Bioremediation of petroleum refinery wastewater using Bacillus subtilis IH-1 and assessment of its toxicity.

Environmental contamination from petroleum refinery operations has increased due to the rapid population growth and modernization of society, necessitating urgent repair. Microbial remediation of petroleum wastewater by prominent bacterial cultures holds promise in circumventing the issue of petroleum-related pollution. Herein, the bacterial culture was isolated from petroleum-contaminated sludge samples for the valorization of polyaromatic hydrocarbons and biodegradation of petroleum wastewater samples. The bacterial strain was screened and identified as Bacillus subtilis IH-1. After six days of incubation, the bacteria had degraded 25.9% of phenanthrene and 20.3% of naphthalene. The treatment of wastewater samples was assessed using physico-chemical and Fourier-transform infrared spectroscopy analysis, which revealed that the level of pollutants was elevated and above the allowed limits. Following bacterial degradation, the reduction in pollution parameters viz. EC (82.7%), BOD (87.0%), COD (80.0%), total phenols (96.3%), oil and grease (79.7%), TKN (68.8%), TOC (96.3%) and TPH (52.4%) were observed. The reduction in pH and heavy metals were also observed after bacterial treatment. V. mungo was used in the phytotoxicity test, which revealed at 50% wastewater concentration the reduction in biomass (30.3%), root length (87.7%), shoot length (93.9%), and seed germination (30.0%) was observed in comparison to control. When A. cepa root tips immersed in varying concentrations of wastewater samples, the mitotic index significantly decreased, suggesting the induction of cytotoxicity. However, following the bacterial treatment, there was a noticeable decrease in phytotoxicity and cytotoxicity. The bacterial culture produces lignin peroxidase enzyme and has the potential to degrade the toxic pollutants of petroleum wastewater. Therefore the bacterium may be immobilised or directly used at reactor scale or pilot scale study to benefit the industry and environmental safety.

Thermal pretreatment of Lantana camara for improved biogas production: Process parameter studies for energy evaluation.

The rigid lignocellulosic structure of Lantana camara impedes the hydrolysis phase and reduces the biogas production during anaerobic digestion of Lantana camara. Hence, the current study focuses on the impact of various heating pretreatment techniques, viz., hot air oven (HAO), autoclave (ATC), hot water bath (HWB), and microwave (MCW) on L. camara to speed up hydrolysis and boost up biogas production. ATC pretreatment of L. camara was witnessed to be most efficient compared to HAO, MCW, and HWB pretreatment. ATC pretreatment enhanced the solubilization (45.44%), and an increment in volatile fatty acids (VFA) was observed (56.75%) at 110 °C for 80 min when correlated to the untreated (control). Cumulative methane production following ATC pretreatment had risen to 3656 mL in 5 weeks from 2895 mL in 7 weeks. Thermal pretreatment of Lantana camara broke down the rigid lignocellulosic structure, accelerating the hydrolysis stage and improving biogas production simultaneously. To the best of our knowledge, this is the first thermal pretreatment study conducted on Lantana camara for biogas production.

Biological treatment of Climbing Hempweed biomass through optimized composting technologies - Toxicity assessment and morphological study of Abelmoschus esculentus.

Climbing Hempweed (CH) is one of the top ten most obnoxious weeds on the planet, as well as one of the most destructive weeds. Its disastrous spread on the agricultural field has hampered the production of a wide range of crops. Various management techniques have been used to eradicate the weed, but none have been completely successful. As a result, management through the use of weed biomass will aid in the eradication of the weed as well as the production of a value-added product. To utilize invasive weed CH for the production of rotary drum compost (R1) and rotary drum followed by vermicompost (V1), two composting technologies were used. These technologies are being compared on several physicochemical parameters to determine their efficacy. V1 compost had the highest total Kjeldahl Nitrogen (TKN) (3.01%), potassium (3.45%), and total phosphorus (16.42 g/kg) levels, while R1 compost had 2.58% TKN, 2.8% potassium, and 14.25 g/kg total phosphorus. Subsequently, the increasing trends in mitotic index (%) of R1 and V1 samples imply that the cytotoxic effects of CH were decreased due to composting and vermicomposting processes. Genotoxicity assessment revealed that an aberration percentage of 1.64 was observed in 100% concentration of V1 (after 30 days) and 4.34% in R1(after 20 days). R1 and V1 were used to evaluate the performance of Abelmoschus esculentus where the highest fruit harvest was seen at 25% amended R1 compost and 35% amended V1 compost. The application of 25-35% R1 compost and 35-40% V1 compost was found to be the most beneficial for the development of Abelmoschus esculentus. There was no significant difference in heavy metal (Mn, Fe, Cu, Co, and Zn) content in the fruit of Abelmoschus esculentus post-application of R1 and V1 compost.

Genotoxicity evaluation of tannery effluent treated with newly isolated hexavalent chromium reducing Bacillus cereus.

In this study, the efficiency of free and immobilized cells of newly isolated hexavalent chromium [Cr(VI)] reducing Bacillus cereus strain Cr1 (accession no. KJ162160) was studied in the treatment of tannery effluent. The analysis of effluents revealed high chemical oxygen demand (COD-1260 mg/L), biological oxygen demand (BOD5-660 mg/L), total dissolved solids (TDS-14000 mg/L), electrical conductivity (EC-21.5 mS/cm) and total chromium (TC-2.4 mg/L). The effluents also showed genotoxic effects to Allium cepa. Treatment of tannery effluent with isolated B. cereus strain led to considerable reduction of pollutant load. The pollutant load reduction was studied with both immobilized and free cells and immobilized cells were more effective in reducing COD (65%), BOD (80%), TDS (67%), EC (65%) and TC (92%) after 48 h. GC-MS analysis of pre and post-treatment tannery effluent samples revealed reduction of organic load after treatment with free and immobilized cells. An improvement in mitotic index and reduction in chromosomal aberrations was also observed in A. cepa grown with post-treatement effluent samples compared to untreated sample. Results demonstrate that both methods of bacterial treatment (free and immobilized) were efficient in reducing the pollutant load of tannery effluent as well as in reducing genotoxic effects, however, treatment with immobilized cells was more effective.

Unleashing synergistic potential of microbially enhanced anaerobic co-digestion of petroleum refinery biosludge and yard waste: Impact of nutrient balance and microbial diversity.

Petroleum refinery sludge, an egregious solid residue generated from the wastewater treatment plants poses an environmental hazard owing to its intricate hydrocarbon composition, necessitating competent treatment for secure disposal. The study proposes a green solution through anaerobic co-digestion of nitrogen-rich petroleum refinery sludge (PS) with carbon-rich yard waste (YW), balancing the nutrients and moisture content for efficient microbial proliferation. Using Central Composite Design-Response Surface Methodology, 1 L batch experiments were conducted with varying carbon/nitrogen (C/N) ratios and pH to achieve maximum biogas yield within 50 days of co-digestion. However, the sluggish biogas recovery (40%) indicated a slow rate-limiting hydrolysis, necessitating pretreatment. Feedstock incubation with Bacillus subtilis IH1 strain, isolated from the microbially-enriched PS, at 108 colony forming units (CFU) per mL for 5 days maximized the soluble chemical oxygen demand and volatile fatty acids by 2.2 and 1.4 folds respectively compared to untreated feedstock. Scale-up Bacillus subtilis aided co-digestion studies further augmented biogas by 76% against untreated monodigestion of PS with significant total petroleum hydrocarbons, emulsions, and lignocellulosic degradation. Further identification of major organic pollutants in the batch digestate revealed significant degradation of the toxic organic hydrocarbon pollutants apotheosizing the efficacy of the synergistic sustainable technique for the management of PS. ENVIRONMENTAL IMPLICATION: The effluent treatment plants (ETPs) of petroleum refining industries generate sludge which is a complex mixture of petroleum hydrocarbons, oil-water (O/W) emulsions and heavy metals. These petroleum hydrocarbon constituents can be linear/cyclic alkanes, polyaromatics, resins and asphaltenes, whose intricate composition is reportedly carcinogenic, cytogenic and mutagenic, classifying it as hazardous waste. Biological treatment of these sludge through anaerobic digestion leads to utilization of petroleum hydrocarbons with subsequent energy recovery. Co-digestion of these sludge with competent co-substrates leads to nutrient balance, diverse microbial proliferation and toxicant dilution. Microbially aided co-digestion further augments methane rendering a digestate with utmost pollutant degradation.

Performance assessment of in-vessel composter through heavy metal immobilization and humification of Parthenium hysterophorus.

The bioconversion of Parthenium hysterophorus was performed through rotary drum composter and examined the mechanism of humification and heavy metals immobilization in the process. The 20th day compost contains a significant increase in humic substances of 28.7% compared to the initial day mix. The bioavailable fractions of heavy metals have reduced by 30 to 55% in the 20th day compost compared to the initial day mix. The leaching potential of cadmium has been reduced by 69% in the 20th day compost. The immobile fractions (F5) of Cd, Ni and Pb have been increased to 100, 99 and 78% in the 20th day compost. The mitotic index was increased by 1.7 and 51.6% in 25% dosed compost extract compared to the control and P. hysterophorus extract respectively. The transition of heavy metals to immobile fraction indicated the biodegradation capability of P. hysterophorus through rotary drum composting.

Biodegradation of an intrusive weed Parthenium hysterophorus through in-vessel composting technique: toxicity assessment and spectroscopic study.

Parthenium hysterophorus is a toxic terrestrial weed with its erratic behavior brought on by the presence of toxic compounds. A numerous works have been conducted on the complete eradication of this weed, but due to the residuals exists in soil, the weed re-grows. Current study therefore aims at examining the transformation of this weed by an in-vessel composting approach (rotary drum composter) and the evaluation of toxicity characteristics using Vigna radiata and Allium cepa as bioindicators. The nutritional content such as total Kjeldahl nitrogen (TKN), total phosphorus (TP), and total potassium were increased by 38.8, 39.1, and 49.5%, respectively, and the reactor was effective in reducing the biochemical content such as lignin, hemicellulose, and cellulose by 43.5, 50.7, and 57.3%, respectively, in the final compost. The thermophilic degradation phase in the reactor existed up to the 8th day of the composting process, which exhibits the highest degradation phase. Meanwhile, the degradation of phenolic, aliphatic, and lignocellulose was investigated and validated using Fourier transform infrared spectroscopy (FTIR) and powdered X-ray diffraction (PXRD) analysis. Although P. hysterophorus exhibited phytotoxic and cyto-genotoxic effects in plant models at the beginning of the composting process, the toxicity potential appeared to be reduced after 20 days of composting. Therefore, the study's findings proved that the in-vessel composting of P. hysterophorus can produce a nontoxic, nutrient-rich compost product that could be used as a soil conditioner in agricultural farmlands. The insights of the study are not limited to the nutritional, stability, and quality characteristics but also the toxicity characteristics during the composting process.

Enhanced methane production and hydrocarbon removal from petroleum refinery sludge after Pseudomonas putida pretreatment and process scale-up.

The influence of Pseudomonas putida 7525 strain on the pretreatment of petroleum refinery sludge was optimized at different dosages to maximize solubilization for improved biodegradability. Laccase-producing P. putida strain at a dosage of 108 CFU/mL resulted in 249% and 121.57% increments in soluble chemical oxygen demand and volatile fatty acids production respectively as compared to untreated within 6 days of incubation. 1L biochemical methane potential test conducted for optimization of different inoculum and pretreated substrate ratios (0.3, 0.4, 0.5, 0.7 and 1.0) revealed maximum methane augmentation (62%) and volatile solids degradation (66.7%) at ratio 0.5. Scaled-up study (20L) for ratio 0.5 resulted in 57.07% total petroleum hydrocarbon, 62.98% oil and grease and 91.9% phenol removal within 50 days of digestion of pretreated PS. Kinetic modelling of cumulative methane yield indicated that modified Gompertz model showed the best fit thereby, evincing the potency of bacterial species for bioremediation of PS.

Mixed Convection Nanofluid Flow with Heat Source and Chemical Reaction over an Inclined Irregular Surface.

Two-dimensional mixed convection radiative nanofluid flow along with the non-Darcy permeable medium across a wavy inclined surface are observed in the present analysis. The transformation of the plane surface from the wavy irregular surface is executed via coordinate alteration. The fluid flow has been evaluated under the outcomes of heat source, thermal radiation, and chemical reaction rate. The nonlinear system of partial differential equations is simplified into a class of dimensionless set of ordinary differential equations (ODEs) through a similarity framework, where the obtained set of ODEs are further determined by employing the computational technique parametric continuation method (PCM) via MATLAB software. The comparative assessment of the current outcomes with the earlier existing literature studies confirmed that the present findings are quite reliable, and the PCM technique is satisfactory. The effect of appropriate dimensionless flow constraints is studied versus energy, mass, and velocity profiles and listed in the form of tables and figures. It is perceived that the inclination angle and wavy surface assist to improve the flow velocity by lowering the concentration and temperature. The velocity profile enhances with the variation of the inclination angle of the wavy surface, non-Darcian term, and wavy surface term. Furthermore, the rising value of Brownian motion and thermophoresis effect diminishes the heat-transfer rate.

Impact of homogeneous and heterogeneous reactions in the presence of hybrid nanofluid flow on various geometries.

The current work investigates the influence of porous media, homogeneous and heterogeneous reactions, and a heat source/sink on the hybrid nanoliquid circulation on three distinct surfaces (cone, plate, and wedge). The system of equations that describe the circulation issue and operating conditions is reduced to ordinary differential equations (ODEs) by using the proper similarity transformations. The Runge-Kutta-Fehlberg 45 order and the shooting approach are used to generate the numerical results. Graphs are used to show how various dimensionless limits affect the associated profiles. The results demonstrate that, in the presence of heat source/sink and porous medium characteristics, respectively, fluid velocity and heat dispersion are high in plate geometry and lower in cone geometry. The concentration profile shows the declination in the presence of both homogeneous and heterogeneous reaction intensities. The surface drag force decreases and the rate of heat dispersion rises with the addition of a porous attribute. Furthermore, cones sprinkle the heat more quickly than wedges, which disperse heat more slowly.

Novel coronavirus disease (COVID-19): origin, transmission through the environment, health effects, and mitigation strategies-a review.

The novel coronavirus disease (COVID-19), caused by severe acute respiratory coronavirus-2 (SARS-CoV-2), was first identified in China and subsequently spread globally, resulting in a severe pandemic, and officially declared a significant health emergency by World Health Organization (WHO). Genetic analysis of coronavirus isolated from bats, snakes, and Malay pangolins suggested that they could be intermediate hosts for SARS-CoV-2. The transfer of virus from person to person has been confirmed widely, while the actual source of origin is still unknown. COVID-19 is a highly contagious and infectious disease, and the worldwide transmission of coronavirus has intense effects on the lives of human beings. The spread of the virus is observed mainly through close contact with the infected person due to coughing, sniffing or indirectly through the contaminated surfaces. If people touch contaminated surfaces through their hands, mouth, nose, or eye, it enters the body and causes disease. Also, the virus may transmit through air droplets, water, food, fecal-oral transmission, etc. The infection of virus in human beings could be detected by direct symptoms, or different diagnostic tools are available to determine the viral load. Various safety measures are used to contain the virus, including disinfectants, antiviral drugs, vaccines, wearing masks, social distancing, etc. In the present review, we have focused on transmission of COVID-19 through air and wastewater as environmental transmission modes. We have also discussed the origin of the virus, its mode of action, host immune response, vulnerability, varying symptoms and diagnosis, prevention and control. Further, we have discussed the various treatment options to cope with this viral outbreak.

Evaluation of rotary drum composting for the management of invasive weed Mikania micrantha Kunth and its toxicity assessment.

Mikania micrantha Kunth is an abhorrent weed that destroys agricultural output. It contains toxic compounds that are detrimental to the natural ecosystem and have negative impacts on the economic and aesthetic aspects of the environment. This study depicts the treatment and management of this plant by in-vessel composting using a 550 L rotary drum composter. Six different mix proportions of biomass, cow dung, and sawdust were used for the study. Rotary drum (RD2) with 2.71% has the highest Total Kjeldahl Nitrogen (TKN). Total Organic Carbon (TOC) decreased to 19.72% at the end of the 20th day. Final C/N ratio falls between 7 and 14 in all the reactors. The phytotoxicity test of Mikania was evaluated using Vigna radiata and Allium cepa. The findings of the study suggest that Mikania can be efficiently utilised to produce mature and stable compost that might be recommended for field application as the process can reduce toxicity.

Recent advances in removal of lignin from paper industry wastewater and its industrial applications - A review.

Pulp and paper mill wastewater contains lignin related synthetic, aromatic and chlorinated chemical compounds. Extracting lignin from pulp and paper mill wastewater is one way of recovering valuable organic material. Due to its complex structure, lignin is difficult to break and provides economical and technical provocations in biomass recovery. The conventional wastewater treatment processes are seldom efficacious for the complete removal of lignin from paper mill effluents. A wide range of thermal, mechanical and physico-chemical methods have been reported for the removal of lignin. Moreover, biological method of lignin removal employed microorganisms including bacteria and fungi as a one-step treatment and/or amalgamation of various physico-chemical techniques. Compared with other methods, biological process for degradation of lignin is regarded as eco-friendly, cost-effective and sustainable. Therefore, this review will provide insight into the recent breakthroughs and future trends in lignin removal with special emphasis on biological treatment and scope of lignin utilization.

Biodegradation of Azure-B dye by Serratia liquefaciens and its validation by phytotoxicity, genotoxicity and cytotoxicity studies.

The azo dyes in textile industry are a major source of environmental pollution and cause serious threat to aquatic flora and fauna. The present study aims to evaluate the potential of previously isolated lignin peroxidase (LiP) enzyme producing Serratia liquefaciens in degradation of Azure-B (AB) dye. S. liquefaciens showed rapid decolourisation of AB dye (100 mg L-1) in mineral salt medium (MSM) supplemented with 0.2% glucose and yeast extract, and more than 90% dye decolourisation was observed at 48 h when incubated at 30 °C. Decolourisation conditions were optimized by Response Surface Methodology (RSM) using Box-Behnken Designs (BBD). The dye degradation was further confirmed by ATR-FTIR and GC-MS analysis. Toxicological studies of untreated (UT) and bacterial treated (BT) AB dye solutions were studied by using phytotoxicity, genotoxicity and cytotoxicity endpoints. Phytotoxicity assay using Vigna radiata indicated that bacterial treatment led to detoxification of AB dye. Genotoxicity assay with Allium cepa showed that pure AB dye solutions significantly reduced mitotic index (MI) and induced various chromosomal abnormalities (CAs) like c-mitosis, stickiness, chromosome break, anaphase bridges, vagrant chromosomes and binucleated and micronucleated cell in the root tip cells, whereas, bacterial treated solutions induced relatively less genotoxicity in nature. Improved cell survivability (%) was also noted in kidney cell line (NRK-52E) after S. liquefaciens treated dye solutions than the pure dye solutions. The findings suggest that S. liquefaciens could be a potential bacterium for azo dye degradation, as it is effective in lowering of toxic effects of AB dye.

Improved enzyme properties upon glutaraldehyde cross-linking of alginate entrapped xylanase from Bacillus licheniformis.

Enzyme immobilization is an exciting alternative to improve the stability of enzymatic processes and economic viability in terms of reusability. In the current study, purified xylanase from B. licheniformis Alk-1 was immobilized within glutaraldehyde activated calcium alginate beads and characterized in respect of free enzyme. Immobilization increases the optimum pH and temperature of entrapped and cross-linked enzyme from pH=8.0 to 9.0 and 50-60°C. The kinetics parameter of immobilized (cross-linked) enzyme showed an increase in Km (from 4.36mg/mL to 5.38mg/mL) and decrease in Vmax (from 383 IU/mg/min to 370 IU/mg/min). Immobilization increases the optimum reaction time for xylan degradation of immobilized xylanase from 15 to 30min when compare to free form. The storage stability study suggested that the immobilized enzyme retains 80% of its original activity at 4°C after 30days compared to free enzyme (5%). Further, immobilization improved enzyme stability in presence of different additives. The immobilized (cross-linked) enzyme also exhibited adequate recycling efficiency up to five reaction cycles with 37% retention activity. The finding of this study suggests improvement of overall performance of immobilized xylanase in respect to free form and can be used to make a bioreactor for various applications such as poultry feed preparations.

Genotoxicity assessment of pulp and paper mill effluent before and after bacterial degradation using Allium cepa test.

A lignin peroxidases-producing Serratia liquefaciens was used for bioremediation of pulp and paper (P&P) mill effluent. The treatment led to reduction of chemical oxygen demand (COD), colour, lignin and phenolic content by 84%, 72%, 61% and 95%, respectively. The effluent detoxification was studied by genotoxicity assays using Allium cepa L. (onion) root tip cells. Genotoxicity studies included measuring mitotic index (MI), chromosomal aberrations (CA) and nuclear abnormalities (NA) in root tip cells following treatment with 25, 50, 75 and 100% (v/v) of effluent. The root tip cells grown in untreated effluent showed a significant decrease in MI from 69% (control) to 32%, 27%, 22% and 11% at 25%, 50%, 75% and 100% effluent concentration, respectively. This indicated that the untreated effluent was highly cytotoxic in nature. Further, root tip cells, when treated with different concentrations of effluent showed various CA and NA including c-mitosis, stickiness, chromosome loss, chromosome break, anaphase bridge, multipolar anaphase, vagrant chromosomes, micronucleated and binucleated cells. The MI observed in root tip cells grown in bacterial treated effluents at similar concentrations (25, 50, 75 and 100% v/v) showed an increase of 33%, 36%, 42% and 66%. CA showed a substantial decrease and in some instances, complete absence of CA was also observed. The findings suggest that S. liquefaciens culture could be a potential bacterial culture for bioremediation of P&P mill effluent, as it is effective in substantial lowering of pollutants load as well as reduces the cytotoxic and genotoxic effects of effluent.

Purification, characterization and thermostability improvement of xylanase from Bacillus amyloliquefaciens and its application in pre-bleaching of kraft pulp.

Xylanases have important industrial applications but are most extensively utilized in the pulp and paper industry as a pre-bleaching agent. We characterized a xylanase from Bacillus amyloliquefaciens strain SK-3 and studied it for kraft pulp bleaching. The purified enzyme had a molecular weight of ~50 kDa with optimal activity at pH 9.0 and 50 °C. The enzyme showed good activity retention (85%) after 2 h incubation at 50 °C and pH 9.0. This enzyme obeyed Michaelis-Menten kinetics with regard to beechwood xylan with K m and V max values of 5.6 mg/ml, 433 µM/min/mg proteins, respectively. The enzyme activity was stimulated by Mn2+, Ca2+ and Fe2+ metal ions. Further, it also showed good tolerance to phenolics (2 mM) in the presence of syringic acid (no loss), cinnamic acid (97%), benzoic acid (94%) and phenol (97%) activity retention. The thermostability of xylanase was increased by 6.5-fold in presence of sorbitol (0.75 M). Further, pulp treated with 20U/g of xylanase (20IU/g) alone and with sorbitol (0.75M) reduced kappa number by 18.3 and 23.8%, respectively after 3 h reaction. In summary, presence of xylanase shows good pulp-bleaching activity, good tolerance to phenolics, lignin and metal ions and is amenable to thermostability improvement by addition of polyols. The SEM image showed significant changes on the surface of xylanase-treated pulp fiber as a result of xylan hydrolysis.

Evaluation of bioremediation potentiality of ligninolytic Serratia liquefaciens for detoxification of pulp and paper mill effluent.

Due to high pollution load and colour contributing substances, pulp and paper mill effluents cause serious aquatic and soil pollution. A lignin-degrading bacterial strain capable of decolourising Azure-B dye was identified as lignin peroxidase (LiP) producing strain LD-5. The strain was isolated from pulp and paper mill effluent contaminated site. Biochemical and 16S rDNA gene sequence analysis suggested that strain LD-5 belonged to the Serratia liquefaciens. The strain LD-5 effectively reduced pollution parameters (colour 72%, lignin 58%, COD 85% and phenol 95%) of real effluent after 144h of treatment at 30°C, pH 7.6 and 120rpm. Extracellular LiP produced by S. liquefaciens during effluent decolourisation was purified to homogeneity using ammonium sulfate (AMS) precipitation and DEAE cellulose column chromatography. The molecular weight of the purified lignin peroxidase was estimated to be ∼28kDa. Optimum pH and temperature for purified lignin peroxidase activity were determined as pH 6.0 and 40°C, respectively. Detoxified effluent was evaluated for residual toxicity by alkaline single cell (comet) gel electrophoresis (SCGE) assay using Saccharomyces cerevisiae MTCC 36 as model organism. The toxicity reduction to treated effluent was 49.4%. These findings suggest significant potential of S. liquefaciens for bioremediation of pulp and paper mill effluent.

Assessing hazardous risks of indoor airborne polycyclic aromatic hydrocarbons in the kitchen and its association with lung functions and urinary PAH metabolites in kitchen workers.

BACKGROUND: Indoor air pollution is associated with decreased pulmonary function but the relative impact of pollution from kitchen sources on health risks in kitchen workers is not well-known or studied. A study was conducted to measure the kitchen indoor air quality including PAHs estimation and risk assessment based on reported PAHs in indoor air in a central kitchen at North India. METHODS: A cross sectional study was undertaken to assess the lung function status using spirometer and urinary PAH metabolite measurements using GC-MS/MS among 94 male kitchen workers and their corresponding controls. Assessment of the indoor air quality levels was evaluated using standard methods. RESULTS: All the indoor air pollutants were within the recommended guidelines except CO, TVOC and PAH emission in the kitchen. Incremental life time cancer risk (ICLR) based on indoor air PAH measurements indicates potential for carcinogenic risk. Significant lung function decline was observed among kitchen workers as compared to controls after adjusting for smoking habits. Urinary PAH metabolites were detected in kitchen workers and measured concentrations were comparatively higher than control subjects. CONCLUSION: The decline in lung functions after adjustment for confounders and detection of urinary PAH metabolites in kitchen workers can be associated with higher concentrations of PAHs, CO and TVOCs in kitchen indoor air.

Detection of tannery effluents induced DNA damage in mung bean by use of random amplified polymorphic DNA markers.

Common effluent treatment plant (CETP) is employed for treatment of tannery effluent. However, the performance of CETP for reducing the genotoxic substances from the raw effluent is not known. In this study, phytotoxic and genotoxic effects of tannery effluents were investigated in mung bean (Vigna radiata (L.) Wilczek). For this purpose, untreated and treated tannery effluents were collected from CETP Unnao (UP), India. Seeds of mung bean were grown in soil irrigated with various concentrations of tannery effluents (0, 25, 50, 75, and 100%) for 15 days. Inhibition of seed germination was 90% by 25% untreated effluent and 75% treated effluent, compared to the control. Plant growth was inhibited by 51% and 41% when irrigated with untreated and treated effluents at 25% concentration. RAPD technique was used to evaluate the genotoxic effect of tannery effluents (untreated and treated) irrigation on the mung bean. The RAPD profiles obtained showed that both untreated and treated were having genotoxic effects on mung bean plants. This was discernible with appearance/disappearance of bands in the treatments compared with control plants. A total of 87 RAPD bands were obtained using eight primers and 42 (48%) of these showed polymorphism. Irrigating plants with untreated effluent caused 12 new bands to appear and 18 to disappear. Treated effluent caused 8 new bands and the loss of 15 bands. The genetic distances shown on the dendrogram revealed that control plants and those irrigated with treated effluent were clustered in one group (joined at distance of 0.28), whereas those irrigated with untreated effluent were separated in another cluster at larger distance (joined at distance of 0.42). This indicates that treated effluent is less genotoxic than the untreated. Nei's genetic similarity indices calculated between the treatments and the control plants showed that the control and the plants irrigated with treated tannery effluent had a similarity index of 0.75, the control and plants irrigated with untreated 0.65, and between the treatments 0.68. We conclude that both untreated and treated effluents contain genotoxic substances that caused DNA damage to mung beans. CETP Unnao removes some, but not all, genotoxic substances from tannery effluent. Consequently, use of both untreated and treated wastewater for irrigation poses health hazard to human and the environment.