but also supported seedling growth. The results from this flask-scale work suggest that immobilized cell methods of bacterial treatment can potentially be applied in tannery effluent treatment to reduce the pollution load as well as phytotoxic effects.

Investigation of Human Health Risks Influenced by Trace Metals (TMs) in Chili Plant (<i>Capsicum annuum</i> L.) Grown on Tannery Effluents Contaminated Soil

This study investigated the characteristics of tannery effluents of Hazaribagh area, Dhaka, Bangladesh, as well as assess the human health risks due to the accumulation and translocation of trace metals (TMs) in different parts of the chili plant (Capsicum annuum L.) grown on tannery effluents contaminated soil at three levels of contamination. The mean values of pH, TDS, EC, DO, turbidity, BOD, and TOC were 5.98, 4195 mg/L, 7950 μS/cm, 3.20 mg/L, 358 FTU, 660 mg/L and 3368.74 mg/L, respectively whereas the mean concentration of Cr, Pb, Fe, Zn, Cd, Mn and Cu was 374.40, 27.70, 26.06, 1.80, 1.27, 1.26 and 1.24 mg/L, correspondingly. The TMs constituents and water quality parameters in the tannery effluents exceeded both the national and international standards. A significant amount of Cr and Pb was traced in fruits of the medium and low level of contamination that exceeded the standard limit set by FAO/WHO. The highest transfer factor was found on Pb and it was mostly accumulated in the leaves. Cr and Pb concentrations in fruits of medium level exceeded the standard given by WHO/FAO/ SEPA. Although the daily intake of metals in combination with health and carcinogenic risk indexes indicated that the edible parts of Chili plants are within the safe limit, the potential human health risks cannot be abandoned for the consistent/long term consumption of TMs contained Chili plants (Capsicum annuum L.).

Photocatalytic degradation of real textile and tannery effluent using biosynthesized magnesium oxide nanoparticles (MgO-NPs), heavy metal adsorption, phytotoxicity, and antimicrobial activity

Industrial wastewater treatment is one of the greatest challenges of humanity that require an increased awareness to address water scarcity worldwide. Herein, an eco-friendly and cost-effective approach was established to cope with real textile and tannery effluents via the biosynthesis of highly adsorbent magnesium oxide nanoparticles (MgO-NPs). Physicochemical characterization of as-formed MgO-NPs confirms the successful fabrication of MgO nano-rods (30–85 nm) and nano-rectangular (18.6–27.6 nm) by harnessing metabolites secreted by Aspergillus niger strain F1. Moreover, the energy dispersive spectroscopy (EDX) confirms that Mg and O are the main components in the sample with weight percentages of 41.1% and 33.6%, respectively. X-ray photoelectron spectroscopy (XPS) confirms the successful formation of MgO at different bending energies. The catalytic degradation and decolorization analyses were conducted under sunlight and dark conditions. These analyses demonstrated that the highest decolorization of real textile and tannery effluents (92.8% ± 0.06% and 97.5% ± 0.7%, respectively) was accomplished after 180 min by treatment with 1.0 mg mL−1 of MgO-NPs in the presence of sunlight. At optimum experimental conditions, the quality of treated effluents was monitored by the reduction of total suspended solid (TSS), total dissolved solid (TDS), and chemical oxygen demand (COD) levels at the percentages of 86.9% ± 0.8%, 77.0% ± 0.8%, and 89.3% ± 0.9%, respectively, for textile effluent and the percentages of 94.3% ± 1.6%, 80.7% ± 1.6%, and 97.4% ± 0.9% respectively, for tannery effluent. The reusability of MgO-NPs showed its activity for textile effluents treatment for four cycles. Biosynthesized MgO-NPs showed a high adsorption capacity for predominant tannery heavy metals, namely, Cr, Co, Pb, Cd, and Ni having removal percentages of 94.2% ± 1.2%, 63.4% ± 1.7%, 72.7% ± 1.3%, 74.1% ± 1.8%, and 70.8% ± 1.5%, respectively. The toxicity of treated effluents was assessed by the germination of corn and broad bean seeds, which exhibited a decreased toxicity as compared with untreated effluents. Interestingly, the biosynthesized MgO-NPs exhibit antimicrobial activity against different pathogenic microbes and their activities were dose-dependent.