A holistic review on trend, occurrence, factors affecting pesticide concentration, and ecological risk assessment.

Demographic outbursts and increased food demands invoke excessive use of pesticides in the agricultural field for increasing productivity which leads to the relentless decline of riverine health and its tributaries. These tributaries are connected to a plethora of point and non-point sources that transport pollutants including pesticides into the Ganga river's mainstream. Simultaneous climate change and lack of rainfall significantly increase pesticide concentration in the soil and water matrix of the river basin. This paper is intended to review the paradigm shift of pesticide pollution in the last few decades in the river Ganga and its tributaries. Along with this, a comprehensive review suggests the ecological risk assessment method which facilitates policy development, sustainable riverine ecosystem management, and decision-making. Before 2011, the total mixture of Hexachlorocyclohexane was found at 0.004-0.026 ng/mL in Hooghly, but now, the concentration has increased up to 0.465-4.132 ng/mL. Aftermath of critical review, we observed maximum residual commodities and pesticide contamination reported in Uttar Pradesh > West Bengal > Bihar > Uttara Khand possibly because of agricultural load, increasing settlement, and incompetency of sewage treatment plant in the reclamation of pesticide contamination.

Impact of Pollutant Load from Textile Dyeing Industry Wastewater on Biometric Growth Profile of Vigna radiata.

The phytoremediation of wastewater has certain advantages, but the interactions of soil and crop properties have not been systematically studied. This study aimed to analyze how different concentrations of textile dyeing industry wastewater (25%, 50%, 75%, and 100%) affected soil qualities, growth, and yield attributes (Vigna radiata). In reaction to dyeing effluent at varying concentrations, the seed germination percentage, growth metrics such as tolerance index, phytotoxicity percentage, relative toxicity, extreme and plumule length were calculated. With increasing effluent concentrations, a gradual decrease in the germination of seed and seedling growth was observed. The maximal relative toxicity and percentage of phytotoxicity was 100%. Interaction of biometric growth profile relative seed germination, relative root growth, relative shoot growth, growth index, and seedling vigor index of V. radiata and physicochemical parameter of textile dyeing industry wastewater were also investigated by using the Pearson correlation co-efficient. Principal component analysis (PCA) is helped to obtain and recognize the factors/sources accountability of different concentrations of textile dyeing industry wastewater. The results of the PCA revealed that four components (PC1 to PC4) out of total principal components retained PC1, PC2, with values of 69.25% and 28.85%, respectively.

A comprehensive study on aquatic chemistry, health risk and remediation techniques of cadmium in groundwater.

Cadmium (Cd), a non-essential trace element, it's intrusion in groundwater has ubiquitous implications on the environment and human health. This review is an approach to comprehensively emphasize on i) chemistry and occurrence of Cd in groundwater and its concomitant response on human health ii) sustainable Cd remediation techniques, iii) and associated costs. Current study is depending on meta-analysis of Cd contaminations in groundwater and discusses its distributions around the globe. Literature review primarily comprises from the last three decades online electronic published database, which mainly includes i) research literatures, ii) government reports. On the basis of meta-data, it was concluded that Cd mobility depends on multiple factors: such as pH, redox state, and ionic strength, dissolved organic (DOC) and inorganic carbon (DIC). A substantially high Cd concentration has been reported in Lagos, Nigeria (0.130 mg/L). In India, groundwater is continuing to be contaminated by Cd in the proximity of industrial, agricultural areas, high concentrations (>8.20 mg/L) were reported in Tamil Nadu and Maharashtra. Depending on chemical behavior and ionic radius cadmium disseminate into the food chain and ultimately cause health hazard that can be measured by various index-based assessment tools. Instead of chemical adsorbents, nanoparticles, phytoextraction, and bioremediation techniques can be very useful in the remediation and management of Cd polluted groundwater at a low-cost. For Cd pollution, the development of a comprehensive framework that links the hydro-geological, bio-geochemical processes to public health is important and need to be further studied.

COVID-19 and waste management in Indian scenario: challenges and possible solutions.

The outbreak of COVID-19 pandemic has created havoc all across the globe causing exponential casualties and tremendous health and economic loss. With increasing COVID-19 cases, the amount of biomedical waste has increased manifolds making more people vulnerable to the pandemic. The developing and underdeveloped countries are already facing the challenges of waste management, and the waste generated during the pandemic scenario has added to the already existing challenges. The improper waste management practices need to be corrected; otherwise, the world will be facing a new disaster that could be termed as 'waste disaster'. The increase in COVID-19-associated waste (CAW) quantity and their availability in the environment will result in their easy approach to other organisms, which will possibly increase the potential risk of food chain contamination. Some of the countries have already started to make backup plans and are struggling to overcome the 'waste disaster'. In light of the limited knowledge available on the mutational properties and possible hosts of this newly emerged COVID-19, there is a great demand to have an efficient strategy to prevent the environment from further contamination in India. The necessity of the prevailing time is to create a more efficient, automatic, mechanized, and well-modified waste management system for handling the present situation and delaying the projected waste disaster in the near future in the era of COVID-19. The article aims to address the issues that originated from waste discharges, their potential sources along with possible sustainable solutions.

Potential risk assessment of soil salinity to agroecosystem sustainability: Current status and management strategies.

Soil salinization has become a major global agricultural issue that threatens sustainable development goals related to food security, agriculture, resource conservation, and nutrition. The higher levels of salinity have detrimental effects on soil physico-chemical and biological characteristics and plant metabolism. Also, salinity poses a negative impact on the abundance and distribution of soil microbes and soil-dwelling organisms. Research has always been trying to overcome the salinity issue, but it does not fit well in conventional approaches. This review unravels traditional and modern salinity management techniques. Out of the available salinity management techniques, some are focused on enhancing soil properties (chemical amendments, biochar, earthworms, and their vermicompost, compost, microbial inoculants, electro remediation), some focus on improving plant properties (seed priming, afforestation, crop selection, genetic improvements, agroforestry) and some techniques augment both soil as well as plant properties in a synergic manner. Therefore, it is imperative to find a conclusive solution by integrating traditional and modern methods to find the most effective response to regionally-specific salinity related problems. This review aimed at critical analysis of the salinity problems, its impact on agroecosystem, and different management approaches available to date with a balanced viewpoint that would help to draw a possible roadmap towards the future investigation in this domain for sustainable management of salinity issues around the globe.

Metabarcoding analysis of the bacterial succession during vermicomposting of municipal solid waste employing the earthworm Eisenia fetida.

A culture-independent DNA metabarcoding analysis of the bacterial communities was carried out throughout a complete vermicomposting cycle of municipal solid waste material using the earthworm Eisenia fetida. 16S rRNA amplicons from the initial material (0 days), an intermediate (42 days), and a final stage (84 days) were sequenced in an Illumina NGS platform and compared. A steady increase in community diversity was observed corresponding to a 2.5-fold higher taxa richness and correspondingly risen values of the Shannon and Simpson ecological indexes and the evenness parameter. A total of 49,665 operational taxonomic units (OTUs) were counted. From the qualitative standpoint, a clear successional shift was observed with an initial community dominated by putatively plant-associated groups belonging to the Rhizobiales order within the Alphaproteobacteria class, regressively leaving the scores of relative abundance (RA) to the Firmicutes phylum and in particular to the Bacilli. Vermistabilization of municipal solid waste (MSW) increased (p < 0.001) the TKN and total P content in the final vermicompost, while pH, TOC, and C/N ratio declined (p < 0.001) in the process. Likewise, a progressive decrease was noticed in ß-glucosidase, acid phosphatase, and urease activity while protease and dehydrogenase showed a slight increase, followed by a steep fall. A strong positive correlation was observed among the canonical functions of physico-chemical attributes and enzyme activities. The canonical correspondence analysis (CCA) revealed that significant families did not change on the temporal scale; however, their abundance was influenced by the abiotic environmental factors. In comparison to prior studies on vermicomposting that used different earthworm species (Eisenia andrei) and different substrates, results reflect a considerable degree of substrate specificity for the earthworm species used. The results offer clues to optimize the vermistabilization of MSW along with its potential use in agriculture, to foster improved levels of the circular economy.

Analysis and advanced characterization of municipal solid waste vermicompost maturity for a green environment.

Rapid demographic expansion along with increasing urbanization has aggravated the problem of solid waste management. Therefore, scientists are seeking waste management methods that are eco-friendly, cost effective and produce immediate results. In the developing world, municipal solid waste (MSW) contains mostly organic substances, therefore vermicomposting could be a better and cost-effective option for waste management. In this study, vermicomposting of organic portion of MSW with cow dung (additive) was performed using Eisenia fetida. The results showed significant (p < 0.001) decline in pH (13.17%), TOC (21.70%), C: N (62.53%) and C: P (57.66%) ratios, whilst total N (108.9%), P (84.89%) and K (21.85%) content increased (p < 0.001) in matured vermicompost. Different enzymatic activities declined during termination phase of vermicomposting experiment with maximum decrease of 41.72 (p = 0.002) and 39.56% (p = 0.001) in protease and ß-glucosidase, respectively. FT-IR, TGA, DSC and SEM studies suggested that final vermicompost was more stabilized as compared to initial waste mixture, characterized by reduced levels of aliphatic materials, carbohydrates and increase in aromatic groups possibly due to biosynthesis of humic substances. Both, the conventional (physicochemical and enzyme activity) and advanced techniques depict maturity and stability of the ready vermicompost. However, FT-IR, TGA, DSC and SEM were proved to be more promising, fast and reliable techniques over conventional analyses.

An insight to municipal solid waste management of Varanasi city, India, and appraisal of vermicomposting as its efficient management approach.

Varanasi, India's historic cultural capital, struggles with efficient waste management practices. This impacts environment and human well-being in terms of waste generation that is estimated around 550-650 TPD with a generation rate of 0.42 kg capita-1 day-1 (n = 117). The present study aims to explore and characterize wastes, current practices, ecological profiling, and phytotoxicity of an abandoned open dumping site, and vermicomposting of organic fraction of municipal solid waste (OFMSW) as sustainable waste management approach. Compositional analysis of waste indicates organic fraction (46.13%) as a major component along with a considerable amount of heavy metals. The calorific value and moisture content of municipal solid waste (MSW) was 2351.4 cal g-1 and 34.72%, respectively. Ecological profiling of the dumping site revealed that floral diversity and ecological species/indicators were negatively affected. Likewise, phytotoxicity results displayed a negative impact on germination and physiology of maize (Zea mays L.) plants grown on dumping site soil. Vermistabilization of OFMSW showed a significant increase in N (56.10-89.48%), P (33.93-82.87%), and K (25.55-50.42%) and a decrease in total organic carbon (15.15-24.81%). Similarly, C/N and C/P ratios decreased by 1.89-2.51 and 1.72-2.18 folds, respectively. A survey of stakeholders suggested that open dumping was the main practice adopted by Varanasi Municipal Corporation (VMC) during 2013-2015. Recently (2017-2018), VMC adopted different methods, such as door-to-door collection and source segregation for effective waste management. Waste characteristics and nutrient profile of the vermicompost explains that vermicomposting could be used for efficient waste management in Varanasi, further reducing the collection, transportation, and disposal costs of waste, which enables to close the loop and move towards a circular economy. Moreover, implications of existing waste management practices and possible management options need to be addressed scientifically. Therefore, this research outcome will help in designing a successful waste management plan for Varanasi and other cities with similar waste characteristics.

Characterization of heavy metal pollution in an anthropogenically and geologically influenced semi-arid region of east India and assessment of ecological and human health risks.

The present study evaluated the heavy metal contamination in groundwater and associated ecological and human health risks of a geologically and anthropogenically diverse semi-arid region of Birbhum district, India. For a reliable evaluation, concentrations of nine heavy metals in 680 groundwater samples (N = 680) which were collected during premonsoon and postmonsoon seasons of consecutive two years from 170 wells were measured. The human health risk assessment using the USEPA model which is based on single value for each parameter may inherit certain inaccuracy and uncertainties in the evaluation. Unlike earlier studies, a higher degree of accuracy in carcinogenic and noncarcinogenic health risk assessments was achieved through Monte Carlo simulations, sensitivity analysis and uncertainty analysis. The study revealed the occurrence of the target heavy metals in groundwater with mean dominance order of Fe > Zn > Sr > Mn > Cr > Pb > Ni > Cu > Cd where mean concentrations of the carcinogens, Pb and Fe exceeded their maximum permissible limits. The water quality status evaluated using the modified heavy metal pollution index, Nemerow index and Heavy metal evaluation index methods resulted in medium to high heavy metal contamination in groundwater within a large portion of the study area which indicated its unsuitability for drinking purpose. The study suspects a moderate to very high risk for the groundwater dependent ecosystems in major part of the study area. The study further revealed cancer risks, ranging from high to very high within the residents due to accumulative exposure of the carcinogenic heavy metals in groundwater through ingestion and dermal contact. Minor populations of the study area were found to be more vulnerable to the carcinogenic and noncarcinogenic diseases than teenagers and adults, mainly through oral exposure. The study recommends the residents to consume treated groundwater since the primary route of heavy metal exposure was identified to be the ingestion route.

Growth performance, metal accumulation and biochemical responses of Palak (Beta vulgaris L. var. Allgreen H-1) grown on soil amended with sewage sludge-fly ash mixtures.

Agricultural utilization of sewage sludge (SS) and fly ash (FA) has become both, a common practice and an alternative disposal method for these wastes all around the world. The present study was conducted to assess the effect and viability of co-application of SS and FA (SLASH) in four mixing ratios denoted as A [4 (SS): 1(FA)], B [4 (SS): 2 (FA)], C [4 (SS): 3 (FA)] and D [4 (SS): 4(FA)] at three application rates viz. 20, 40 and 60% (w/w) with agricultural soil on biochemical, physiological and growth response of Palak (Beta vulgaris L. var. Allgreen H-1), a commonly used green leafy vegetable. SLASH amendment modified the physico-chemical properties of soil and increased the concentration of heavy metals (Cd, Cr, Cu, Fe, Ni, Pb, Zn) in soil and plant parts however, within the Indian permissible limit except for Cr, Cd and Zn in shoot. Experimental results revealed decrease in morphological and growth parameters such as root and shoot length, leaf area, root, shoot biomass etc. Lipid peroxidation, ascorbic acid, proline and protein content increased however, total chlorophyll and carotenoid content decreased indicating towards heavy metal stress induced biochemical and physiological response in Palak plants. Significant increase in yield was seen in some of the treatments viz. three mixing ratios B, C and D, with maximum increment shown by mixture D at 20 and 40% amendment rate. The results of this study suggest that though SLASH amendment for growing Palak improved the physico-chemical properties of soil amended and also the yield of the plants in some treatments, it may not be a good option due to risk of contamination of heavy metals such as Cr, Cd and Zn showing higher accumulation.

Agricultural utilization of biosolids: A review on potential effects on soil and plant grown.

Environmental and economic implications linked with the proper ecofriendly disposal of modern day wastes, has made it essential to come up with alternative waste management practices that reduce the environmental pressures resulting from unwise disposal of such wastes. Urban wastes like biosolids are loaded with essential plant nutrients. In this view, agricultural use of biosolids would enable recycling of these nutrients and could be a sustainable approach towards management of this hugely generated waste. Therefore biosolids i.e. sewage sludge can serve as an important resource for agricultural utilization. Biosolids are characterized by the occurrence of beneficial plant nutrients (essential elements and micro and macronutrients) which can make help them to work as an effective soil amendment, thereby minimizing the reliance on chemical fertilizers. However, biosolids might contain toxic heavy metals that may limit its usage in the cropland. Heavy metals at higher concentration than the permissible limits may lead to food chain contamination and have fatal consequences. Biosolids amendment in soil can improve physical and nutrient property of soil depending on the quantity and portion of the mixture. Hence, biosolids can be a promising soil ameliorating supplement to increase plant productivity, reduce bioavailability of heavy metals and also lead to effective waste management.

Biological response of using municipal solid waste compost in agriculture as fertilizer supplement.

Waste management and declining soil fertility are the two main issues experienced by all developing nations, like India. Nowadays, agricultural utilization of Municipal Solid Waste (MSW) is one of the most promising and cost effective options for managing solid waste. It is helpful in solving two current burning issues viz. soil fertility and MSW management. However, there is always a potential threat because MSW may contain pathogens and toxic pollutants. Therefore, much emphasis has been paid to composting of MSW in recent years. Application of compost from MSW in agricultural land helps in ameliorating the soil's physico-chemical properties. Apart from that it also assists in improving biological response of cultivated land. Keeping the present situation in mind, this review critially discusses the current scenario, agricultural utilization of MSW compost, role of soil microbes and soil microbial response on municipal solid waste compost application.

Biological responses of agricultural soils to fly-ash amendment.

The volume of solid waste produced in the world is increasing annually, and disposing of such wastes is a growing problem. Fly ash (FA) is a form of solid waste that is derived from the combustion of coal. Research has shown that fly ash may be disposed of by using it to amend agricultural soils. This review addresses the feasibility of amending agricultural field soils with fly ash for the purpose of improvings oil health and enhancing the production of agricultural crops. The current annual production of major coal combustion residues (CCRs) is estimated to be -600 million worldwide, of which about 500 million t (70-80%) is FA (Ahmaruzzaman 2010). More than 112 million t of FA is generated annually in India alone, and projections show that the production (including both FA and bottom ash) may exceed 170 million t per annum by 2015 (Pandey et al. 2009; Pandey and Singh 20 I 0). Managing this industrial by-product is a big challenge, because more is produced each year, and disposal poses a growing environmental problem.Studies on FA clearly shows that its application as an amendment to agricultural soils can significantly improve soil quality, and produce higher soil fertility. What FA application method is best and what level of application is appropriate for any one soil depends on the following factors: type of soil treated, crop grown, the prevailing agro climatic condition and the character of the FA used. Although utilizing FA in agricultural soils may help address solid waste disposal problems and may enhance agricultural production, its use has potential adverse effects also. In particular, using it in agriculture may enhance amounts of radionuclides and heavy metals that reach soils, and may therefore increase organism exposures in some instances.

Land application of sewage sludge: physicochemical and microbial response.

In the present review, we address the effects of sewage sludge amendment on soil physicochemical properties and on soil microbial biomass. Sewage sludge is a by-product of sewage treatment processes and is increasingly applied to agricultural lands as a source of fertilizer, and as an alternative to conventional means of disposal. The particular characteristics of sewage sludge depend upon the quality of sewage from which it is made, and the type of treatment processes through which it passes. Sewage sludge may substitute for inorganic fertilizers because it is rich in organic and inorganic plant nutrients. However, the presence of potentially toxic metals and pathogens in sewage sludge often restricts its uses. Ground water and food chain contamination resulting from sewage sludge amendment is one major concern worldwide. The health of soils is represented by a composite of their physical, chemical and biological properties. Amending soil with sewage sludge modifies the physicochemical and biological properties of soils. Perhaps the central constituent of soil that is important in the context of sewage sludge amendment is microbial biomass. Soil microbial biomass, the key living part of the soil, is very closely associated with the content of organic matter that exists in arable agricultural soils. When sewage sludge is land-applied, soil enzyme activities may be directly or indirectly affected by the presence of heavy metals. In several studies, results have shown that sewage sludge amendment increased soil microbial and soil enzyme activities; however, reduction in soil enzyme activity has also been reported. When incubation periods of sewage sludge were longer, heavy metal bioavailability increased. Soil pathogenic activity has also been reported to increase as a result of land application of sewage sludges. The level of pathogens in treated sewage sludge (biosolids) depends on the processes used to treat wastewater and sewage sludge. Agricultural application of sewage sludge may result in the transport of pathogens through aerosols downwind of sludge storage or dispersal sites, may contaminate ground water, stock ponds, or may produce food chain contamination from eating food grown in sludge-treated land.