Potential of ionic liquids as emerging green solvent for the pretreatment of lignocellulosic biomass

Lignocellulosic biomass is available in abundance as a renewable resource, but the major portion of it is often discarded as waste without utilizing its immense potential as an alternative renewable energy resource. To overcome recalcitrance of lignocellulosic biomass, various pretreatment methods are applied to it, so that the complex and rigid polymeric structure can be broken down into fractions susceptible for enzymatic hydrolysis. Effective and efficient biomass processing is the goal of pretreatment methods, but none of the explored pretreatment methods are versatile enough to fulfil the requirement of biomass processing with greater flexibility in terms of operational cost and desired output efficiency. Deployment of green solvents such as ionic liquids for the pretreatment of lignocellulosic biomass has been a topic of discussion amongst the scientific community in recent times. The presented work provides a detailed overview on the deployment of ionic liquid for the pretreatment of lignocellulosic biomass coupled with a brief discussion on other pretreatments methods. The recyclability and reusability along with other unique properties makes an ionic liquid pretreatment different from the other traditional pretreatment methods. Also, this study explores diverse critical parameters that governs the dissolution process of biomass. Hazardous properties of ionic liquids have also been explored. Future perspective and recommendations have been given for an efficient, effective, and eco-friendly deployment of ionic liquid in biomass pretreatment process.

Polycyclic Aromatic Hydrocarbons (PAHs) in aquatic ecosystem exposed to the 2020 Baghjan oil spill in upper Assam, India: Short-term toxicity and ecological risk assessment

This study focuses on the short-term contamination and associated risks arising from the release of Polycyclic Aromatic Hydrocarbons (PAHs) due to the 2020 Baghjan oil blowout in upper Assam, India. Shortly after the Baghjan oil blowout, samples were collected from water, sediment, and fish species and examined for PAHs contents. The results of the analysis revealed ΣPAHs concentrations ranged between 0.21-691.31 μg L-1 (water); 37.6-395.8 μg Kg-1 (sediment); 104.3-7829.6 μg Kg-1 (fish). The prevalence of 3-4 ring low molecular weight PAHs compounds in water (87.17%), sediment (100%), and fish samples (93.17%) validate the petrogenic source of origin (oil spill). The geographic vicinity of the oil blowout is rich in wildlife; thus, leading to a significant mass mortality of several eco-sensitive species like fish, plants, microbes, reptiles, amphibians, birds and mammals including the Gangetic River dolphin. The initial ecological risk assessment suggested moderate to high-risk values (RQ >1) of majority PAHs concerning fish, daphnia, and algae species. This study highlights the need for recognizing the potential for short-term exposure to local species. To safeguard local ecosystems from potential future environmental disasters, it is imperative for the government to adopt a precautionary strategy.

Bioconversion of fruit waste and sewage sludge mixtures by black soldier fly (Diptera: Stratiomyidae) larvae

Bioconversion of fruit waste (FW) and sewage sludge (SS) sludge mixtures into valuable products was investigated using black soldier fly (Hermetia illucens) larvae (BSFL) under a lab-scale trial. For that, five different setups of FW and SS mixtures (100FW; 100SS; 70SS+30FW; 50SS+50FW; 70FW+30SS) were prepared and changes in larval biomass, feed loss, and residual waste physicochemical properties were estimated until the emergence of fly in all waste mixtures. BSFL caused a significant decrease in total organic carbon (11.71-34.79%) and carbon-to-nitrogen ratio (C/N ratio) while the increase in total nitrogen (8.35-123.30%), total phosphorus (17.02-143.36%), and total potassium (19.40-48.87%) contents in the feedstock. The germination index and C/N ratio of frass were below the standards decided for manure quality in a few setups suggesting the non-stability of frass for agronomic applications due to the short duration (20 d) of composting. Larval biomass yield, feed conversion ratio and nutrient mineralization were found to be higher in 50SS+50FW and 70FW+30SS feedstock combinations suggesting their suitability as ideal feedstock for optimal BSFL cultivation. The impact of toxic substances in sewage on BSFL survival, growth and waste stabilization processes, and frass metal enrichment could be investigated in future studies.

Synthesizing biochar-based slow-releasing fertilizers using vermicompost leachate, cow dung, and plant weed biomass

Biochar-based slow-releasing fertilizers (BSRF) have been recommended widely for efficient soil nutrient management and crop production. In this study, we examined the N, P, and K release behaviour of pyrolysed (at 350 °C) cow dung (CDB), vermicompost (VCB), and Lantana (LB) weed and impregnated LB (LBVW) and CDB (CDBVW) with vermicompost leachate (1:1 v/v) under a lab-scale trial. BSRFs (CDB, VCB, LBVW and VCBVW) characterization (FT-IR, SEM-EDX and surface area analysis) was done and then tested for its suitability for soil-plant applications. Soil incubation study indicated the slow-releasing behaviour of BSRFs and overall P, N, and K release was found to be in the ranges of 72.3-84.5%, 73.1-79.0%, and 43.1-85.3%, respectively in different BSRFs setups. Furthermore, lab trials suggested the highest P (64.5%), N (75.3%), and K (86.8%) uptakes by the plant (Vigna radiata) in CDBVW and LBVW setups. Moreover, pot trails with moong bean (Vigna radiata) suggested a high growth in shoot and root and plant yield as well in seedlings cultivated with BSRFs. This study indicates that animal manure, vermicompost and terrestrial weed Lantana biochar can be used effectively to prepare BSRFs for efficient soil-plant nutrient management with multiple environmental benefits.

Fate and toxicity of triclosan in tidal flow constructed wetlands amended with cow dung biochar

Triclosan (TC) is one of the threats to the environment due to its bioaccumulative nature, persistency, combined toxicity in aquatic biota, and endocrine-disrupting nature. This study revealed the removal of TC via three distinct setups of vertical flow constructed wetlands (VFCW: B-VFCW (with biochar); PB-VFCW (with plant Colocasia and biochar); C-VFCW (without biochar but with plant)) operated with normal flow and tidal-flow (flooding/drying cycles of 72 h/24 h: B-TFCW; PB-TFCW; C-TFCW) mode for 216 h of the operation cycle. The effluent was analyzed for changes in TC load and wastewater parameters (COD, NO₃-N, NH₄⁺-N, and DO). TC reduction efficiency (%) was found to be higher in PB-TFCW (98.41) followed by, C-TFCW (82.41), B-TFCW (77.51), PB-VFCW (71.83), C-VFCW (64.25), and B-VFCW (52.19) (p < 0.001). Reduction efficiency for COD (29-75 - 53.10%), and NH₄⁺-N (86.5-97.9%) was better in TFCWs than that of setups with a normal mode of operation. TFCWs showed higher DO (3.87-4.89 mg L^-1) during the operation period than that of VFCWs. The toxic impact of TC in plant stand was also assessed and results suggested low phototoxic and oxidative enzyme activities (catalase, CAT; superoxide dismutase, SOD; hydrogen peroxide, H₂O₂; malondialdehyde, MDA) in TFCWs. In summary, biochar addition and tidal flow operation played a significant role in oxidative- and microbial-mediated removals of TC in wastewater. This study provides an alternative strategy for the efficient removals of TC in constructed wetland systems and new insights into the toxic impact of pharmaceuticals on wetland plants.

Effect of biochar amendment on metal mobility, phytotoxicity, soil enzymes, and metal-uptakes by wheat (Triticum aestivum) in contaminated soils

The use of low-cost substances such as biochar could be a sustainable approach to reduce the mobility, accumulation, and toxic impact of heavy metals in crop systems. This study investigates the effect of biochar amendment on heavy metal (Cr, Cd, Cu, Pb, Ni, Zn, Mg and Fe) mobility, bioaccumulation factor (BAF), plant (wheat) metal-uptake, plant oxidative stress, and soil enzymatic profile in contaminated industrial soil. Biochar was obtained from slow pyrolysis of Lantana (LBC), and Parthenium (PBC) biomass, and applied at 3% rates in contaminated soils for wheat crop study under a greenhouse experimental setup. Results show in comparison with control setups, low mobility of Cr (14.15-16.35%), Cd (7.17-15.24%), Cu (9.81-12.97%), Pb (7.99-15.23%), Ni (1.52-2.38%), Zn (10.47-14.42%), Mg (48.85-52.89%), and Fe (19.13-19.90%) contents in soils. The heavy metal uptake rates were 63.08% (Cr), 78.07% (Cd), 74.61% (Cu), 78.11% (Pb), 75.73% (Ni), 69.71% (Zn), 28.78% (Mg), and 49.26% (Fe) lower in biochar amendments, compared with the control treatments. Similarly, the biochar amended treatments exhibited low oxidative stress in wheat plants than control setups. In addition, soil enzymes (dehydrogenase, β-glucosidase, alkaline phosphatase, and urease) alleviated in biochar amended soils indicating reduced toxicity of metals in experimental soils. In summary, this study indicates that biochar amendment in contaminated soils not only improves plant growth but also lowers the rates of soil and plant toxicity and metal bioavailability as well.

Removal of pharmaceuticals by vertical flow constructed wetland with different configurations: Effect of inlet load and biochar addition in the substrate

Pharmaceuticals (PCs) residues are considered an emerging threat to the environment due to their persistency, ecotoxicity and bioaccumulative nature. To study the PC (amoxicillin, AMX; caffeine, CF; ibuprofen, IBU) removal efficiency of vertical flow constructed wetland (VFCW), three setups of VFCWs were configured: SB (substrate matrix + biochar (BC)); SBP (substrate matrix + BC + plant); SP (substrate matrix + plant) and changes in effluent PC load was estimated at 24, 48, 72, 96, 120, 144 and 168 h intervals. SBP with an influent load of 1,000 μg L^-1 showed the maximum removals of 75.51% (AMX), 87.53% (CF), and 79.93% (IBU) significantly higher than that of SB and SP (p < 0.00). Results showed an inverse relationship between removal efficacy and influent PCs loading. The average removal (%) by VFCWS (of all studied setups) was in the order: 66.20 > 47.88 > 39.0 (IBU), 56.56 > 42.12 > 34.36 (AMX), and 74.13 > 64.0 > 52.07 (CF) with 1,000, 5,000 > 10,000 μg L^-1 influent load, respectively. The maximum removal of COD, NH₄⁺-N, and NO₃-N was recorded at 88.8%, 83.1%, and 64.9%, respectively in SBP, and their removal was hardly affected by influent PC concentration. In summary, planted VFCW spiked with BC could be a viable approach for the removal of PCs in wastewater. The impact of PC load on plant toxicity in VFCWs can be taken as a research problem for future work in this series.

Phycoremediation of milk processing wastewater and lipid-rich biomass production using Chlorella vulgaris under continuous batch system

This study compiles the results of phycoremediation of milk processing wastewater (MPWW) and production of lipid-rich Chlorella vulgaris biomass using a continuous batch system operated for 12-wks. After a 4-wks interval, a new MPWW was loaded photobioreactor to provide appropriate nutrient supply to algae. Results indicated that MPWW supported the algal growth efficiently and the maximum algal growth was recorded in the ranges of 400.36 to 421.58 mg L^-1 during 4-wk's of the cultivation cycle. Average reduction in total nitrogen, TN (45.82-69.18%); nitrate, NO₃ (93.32-94.54%); total ammonium nitrogen, TAN (92.94-94.54%); sulphate, SO₄^-2 (85.13-87.34%); total phosphorus (75.09-78.78%); and biochemical oxygen demands, BOD (89.53-92.40%) was recorded during 12-wks phycoremediation of MPWW. Harvested algal biomass (dry weight basis, DW) exhibited a significant content of total sugar (45.5%) and total lipid (39.7%). The lipid profiling results indicated the presence of palmitic acid (39.9%), oleic acid (21.08%), linoleic acid (13.13%), and other C18 compounds in algal biomass, suggesting the suitability of MPWW for Chlorella vulgaris cultivations. Algal biomass exhibited a high heating value (MJ/Kg of DW) in the range of 17.3 to 25.1, comparable to other lignocellulose biomass to be used for bioenergy purposes. Results of this study indicate that MPWW could be utilized as a valuable medium for Chlorella vulgaris cultivation under a circular economy approach: wastewater treatment and bioenergy feedstock production. The effect of controlled environmental conditions on algal growth behavior and lipid composition in biomass, while using MPWW as a medium, could be investigated in future studies.

Fungal pretreatment facilitates the rapid and valuable composting of waste cardboard

This study investigates the waste cardboard (WCB) fungal pretreatment (Oligoporus placenta and Tremetes hirsuta) under monoculture and mixed culture and then composting for 35 d after mixing with cow dung in different ratios. Fungal pretreatment caused significant reduction in cellulose (28.3-35.8%), hemicellulose (61.4-68.4%), lignin (67.5-69.3%) content in WCB. Pretreated WCB showed better rates of decrement in total organic carbon (26.02-47.92%), carbon-to-nitrogen ratio (19.4-23.5), and lignocellulose contents, as well as incensement in total nitrogen (40.48-63.31%), total potassium (51.92-73.91%), germination index (88.5-102.0%), and elemental (Cu, Fe, Zn, Cr, and Mn) levels. Dehydrogenases (142-210 µg g^-1h^-1), and β-galactosidase (210-256 µg g^-1h^-1) activities indicates high microbial-mediated mineralization in setups. Results suggested that WCB could be used as a valuable substrate for valuable-added compost preparation after pretreating with a consortium of white-rot fungi.

Enhanced wastewater nutrients removal in vertical subsurface flow constructed wetland: Effect of biochar addition and tidal flow operation

Dissolved oxygen (DO) and carbon stock in substrate medium play a vital role in the nutrient removal mechanism in a constructed wetland (CW). This study compiles the results of dynamics of DO, ammonium N (NH₄⁺-N), nitrate (NO₃-N), sulfate (SO₄^-2), phosphate (PO₄^-3), chemical oxygen demand (COD), in three setups of vertical-flow constructed wetlands (TFCWs) (SB: substrate + biochar; SBP: substrate + biochar + Colocasia esculenta plantation; SP: substrate + Colocasia esculenta (SP), operated with tidal flow cycles. Experimental analyses illustrated the continuous high DO level (2.743-5.66 mg L^-1) in SB and SBP after the I and II cycle of tidal flow (72 h flooding and 24 h dry phase). COD reduction efficiencies increased from 15.75 - 61.86% to 48.55-96.80% after tidal operation among operating TFCWs. N (NH₄⁺-N) and N (NO₃-N) removal were found to be 88.16%, and 76.02%; 49.32, and 57.85%; and 40.23%, and 48.94 % in SBP, SP and SB, respectively. The theory of improved nitrification and adsorption through biochar amended substratum was proposed for TFCW systems. PO₄^-3 and SO₄^-2 removal improved from 22.63 to 80.50%, and 19.69 to 75.20%, respectively after first tidal operation in all TFCWs. The microbial inhabitation on porous biochar could promote the transformation of available P into microbial biomass and also helped by the plant uptake process while SO₄^-2 reduction in TFCWs could be mainly due to sulfate-reducing bacterial activity and nitrate reduction process, mainly facilitated by high DO and biochar addition in such setups. The study suggests that effluent re-circulation through tidal operation and biochar supplementation in the substratum could be an effective mechanism for the improvement of the working efficiencies of CWs operated with low energy input systems.

Occurrence, seasonal variations, and ecological risk of pharmaceuticals and personal care products in River Ganges at two holy cities of India

Occurrence of 15 different pharmaceuticals and personal care products (PPCPs) (ibuprofen, diclofenac, ketoprofen, acetaminophen, ciprofloxacin, erythromycin, amoxicillin, ofloxacin, tetracycline, metoprolol, triclosan, salicylic acid, N, N diethyl-meta-toluamide, caffeine and β-Estradiol) belongs to eight different classes in an urban stretch of River Ganges were detected for three seasons in two holy cities Rishikesh and Haridwar (India). The overall concentration of PPCPs in the River Ganges ranged between Below Detectable Limit (BDL) to 1104.84 ng/L, with higher concentrations at anthropogenically influenced lower reaches of the River Ganges at Haridwar. Acetaminophen, triclosan, N, N diethyl-meta-toluamide (DEET), tetracycline, and caffeine showed the highest detection frequency (>90-100%) in the river. PPCPs concentration, especially for NSAIDs (Ibuprofen, ketoprofen and acetaminophen), antibiotics (ciprofloxacin, tetracycline and ofloxacin) and metabolite (salicylic acid) was found to be higher in winter compared to summer in the Ganges, possibly due to the lower biodegradation efficiency related to lesser temperatures and inadequate sunlight. While metoprolol (beta-blockers), triclosan (antibacterial), DEET (insect repellent) and caffeine (human indicator) showed a higher load in summer, possibly due to their intense uses during this period. Results of risk quiescent (RQ) revealed higher ecological risk for algae while the moderate risk for river fish biota.

Epidemiology and diagnosis, environmental resources quality and socio-economic perspectives for COVID-19 pandemic

The COVID-19 pandemic caused by SARS-CoV-2 has emerged as a global issue of concern for public health, environment and socio-economic setup. This review addresses several aspects of epidemiology, and pathogenesis, environmental resource quality (air quality, hazardous waste management, and wastewater surveillance issues), and socio-economic issues worldwide. The accelerated research activity in the development of diagnostic kits for SARS-CoV-2 is in progress for the rapid sequencing of various strains of SARS-CoV-2. A notable reduction in air pollutants (NO2 and PM2.5) has been observed worldwide, but high air polluted cities showed intense mortalities in COVID-19 affected areas. The use of health safety equipment halted transportation, and work-from-home policy drastically impacted the quantity of solid and hazardous wastes management services. Wastewater appeared as another mode of enteric transmission of SARS-CoV-2. Thus, wastewater-based surveillance could act as a mode of the data source to track the virus's community spread. The pandemic also had a substantial socio-economic impact (health budget, industrial manufacturing, job loss, and unemployment) and further aggravated the countries' economic burden.

Occurrence, fate, and persistence of emerging micropollutants in sewage sludge treatment

Sludge generated at sewage treatment plants is of environmental concern due to the voluminous production and the presence of a high concentration of emerging contaminants (ECs). This review discusses the fate of ECs in sewage sludge treatment with an emphasis on fundamental mechanisms driving the degradation of compounds based on chemical properties of the contaminant and process operating conditions. The removal of ECs in sewage sludge through various treatment processes of sludge stabilization, such as anaerobic digestion (AD), composting, and pre-treatment methods (thermal, sonication, and oxidation) followed by AD, are discussed. Several transformation mechanisms and remediation strategies for the removal of ECs in sludge are summarized. The study concludes that pH, sludge type, and the types of functional groups are the key factors affecting the sorption of ECs to sludge. During conventional waste stabilization processes such as composting, the degradation of ECs depends on the type of feedstock (TOC, N, P, C/N, C/P) and the initial concentration of the contaminant. In AD, the degree of degradation depends on the hydrophilicity of the compound. The estrogenicity of the sludge may sometimes increase due to the conversion to estrogenic compounds. The pre-treatment techniques can increase the partitioning of ECs in the soluble fraction resulting in enhanced biodegradation up to 10-60%. However, the formation of by-products and loss of OH· to scavenging under high organic content during advanced oxidation processes can make the process uneconomical and require further research.

Production of compost with biopesticide property from toxic weed Lantana: Quantification of alkaloids in compost and bacterial pathogen suppression

Toxic weed Lantana camara foliage was composted with cow dung in 2:1 and 1:1 ratio (v/v) and changes in physicochemical characteristics, and faecal coliform bacterial population (Escherichia coli and Salmonella) was estimated for 35 d. Results showed a significant increase in total N (1.48-1.69-folds), Paval (6.87-9.19-folds), and total K (1.08-1.23-folds) content, while a decrease in C/N ratio (1.87-2.13-folds) and total organic carbon (1.12-1.46-folds) after composting process. Germination index (GI) results (> 70 %) suggested the non-toxic property of Lantana compost against tested rapeseed mustard seeds. E. coli and Salmonella population reduced to the safe limit after 35 d composting. Compost extract (sterilized and non-sterilized) (from 2:1 setup) showed about 0.88 - 1.08-, 0.88 - 0.96-, 0.83 - 0.94-, and 0.79-1.08-folds higher inhibition in Xanthomonas citrus, Xanthomonas campestris, Erwinia carotovora, and Pseudomonas aerogenosa, respectively, indicating strong pathogen-inhibiting substances in Lantanacompost. GC-MS analysis of compost extract indicated the presence of isomers of several compounds of biocidal property - hexadecane (9-hexyl and 9-octyl); 2-tridecyl ester; eicosane; tetradecane, heptacosane (1-chloro- and 9-hexyl); heptadecane, octadecane, 3-ethyl-5-(2-ethylbutyl)-, heptacosane, tetradecane, 2,6,10-trimethyl-, etc.). Result revealed that Lantana compost could be used as biomanure with biopesticide properties for sustainable organic farming system.

Ti-pillared montmorillonite clay for adsorptive removal of amoxicillin, imipramine, diclofenac-sodium, and paracetamol from water

The adsorptive removal of natural montmorillonite (MMT) clay pillared with titanium oxide (Ti-PILC) was examined in this study to see the adsorptive remove of pharmaceutical compounds (PCs): amoxicillin (AMOX), imipramine (IMP), Diclofenac-Sodium (DIF-S), and paracetamol (PCM) from water under a batch-scale study. The post-intercalation changes in clay were investigated with various surface and structural analysis techniques. The results confirm an increase in the surface area, microporosity, and acidic sites (lewis acid) which improved and regulates Ti-PILC interactions with electron-rich PPCPs molecules. The FTIR bands for Si-OH and Al-OH show a shift in MMT, after pillaring, indicates the intercalation of Ti pillared in its interlayer space. The isotherms studies suggested the best fitting of Redlich Peterson models for all pharmaceutical adsorption data. The Langmuir adsorption (maximum) was recorded for Ti-PILC in the order: 82.68 (IMP) > 23.05 (DIF-S) > 20.83 (PCM) > 4.26 (AMOX) mg.g^-1 at a fixed adsorbent dose i.e. 0.1 g·L^-1. The PCs adsorption kinetics was also evaluated by Pseudo-first-, and second-order model and results showed the best curve fitting for all PCs. Results of regeneration studies showed that modified Ti-PILC could be a low-cost cleaner material for adsorption of pharmaceuticals from water.

Composting of toxic weed Parthenium hysterophorus: Nutrient changes, the fate of faecal coliforms, and biopesticide property assessment

This study aimed to investigate; composting of toxic weed Parthenium with cow dung in (2:1, and 1:1 ratio); and the changes in Escherichia coli and Salmonella population; as well as the antimicrobial property of ready compost. Organic carbon decreased by 45-52% while total nitrogen, total potassium, available phosphorus increased by 1.87- to 3.21-, 1.65- to 1.83-, and 4.03- to 3.33-folds, respectively in Parthenium setups. Germination index value (110-132%) indicates no phytotoxicity of composted Parthenium. E. coli reduced by 6.87 to 6.90 log population (<1000 CFU g^-1, safe limit) while Salmonella was in non-detectable limit in compost samples. Results of the antimicrobial test indicate a strong biocidal activity by non-sterilized compost extract against plant pathogens Xanthomonas citrus, Xanthomonas campestris, and Erwinia carotovora. Xanthomonas spp. It is concluded that thermophilic composting could convert Parthenium into a product with biomanure and biopesticide property for sustainable agriculture production.

Vermicomposting of invasive weed Ageratum conyzoids: Assessment of nutrient mineralization, enzymatic activities, and microbial properties

Ageratum conyzoids biomass was vermicomposted with cow dung in 25 (T₂₅), 50 (T₅₀), and 75 (T₇₅) % (v/v) ratios and changes in physicochemical characteristics, enzymatic activities (proteases, dehydrogenases, β-galactosidase and phosphatases), and microbial population (bacterial, fungal, and actinomycetes) was recorded. Vermicomposting caused a decrease in pH, OC_total (27.3-35.3%), but an increase in N_total (59.6-69.9%), P_aval (53.8-148.7%), K_total (32.2-92.43%), and Ca_total (25.5-55.3%). The peaked enzymatic activities were recorded between 5 and 15 d. T₅₀ and T₇₅ showed the highest fold increase in bacteria (2.09-to-2.51), fungi (1.48-to-2.41), actinomycetes (1.52-to-1.79) population. The maximum biomass (883.67-1480 mg), cocoon production (85.33-145.33), and population build-up in earthworm were recorded in setups with a high content of Ageratum. Germination index (>80%) and soil respiration rate suggested the non-toxic impact of vermicomposted Ageratum. Results indicate that Ageratum could be biotransformed into toxic-free manure through vermitechnology.

Vermicomposting of duckweed (Spirodela polyrhiza) by employing Eisenia fetida: Changes in nutrient contents, microbial enzyme activities and earthworm biodynamics

This study investigated the vermicomposting of duckweed (DW) mixed with cow dung in 25 (T₂₅), 50 (T₅₀), 75 (T₇₅), 100% (T₁₀₀) ratio using Eisenia fetida under a 35 d trail. Decrease in pH, organic carbon (33.54-38.25%), C/N ratio (43.6-56.6%), but increase in total N (18.2-42.4%), P_aval (137-187%), and TK (7.76-79.4%) was recorded. Macro-elements (Mg, Fe, Zn, Mn, and Cu) also showed a many-fold increase in vermicomposts. T₅₀ and T₇₅ showed the highest mineralization rates. Activities of enzymes (proteases; dehydrogenases; β-galactosidase; acid phosphatase; and alkali phosphatases) and soil respiration rate was also higher in DW-rich waste mixtures. Seed bioassay test indicates the high agronomic application of DW-based vermicomposts. High earthworm biomass (975-1395 mg) and fecundity rate (1.53-4.07 cocoons worm^-1) was recorded in all vermi-setups suggesting the suitability of DW as a substrate for E. fetida culture.

Challenges, opportunities and progress in solid waste management during COVID-19 pandemic

At the end of December 2019, Wuhan City became the epicenter of the highly contagious virus known as the novel coronavirus. Now that mid-2020 has already passed, almost every country is adversely affected by Corona Virus Disease (COVID-19). The routine activities of people of all ages are overturned, which has led to a shift in the trends of waste created by households, streets, and most importantly, medical facilities and quarantine centers. Compulsive use of personal protection equipment such as masks, gloves, sanitizers, etcetera by the frontline workers from the medical sector, banks, daily need stores, waste collection industries, etc. and the use of masks by every common man stepping out has skewed the trend of waste generation to a different direction. Recently, the replacement of single-use plastic was accepted by the masses, and the pandemic suddenly rebounded to the previous situation, it is expected to be worse in the long run. Another secondary outcome is reduced waste collection and recycling due to lockdown, leading to a pile-up of wastes. But several nations are adopting strategies to break the transmission chain of the virus by trying to minimize human contact. The study discusses the effect of COVID-19 on the generation, recycling, and disposal of solid waste. A brief collection of different countries' efforts to restrict the transmission of virus through solid waste is also discussed.

Phytotoxicity and degradation of antibiotic ofloxacin in duckweed (Spirodela polyrhiza) system

The phytotoxicity and degradation of ofloxacin (OFX) in duckweed Spirodela polyrhiza based system was estimated in this study. For that, OFX was added in an environmentally relevant range (0.01-1.0 mg L^-1) in medium (Hoagland nutrient) and toxicity biomarkers, i.e. changes in plant biomass, relative growth rate (RGR), photopigment (Chl-a, Chl-b and carotenoids), protein content, antioxidative enzymes (catalase, CAT; superoxide dismutase, SOD; and ascorbate peroxidases, APX) in fronds were estimated. The batch-scale setups (250 ml) was prepared in triplicate for each concentration of OFX and reared in growth chambers (Algae Tron AG 230) for 7 d. Results suggested that the high concentrations of OFX caused a reduction in biomass (4.8-41.3%), relative root growth (RGR), protein (4.16-11.28%) and photopigment contents. The fronds in OFX spiked setups showed an increased level of antioxidative enzymes: CAT (0.230-0.338 mmol_H2O2 mg^-1 protein), APX (0.043-0.074 mmol_ascorbate mg^-1 protein), and SOD (0.267-0.317 U mg^-1 protein) than control. At the end (7 d), the residual OFX content in the medium was also estimated, and results suggested a significant (p < 0.05) reduction (93.73-98.36%) in OFX content than control setup (54.76-75.53%) at the end of the experimentation. The trend of residual OFX suggested phytodegradation as a significant mechanism of antibiotic degradation other than hydrolysis and photodegradation processes. This study indicates that duckweed can be an effective bio-tool for the removal of environmental relevant concentration of the antibiotics from the wastewater.

Groundwater nitrate contamination and associated human health risk assessment in southern districts of Punjab, India

Consumption of high NO₃ containing water may pose serious health hazard especially in children (< 5 years). The source of NO₃ in groundwater includes surface leaching from wastewater and waste dump sites, animal excreta disposal, industrial effluents, and N-based fertilizers, etc. This study aimed to investigate the concentration of NO₃ in groundwater of 14 intensively cultivated districts of Malwa Punjab, India, and its possible health hazards in local residents. The sampling of 76 sites revealed the concentration of NO₃ in ranges of 38.45-198.05 mgL^-1, and over 92% sites showed the high level of it than the safe limits as decided by the Bureau of Indian standards (45 mg L^-1) and World Health Organization (50 mg L^-1). The possible health hazards of high NO₃ intake was estimated using USEPA human health risk assessment (HHRA) model for both adult and children. Results of this study suggested the chronic daily intake (CDI) in the ranges of 1.09-5.65 and 2.56-13.20 in adult and children population of this region, respectively. The hazard quotient (HQ_nitrate) value was > 1 in most sampling locations ranging 1.09-5.65 for the adult and 2.56-13.20 for children population of Malwa. This study indicates that 93.42% adult and 100% young population of the Malwa are at higher risk of chronic toxicity by excess NO₃ intake. The HHRA results suggested a high vulnerability of a local community to NO₃ toxicity in this region; therefore, there is an instant need to take preventive measures to safeguard the health of local residents.

Phytotoxicity of amoxicillin to the duckweed Spirodela polyrhiza: Growth, oxidative stress, biochemical traits and antibiotic degradation

The increasing availability of antibiotics in wastewater has created a serious threat to non-target organisms in the environment. The aim of this study was to evaluate the potential toxicity of amoxicillin on duckweed Spirodela polyrhiza during a short-term exposure (7 d). The duckweed was exposed to a range of environmentally relevant (0.0001-0.01 mg L^-1) and high (0.1 and 1 mg L^-1) concentrations of amoxicillin. Subsequently, biomarkers of toxicity such as growth, pigments (Chl a, Chl b and carotenoids), antioxidative enzyme activity (catalase, CAT; superoxide dismutase, SOD; and ascorbate peroxidases, APX), and biochemical content (protein, lipid and starch) were analysed in their fronds. The high dose (1 mg L^-1) of amoxicillin caused a significant (p < 0.05) decrease in photopigments, protein, starch and lipid content and an increase in carotenoids/total Chl and Chl a/Chl b ratios in fronds of Spirodela polyrhiza. The results showed a shift in biomarkers: a decrease in frond growth and relative growth rate (RGR) (16.2-53.8%) and an increase in the activities (mmol mg protein^-1) of CAT (0.021-0.041), APX (0.84-2.49) and SOD (0.12-0.23) in fronds. The significantly (p < 0.05) greater reduction in amoxicillin content in duckweed setups (84.6-100%) than in the control (62.1-73%) suggested that phytodegradation is an important mechanism in removing antibiotics from water, apart from hydrolysis and photodegradation, which occur in control setups. Overall, the results suggested a toxic effect of amoxicillin on Spirodela polyrhiza, even at low concentrations, and nonetheless, the duckweed contributed directly to the degradation of antibiotics in the water and throughout the phytoremediation process.

Effect of thermal pre-treatment on co-digestion of duckweed (Lemna gibba) and waste activated sludge on biogas production

The duckweeds (DW) are considered as a major problem in tropical aquatic system as they grow very fast and produce enormous rich-biomass, which can be harvested for renewable energy operations. But complex lignocellulosic compounds limit their utility in process like anaerobic digestion. This batch study aimed to analyse characteristics (proximate, ultimate and physico-chemical) and possible utility of DW for anaerobic co-digestion with waste activated sludge (WAS) under mesophilic conditions for 35 d. Two sets of experiment were tested: substrate with and without thermal pre-treatment. Five combinations of DW: WAS (70:20, 60:20, 50:20, 40:20 and 30:20%) were established and biomethanation along with changes in pH, volatile solids (VS), volatile fatty acids (VFAs), and soluble chemical oxygen demand (sCOD) of digestate were recorded. The total CH₄ yield (mL CH₄ g^-1 VS) ranged between 60 and 468 for pre-treated, and 9 and 76 for non-pre-treated. The maximum CH₄ yield was 468 mL CH₄g^-1 VS in DW: WAS (50:20). Thermally treated setups, showed about 13-, 24.1-, 21.1-, 1.4-, and 2.3-fold higher CH₄ than non-treated setups. The treated mixtures showed high reduction of _SCOD (>41-96) and VS (>59-98%) in co-digesters. The high degree of Gompertz curve fitting (R² > 0.99) has suggested pre-treatment of substrate for optimal outputs of co-digester. Based on results obtained, it is suggested that DW (50-60% in digester) can be used as renewable energy resource for biomethanation process after thermal pre-treatment.

Nutrient changes and biodynamics of Eisenia fetida during vermicomposting of water lettuce (Pistia sp.) biomass: a noxious weed of aquatic system

This paper reports the results of vermicomposting of water lettuce biomass (WL) spiked with cow dung at ratios of 20, 40, 60, and 80 % employing Eisenia fetida. A total of four treatments were established and changes in chemical properties of mixtures were observed. Vermicomposting caused a decrease in pH, TOC, volatile solids, and C/N ratio by 1.01-1.08-fold, 0.85-0.92-fold, 0.94-0.96-fold, 0.56-0.70-fold, respectively, but increase in EC, _totN, _totP, _totK, _totCa, _totZn, _totFe, and _totCu, by 1.19-1.42-fold, 1.33-1.68-fold, 1.38-1.69-fold, 1.13-1.24-fold, 1.04-1.11-fold, 1.16-1.37-fold, 1.05-1.113-fold, 1.10-1.27-fold, respectively. Overall, the treatment with 60-80 % of WL showed the maximum decomposition and mineralization rates. The earthworm showed the growth and reproduction rate in considerable ranges in all treatment setups but setups with 60-80 % WL proportion exhibited the optimum results. Results reveal that biomass of water lettuce can be utilized effectively for production of valuable manure through vermicomposting system.

Dynamics of microbiological parameters, enzymatic activities and worm biomass production during vermicomposting of effluent treatment plant sludge of bakery industry

This paper reports the changes in microbial parameters and enzymatic activities during vermicomposting of effluent treatment plant sludge (ETPS) of bakery industry spiked with cow dung (CD) by Eisenia fetida. Six vermibins containing different ratios of ETPS and CD were maintained under controlled laboratory conditions for 15 weeks. Total bacterial and total fungal count increased upto 7th week and declined afterward in all the bins. Maximum bacterial and fungal count was 31.6 CFU × 10(6) g(-1) and 31 CFU × 10(4) g(-1) in 7th week. Maximum dehydrogenase activity was 1921 μg TPF g(-1) h(-1) in 9th week in 100 % CD containing vermibin, whereas maximum urease activity was 1208 μg NH4 (-)N g(-1) h(-1) in 3rd week in 100 % CD containing vermibin. The enzyme activity and microbial counts were lesser in ETPS containing vermibins than control (100 % CD). The growth and fecundity of the worms in different vermibins were also investigated. The results showed that initially biomass and fecundity of the worms increased but decreased at the later stages due to non-availability of the palatable feed. This showed that quality and palatability of food directly affect biological parameters of the system.

Vermiremediation of heavy metals in wastewater sludge from paper and pulp industry using earthworm Eisenia fetida

This work presents the results of removing heavy metals from paper mill wastewater (PMS) sludge spiked with cow dung (CD) employing Eisenia fetida. A total of seven set-ups were prepared: CD (100 percent), PMS: CD (1:3), PMS:CD (1:2), PMS:CD (1:1), PMS (100 percent), PMS:CD (3:1) and PMS:CD (2:1) and changes in chemical parameters were observed for 60 days. Vermistabilization caused the significant decrease in the level of Cd (32-37 percent), Cr (47.3-80.9 percent), Cu (68.8-88.4 percent), and Pb (95.3-97.5 percent) and substantial increase in EC, total-N, available P and K at the end. At the end, the tissues of inoculated worms showed the high load (mg kg(-1), dry biomass) of Pb (8.81-9.69), Cd (2.31-2.71), Cr (20.7-35.9) and Cu (9.94-11.6), respectively which indicated bioaccumulation of metals by worms. The PMS:CD (2:1 and/or 3:1) appeared to be suitable waste mixture in terms of high metal removal and earthworm growth rates. Bioaccumulation, as quantified using BCF, was in the order: Cd>Cr>Pb>Cu. Results suggested vermiremediation as appropriate technology for bioremediation of heavy metals from PMS.

Vermicomposting of toxic weed--Lantana camara biomass: chemical and microbial properties changes and assessment of toxicity of end product using seed bioassay

This work illustrates the results of vermicomposting trials of noxious weed - Lantana camara (LL) leaf litter spiked with cow dung (CD) in different ratios (0%, 20%, 40%, 60% and 80%) using Eisenia fetida. A total of five treatments were established and changes in chemical and microbial properties of vermibeds have been observed for 60 days. In all treatments, a decrease in pH (19.5-30.7%), total organic carbon (TOC) (12-23%) and C:N ratio (25-35%), but increase in ash content (16-40%), total N(N(tot)) (11-32%), available phosphorous (P(avail)) (445-629%), exchangeable potassium (K(exch)) (63-156%) exchangeable calcium (Ca(exch)) (67-94%),and N-NO3(-) (164-499%) was recorded. Vermibeds with 40-60% LL (T2 and T3) showed better mineralization rate. The number of fungi, bacteria and actinomycetes showed 0.33-1.67-fold, 0.72-2.33-fold and 2.03-2.99-fold increase, respectively after vermicomposting process. The germination index (GI) was between 47% and 83% in all vermicomposts as indicated by seed bioassay test. Results thus suggested that Lantana may be a potential source for vermicompost production for sustainable agriculture.

Management of food industry waste employing vermicomposting technology

This paper reports the vermicomposting of food industry sludges (FIS) mixed with different organic wastes employing Eisenia fetida. A total of 10 vermicomposting units containing different wastes combinations were established. After 15 weeks significant increase in total nitrogen (N(total)) (60-214%), total available phosphorous (P(avail)) (35.8-69.6%), total sodium (Na(total)) (39-95%), and total potassium (K(total)) (43.7-74.1%), while decrease in pH (8.45-19.7%), total organic carbon (OC(total)) (28.4-36.1%) and C:N ratio (61.2-77.8%) was recorded. The results indicated that FIS may be converted into good quality manure by vermicomposting if spiked with other organic wastes in appropriate quantities.

Vermicomposting of milk processing industry sludge spiked with plant wastes

This work illustrates the vermistabilization of wastewater sludge from a milk processing industry (MPIS) unit spiked with cow dung (CD), sugarcane trash (ST) and wheat straw (WS) employing earthworms Eisenia fetida. A total of nine experimental vermibeds were established and changes in chemical parameters of waste material have been observed for 90 days. Vermistabilization caused significant reduction in pH, organic carbon and C:N ratio and substantial increase in total N, available P and exchangeable K. The waste mixture containing MPIS (60%)+CD (10%)+ST (30%) and MPIS (60%)+CD (10%)+WS (30%) had better waste mineralization rate among waste mixtures studied. The earthworm showed better biomass and cocoon numbers in all vermibeds during vermicomposting operation. Results, thus suggest the suitability of E. fetida for conversion of noxious industrial waste into value-added product for land restoration programme.

Vermicomposting of herbal pharmaceutical industry waste: earthworm growth, plant-available nutrient and microbial quality of end materials

Efforts were made to decompose herbal pharmaceutical industrial waste (HPIW) spiked with cow dung (CD) using Eisenia fetida. A total of five vermibeds: T(1) - HPIW (0%+CD 100%, control), T(2) - HPIW (25%), T(3) - HPIW (50%), T(4) - HPIW (75%) and T(5) - HPIW (100%) were used for vermicomposting. The changes in biology and chemistry of vermibeds were measured after ten days interval. E. fetida showed high growth and cocoon production rate in all vermibeds. The vermicomposted material contained great population of fungi 6.0-40.6 (CFU × 10(5)g(-1)), bacteria 220-1276.0 (CFU × 10(8)g(-1)) and actinomycetes 410.0-2962.0 (CFU × 10(5)g(-1)) than initial material. Vermicomposted material was rich in plant-available forms of nutrients (N-NO(3)(-),PO(4)(3-),available K and SO(4)(-2)). Results suggested that noxious industrial waste can be converted into valuable product for sustainable soil fertility programme.

Earthworm production in cattle dung vermicomposting system under different stocking density loads

INTRODUCTION

This work illustrates the productivity of composting earthworm Perionyx excavatus under different stocking density (in milligrams biomass per cubic centimeter vermibed space) gradients in cattle dung decomposing system.

MATERIALS AND METHODS

Earthworm biomass and reproduction performance was tested in vermibeds with five different stocking density loads: 0.0680 mg cm⁻³ (T₁), 0.1388 mg cm⁻³ (T₂), 0.205 mg cm⁻³ (T₃), 0.274 mg cm⁻³ (T₄), and 0.342 mg cm⁻³ (T₅).

RESULTS AND CONCLUSION

Results thus suggested the direct relationship between earthworm performance and stocking density load in vermicomposting system. P. excavatus showed the maximum individual biomass production in low-stocking density trials, while cocoon production rate was better in vermibeds with high-density trials. The statistical interrelationships between stocking density load and individual growth parameters of inoculated earthworms were also tested. The statistical interpretation also suggested the impact of stocking density load on earthworm growth and reproduction parameters in vermicomposting system, although further detailed studies are required to measure the earthworm growth behavior under the maximum carrying capacity load of a vermibed.

Phytotoxicity of composted herbal pharmaceutical industry wastes

This work demonstrates the phytotoxicity screening of composted herbal pharmaceutical industry waste (HPIW) using seed bioassay method. The composted industrial waste should be tested at lab scale prior to recommendation for land application. HPIW was mixed with soil to produce four treatments: T(1) (1:1), T(2) (1:2), T(3) (1:3), and T(4) (1:0) for toxicity screening using Pisum sativum seeds. After 72 h relative seed germination (RSG), relative root growth (RRG) and germination index (GI) were recorded. Seedlings were observed for further plant growth and tissue biochemistry (chlorophyll, soluble sugar, starch, carotenoid, and protein) estimation. RSG, RRG, and GI values were better in T(1) and T(2) than others. GI was in the ranges of 36.62 % (T(4)) to 170.38 % (T(2)). The seedling growth and biochemical parameters were better in seedling obtained from potting media containing low proportion of HPIW (i.e., T(1) and T(2)). Results clearly suggested that composted HPIW may be utilized effectively for crop production after dilution under sustainable farming system program.

Contaminated drinking water and rural health perspectives in Rajasthan, India: an overview of recent case studies

Access to safe drinking water is an important issue of health and development at national, regional, and local levels. The concept of safe drinking water assumes greater significance in countries like India where the majority of the population lives in villages with bare infrastructures and poor sanitation facilities. This review presents an overview of drinking water quality in rural habitations of northern Rajasthan, India. Although fluoride is an endemic problem to the groundwater of this region, recently, other anthropogenic chemicals has also been reported in the local groundwater. Recent case studies indicate that about 95% of sites of this region contain a higher fluoride level in groundwater than the maximum permissible limit as decided by the Bureau of Indian Standards. Nitrate (as NO3-) contamination has appeared as another anthropogenic threat to some intensively cultivable rural habitations of this region. Biological contamination has appeared as another issue of unsafe drinking water resources in rural areas of the state. Recent studies have claimed a wide variety of pathogenic bacteria including members of the family Enterobacteriaceae in local drinking water resources. Overall, the quality of drinking water in this area is not up to the safe level, and much work is still required to establish a safe drinking water supply program in this area.

Potential of domestic biogas digester slurry in vermitechnology

This work illustrates the potential of domestic biogas digester slurry in vermicompost production. To achieve the objectives biogas plant slurry (BGS) was mixed with crop residues (CR) in different ratios to produce seven different feed mixtures for earthworm Eisenia fetida. After 15weeks vermicomposted material was analyzed for different chemical parameters. In all waste mixtures, a decrease in pH, organic C and C:N ratio, but increase total N, available P and exchangeable K was recorded. C:N ratio of end material (vermicompost) was within the agronomic acceptable limit (<20). The reproduction biology of E. fetida in different waste mixture was also monitored and they showed excellent biomass gain as well as cocoon production in all waste mixtures. The results clearly suggested that vermitechnology could be a potential technology to convert byproducts of domestic biogas plant slurry into some value-added products.

Water quality assessment of river Hindon at Ghaziabad, India: impact of industrial and urban wastewater

River Hindon is a major source of water to the highly populated and predominantly rural population of western Uttar Pradesh, India. The main goal of the present study was to assess the impact of urban and industrial activities on the water quality of river Hindon at the Ghaziabad. For this, river water samples were collected from six different sites all along the route of Hindon main streamline and its branch and were analyzed for pH, turbidity, electrical conductivity (EC), total dissolved solids (TDS), total alkalinity (TA), total hardness (TH) and calcium hardness (Ca-H), chemical oxygen (COD) demand, biochemical oxygen demand (BOD), dissolved oxygen (D.O.), sulphate (as SO(4)(2-)), nitrate (as NO(3)(-)) and chloride (Cl-) levels. There were drastic variations for EC (0.83-5.04 ms), turbidity (28.7-109.3 NTU), TDS (222.2-2426.3 mg l(-1)), SO(4) (36.4-162.4 mg l(-1)), NO(3) (106-245 mg l(-1)), TA (347.0-596.3 mg l(-1)), TH (235.1-459.9 mg l(-1)), Ca-H (64.5-402.2 mg l(-1)), BOD (27-51 mg l(-1)) and COD (85.0-337.4 mg l(-1)) levels at different sites. Water pollution indicating parameters were manifold higher than the prescribed limit by the National Pollution Control Agency, i.e. CPCB. This is the first study on itself and the interrelationship of human activities and river water quality makes the study significant and interesting to assess the pollution load discharges in catchments of Hindon at Ghaziabad. Overall, the water quality of Hindon was relatively poor with respect to its use for domestic purposes.

Potential of Allolobophora parva (Oligochaeta) in vermicomposting

The aim of this study was to assess the potential of Allolobophora parva Eisen as a candidate for vermicomposting practices. Five organic waste mixtures: cow dung (CD), biogas plant slurry (BGS), cow dung+vegetable waste (CD+VW), BGS+VW and VW+Soil were vermicomposted using A. parva. Vermicomposting showed a decrease in pH, organic C and C:N ratio, but increase total N, available P and exchangeable K at the end. C:N ratio of end material (vermicompost) was within the agronomic acceptable limit (<20). The high level of NPK in worm-processed material indicates the candidature of this species for waste management operations. The earthworm also showed an excellent growth in different wastes. Results thus indicate that A. parva appeared a potential tool for conversion of organic wastes into value added products for sustainable land restoration practices.

Bacterial contamination in drinking water: a case study in rural areas of northern Rajasthan, India

The objective of this study was to determine the bacterial contaminations in drinking water samples collected form some rural habitations of northern Rajasthan, India. A total of ten bacterial species: Escherichia coli, Pseudomonas aeruginosa, Enterobacter aerogenes, Klebsiella sp, Proteus vulgaris, Alcaligenes faecalis, Bacillus cereus, Staphylococcus aureus, Streptococcus lactis and Micrococcus luteum were identified form drinking water samples. The bacteria belonging to the family enterobacteriaceae (coliforms) showed the maximum occurrences in water samples. The total coliforms count, i.e. TTC(m) (m = MPN index/100 ml) in drinking water samples was in the ranges of 25 TTC(m) (village Naiwala)-41 TTC(m) (village Meharwala). The data suggested that the drinking water quality deterioration in rural habitations of this region was due to poor sanitation and unawareness about personal hygienic practices. The occurrences some pathogenic bacteria in drinking water may increase the risks of water-related diseases and health problems in local residents.

Nitrate contamination in groundwater of some rural areas of Rajasthan, India

Efforts were made to evaluate the level of nitrate in some agro-economy based rural habitations of northern Rajasthan, India. A total of 64 groundwater samples from 21 different villages/sub-villages of district Sri Ganganagar, India were collected and analyzed for nitrate (as NO(3)(-)), sulphate (as SO(4)(2-)) and few other parameters. NO(3)(-) level in groundwater was 7.10-82.0 mg l(-1) for individual samples. But average NO(3)(-) for total samples was 60.6+/-33.6 (SD) mg l(-1), which indicates the non-suitability of groundwater for drinking purposes, if BIS permissible limit (22.6 mg l(-1)) is considered as reference level. SO(4)(2-) ranged form 28.6 to 660.3 mg l(-1) in this area. The regression analysis indicates the difference sources for NO(3)(-) and SO(4)(2-) contamination in different regions rather than a common source. The point and non-point sources of NO(3)(-) and SO(4)(2-) in groundwater of this region may be N-fertilizer, sewerage, animal waste, organic manure, geology of sub-surface soil layers, pit latrines, etc. Results thus indicated that groundwater of this part of the State is severely polluted due to anthropogenic activities. The continuous consumption of such water may pose serious health hazardous in local residents.

Assessment of metals in water and sediments of Hindon River, India: impact of industrial and urban discharges

The aim of this study was to assess the level of heavy metals (Cd, Cr, Cu, Fe, Mn, Zn and Pb) in water and sediments of Hindon River in industrialized city Ghaziabad, India. A total of 6 stations, covering the upstream and downstream sites of Hindon, were selected for this study. Metal concentration (mgkg(-1)) ranged: Cd, 1.15-3.47; Cu, 9.42-195.1; Cr, 42.9-250.4; Fe, 221.2-237.9; Mn, 61.0-201.7; Zn, 3.98-85.0; and Pb, 5.07-59.1 in river sediments. The enrichment factor (%) for sediment ranged from 0.05 to 99.8% at point and non-point polluted stations of Hindon. The geoaccumulation index (I(geo)) suggested "unpolluted to moderate pollution" of Mn, Pb and Zn (I(geo)<1), "moderate pollution" of Cu, Cr, Fe (I(geo)<2), and "very strong pollution" of Cd (I(geo)>5) in River Hindon at Ghaziabad city. The industrial and urban discharges in river catchment areas were the major sources of heavy metals in river.

Vermistabilization of municipal sewage sludge amended with sugarcane trash using epigeic Eisenia fetida (Oligochaeta)

Efforts have been made in this study to stabilize the sewage sludge mixed with sugarcane trash in four different proportions: 20% (T(1)); 40% (T(2)); 60% (T(3)) and 80% (T(4)), under laboratory conditions using epigeic earthworm (Oligochaeta) Eisenia fetida. The composting potential of worm was also evaluated in 100% sewage sludge treatment (T(5)). The changes in chemical properties of substrate was measured at the end. The vermicomposted material showed decrease in organic C (4.8-12.7%) and exchangeable K (3.2-15.3%) content, whereas increase in total N (5.9-25.1%) and available P (1.2-10.9%), exchangeable Ca (2.3-10.9%) and exchangeable Mg (4.5-14.0%) contents. Vermicomposting process caused considerable reduction in concentration of diethylene-triaminepentaacetic acid (DTPA) extractable metals: Cu (4.98-30.5%), Fe (5.08-12.64%), Mn (3.31-18.0%), Zn (2.52-15.90%) and Pb (2.38-20.0%). E. fetida showed the better growth performances in first three treatments (T(1)-T(3)) possibly due to higher content of organic matter (supplied by bulking agent, i.e. sugarcane trash). The earthworm mortality was higher in vermibeds those contained more sludge proportions. Study revealed that vermicomposting might be an efficient technology to convert negligible municipal sewage sludge into value-added products. The feasibility of earthworms to mitigate the metal toxicity and to enhance the nutrient profile might be useful to convert noxious sludge into useful products, at low-input basis.

Bioconcentrations of metals (Fe, Cu, Zn, Pb) in earthworms (Eisenia fetida), inoculated in municipal sewage sludge: do earthworms pose a possible risk of terrestrial food chain contamination?

Efforts have been made to evaluate the possible risks of metal bioaccumulation in composting earthworms during vermicomposting of hazardous wastes, e.g., sewage sludge. The sewage sludge was diluted by mixing cow dung in different proportions, and vermicomposted sludge as well as inoculated earthworms were analyzed for metal (Fe, Cu, Zn, Pb) contents. The sludge processed by worms showed a significant reduction in concentration of metals, Cu (29.4-51.6%), Fe (13.1-19.9%), Zn (15.2-25.8%), and Pb (4.6-46.9%), at the end. A considerable concentration of metals, total Cu (16.7-27.6 mg kg(-1)), total Fe (42.9-89.8 mg kg(-1)), total Zn (5.85-75.0 mg kg(-1)), and total Pb (1.79-12.4 mg kg(-1)), in composting earthworms was also recorded. The greater values of bioconcentration factors for metals suggested the possible risk of entering contaminants in higher food chains; since, earthworms are near to the terrestrial food chain, they can potentially mediate metal transfer from soil to a range of predators, including birds. Therefore, feasibility of vermitechnology in hazardous waste recycling needs close attention in respect to possible risk of environmental contamination.

Fluoride contamination in drinking water in rural habitations of northern Rajasthan, India

This study was carried out to assess the fluoride concentration in groundwater in some villages of northern Rajasthan, India, where groundwater is the main source of drinking water. Water samples collected form deep aquifer based hand-pumps were analysed for fluoride content. Fluoride in presently studied sites was recorded in the ranges of 4.78 and 1.01 mg/l. The average fluoride concentration for this region was recorded 2.82 mg/l. As per the desirable and maximum permissible limit for fluoride in drinking water, determined by WHO or by Bureau of Indian Standards, the groundwater of about 95 of the studied sites is unfit for drinking purposes. Due to the higher fluoride level in drinking water several cases of dental and skeletal fluorosis have appeared at alarming rate in this region. The middle and eastern parts of the Hanumangarh, a northern most district of the state, can be classified as higher risk area for fluorosis; due to relatively high concentrations of fluoride (3-4 mg/l) in groundwater of this region. After evaluating the data of this study it is concluded that there is an instant need to take ameliorative steps in this region to prevent the population from fluorosis.

Feasibility of vermicomposting in biostabilization of sludge from a distillery industry

The feasibility of vermicomposting technology to stabilize the distillery industry sludge mixed with a bulking agent (cow dung) in different proportions viz. 20% (T1), 40% (T2), 60% (T3) and 80% (T4), was tested using composting earthworm Perionyx excavatus for 90 days. The vermitreated sludge was evaluated for different physico-chemical parameters and all vermibeds expressed a significant decrease in pH (10.5-19.5%) organic C contents (12.8-27.2%), and an increase in total N (128.8-151.9%), available P (19.5-78.3%) as well as exchangeable K (95.4-182.5%), Ca (45.9-115.6%), and Mg contents (13.2-58.6%). Data suggested that inoculated earthworms could maximize the decomposition and mineralization rate, if sludge is used with appropriate bulking material for earthworm feed. Vermicomposting also caused significant reduction in total concentration of metals: Zn (15.1-39.6%), Fe (5.2-29.8%), Mn (2.6-36.5%) and Cu (8.6-39.6%) in sludge. Bioconcentration factors (BCFs) for metals in different treatments were also calculated and the greater values of BCFs indicate the capability of earthworms to accumulate a considerable amount of metals in their tissues from substrate. The reproduction biology of P. excavatus in different treatments was also monitoring during experimentation and they showed the maximum rate of biomass gain, growth (mg weight worm(-1) week(-1)) and cocoon production rate in T2, while least values of these parameters were in T4 treatment. The feasibility of earthworms to mitigate the metal toxicity and to enhance the nutrient profile in sludge might be useful in sustainable land restoration practices at low-input basis.