Corrigendum: Sensor-based precision nutrient and irrigation management enhances the physiological performance, water productivity, and yield of soybean under system of crop intensification.

[This corrects the article DOI: 10.3389/fpls.2023.1282217.].

Emerging technologies for the removal of pesticides from contaminated soils and their reuse in agriculture.

Pesticides are becoming more prevalent in agriculture to protect crops and increase crop yields. However, nearly all pesticides used for this purpose reach non-target crops and remain as residues for extended periods. Contamination of soil by widespread pesticide use, as well as its toxicity to humans and other living organisms, is a global concern. This has prompted us to find solutions and develop alternative remediation technologies for sustainable management. This article reviews recent technological developments for remediating pesticides from contaminated soil, focusing on the following major points: (1) The application of various pesticide types and their properties, the sources of pesticides related to soil pollution, their transport and distribution, their fate, the impact on soil and human health, and the extrinsic and intrinsic factors that affect the remediation process are the main points of focus. (2) Sustainable pesticide degradation mechanisms and various emerging nano- and bioelectrochemical soil remediation technologies. (3) The feasible and long-term sustainable research and development approaches that are required for on-site pesticide removal from soils, as well as prospects for applying them directly in agricultural fields. In this critical analysis, we found that bioremediation technology has the potential for up to 90% pesticide removal from the soil. The complete removal of pesticides through a single biological treatment approach is still a challenging task; however, the combination of electrochemical oxidation and bioelectrochemical system approaches can achieve the complete removal of pesticides from soil. Further research is required to remove pesticides directly from soils in agricultural fields on a large-scale.

Green nanosensor for precise detection of formaldehyde in fruits and vegetables extract.

Present study reports fabrication of a low cost and eco-friendly formaldehyde nanosensor based on green magnetite nanoparticles synthesized using Mango (Mangifera indica L.) tree leaves extract. The formaldehyde is found in air, water and food. When inhaled or consumed formaldehyde has carcinogenic effects on human health. In this study the cyclic voltammetry technique was used to characterize the performance of the nanosensor. The green nanosensor fabricated in this study, to detect formaldehyde, demonstrated good sensitivity (193.4 µA mg-1 Lcm-2) in linearity range 0.03-0.5 mg/L with low threshold detection limit (0.05 mg/L). The green nanosensor also showed shelf life of four weeks without considerable change in the initial peak oxidation current. The real sample analysis was performed in various fruits and vegetables (Litchi chinensis, Syzygium cumini, Solanum lycopersicum and Cucumis sativus). The recovery rates were more than 93 % in sample extracts for formaldehyde detection. The comparison of the nanosensor for detection of formaldehyde with the colorimetric sensor revealed that the green nanosensor reproducibility (RSD = 1.8 %) is better than colorimetric sensor (RSD = 3.23 %). The results from the comparative studies of green nanosensor with colorimetric sensor established the potential of the green nanosensor as a forefront technology for futuristic smart detection of formaldehyde.

Sustainable environmental practices of tea waste-a comprehensive review.

Tea, the major beverage worldwide, is one of the oldest commercial commodities traded from ancient times. Apart from many of its advantages, including health, socio-economic, climatic, and agro-ecological values, FAO has recognized that the tea value chain covering its growth in the field, processing and marketing, and finally, the hot cup at the user's hand needs to be made sustainable during all these stages. Tea generates a lot of waste in different forms in different stages of its growth and processing, and these wastes, if not managed properly, may cause environmental pollution. A planned utilization of these wastes as feedstocks for various processes can generate more income, create rural livelihood opportunities, help grow tea environmentally sustainable, avoid GHG emissions, and make a real contribution to SDGs. Thermochemical and biological conversion of tea wastes generates value-added products. This review provides an overview on the impacts of the tea wastes on the environment, tea waste valorization processes, and applications of value-added products. The application of value-added products for energy generation, wastewater treatment, soil conditioners, adsorbents, biofertilizers, food additives, dietary supplements, animal feed bioactive chemicals, dye, colourant, and phytochemicals has been reviewed. Further, the challenges in sustainable utilization of tea wastes and opportunities for commercial exploitation of value-added products from tea wastes have been reviewed.

Reducing options of ammonia volatilization and improving nitrogen use efficiency via organic and inorganic amendments in wheat (Triticum aestivum L.).

Background: This study investigates the effect of organic and inorganic supplements on the reduction of ammonia (NH3) volatilization, improvement in nitrogen use efficiency (NUE), and wheat yield. Methods: A field experiment was conducted following a randomized block design with 10 treatments i.e., T1-without nitrogen (control), T2-recommended dose of nitrogen (RDN), T3-(N-(n-butyl) thiophosphoric triamide) (NBPT @ 0.5% w/w of RDN), T4-hydroquinone (HQ @ 0.3% w/w of RDN), T5-calcium carbide (CaC2 @ 1% w/w of RDN), T6-vesicular arbuscular mycorrhiza (VAM @ 10 kg ha-1), T7-(azotobacter @ 50 g kg-1 seeds), T8-(garlic powder @ 0.8% w/w of RDN), T9-(linseed oil @ 0.06% w/w of RDN), T10-(pongamia oil @ 0.06% w/w of RDN). Results: The highest NH3 volatilization losses were observed in T2 at about 20.4 kg ha-1 per season. Significant reduction in NH3 volatilization losses were observed in T3 by 40%, T4 by 27%, and T8 by 17% when compared to the control treatment. Soil urease activity was found to be decreased in plots receiving amendments, T3, T4, and T5. The highest grain yield was observed in the T7 treated plot with 5.09 t ha-1, and straw yield of 9.44 t ha-1 in T4. Conclusion: The shifting towards organic amendments is a feasible option to reduce NH3 volatilization from wheat cultivation and improves NUE.

Treatment of petroleum hydrocarbon contaminated soil by combination of electro-Fenton and biosurfactant-assisted bioslurry process.

Removing petroleum hydrocarbons (PHCs) from polluted soil is challenging due to their low bioavailability and degradability. In this study, an experiment was carried out to treat soil polluted with petroleum hydrocarbon using a hybrid electro-Fenton (with BDD anode electrode) and biological processes stimulated with long-chain rhamnolipids (biosurfactants). Electro-Fenton treatment was applied as a pretreatment before the biological process to enhance PHC biodegradability, which would benefit the subsequent biological process. The effects of initial pH, hydroxide concentration, soil organic matter composition, PHCs intermediates during the electro-Fenton process, and total numbers of bacteria in the biological process were analyzed to determine the optimum conditions. The results showed that the optimized electrolysis time for the electro-Fenton was 12 h. The change induced during pretreatment at a specified time was found suitable for the biological process stage and led to 93.6% PHC degradation in combination with the electro-Fenton-and-biological process after 72 h. The combined system's performance was almost 40% higher than individual electro-Fenton and biological treatments. GC-MS analysis confirms the formation of 9-octadecen-1-ol (Z), 2-heptadecene, 1-nonadecene, 1-heneicosene, and pentacosane as fragmentation during the PHCs degradation process. Thus, the electro-Fenton process as pretreatment combined with a biological process stimulated with rhamnolipids (biosurfactants) could be effectively applied to remediate soil polluted with PHCs. However, the system needs further research and investigation to optimize electrolysis time and biosurfactant dose to advance this approach in the soil remediation process.

An eco-sustainable approach towards heavy metals remediation by mangroves from the coastal environment: A critical review.

Mangroves provide various ecosystem services, carbon sequestration, biodiversity depository, and livelihoods. They are most abundant in marine and coastal ecosystems and are threatened by toxic contaminants like heavy metals released from various anthropogenic activities. However, they have significant potential to survive in salt-driven environments and accumulate various pollutants. The adverse effects of heavy metals have been extensively studied and recognized as toxic to mangrove species. This study sheds light on the dynamics of heavy metal levels, their absorption, accumulation and transport in the soil environment in a mangrove ecosystem. The article also focuses on the potential of mangrove species to remove heavy metals from marine and coastal environments. This review concludes that mangroves are potential candidates to clean up contaminated water, soil, and sediments through their phytoremediation ability. The accumulation of toxic heavy metals by mangroves is mainly through roots with limited upward translocation. Therefore, promoting the maintenance of biodiversity and stability in the coastal environment is recommended as an environmentally friendly and potentially cost-effective approach.

Sensor-based precision nutrient and irrigation management enhances the physiological performance, water productivity, and yield of soybean under system of crop intensification.

Sensor-based decision tools provide a quick assessment of nutritional and physiological health status of crop, thereby enhancing the crop productivity. Therefore, a 2-year field study was undertaken with precision nutrient and irrigation management under system of crop intensification (SCI) to understand the applicability of sensor-based decision tools in improving the physiological performance, water productivity, and seed yield of soybean crop. The experiment consisted of three irrigation regimes [I1: standard flood irrigation at 50% depletion of available soil moisture (DASM) (FI), I2: sprinkler irrigation at 80% ETC (crop evapo-transpiration) (Spr 80% ETC), and I3: sprinkler irrigation at 60% ETC (Spr 60% ETC)] assigned in main plots, with five precision nutrient management (PNM) practices{PNM1-[SCI protocol], PNM2-[RDF, recommended dose of fertilizer: basal dose incorporated (50% N, full dose of P and K)], PNM3-[RDF: basal dose point placement (BDP) (50% N, full dose of P and K)], PNM4-[75% RDF: BDP (50% N, full dose of P and K)] and PNM5-[50% RDF: BDP (50% N, full P and K)]} assigned in sub-plots using a split-plot design with three replications. The remaining 50% N was top-dressed through SPAD assistance for all the PNM practices. Results showed that the adoption of Spr 80% ETC resulted in an increment of 25.6%, 17.6%, 35.4%, and 17.5% in net-photosynthetic rate (Pn), transpiration rate (Tr), stomatal conductance (Gs), and intercellular CO2 concentration (Ci), respectively, over FI. Among PNM plots, adoption of PNM3 resulted in a significant (p=0.05) improvement in photosynthetic characters like Pn (15.69 µ mol CO2 m-2 s-1), Tr (7.03 m mol H2O m-2 s-1), Gs (0.175 µmol CO2 mol-1 year-1), and Ci (271.7 mol H2O m2 s-1). Enhancement in SPAD (27% and 30%) and normalized difference vegetation index (NDVI) (42% and 52%) values were observed with nitrogen (N) top dressing through SPAD-guided nutrient management, helped enhance crop growth indices, coupled with better dry matter partitioning and interception of sunlight. Canopy temperature depression (CTD) in soybean reduced by 3.09-4.66°C due to adoption of sprinkler irrigation. Likewise, Spr 60% ETc recorded highest irrigation water productivity (1.08 kg ha-1 m-3). However, economic water productivity (27.5 INR ha-1 m-3) and water-use efficiency (7.6 kg ha-1 mm-1 day-1) of soybean got enhanced under Spr 80% ETc over conventional cultivation. Multiple correlation and PCA showed a positive correlation between physiological, growth, and yield parameters of soybean. Concurrently, the adoption of Spr 80% ETC with PNM3 recorded significantly higher grain yield (2.63 t ha-1) and biological yield (8.37 t ha-1) over other combinations. Thus, the performance of SCI protocols under sprinkler irrigation was found to be superior over conventional practices. Hence, integrating SCI with sensor-based precision nutrient and irrigation management could be a viable option for enhancing the crop productivity and enhance the resource-use efficiency in soybean under similar agro-ecological regions.

Bioengineering to Accelerate Biodiesel Production for a Sustainable Biorefinery.

Biodiesel is an alternative, carbon-neutral fuel compared to fossil-based diesel, which can reduce greenhouse gas (GHGs) emissions. Biodiesel is a product of microorganisms, crop plants, and animal-based oil and has the potential to prosper as a sustainable and renewable energy source and tackle growing energy problems. Biodiesel has a similar composition and combustion properties to fossil diesel and thus can be directly used in internal combustion engines as an energy source at the commercial level. Since biodiesel produced using edible/non-edible crops raises concerns about food vs. fuel, high production cost, monocropping crisis, and unintended environmental effects, such as land utilization patterns, it is essential to explore new approaches, feedstock and technologies to advance the production of biodiesel and maintain its sustainability. Adopting bioengineering methods to produce biodiesel from various sources such as crop plants, yeast, algae, and plant-based waste is one of the recent technologies, which could act as a promising alternative for creating genuinely sustainable, technically feasible, and cost-competitive biodiesel. Advancements in genetic engineering have enhanced lipid production in cellulosic crops and it can be used for biodiesel generation. Bioengineering intervention to produce lipids/fat/oil (TGA) and further their chemical or enzymatic transesterification to accelerate biodiesel production has a great future. Additionally, the valorization of waste and adoption of the biorefinery concept for biodiesel production would make it eco-friendly, cost-effective, energy positive, sustainable and fit for commercialization. A life cycle assessment will not only provide a better understanding of the various approaches for biodiesel production and waste valorization in the biorefinery model to identify the best technique for the production of sustainable biodiesel, but also show a path to draw a new policy for the adoption and commercialization of biodiesel.

Integrated management enhances crop physiology and final yield in maize intercropped with blackgram in semiarid South Asia.

Photosynthesis, crop health and dry matter partitioning are among the most important factors influencing crop productivity and quality. Identifying variation in these parameters may help discover the plausible causes for crop productivity differences under various management practices and cropping systems. Thus, a 2-year (2019-2020) study was undertaken to investigate how far the integrated crop management (ICM) modules and cropping systems affect maize physiology, photosynthetic characteristics, crop vigour and productivity in a holistic manner. The treatments included nine main-plot ICM treatments [ICM1 to ICM4 - conventional tillage (CT)-based; ICM5 to ICM8 - conservation agriculture (CA)-based; ICM9 - organic agriculture (OA)-based] and two cropping systems, viz., maize-wheat and maize + blackgram-wheat in subplots. The CA-based ICM module, ICM7 resulted in significant (p < 0.05) improvements in the physiological parameters, viz., photosynthetic rate (42.56 µ mol CO2 m-2 sec-1), transpiration rate (9.88 m mol H2O m-2 sec-1) and net assimilation rate (NAR) (2.81 mg cm-2 day-1), crop vigour [NDVI (0.78), chlorophyll content (53.0)], dry matter partitioning toward grain and finally increased maize crop productivity (6.66 t ha-1) by 13.4-14.2 and 27.3-28.0% over CT- and OA-based modules. For maize equivalent grain yield (MEGY), the ICM modules followed the trend as ICM7 > ICM8 > ICM5 > ICM6 > ICM3 > ICM4 > ICM1 > ICM2 > ICM9. Multivariate and PCA analyses also revealed a positive correlation between physiological parameters, barring NAR and both grain and stover yields. Our study proposes an explanation for improved productivity of blackgram-intercropped maize under CA-based ICM management through significant improvements in physiological and photosynthetic characteristics and crop vigour. Overall, the CA-based ICM module ICM7 coupled with the maize + blackgram intercropping system could be suggested for wider adoption to enhance the maize production in semiarid regions of India and similar agroecologies across the globe.

Recent progress and challenges on the removal of per- and poly-fluoroalkyl substances (PFAS) from contaminated soil and water.

Currently, due to an increase in urbanization and industrialization around the world, a large volume of per- and poly-fluoroalkyl substances (PFAS) containing materials such as aqueous film-forming foam (AFFF), protective coatings, landfill leachates, and wastewater are produced. Most of the polluted wastewaters are left untreated and discharged into the environment, which causes high environmental risks, a threat to human beings, and hampered socioeconomic growth. Developing sustainable alternatives for removing PFAS from contaminated soil and water has attracted more attention from policymakers and scientists worldwide under various conditions. This paper reviews the recent emerging technologies for the degradation or sorption of PFAS to treat contaminated soil and water. It highlights the mechanisms involved in removing these persistent contaminants at a molecular level. Recent advances in developing nanostructured and advanced reduction remediation materials, challenges, and perspectives in the future are also discussed. Among the variety of nanomaterials, modified nano-sized iron oxides are the best sorbents materials due to their specific surface area and photogenerated holes and appear extremely promising in the remediation of PFAS from contaminated soil and water.

Appraisal of probabilistic levels of toxic metals and health risk in cultivated and marketed vegetables in urban and peri-urban areas of Delhi, India.

A total of six vegetables (S. tuberosum, D. carota, S. lycopersicum, A. esculentus, S. oleracea and B. juncea) were analysed for five heavy metals (As, Cd, Cr, Hg, and Pb) to evaluate the contamination load in vegetables collected from five cultivated and two market sites (n = 504) at Delhi, India. The irrigation water samples and soil samples (n = 180) were only collected from cultivated sites. The results showed that the concentration of heavy metals in soil and water samples were well below the permissible level except for Cd 0.001-0.013 µg g-1. Similarly, the concentration of Cd (>0.20 µg g-1) was detected higher in all investigated vegetables except for tomato. The evaluation index value was highest for spinach and lowest for tomato. The transfer factor values and metal pollution index was maximum in spinach and okra. Principal component analysis (PCA), Tukey's HSD (Honestly Significant Difference) test, and one-way and two-way ANOVA (Analysis of Variance) were also applied to statistically analyse the results.

Stepped Care Model for Developing Pathways of Screening, Referral, and Brief Intervention for Depression in Pregnancy: A Mixed-Method Study from Development Phase.

Background: Depression in pregnancy affects nearly one in five women in low- and middle-income countries and is associated with adverse obstetric and neonatal outcome. Burden of morbidity is high, but specialized mental health resources are meager. Effective low intensity psychosocial interventions hold promise to fill the treatment gap for maternal depression. In this paper, we aim to describe the process of development of a stepped care model incorporating screening, providing brief intervention, and referral pathways developed for managing depression in pregnancy in antenatal care health facilities in India. Methodology: Using complex intervention development and evaluation method of Medical Research Council, United Kingdom, we searched evidence-based strategies from preexisting manuals, conducted formative research for need assessment and stakeholder engagement, and developed the intervention following an expert review panel. We conducted pilot testing to assess the feasibility and acceptability of intervention supplemented by three focused group discussions. Results: Manual review identified psychoeducation, empathetic listening, behavior activation, and supportive counseling as important elements. Need assessment revealed huge gap in perinatal mental health knowledge. Nearly 92% of total 272 perinatal women had poor awareness and 35%-70% of total 62 health-care providers had poor knowledge. In qualitative interview, women reported depressive symptoms as a normal part of pregnancy and had poor help seeking, behavior symptoms of depression were more prominent. A stepped care algorithm was developed for screening all expectant mothers in each trimester for depression using Patient Health Questionnaire-9 (PHQ-9). Women with PHQ-9 score >19 or reporting self-harm ideation were urgently referred to psychiatrist. Women with PHQ-9 score 5-19 were given brief intervention for depression in pregnancy intervention by antenatal nurse. The intervention developed consists of three sessions of psychoeducation, relaxation exercise, and mental health promotion, each lasting 20 min and at gap of 2 weeks each. Service providers and mothers reported good acceptability of psychosocial intervention and reported satisfaction with content and delivery of intervention. Conclusion: Low intensity brief psychosocial interventions can be adapted for implementation if relevant stakeholders are engaged at each step right from development of such as screening, intervention pathway to delivery, and effectiveness study.

Double zero tillage and foliar phosphorus fertilization coupled with microbial inoculants enhance maize productivity and quality in a maize-wheat rotation.

Maize is an important industrial crop where yield and quality enhancement both assume greater importance. Clean production technologies like conservation agriculture and integrated nutrient management hold the key to enhance productivity and quality besides improving soil health and environment. Hence, maize productivity and quality were assessed under a maize-wheat cropping system (MWCS) using four crop-establishment and tillage management practices [FBCT-FBCT (Flat bed-conventional tillage both in maize and wheat); RBCT-RBZT (Raised bed-CT in maize and raised bed-zero tillage in wheat); FBZT-FBZT (FBZT both in maize and wheat); PRBZT-PRBZT (Permanent raised bed-ZT both in maize and wheat], and five P-fertilization practices [P100 (100% soil applied-P); P50 + 2FSP (50% soil applied-P + 2 foliar-sprays of P through 2% DAP both in maize and wheat); P50 + PSB + AM-fungi; P50 + PSB + AMF + 2FSP; and P0 (100% NK with no-P)] in split-plot design replicated-thrice. Double zero-tilled PRBZT-PRBZT system significantly enhanced the maize grain, starch, protein and oil yield by 13.1-19% over conventional FBCT-FBCT. P50 + PSB + AMF + 2FSP, integrating soil applied-P, microbial-inoculants and foliar-P, had significantly higher grain, starch, protein and oil yield by 12.5-17.2% over P100 besides saving 34.7% fertilizer-P both in maize and on cropping-system basis. P50 + PSB + AMF + 2FSP again had significantly higher starch, lysine and tryptophan content by 4.6-10.4% over P100 due to sustained and synchronized P-bioavailability. Higher amylose content (24.1%) was observed in grains under P50 + PSB + AMF + 2FSP, a beneficial trait due to its lower glycemic-index highly required for diabetic patients, where current COVID-19 pandemic further necessitated the use of such dietary ingredients. Double zero-tilled PRBZT-PRBZT reported greater MUFA (oleic acid, 37.1%), MUFA: PUFA ratio and P/S index with 6.9% higher P/S index in corn-oil (an oil quality parameter highly required for heart-health) over RBCT-RBCT. MUFA, MUFA: PUFA ratio and P/S index were also higher under P50 + PSB + AMF + 2FSP; avowing the obvious role of foliar-P and microbial-inoculants in influencing maize fatty acid composition. Overall, double zero-tilled PRBZT-PRBZT with crop residue retention at 6 t/ha per year along with P50 + PSB + AMF + 2FSP while saving 34.7% fertilizer-P in MWCS, may prove beneficial in enhancing maize productivity and quality so as to reinforce the food and nutritional security besides boosting food, corn-oil and starch industry in south-Asia and collateral arid agro-ecologies across the globe.

Remediation of soil polluted with petroleum hydrocarbons and its reuse for agriculture: Recent progress, challenges, and perspectives.

Petroleum hydrocarbons (PHs) are used as raw materials in many industries and primary energy sources. However, excessive PHs act as soil pollutants, posing serious threats to living organisms. Various ex-situ or in-situ chemical and biological methods are applied to restore polluted soil. However, most of the chemical treatment methods are expensive, environmentally unfriendly, and sometimes inefficient. That attracts scientists and researchers to develop and select new strategists to remediate polluted soil through risk-based analysis and eco-friendly manner. This review discusses the sources of PHs, properties, distribution, transport, and fate in the environment, internal and external factors affecting the soil remediation and restoration process, and its effective re-utilization for agriculture. Bioremediation is an eco-friendly method for degrading PHs, specifically by using microorganisms. Next-generation sequencing (NGS) technologies are being used to monitor contaminated sites. Currently, these new technologies have caused a paradigm shift by giving new insights into the microbially mediated biodegradation processes by targeting rRNA are discussed concisely. The recent development of risk-based management for soil contamination and its challenges and future perspectives are also discussed. Furthermore, nanotechnology seems very promising for effective soil remediation, but its success depends on its cost-effectiveness. This review paper suggests using bio-electrochemical systems that utilize electro-chemically active microorganisms to remediate and restore polluted soil with PHs that would be eco-friendlier and help tailor-made effective and sustainable remediation technologies.

Preparation and applications of chitosan and cellulose composite materials.

Chitosan is a natural fiber, chemically cellulose-like biopolymer, which is processed from chitin. Its use as a natural polymer is getting more attention because it is non-toxic, renewable, and biocompatible. However, its poor mechanical and thermal strength, particle size, and surface area restrict its industrial use. Consequently, to improve these properties, cellulose and/or inorganic nanoparticles have been used. This review discusses the recent progress of chitosan and cellulose composite materials, their preparation, and their applications in different industrial sectors. It also discusses the modification of chitosan and cellulose composite materials to allow their use on a large scale. Finally, the recent development of chitosan composite materials for drug delivery, food packaging, protective coatings, and wastewater treatment are discussed. The challenges and perspectives for future research are also considered. This review suggests that chitosan and cellulose nano-composite are promising, low-cost products for environmental remediation involving a simple production process.

Appraisal of contamination of heavy metals and health risk in agricultural soil of Jhansi city, India.

The accumulation of heavy metals (HMs) in soil is presently a significant threat to the environment. The Cu, Mn, Zn, Cd, Pb, Ni, and Co concentrations were assessed in the agricultural soil samples. The results of various contamination indices including contamination factor, geo-accumulation indices, and ecological risk indices revealed that Cd is responsible for moderate to high contamination of soil. The multivariate statistical analyses including PCA, HCA, and correlation matrix suggested the mixed origin of HMs in the soil. Ingestion was found to be a primary route of exposure while dermal and inhalation exposure was negligible. Overall, the non-carcinogenic health risks were well within the safe limit to human health. However, healthwise, children were likely to be at greater risk compared with adults, due to their generally increased exposure to toxic agents through hand/mouth ingestion. Moreover, no carcinogenic risks were determined through the inhalation exposure of Cd, Ni, and Co.