About

Sanjay Mohanty, Ph.D., is an Associate Professor in the Department of Civil and Environmental Engineering at the University of California, Los Angeles. His research focuses on environmental science and sustainability, with recent work highlighting issues such as the presence of plastic particles in biosolids used as fertilizer. Mohanty is involved in projects addressing water and climate challenges, including the Wildfire-Stormwater Nexus, which aims to understand the interactions between wildfire events and stormwater management. His contributions emphasize the importance of environmental sustainability and innovative solutions to pressing ecological problems.

Research topics

• Environmental science
• Geology
• Chemistry
• Environmental engineering
• Environmental chemistry
• Soil science
• Ecology
• Waste management
• Geomorphology
• Biology
• Organic chemistry
• Water resource management
• Oceanography
• Environmental planning
• Engineering
• Geotechnical engineering

Selected publications

• Ingestion of microplastics during chewing gum consumption

  Journal of Hazardous Materials Letters · 2025-09-23 · 2 citations

  articleOpen accessSenior authorCorresponding

  Chewing gums typically contain plant-based or synthetic plastic polymers to improve their texture and flavor retention. These polymer fragments or microplastics can be released into the environment when disposed of improperly or ingested while chewing gums. Yet, how many microplastics a person may ingest while chewing gums is unknown. Analyzing microplastics released into saliva from 5 natural and 5 synthetic chewing gums, we found that each gram of chewing gum could release up to 637 microplastics, and 94 % of microplastics were released within the first 8 min of chewing. Surprisingly, synthetic chewing gum released a similar (p > 0.8) number of microplastics as natural or plant-based chewing gums. Microplastics released from the chewing gums were predominantly small, with a median size of 45.4 µm. Both of the chewing gum types released four types of plastic polymers—polyolefins, polyterephthalates (PET), polyacrylamides, and polystyrenes,— among which polyolefins were the most abundant. The result reveals that chewing gum consumption, irrespective of the type of chewing gums, could result in direct ingestion of microplastics. • Chewing gums released 4–636 microplastics g −1 to saliva. • Synthetic and natural chewing gums released similar numbers of microplastics. • 94 % of microplastics are released within the first 8 min of chewing. • Most microplastics released are smaller than 50 µm.

  PublisherDOI

• Care cascade of hypertension across stages among older adults in India

  PLoS ONE · 2025-12-03

  articleOpen accessSenior authorCorresponding

  Hypertension is now a common disease and the single largest risk factor for premature mortality in India. Hypertensive individuals are not homogenous and have varying risks to life. Although the number of studies on the care cascade of hypertension in India is increasing, no attempts have been made to estimate the prevalence and cascade of care across different stages of hypertension. This study estimates the prevalence, awareness, and treatment of hypertension by stages of hypertension among older adults in India. We analyzed data on 58,787 adults aged 45 years and above from the Longitudinal Ageing Study in India (LASI), Wave 1 (2017-18). Hypertension stages were categorized in accordance with the classification given by the Ministry of Health and Family Welfare, Government of India, and regrouped as per global classification. The age-sex adjusted prevalence, awareness, and treatment rates for different stages of hypertension were estimated. Multinomial logistic regression and the Erreygers' Concentration Index were used to assess socioeconomic inequalities in hypertension care. We estimated the prevalence of pre-hypertension at 39.9%, stage 1 hypertension at 22.1% and stage 2 hypertension at 9.9%. Increasing age and body mass index were associated with a higher chance of hypertension, whereas living with spouses and children meant having lower odds of hypertension across all stages. The economic condition of the household, educational attainment, and social groups were not significant predictors of hypertension across the stages. The awareness and treatment of hypertension were low across all the stages. The Erreygers' Concentration Index on awareness and treatment was pro-rich across all the stages of hypertension. A large proportion of hypertensive patients at the advanced stage remain undiagnosed and untreated and carry a higher risk of premature mortality. The awareness and treatment of hypertension are lower among the poorer and socially disadvantaged populations than their richer and more privileged counterparts across all stages.

  PublisherDOI

• Implications of Pyrolytic Gas Dynamic Evolution on Dissolved Black Carbon Formed During Production of Biochar from Nitrogen-Rich Feedstock

  Environmental Science & Technology · 2025-01-13 · 22 citations

  articleOpen access

  Gases and dissolved black carbon (DBC) formed during pyrolysis of nitrogen-rich feedstock would affect atmospheric and aquatic environments. Yet, the mechanisms driving biomass gas evolution and DBC formation are poorly understood. Using thermogravimetric-Fourier transform infrared spectrometry and two-dimensional correlation spectroscopy, we correlated the temperature-dependent primary noncondensable gas release sequence (H2O → CO2 → HCN, NH3 → CH4 → CO) with specific defunctionalization stages in the order: dehydration, decarboxylation, denitrogenation, demethylation, and decarbonylation. Our results revealed that proteins in feedstock mainly contributed to gas releases, and low-volatile pyrolytic products contributed to DBC. Combining mass difference analysis with Fourier transform ion cyclotron resonance mass spectrometry, we showed that 44–60% of DBC molecular compositions were correlated with primary gas-releasing reactions. Dehydration (−H2O), with lower reaction energy barrier, contributed to DBC formation most at 350 and 450 °C, whereas decarboxylation (−CO2) and deamidization (−HCNO) prevailed in contributing to DBC formation at 550 °C. The aromaticity changes of DBC products formed via gas emissions were deduced. Compared to their precursors, dehydration increased DBC aromaticity, while deamidization reduced the aromaticity of DBC products. These insights on pyrolytic byproducts help predict and tune DBC properties via changing gas formed during biochar production, minimizing their negative environmental impacts.

  PublisherDOI

• Coarse Biochar Improves the Hydraulic Performance of Compacted Roadside Soil Media

  Journal of Sustainable Water in the Built Environment · 2025-08-22 · 2 citations

  article

  Compacting engineered soil media is necessary to ensure its stability in many urban contexts, such as in road embankments. However, compaction can reduce infiltration rates, increase runoff volumes, and impede vegetation growth. Amending soil media that is to be compacted by mixing it with biochar may largely mitigate the consequences of compaction, effectively helping road embankments and similar areas function as green stormwater infrastructure. Here, we report the results of a lab experiment intended to determine how biochar particle size and application rate influence the hydraulic properties of compacted roadside media. Specifically, we amended a loamy sand collected from the field with biochar ranging from 0 to 6% (w/w) and that was either unsieved or sieved to remove most coarse particles. The addition of biochar with many coarse particles (>2 mm) improved the saturated hydraulic conductivity (Ksat) of the medium postcompaction, but this effect diminished at biochar dosages above 3% (w/w). In contrast, the addition of biochar with few coarse particles did not improve Ksat postcompaction. These changes likely arose because unsieved biochar facilitated the addition of interconnected pores and did so to a greater extent than particle breakage led to pore restriction. Also, biochar addition improved water retention in the plant available suction range postcompaction, whether the biochar was sieved or unsieved. Amendment with relatively coarse biochar could therefore help compacted roadside soil media manage stormwater while also reducing plant water-stress in a frequently water-limited setting.

  PublisherDOI

• Bioleaching of waste-derived rare earth elements: An integrated approach with meta-analysis and predictive analytics for scale-up

  Results in Engineering · 2025-10-15 · 5 citations

  articleOpen access

  • Meta-analysis shows 56% avg REE recovery from waste via bioleaching. • E-waste and coal fly ash yield highest recovery (∼89% and ∼76%). • Fungal consortia outperform bacteria, achieving up to 75% recovery. • Process parameters (pH, temp) are the strongest recovery drivers (β=0.895). • Machine learning models predict recovery well (SVRM R²=0.87, KNN R²=0.787). This review provides a comprehensive, data-driven perspective on rare earth element (REE) recoveries from various waste streams by bioleaching, integrating mechanistic insights, microbial performance data, advanced statistical and machine learning tools. A total of 77 observations across 10 waste types were analyzed via Bayesian meta-analysis, yielding an average REE recovery of 56.2% (95% credible interval: 51.1–61.0%). Among the waste types, coal fly ash and electronic waste (e-waste) demonstrated the highest recoveries (76% and 89%, respectively). Fungi, particularly Aspergillus and Penicillium, performed better than bacteria, despite being less commonly used in bioleaching studies. Fungal-only systems typically achieved 60–76% recovery, whereas values above 85% were reported when fungal bioleaching was combined with chemical or physical pretreatments. Acidophilic bacteria exhibited the highest recovery efficiency among the bacterial species (66%). The microbial consortia (combinations of fungi and bacteria) achieved up to 76% recovery efficiency due to synergistic interactions. Importantly, many of the highest recoveries (≥90%) reported in the literature refer to base metals such as Cu, Ni, and Zn, which are more easily solubilized than REEs; harmonizing claims requires distinguishing organism-only effects from organism + pretreatment strategies, and base metal recoveries from REE recoveries. Structural equation modeling (SEM) revealed that factors such as pH, type of waste, and process parameters, played key roles in determining REE recovery success. Among these, process variables (e.g. pH and pulp density) had the strongest direct influence (β = 0.895). Machine learning models, including support vector machine regression (SVMR) and K-nearest neighbor regression (KNNR), further highlight the importance of metal content, process parameters, and microbial presence. These models performed well, with R² values of 0.87 for SVMR and 0.787 for KNNR. Overall, this integrated approach demonstrates the potential for scaling-up bioleaching processes. By combining biological insights with predictive analytics, this integrated framework demonstrates strong foundation for industrial-scale REE recovery and supports shifting toward a more circular and sustainable economy.

  PublisherDOI

• Are we underestimating microplastic emissions from agricultural soils?

  2025-03-14

  preprintOpen accessSenior author

  Agricultural management practices significantly influence the the emission of particulate matter into the atmosphere, which is a key component of air quality indicators. In particular, agricultural soils in drylands, which constitute ~40% of Earth's terrestrial surface, are highly vulnerable to emissions via accelerated wind erosion because of factors such as increased aridity, recurrent droughts, crop failures, lack of irrigation, and unsustainable soil management practices. These lands are often subjected to large-scale biosolid application, irrigation with reclaimed (grey) water, and plastic mulching to meet the growing demand for water and to reduce reliance on fossil fuel-intensive fertilizers. However, these practices could significantly increase microplastics in the topsoil. Wind can transport these microplastic particles beyond agricultural systems, potentially carrying adsorbed contaminants such as per- and polyfluoroalkyl substances (PFAS). To evaluate inhalation exposure risks, it is crucial to understand the extent of microplastic pollution and the mechanisms driving their resuspension from agricultural soils. To investigate microplastic emission potential, we used a combination of wind tunnel studies and laboratory experiments on biosolid-amended agricultural soils. Our findings reveal that inhalable microplastics are preferentially entrained and enriched through two primary mechanisms: (1) the accelerated emission of fine plastic particles under wind conditions that are lower than those required for initiating movement of background soil particles (direct suspension without saltation), and (2) the generation and resuspension of fine plastic particles resulting from the abrasion of larger plastic fragments or soil-plastic aggregates by sand grains (saltation-induced suspension). We developed a theoretical framework to explain this preferential transport, attributing it to the low density and reduced interparticle forces between microplastics and soil. Our findings suggest that current methods and models for fugitive dust emissions may underestimate the particulate matter emission potential of amended soils. This is due to limitations in detecting fine particles during sampling and the inadequate representation of plastic entrainment mechanisms (e.g., suspension without saltation) in existing dust emission models. To illustrate this, we demonstrated that over 85% of wind events above bare soil surface exceed the threshold velocity required to mobilize microplastics of a specific size, while only 20% of these events surpass the threshold velocity for background soil particles. Given that fine microplastics may adsorb contaminants from agricultural soils, their preferential entrainment by wind could lead to a concentration of these contaminants in airborne dust, posing potential environmental and health risks.

  PublisherDOI

• Estimates of life expectancy and premature mortality among multidimensional poor and non-poor in India

  BMC Public Health · 2024-12-20 · 5 citations

  articleOpen accessSenior author

  BACKGROUND: In Low and Middle Income Countries (LMICs), reduction of multidimensional poverty and the increase in longevity are concomitant. Although a number of studies have estimated multidimensional poverty, studies on estimates of life expectancy and pre-mature mortality by multidimensional poverty are limited. We estimated life expectancy and premature mortality among multidimensionally poor and multidimensionally non-poor in India. METHODS: We have used the micro data of 636,699 households and 2,843,917 individuals from the National Family and Health Survey-5, 2019-21. We estimated multidimensional poverty in three dimensions-education, health, and standard of living using 11 indicators. Data on birth-history of women (15-49 years of age) and household-reported deaths was utilised to estimate deaths and person years and used to construct the life tables. The life tables were used to estimate life expectancy, premature mortality (the probability of dying before age 70), and adult mortality (the probability of dying between age 15-59) among multidimensionally poor and non-poor across socio-demographic characteristics.. RESULTS: We estimated multidimensional poverty in India at 26%, with large variation across states and union territories. Multidimensionally poor individuals had a life expectancy at birth (LEB) 4 years lower compared to multidimensionally non-poor individuals (poor: 65.2 years vs non-poor 69.0 years). The lower life expectancy of the multidimensionally poor compared to multidimensionally non-poor was found across all the sub-categories. The difference in life expectancy at birth between multidimensionally poor and non-poor was higher among urban dwellers (4.6 years) than rural individuals (1.8 years). The premature mortality was estimated at 0.33 among the multidimensionally poor and at 0.25 among the multidimensionally non-poor. Adult mortality was estimated to be 0.17 among the multidimensionally poor compared to 0.12 among the non-poor individuals. Our findings on the differences in adult mortality and premature mortality between multidimensional poor and non-poor across socio-demographic characteristics were large. CONCLUSION: Multidimensionally poor individuals had lower longevity and higher premature mortality than their multidimensionally non-poor counterparts in India. Such differences were higher by residence (rural-urban) than by caste and religion.

  PublisherOA PDFDOI

• Performance of wood waste biochar and food waste compost in a pilot-scale sustainable drainage system for stormwater treatment

  Environmental Pollution · 2024-03-14 · 6 citations

  article
  PublisherDOI

• Evaluation of historical data on persistent organic pollutants and heavy metals in Lake Baikal: Implications for accumulation in marine environments

  Environmental Research · 2024-04-27 · 8 citations

  article
  PublisherDOI

• Preferential Emission of Microplastics from Biosolid-Applied Agricultural Soils: Field Evidence and Theoretical Framework

  Environmental Science & Technology Letters · 2024-01-17 · 32 citations

  articleSenior authorCorresponding

  Land application of wastewater biosolids on agricultural soils is suggested as a sustainable pathway to support the circular economy; however, this practice often enriches microplastics and associated contaminants in topsoil. Wind could transport these contaminated microplastics, thereby increasing their inhalation health risks. Analyzing wind-borne sediments collected from wind tunnel experiments on biosolid-applied agricultural fields, we show enrichment of microplastics in wind-blown sediments. We explain this preferential transport and enrichment of microplastics by using a theoretical framework. This framework reveals how the combined effects of the low density of microplastics and weakened wet-bonding interparticle forces between microplastics and soil particles lower their threshold velocity, the minimum wind velocity necessary for wind erosion to occur. Our calculations indicate that microplastics could be emitted at wind speeds lower than the characteristic threshold of background soil. Analyzing the windspeed distribution for 3 months of wind events over a bare soil surface, we showed that more than 84% of the wind events exceed the threshold velocity of microplastics of size 150 μm, while only 23% of the wind events exceed the threshold velocity of the background soil. Thus, current models for fugitive dust emissions may underestimate the microplastic emission potential of biosolid-amended soils.

  PublisherDOI

Frequent coauthors

• Alexandria B. Boehm

  18 shared

• Annesh Borthakur

  Saint Louis University

  18 shared

• Sujith Ravi

  Temple University

  18 shared

• Jamie Leonard

  University of California, Los Angeles

  18 shared

• Vera S. Koutnik

  Boston Consulting Group (United States)

  17 shared

• Renan Valenca

  University of California, Los Angeles

  15 shared

• Michael K. Stenstrom

  University of California, Los Angeles

  11 shared

• Kara L. Nelson

  10 shared

Education

• Ph.D., Environmental Science and Engineering

  University of California, Los Angeles

  2000

• M.S., Environmental Science and Engineering

  University of California, Los Angeles

  1997

• B.S., Environmental Science

  University of California, Los Angeles

  1995