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Removal of benzene from indoor air by Dracaena sanderiana: Effect of wax and stomata
Abstract
From screening 8 ornamental plants, it was found that Dracaena sanderiana had the highest benzene removal efficiency. In a long-term study, 4 cycles of benzene were studied under both 24 h dark and 24 h light conditions. From the 2nd to 4th cycle, benzene uptake by plants under 24 h light condition had higher intensity than under 24 h dark conditions, and the close of D. sanderiana stomata was found only in 24 h dark condition. At the final cycle, D. sanderiana still survived, and benzene uptake continued. From the calculation, 46% of benzene was taken up by D. sanderiana crude wax, while 54% was predicted to be taken up by the stomata by 72 h.
... All of these VOC phytoremediation processes occur either at the site of uptake or after being translocated to other parts of the plant, such as the roots. The ability of VOC removal by the leaves of plants was confirmed by conducting experiments on VOC removal with aboveground plant parts after isolating and separating them from the roots and growing media using some physical obstructions (Tani and Hewitt 2009;Treesubsuntorn and Thiravetyan 2012;Sriprapat et al. 2014). The stomatal conductance determines VOC uptake by leaves. ...
... However, it was observed that despite the darkness and aerial parts, the elimination of VOCs was continuous. This continued VOC removal under dark conditions was attributed to the absorption of VOCs by the cuticle (Treesubsuntorn and Thiravetyan 2012). Thus, among the aerial parts of plants besides stomata, the cuticle also offers an efficient means of VOC removal by adsorbing or diffusing VOCs (Treesubsuntorn et al. 2013). ...
... Few researchers have suggested the role of cuticle wax quantity and its chemical structure in the elimination of VOCs (Treesubsuntorn et al. 2013). The removal of benzene, toluene, ethylbenzene, and xylene has been reported in Dracaena sanderiana and Z. zamiifolia (Treesubsuntorn and Thiravetyan 2012;Sriprapat and Thiravetyan 2013). The chemical properties of VOCs also determine the rate of VOC removal by plants. ...
Environmental pollution, especially indoor air pollution, has become a global issue and affects nearly all domains of life. Being both natural and anthropogenic substances, indoor air pollutants lead to the deterioration of the ecosystem and have a negative impact on human health. Cost-effective plant-based approaches can help to improve indoor air quality (IAQ), regulate temperature, and protect humans from potential health risks. Thus, in this review, we have highlighted the common indoor air pollutants and their mitigation through plant-based approaches. Potted plants, green walls, and their combination with bio-filtration are such emerging approaches that can efficiently purify the indoor air. Moreover, we have discussed the pathways or mechanisms of phytoremediation, which involve the aerial parts of the plants (phyllosphere), growth media, and roots along with their associated microorganisms (rhizosphere). In conclusion, plants and their associated microbial communities can be key solutions for reducing indoor air pollution. However, there is a dire need to explore advanced omics technologies to get in-depth knowledge of the molecular mechanisms associated with plant-based reduction of indoor air pollutants.
... In view of phytoremediation, studies show that the openings (cuticle and stomata) of plant bodies are responsible for potential VOC uptake, predominantly via stomata during the daytime when the stomata are open, unless it is a CAM plant (Weyens et al., 2015). Additionally, the occupied amount of VOCs on the waxy layer determine the potential of cuticular absorption (Treesubsuntorn and Thiravetyan, 2012;Sriprapat and Thiravertyan 2013). Once inserted into the plant system, either the VOCs undergo sequential degradation through the plant itself thereby transforming them into harmless constituents or the excretion and storage method in case degradation fails to occur (Weyens et al., 2015). ...
... Through the efficacy of phytoremediation based on plants' species specificity and pollutants' characteristics (Papinchak et al., 2009), it may easily provide a low-cost, energy-efficient, self-regulating, potential green replacement Luengas et al., 2015;Pettit et al., 2018a) either by active (green roof, green walls, bio-covers) or passive (potted plants and their association with microorganisms) approaches. There are several well-reported ornamental plants that are involved in abatement of particular air pollutions like Dracaena sanderiana (Treesubsuntorn and Thiravetyan, 2012), Schefflera arboricola, and Spathiphyllum wallisii (Parseh et al., 2018) for benzene; Schefflera actinophylla for xylene and toluene (Kim et al., 2016); Dieffenbachia compacta (Aydogan and Montoya, 2011) and Chamaedorea elegans (Teiri et al., 2020) for fomaldehyde; Chlorophytum comosum, Dracaena deremensis, and for trichloroethylene, benzene, and formaldehyde (Wolverton et al., 1989); and Dypsis lutescens for total volatile organic compounds, CO 2 , and CO (Bhargava et al., 2021). The initial idea that green systems can effectively ameliorate high levels of indoor air pollutants was investigated from space science research in order to evolve a spacecraft that is self-sustaining by utilising a biological life support system (Salisbury et al., 1997;Andre and Chagvardieff, 1997). ...
... The potted plants enable the decomposition of VOCs and were reported to reduce benzene by 15% (Lim et al., 2009). Nonetheless, to observe the VOC removal capacity of aerial parts, in a few experiments the aboveground part of the plant was subjected to a physical barrier and isolated from the rest of the substrate, along with the root zone, which showed a positive response independently (Tani et al., 2007;Tani and Hewitt, 2009;Treesubsuntorn and Thiravetyan, 2012;Treesubsuntorn et al., 2013;Sriprapat and Thiravertyan, 2013;Sriprapat et al., 2014a, b). Aydogan and Montoya (2011) set an experiment to observe the efficiency of the formaldehyde-removal capacity of plant root zones and aerial parts separately. ...
... In addition, wood-based panel products commonly used in the residential unit are the main sources of VOCs, especially particleboards emitting halogenated compounds, ester, and aromatic hydrocarbons . Even though VOCs can be oxidized by UV light or sunlight, the indoor conditions have low light intensity, which may not be adequate to oxidize these compounds (Talhout et al. 2011;Treesubsuntorn and Thiravetyan 2012). In addition, poor air ventilation is generally the main problem for indoor pollutant accumulation since ventilation can help dilute pollutant concentrations by bringing in fresh outdoor air (Treesubsuntorn and Thiravetyan 2012). ...
... Even though VOCs can be oxidized by UV light or sunlight, the indoor conditions have low light intensity, which may not be adequate to oxidize these compounds (Talhout et al. 2011;Treesubsuntorn and Thiravetyan 2012). In addition, poor air ventilation is generally the main problem for indoor pollutant accumulation since ventilation can help dilute pollutant concentrations by bringing in fresh outdoor air (Treesubsuntorn and Thiravetyan 2012). Cavalcante et al. (2006) indicated that the indoor level of carbonyl compounds (CCs) is higher than outdoor affecting increasing of cancer risk in indoor air. ...
... Many studies report the accumulation of several pollutants indoors such as benzene, toluene, ethylbenzene, xylene, and formaldehyde (Chikara et al. 2009). High BTEX, formaldehyde, ozone, and trimethylamine concentrations are frequently found in indoor conditions (Treesubsuntorn et al., 2012;Sriprapat and Thiravetyan 2013;Boraphech and Thiravetyan 2015;Chen et al. 2018;Li et al. 2019). Taking in these compounds in high concentration can affect human systems such as the nervous and respiratory systems. ...
High-rise residential developments are rapidly increasing in urban areas. Smaller residential units in this high rise bring a reduction in windows, resulting in poor indoor air ventilation. In addition, materials used in interiors can emit volatile organic compounds (VOCs), which can significantly affect human health. Since people spend 90% of their time indoors, an evaluation of indoor air quality is especially important for high-rise residential buildings with an analysis of determining factors. This study aims to measure the concentrations of VOCs, formaldehyde, and particulate matter (PM2.5 and PM10) in 9 high-rise residential buildings in Bangkok by using the accidental sampling method (n = 252) and to investigate possible important determining factors. The results show that the average concentrations of VOCs, formaldehyde, PM2.5, and PM10 in 9 high-rise residential buildings were at good to moderate levels in the indoor air quality index (IAQI) and that high pollutant concentrations were rarely found except in new constructions. Moreover, it was found that the age of buildings shows strong correlations with all pollutants (p value < 0.0001). Old buildings showed significantly lower pollutant concentrations than new and under-construction buildings at a 95% confidence level. The findings from this investigation can be used as part of sustainable well-being design guidelines for future high-rise residential developments.
... For instance, P450 monooxygenase has been used to convert benzene to phenol, and formaldehyde dehydrogenase has been employed for formaldehyde degradation. (Treesubsuntorn and Thiravetyan 2012;Khaksar et al. 2017a). Many plant species can remove PM and VOCs effectively. ...
... Dracaena braunii Engl. was proposed as the most efficient plant for benzene remediation (Treesubsuntorn and Thiravetyan 2012). In 2013, Zamioculcas zamiifolia (Lodd.) ...
Particulate matters (PM) and volatile organic compounds (VOCs) are the sources of toxic substances that hurt human health and can cause human carcinogens. An active living wall was applied to reduce PM and VOC contamination, while Sansevieria trifasciata cv. Hahnii, a high-performance plant for VOC removal, was selected to grow on the developing wall and used to treat PM and VOCs. The active living wall operating in a 24 m³ testing chamber showed the ability to remediate more than 90% PM within 12 h. The VOC removal can be approximately 25–80% depending on each compound. In addition, the suitable flow velocity of the living wall was also investigated. The flow rate of 1.7 m³ h⁻¹ in front of the living wall was found as the best inlet flow velocity for the developed active living wall. The suitable condition for PM and VOC removal in the active living wall application on the real side was presented in this study. The result confirmed that the application of an active living wall for PM phytoremediation can be an alternative effective technology.
... Various methods can be applied to remove air contamination. Air phytoremediation is well-known as feasible biotechnology and easy-toapply, low-cost, eco-friendly, and sustainable technology [13,18,19]. NASA started to give funding in 1989s to support project air phytoremediation technology. ...
... It is well known that stomata are located along hypocotyl in higher plants such as Cucumis sativus, Arabidopsis thaliana, as well as V. radiata sprouts [49][50][51]. Where stomata are known as major pathways of VOCs removal by plants [19,52,53]. Since simulated microgravity did not affect stomata density in plant seedlings [54], it might be that longer hypocotyl of V. radiata under μG may allow gaseous toluene to be removed faster than V. radiata under 1G. ...
Air phytoremediation is one of the sustainable and eco-friendly biotechnology to remedy polluted atmospheric environment. The microgravity environment in International Space Station (ISS) cabin is contaminated with various traces of volatile organic compounds (VOCs), such as toluene. The mature plant showed the capability to remove air pollution under simulated microgravity (μG). However, generally, plants are brought to space in seed form. In this study, we tried to observe gaseous toluene phytoremediation by Vigna radiata seedlings grown under μG started from the seeds form and evaluate its effect on seedling's growth and plant stress response through endogenous hormones auxin and gibberellin. V. radiata could remove toluene under μG generated by Random Positional Machine at 24 h, 72 h, and 120 h and seem better compared to V. radiata under 1G. Under μG, V. radiata with or without toluene showed strange hypocotyl bending direction, and some roots grew to aerial parts. Gibberellic acid (GA3) showed higher under μG compared to under 1G. Indole-3-acetic acid (IAA) content in shoots of V. radiata under μG + toluene showed similar to that of V. radiata under μG and 1G, whereas V. radiata under 1G + toluene had higher IAA almost two times compared to other treatments. V. radiata under 1G + toluene likewise showed shorter hypocotyl length and lower fresh weight compared to other treatments. This study demonstrated that IAA of V. radiata under μG was maintained at a suitable level, although being exposed to 50 ppm toluene resulted in preventing stunted growth.
... Additionally, indoor plants can add life to a sterile office, provide privacy, and abate noise levels(Burton 2001). Compared to conventional air purification techniques, indoor plants offer an environment-friendly cost-effective purification of indoor air by eliminating harmful toxins and particulate matter(Gawronska and Bakera 2015) as proven by systematic evaluation of 28 commonly used ornamental indoor plant species for their ability to remove volatile indoor pollutants: aromatic hydrocarbons (benzene and toluene), aliphatic hydrocarbon (octane), halogenated hydrocarbon, and terpene (α-pinene)(Yang et al. 2009;Treesubsuntorn and Thiravetyan 2012;Cruz et al. 2014;Parseha et al. 2018). ...
... ). Indoor plants consist of a wide variety of native and introduced herbs, shrubs, dwarf trees, climbers, and succulents. The potential role of the indoor plants largely varies with their genetic variation, species, and habit(Park et al. 2010;Aydogan and Montoya 2011;Treesubsuntorn and Thiravetyan 2012; ...
Integrating greeneries into the indoor dwelling environment boosts work performance and relieves stress to add to the overall psychological well-being especially in deserted urban settings. In addition to mental soothing, thermal regulation, air purification, aesthetics, public health, and comfort, the addition of plants to indoor settings may also contribute to the conservation of dwindling floral biodiversity. Despite authorities’ pledge for sustainable urban management, the status of indoor gardening has hitherto remained unexplored in the emerging megapolis of Bangladesh—Chattogram—the second largest urban center of the country. In addressing that gap, this study aims to explore the composition, diversity, and management of indoor plants in urban dwellings at Halishahar of Chattogram based on interviews on 48 households selected through multistage random sampling. Data from all selected households were collected by using a semi-structured questionnaire through physically visiting the households. Almost half of the households (48%) living at Halishahar had indoor plants in their dwellings. The study recorded a handsome 120 indoor plant species belonging to 108 genera from 60 families. While the diversity was in no way comparable to the tropical ecosystem of the country, in consideration of the strict set of requirements for plants to be suitable for an indoor setting, the diversity seemed excellent as evident from four diversity indices. Soil mixed with compost, sand, and surki at different ratios is used as potting media. Pests were identified as the major challenge in managing the indoor plants. Application of domestic manure with the potting media was common as a means to maintain the nutrient flow. Bruised tea leaf is the most frequently added nutrient supplement. Apart from the aesthetic values, urban dwellers from Halishahar reported the immense potential of indoor gardening in supplementing daily nutrition and in mitigating the impacts of climate change. The lessons from this study can be used in informed policymaking for the promotion of biodiversity conservation and other benefits from indoor greening among urban dwellers in Bangladesh.
... Additionally, indoor plants can add life to a sterile office, provide privacy, and abate noise levels(Burton 2001). Compared to conventional air purification techniques, indoor plants offer an environment-friendly cost-effective purification of indoor air by eliminating harmful toxins and particulate matter(Gawronska and Bakera 2015) as proven by systematic evaluation of 28 commonly used ornamental indoor plant species for their ability to remove volatile indoor pollutants: aromatic hydrocarbons (benzene and toluene), aliphatic hydrocarbon (octane), halogenated hydrocarbon, and terpene (α-pinene)(Yang et al. 2009;Treesubsuntorn and Thiravetyan 2012;Cruz et al. 2014;Parseha et al. 2018). ...
... ). Indoor plants consist of a wide variety of native and introduced herbs, shrubs, dwarf trees, climbers, and succulents. The potential role of the indoor plants largely varies with their genetic variation, species, and habit(Park et al. 2010;Aydogan and Montoya 2011;Treesubsuntorn and Thiravetyan 2012; ...
Permaculture has been known to intentionally integrate diversity into the design of farms and mimic natural landscapes. This approach is in contrast to the mainstream monocropping system in conventional agriculture. The objectives of the study were to identify what plant species are commonly cultivated in permaculture farms and determine its uses as narrated by farmers and practitioners. The researchers conducted a crop inventory in 12 permaculture sites in the Philippines from August to November in 2018. To survey a 1 ha sampling area, a modified belt transect method with alternating 20 m2 plots was employed for full enumeration of plant species in each plot. To determine uses, key informant interviews and focus group discussions were conducted among farm staff. A total of 215 plant species were identified with an average species richness of 46 per farm. A comparison of crop inventories revealed that Colocasia esculenta and Capsicum frutescens were the most commonly cultivated crops found in ten sites (83%). It is followed by Annona muricata (nine sites) and Bambusoideae (eight). Results revealed that the majority of crops found were cultivated for household consumption.
... Additionally, indoor plants can add life to a sterile office, provide privacy, and abate noise levels(Burton 2001). Compared to conventional air purification techniques, indoor plants offer an environment-friendly cost-effective purification of indoor air by eliminating harmful toxins and particulate matter(Gawronska and Bakera 2015) as proven by systematic evaluation of 28 commonly used ornamental indoor plant species for their ability to remove volatile indoor pollutants: aromatic hydrocarbons (benzene and toluene), aliphatic hydrocarbon (octane), halogenated hydrocarbon, and terpene (α-pinene)(Yang et al. 2009;Treesubsuntorn and Thiravetyan 2012;Cruz et al. 2014;Parseha et al. 2018). ...
... ). Indoor plants consist of a wide variety of native and introduced herbs, shrubs, dwarf trees, climbers, and succulents. The potential role of the indoor plants largely varies with their genetic variation, species, and habit(Park et al. 2010;Aydogan and Montoya 2011;Treesubsuntorn and Thiravetyan 2012; ...
Breeders need access to unique genetic variability to meet the growing demand for food while maintaining sustainable agricultural production with the impacts of climate change for generating high-quality nutritional food. Changes in climate and anthropogenic activities and a multitude of environmental influences pose severe threats to food supply and preservation of natural diversity. For example, unpredictable droughts, elevated temperature, and new diseases and pests threaten crop production. Thus, breeding with crop wild relatives (CWR) gives significant resilience to modern agricultural systems and the ability to help sustainably boosting agricultural productivity. As a result, numerous genotype screenings are necessary for broad adaptability, producing a segregating material through fast breeding or rapid generation to shorten the breeding cycle and improving genetic gain. In addition, CWR genomics generates data that support CWR’s usage to boost agricultural genetic diversity. QTL mapping, identifying of candidate genes by next-generation sequencing, gene-based marker development, or significant candidate gene pyramiding of stress-responsive loci in popular cultivar are required to maintain the sustainability of crop production. Thus, genomic data is useful for identifying and isolating novel and dominant alleles of genes from crop gene pools that are agronomically important, which can be used to generate improved crop cultivars. Hence, the natural allelic difference in candidate genes that influences major agronomic characteristics and crop development initiatives is being investigated via allele mining. Among the CWRs of economically important crops, the wild species of rice is essential to improve modern rice cultivars. The awareness of novel genetic and genomic approaches of rice genetic resources for efficient utilization is crucial. Further, their conservation status and availability have not been quantified globally. As a result, a joint effort is required to improve the conservation and accessibility of crop wild relatives for rice breeding.
Keywords: Genomics of CWR, Crop improvement, Rice genetic resources
... Although the stomata were closed during drought conditions, the increased VOC removal may be attributed to the presence or increase in wax on the leaf surface [13,14]. Briefly, the quantity and composition of wax can influence VOC removal during the closed stomata as reported in the previous studies [15,16]. In contrast, the pattern of CO 2 RE varied with that of PM2.5 and VOCs. ...
... The accumulated RE of VOCs observed a similar trend as that of PM2.5. Although drought conditions revealed closed stomata, the higher VOCs removal may likely be due to the presence or increase of wax on the leaf surface; previous studies have reported the removal of benzene using wax [15,16]. ...
Particulate matter has been increasing worldwide causing air pollution and serious health hazards. Owing to increased time spent indoors and lifestyle changes, assessing indoor air quality has become crucial. This study investigated the effect of watering and drought and illumination conditions (constant light, light/dark cycle, and constant dark) on particulate matter2.5 (PM2.5) removal and surface characterization of leaf in a botanical plant-based biofilter system. Using Ardisia japonica and Hedera helix as experimental plants in the plant-based biofilter system, PM2.5, volatile organic carbon, and CO2, as the evaluators of indoor air quality, were estimated using a sensor. Morphological and chemical changes of the leaf surface (i.e., roughness and wax) associated with PM2.5 removal were characterized via scanning electron microscopy, Fourier transform infrared spectroscopy, and atomic force microscopy. The highest PM2.5 removal efficiency, stomata closure, high leaf roughness, and wax layer were observed under drought with constant light condition. Consequently, PM2.5 removal was attributed to the combined effect of leaf roughness and wax by adsorption rather than stomatal uptake. These results suggest that operating conditions of indoor plant-based biofilter system such as watering (or drought) and illumination may be applied as a potential strategy for enhancing PM2.5 removal.
... With the development of society and the transformation of lifestyles, indoor air quality is garnering increasing amounts of attention as people spend more than 90% of their time indoors each day (Treesubsuntorn and Thiravetyan 2012;Cruz et al. 2014). Although the awareness of the human health impacts of exposure to air pollution growing rapidly (Caplin et al. 2019), indoor air quality is undergoing deterioration. ...
... Both hydrophilic and hydrophobic pollutants can adhere to the surface of the cuticular wax and penetrate into the plant when the concentration of pollutants on the leaf surface exceeds the equilibrium value (Kvesitadze et al. 2006). The adsorption of cuticular wax comprises 46% of the capacity of Dracaena sanderiana to remove benzene (Treesubsuntorn and Thiravetyan 2012), and 20%, 23%, 25%, and 26% of the capacity of Zamioculcas zamiifolia Engl. to remove benzene, toluene, ethylbenzene, and xylene, respectively (Sriprapat and Thiravetyan 2013). Formaldehyde can also enter the plant directly through the opened stomata, which play a significant role in the purification of pollutants in the aerial part. ...
Decorative plants can efficiently purify formaldehyde and improve the quality of indoor air. The existing studies primarily revealed that the aerial and underground parts of plants’ capacity to purify formaldehyde, while the performance of stems is unclear. A formaldehyde fumigation experiment was conducted on Epipremnum aureum and Rohdea japonica in a sealed chamber. Results showed the stems could remove formaldehyde. The efficiency of removal by the stems of each plant was 0.089 and 0.137 mg∙m−3∙h−1, respectively, the rate of purification was 40.0 and 61.6%, respectively. Both were related to plant species and the latter was affected by other factors like exposed area. To further explore the mechanism of phytoremediation, the correlation between the concentration of formaldehyde and CO2 during the experiment was investigated. Results showed when leaves of plants were exposed to formaldehyde, the concentration of CO2 increased with the decrease in concentration of formaldehyde, and the change in concentration of CO2 could be used as an indicator of the degree of decontamination of formaldehyde by the plants.
... The research has also indicated that plants' purifying ability is directly impacted by the pollutant's concentration (Cesur et al., 2022) and the environment they are exposed to it (Cicek et al., 2022). Airborne benzene entered the plant via foliar adsorption and leaf stomatal uptake (Treesubsuntorn & Thiravetyan, 2012), was transported downward through the phloem to the roots, and was released into the rhizosphere environment (Li et al., 2023). In this process, the plant's ability to transport pollutants plays a central role, which determines whether the plant can effectively move pollutants to various parts of its body where enzymes can break them down. ...
With the increasingly serious problem of air pollution, although plants have a certain air purification function, their inherent purification ability and efficiency are generally low. This study innovatively combined immobilized enzyme MIL-88B (Fe)/HRP with three plant species to construct a novel air purification system. The aim is to enhance the purification rate of plants for benzene. By evaluating the purification effects of the combined system on benzene under different initial concentrations and exposure times, the study also analyzes the impact of immobilized enzymes on the antioxidant system of plants. The results indicate that after introducing MIL-88B (Fe)/HRP into the rhizosphere solution of plants, the transport rates of Spathiphyllum kochii, Epipremnum aureum, and Chlorophytum comosum in the combined system significantly increased, by 294, 418, and 334 times, respectively, compared to the single plant system. The maximum purification rates were 3.87, 3.18, and 1.42 times higher than the single systems. Immobilized enzymes increased the activity of POD enzymes in plants, enhancing plant tolerance to benzene. The effective degradation of benzene in the rhizosphere solution by MIL-88B (Fe)/HRP has led to the creation of a benzene concentration gradient across multiple interfaces of the air-leaf-root-rhizosphere solution, facilitating the unidirectional transport of benzene within the plant body. This process enhances the plant's purification ability towards benzene. This work offers novel concepts and a theoretical foundation for environmental pollution control, in addition to broadening the application boundaries of phytoremediation technology.
... Stomata and cuticle wax also influence plants' pollutant removal efficiency. Several studies have found that the opening and the closure of stomata influence the pollutant removal rate of the plants since the pollutants are absorbed through the stomata or the cuticle [43,51]. Dieffenbachia maculata and Spathiphyllum wallisii have higher 2-ethyl hexanol removal rates during open stomata than in closed stomata. ...
Degradation of Indoor Air Quality (IAQ) due to confined spaces and insufficient ventilation has become a serious concern to human health. Published literature has established phytoremediation as an efficient removal mechanism of indoor air pollutants such as formaldehyde, Benzene, Toluene, Ethyl benzene, Xylene (BTEX), Volatile Organic Compounds (VOCs), and Particulate Matter (PM) using potted plants. This review discusses both conventional and enhanced phytoremediation for removing air pollutants and the parameters influencing the removal efficiencies. A literature review was conducted following the PRISMA guidelines to identify published literature on indoor air phytoremediation. After eliminating duplicates and reviewing articles, the articles related to indoor air phytoremediation from 2011 to the present were selected. The database was managed using Mendeley reference manager. Indoor air pollutants can be removed efficiently through phytoremediation using potted plants. Chlorophytum comosum removed the broadest range of contaminants, whereas Epipremnum aureum is the frequently used plant species for pollutant removal. Adding enhancing factors to the plant enhances their ability to remove pollutants. Inoculation of plants with soil bacteria such as Bacillus cereus ERBP is the most common enhancement method reported. The present study highlighted advancements in phytoremediation and factors affecting the pollutant removal efficiencies of plants. The findings demonstrated that enhanced phytoremediation is more effective at removing pollutants than the conventional method. Depending on the plant species used, the removal of indoor air pollutants may vary. The findings suggested that a combination of various plant species could be used to remove indoor air pollutants more efficiently.
... At present, relevant scholars have conducted many relevant studies on the purification ability and resistance of indoor plants to benzene and other indoor chemical pollution 12,[29][30][31] . However, previous studies have mainly focused on determining the single purification rate [32][33][34] or purification amount of indoor plants for benzene and other pollutants [35][36][37][38][39] , and few studies have been reported to comprehensively evaluate the purifying ability of multiple indoor plants against benzene pollution in terms of both plant purification rate and purification amount per unit area. ...
The ability of indoor plants to purify benzene pollution is the basic basis for the selection of plants for ecological remediation of indoor benzene pollution. In this study, the purification rate and the purification amount per unit leaf area of 13 test plants at three benzene concentrations were determined by indoor fumigation experiments, and the benzene absorption and purification abilityability of indoor plants were comprehensively evaluated. The results showed that (1) there was a significant correlation between benzene concentration and purification rate and purification amount per unit leaf area. (2) At the three concentrations, Spathiphyllum floribundum showed the highest purification rate and Sansevieria trifasciata var. laurentii showed the highest purification per unit leaf area. (3) The combined results showed that Sansevieria trifasciata var. laurentii, Spathiphyllum floribundum and Aloe arborescens were the strongest absorbers and purifiers, while Podocarpus nagi and Anthurium andraeanum ‘Pink champin’ had the weakest absorption and purification capacity. The results of this study provide a theoretical basis and reference for the selection of plants with strong capacities to adsorb and purify benzene pollution in indoor air.
... Since several inorganic air pollutants (e.g., ozone and CO 2 ) and biogenic volatiles are unable to directly penetrate plant tissues, stomata are major passages for these pollutants to enter the interior part of leaves (Engineer et al. 2016;Hasan et al. 2021;Li et al. 2017;López-Gresa et al. 2018;Wu et al. 2018). In Chinese water bamboo Dracaena sanderiana, stomata can take up more than 50% of the total amount of benzene when fumigated for 72 h (Treesubsuntorn and Thiravetyan 2012). Once these inorganic air pollutants enter the leaf, they diffuse into intercellular spaces, get absorbed by water films and may generate acids, react with inner leaf surfaces, transform into less toxic compounds, or be translocated and stored in other plant organs (Hill 1971;Nowak et al. 2014;Agarwal et al. 2018;Ravindra and Mor 2022;Yoo et al. 2006). ...
Indoor air pollution is a global problem and one of the main stress factors that has negative effects on plant and human health. 3-methyl-1-butanol (3MB), an indoor air pollutant, is a microbial volatile organic compound (mVOC) commonly found in damp indoor dwellings. In this study, we reported that 1 mg/L of 3MB can elicit a significant reduction in the stomatal aperture ratio in Arabidopsis and tobacco. Our results also showed that 3MB enhances the reactive oxygen species (ROS) production in guard cells of wild-type Arabidopsis after 24 h exposure. Further investigation of 24 h 3MB fumigation of rbohD, the1-1, mkk1, mkk3, and nced3 mutants revealed that ROS production, cell wall integrity, MAPK kinases cascade, and phytohormone abscisic acid are all involved in the process of 3MB-induced stomatal. Our findings proposed a mechanism by which 3MB regulates stomatal closure in Arabidopsis. Understanding the mechanisms by which microbial indoor air pollutant induces stomatal closure is critical for modulating the intake of harmful gases from indoor environments into leaves. Investigations into how stomata respond to the indoor mVOC 3MB will shed light on the plant’s “self-defense” system responding to indoor air pollution.
Graphical Abstract
... Fortunately, there is a rapidly growing body of literature documenting the capacity of plant-based systems to remove volatile organic compounds (VOCs) from indoor environments (Aydogan and Montoya 2011;Torpy et al. 2018b;Wolverton et al. 1984;Wood et al. 2006). For instance, Liu et al. (2022) observed 30.04% removal of total VOCs (TVOC) from cigarettes over a 12-h period, while Treesubsuntorn and Thiravetyan (Treesubsuntorn and Thiravetyan 2012) documented 45-77% removal of benzene over 72 h using Dracaena sanderiana Mast. ...
The capacity for indoor plants including green wall systems to remove specific volatile organic compounds (VOCs) is well documented in the literature; however under realistic settings, indoor occupants are exposed to a complex mixture of harmful compounds sourced from various emission sources. Gasoline vapour is one of the key sources of these emissions, with several studies demonstrating that indoor occupants in areas surrounding gasoline stations or with residentially attached garages are exposed to far higher concentrations of harmful VOCs. Here we assess the potential of a commercial small passive green wall system, commercially named the ‘LivePicture Go’ from Ambius P/L, Australia, to drawdown VOCs that comprise gasoline vapour, including total VOC (TVOC) removal and specific removal of individual speciated VOCs over time. An 8-h TVOC removal efficiency of 42.45% was achieved, along with the complete removal of eicosane, 1,2,3-trimethyl-benzene, and hexadecane. Further, the green wall also effectively reduced concentrations of a range of harmful benzene derivatives and other VOCs. These results demonstrate the potential of botanical systems to simultaneously remove a wide variety of VOCs, although future research is needed to improve upon and ensure efficiency of these systems over time and within practical applications.
... plant-mediated Ag NPs are still needed to be explored [18]. Dracaena Trifasciata plants [19], commonly known as snake plant, is an evergreen indoor plant from the Asparagaceae family. The typical color of their leaves is dark green containing distinct white or yellow vertical lines (figure 1). ...
Green synthesis of NPs evades many of the deleterious aspects by permitting the synthesis of nanoparticles at relatively low temperatures, pH and pressure, all at a significantly lower cost and short time. A bottom-up approach is used for the synthesis of silver nanoparticles formed due to the reduction of silver ions because of the existence of the phytochemicals contained in the Dracaena Trifasciata plant extract, which is primarily used for the study of green synthesis. X-ray diffraction, scanning electron microscope, Uv-Vis spectroscopy, and Fast Fourier Infrared spectroscopy characteristic techniques are used to analyze the nature of the silver nanoparticles formed by the green synthesis method. To prevent the over-growth of silver nanoparticles and avoid their aggregation, one fatty acids based and one amides based capping agent has been used for the comparison purpose for the preservation of the silver nanoparticles in term of shape, size and coagulation, which is a novel study. Amides interacted with the silver nanoparticles via electrostatic interactions which result in strong stabilization compared to the fatty acids which make van der wall interactions with the surface of the nanoparticles but for bio compatibility and environmentally friendly applications, fatty acid based capping agent can be preferred as these NPs are also suitable for the use in the field of medicine and pharmaceuticals.
... However, the ability of the whole potted plant system to remove air pollutants is the gathering effect of the plant, and its associated microflora are scarce in the literature Khalifa et al. 2023;Matheson et al. 2023). In the literature, S. trifasciata plant is also recommended as a good and hardy plant that can be kept indoors at many times of the year (Yang et al. 2009;Zhou et al. 2011;Treesubsuntorn and Thiravetyan 2012;Sriprapat et al. 2014). ...
Sansevieria trifasciata plant is one of the most popular indoor plant around the world. Its potential for toluene removal in intramural conditions is well known. S. trifasciata potted plants also degrade toluene through their phyllosphere, rhizosphere, endophytes, and soil-associated microbial activities. Since the phyllosphere is a transient habitat, this study focused on the other microbial habitats associated with the S. trifasciata potted plant. Hence, the soil and endophytic bacterial isolates were selected after three successive enrichments with 1% toluene. The redox indicator 2.6-dichloro phenol indophenol (DCPIP) activity was used to rank this bacteria's ability to degrade toluene. The two most active isolates were chosen and subjected to molecular identification and quantitative analysis to measure toluene degradation. The headspace initial toluene concentration was 41,385 ± 404 mg/m3 ~ 104 ppm, after 28 days, bacterial isolates Priestia aryabhattai TE2 and Metabacillus halosaccharovorans 3S1 were found to have reduced toluene by 17.34% and 40.53%, respectively, while the survival rates were revealed as 96.8 ± 14.6% and 1863 ± 143%, respectively. M. halosaccharovorans 3S1 has good growth over the time while degrading toluene.
... Many studies on the effect of light intensity on the decontamination capacity of plants have been conducted, but the conclusions were not consistent. Similar to the results of this study, some researchers concluded that the capacity of plants to remove air pollutants in the light was stronger than that in the dark (Teiri et al. 2018, Treesubsuntorn andThiravetyan 2012). Xu et al. ) supposed that the metabolic activities of plants and microorganisms in the soil were stronger in the light, which promoted the overall purifying capacity of plants. ...
Phytoremediation technology is an effective method to remove formaldehyde indoors, but the purification capacity and physiological response of plants to formaldehyde under the simultaneous influence of light and CO2 have not been examined in previous studies. In this study, formaldehyde fumigation experiments were conducted on the C3 plants Epipremnum aureum A. and Chlorophytum comosum L., and the crassulacean acid metabolism (CAM) plant Dieffenbachia maculate A. The phytoremediation performance and physiological response of plants were studied. The initial concentration of formaldehyde was established at 11.950 ± 1.442 [Formula: see text]; the light intensities were 448 ± 7 [Formula: see text], 1628 ± 22 [Formula: see text], and 3259 ± 22 [Formula: see text], respectively; and the concentrations of CO2 were 455 ± 29 [Formula: see text], 978 ± 50 [Formula: see text], 2020 ± 66 [Formula: see text], and 3006 ± 95 [Formula: see text], respectively. The results indicated that the highest purification rates of formaldehyde by E. aureum, D. maculata, and C. comosum were 55.8%, 43.7%, and 53.2%, respectively. The light intensity had a positive effect on the formaldehyde purification rates of all three plants and positively stimulated peroxidase (POD) activity, while the CO2 concentration had no significant impact on the formaldehyde purification capacity and plants' physiological characteristics. Exposure to formaldehyde inhibited formaldehyde dehydrogenase (FADH) activity and positively stimulated catalase (CAT) activity. The superoxide dismutase (SOD) activity positively correlated with the formaldehyde purification capacity of plants.
... While differences between species were observed, the general conclusion was that all plant species were effective at removing VOCs to some degree, and that the driver for phytoremediation was likely to be the rhizospheric microbial community which existed in a symbiotic relationship with the plant (Irga et al. 2013;Torpy et al. 2013). This idea was further affirmed through experimentation where plant parts were isolated using foil or Teflon bags to determine the effect of specific plant parts or the substrate bacterial community (Aydogan and Montoya 2011;Sriprapat et al. 2014a, b;Sriprapat et al. 2014a, b;Treesubsuntorn and Thiravetyan 2012). It was assumed that light intensity would enhance foliar uptake of VOCs through an increase in stomatal conductance (Kondo et al. 1995;Porter 1994), however the results from these experiments were inconsistent, and phytocatalysation may have been a factor in the removal of certain chemical species, especially formaldehyde which is known to be susceptible to photocatalysis (Kondo et al. 1995;Teiri et al. 2018;Xu et al. 2011), whereas more stable aromatics such as benzene and toluene were unaffected (Hörmann et al. 2018;Orwell et al. 2004;Wood et al. 2002). ...
Poor indoor air quality has become of particular concern within the built environment due to the time people spend indoors, and the associated health burden. Volatile organic compounds (VOCs) off-gassing from synthetic materials, nitrogen dioxide and harmful outdoor VOCs such benzene, toluene, ethyl-benzene and xylene penetrate into the indoor environment through ventilation and are the main contributors to poor indoor air quality with health effects. A considerable body of literature over the last four decades has demonstrate the removal of gaseous contaminants through phytoremediation, a technology that relies on plant material and technologies to remediate contaminated air streams. In this review we present a state-of-the-art on indoor phytoremediation over the last decade. Here we present a review of 38 research articles on both active and passive phytoremediation, and describe the specific chemical removal efficiency of different systems. The literature clearly indicates the efficacy of these systems for the removal of gaseous contaminants in the indoor environment, however it is evident that the application of phytoremediation technologies for research purposes in-situ is currently significantly under studied. In addition, it is common for research studies to assess the removal of single chemical species under controlled conditions, with little relevancy to real-world settings easily concluded. The authors therefore recommend that future phytoremediation research be conducted both in-situ and on chemical sources of a mixed nature, such as those experienced in the urban environment like petroleum vapour, vehicle emissions, and mixed synthetic furnishings off-gassing. The assessment of these systems both in static chambers for their theoretical performance, and in-situ for these mixed chemical sources is essential for the progression of this research field and the widespread adoption of this technology.
... Banana plants have various cuticle thicknesses [67]. Although the plants were grown under dark conditions, the plants could still grow and uptake benzene only through cuticular wax because the stomata was closed under dark conditions [68] [69]. Benzene concentration in the atmosphere was found to be higher than the local standard guidelines in many places around the world [70]. ...
The quality of air is vital for our existence. Increasing industrial development and household activities will increase the risk of air pollution and environmental damage. Some air pollution in ambient air quality is very toxic and lethal. One method that can remove gaseous pollutants is adsorption. Previous study about banana plant as adsorbent of gaseous pollutant, banana leaves has the highest adsorption efficiency value of 76.52%. Purpose of this study to discuss characteristics and potential of banana leaves as gaseous adsorbent. This research was carried out by studying literature and testing the Scanning Electron Microscope (SEM) of the banana leaf surface morphology. The structural properties of adsorbent were characterized, which exhibited the adsorbent’s porous surface or stomata. There are several studies of the SEM analysis results that explain stomata are able to trap air pollution. Banana leaves contain lignin, cellulose, and cuticle which have been found in several studies to be useful as gas adsorbents. Based on these studies, it can be concluded that banana leaves have potential as an adsorbent of gaseous pollutants.
... The difference in metabolic activity between compounds is also a key factor; however, it is unclear, with limited evidence in the present study, whether metabolic activity converting benzaldehyde is lower than those converting phenol and benzyl alcohol. Accumulation of MAHs into leaf cuticular wax might occur (Treesubsuntorn and Thiravetyan, 2012). However, in the present study the regression line between stomatal conductance and normalized uptake rate passed through the origin (Fig. 4), indicating that the deposition causing the accumulation into leaf cuticular wax was negligible low when stomata was closed. ...
Large amounts of monocyclic aromatic hydrocarbons (MAHs) are emitted into the atmosphere, but it is unclear which compounds among MAHs are effectively removed by the above-ground parts of plants. Although fumigation experiments of MAHs at unrealistically high concentrations (~ppmv) have been conducted, experiments with ambient concentrations have scarcely been conducted. In the present study, MAHs, including benzene, toluene, phenol, benzaldehyde, and benzyl alcohol, with concentrations ranging from several to several tens ppbv, were individually fumigated to four plant species, and the uptake was monitored using proton-transfer-reaction mass spectrometry and gas chromatography-mass spectrometry. No detectable uptake was observed for benzene and toluene, but phenol, benzaldehyde, and benzyl alcohol were significantly taken up by the plants. The uptake rate normalized to fumigated concentration varied from 3 to 50 mmol m⁻²s⁻¹ during the light period, depending on light intensity and compounds. The difference in uptake capability may be attributed not only to different metabolic activities but also to different values of Henry’s law constant, which regulates the partitioning of these compounds into the liquid phase in leaves. The uptake of phenol, benzaldehyde, and benzyl alcohol was affected by stomatal conductance, suggesting that stomatal opening is the main factor regulating the uptake of the three MAHs. This is the first observation that anisole is emitted when phenol is fumigated to Spathiphyllum clevelandii, suggesting that phenol is methylated to anisole within plant leaves. Anisole is more volatile than phenol, meaning that methylation enhances the emission of xenobiotics into the atmosphere by converting them to more volatile compounds. This conversion ratio decreased with an increase in phenol concentration (from 1.3 to 143 ppbv). Considering low reaction rate coefficient of anisole with OH radicals and low conversion ratio from phenol to anisole, it is concluded that plants act to effectively remove oxygenated MAHs from the atmosphere.
... Moreover, banana leaves have more stomata when compared to branches and peels. Stomata are an important pathway for air pollutant uptake in plants [34]. Thus, having more stomata means having greater potential to absorb gaseous pollutants. ...
Bananas have the highest production rate among fruits in Indonesia, which leads to the generation of a significant amount of banana fruit solid waste. In this study, we assessed the potential use of banana waste to remove hydrogen sulfide (H2S) gas. In particular, the purpose of this study was to analyze the efficiency of banana waste as an adsorbent for H2S gas. We tested the stems, leaves, and peels of banana plants as H2S gas adsorbents with varying contact times. To obtain a microscopic view of the adsorbents before and after the experiment, we conducted measurements using scanning electron microscopy with dispersive X-ray spectroscopy. The banana leaves, stems, and peels were found to have H2S gas absorption efficiency values of 76.52%, 51.83%, and 6.44%, respectively. Based on the experiment, the leaves of the banana plant appear to be the best adsorbents, with an adsorption capacity of 1.67 mg/g. The results also revealed that there was a change in the fiber and stomata appearance of the banana leaves after the adsorption process. Overall, this research indicates that banana leaves have the potential to be used as effective H2S adsorbents.
... However, excessive storage due to the accumulation of deadly concentrations will result in damage to the plant. Eventually, some contaminants can move to the root and remove through the root and can be decomposed by microorganisms in the soil or absorb into the soil (Orwell et al. 2004(Orwell et al. , 2006Wood et al. 2006;Treesubsuntorn and Thiravetyan 2012). In other words, plants can oppose toxic compounds through removal, combination with molecules or decomposition of them into cellular metabolites, and carbon dioxide in some cases, in which the latter is the best way for phytoremediation purposes (Thomas et al. 2015). ...
In recent decades, indoor air pollution has become a major concern due to its adverse health effects on the inhabitants. The presence of fine particles (PM2.5) and hazardous volatile organic compounds (VOCs), such as formaldehyde and benzene, in indoor air and their proven carcinogenic effects, has raised the attention of health authorities. Their very difficult and expensive removal by chemical and mechanical methods has led researchers to seek an economical and environmentally friendly technique. The use of plants in different ways such as potted plants or green walls is considered as a potential green solution for the improvement of indoor air quality and the health level of its inhabitants. A review of the literature cited in this paper suggests that plants absorb some of the pollutants, such as particles directly and remove some pollutants such as VOCs indirectly through biological transfer or by using microorganisms. This review paper discusses the types of plants that have been used for the phytoremediation of airborne pollutants and the routes and mechanisms for removing the pollutants. Removal pathways of the pollutants by aerial parts of the plants, the growth media along with the roots and their microorganisms in the rhizosphere part were also discussed. Sensitive analysis of extracted data from the literature outlined the most useful types of plants and the appropriate substrate for phytoremediation. Also, it showed that factors affecting the removal efficiency such as light intensity and ambient temperature, behave differently depending on pollutants and plants types.
... Benzene is the most prominent volatile organic compound (VOC) known for its harmful impacts on human health. Based on ACGIH, EPA, and IARC classification, it is considered a carcinogen [1,2]. Long-term exposure to benzene may cause anemia, plastic anemia, and leukemia [3]. ...
Activated carbon (AC) was prepared from Diplotaxis acris biomass. The change in the surface functional groups between the biomass raw material and the produced AC was detected using Fourier-transform infrared (FTIR) and Raman spectroscopy. The thermal stability of the prepared AC was determined by using thermogravimetric analysis (TGA). It has a surface area of 40.21 m2/g which gave evidence for its external porous surface. The surface porosity and the graphite properties of the prepared AC were detected by scanning electron microscope (SEM) and X-ray diffraction (XRD) analysis, respectively. The amount of adsorbed benzene on the AC surface was determined using a gas chromatograph supported with a flame ionization detector (GC-FID) after extraction in methanol. The adsorption capacity of benzene was 5.4 mg/g at room temperature (25°C), and its removal efficiency reached 95.58% for low benzene concentration (1000 mg/m3). The obtained results were well fitted by the Langmuir isotherm model. The adsorption kinetics of benzene followed the pseudo-second-order kinetic model accompanied by the intra-particle diffusion model. The reuse of the AC samples for three consecutive cycles retained the removal efficiency by more than 75% of its original efficiency. Overall, the study revealed that the prepared AC from Diplotaxis acris biomass has a great potential in the removal of benzene from polluted air.
... By considering the potential of plants to remove VOCs, there are some studies on benzene removal. Studies showed that plants have high resistance against toxic pollutants [144][145][146]. Recently, Sriprapat et al. [8] exhibited the experimental data for eight species of plant, including Sansevieria trifasciata, Euphorbia milii, Epipremnum aureum, Syngonium podophyllum, Hedera helix, Chlorophytum comosum, Dracaena sanderiana, and Clitoria ternatea, for removing benzene in air and water pollutants. ...
Urban civilization has a high impact on the environment and human health. The pollution level of indoor air can be 2–5 times higher than the outdoor air pollution, and sometimes it reaches up to 100 times or more in natural/mechanical ventilated buildings. Even though people spend about 90% of their time indoors, the importance of indoor air quality is less noticed. Indoor air pollution can be treated with techniques such as chemical purification, ventilation, isolation, and removing pollutions by plants (phytoremediation). Among these techniques, phytoremediation is not given proper attention and, therefore, is the focus of our review paper. Phytoremediation is an affordable and more environmentally friendly means to purify polluted indoor air. Furthermore, studies show that indoor plants can be used to regulate building temperature, decrease noise levels, and alleviate social stress. Sources of indoor air pollutants and their impact on human health are briefly discussed in this paper. The available literature on phytoremediation, including experimental works for removing volatile organic compound (VOC) and particulate matter from the indoor air and associated challenges and opportunities, are reviewed. Phytoremediation of indoor air depends on the physical properties of plants such as interfacial areas, the moisture content, and the type (hydrophobicity) as well as pollutant characteristics such as the size of particulate matter (PM). A comprehensive summary of plant species that can remove pollutants such as VOCs and PM is provided. Sources of indoor air pollutants, as well as their impact on human health, are described. Phytoremediation and its mechanism of cleaning indoor air are discussed. The potential role of green walls and potted-plants for improving indoor air quality is examined. A list of plant species suitable for indoor air phytoremediation is proposed. This review will help in making informed decisions about integrating plants into the interior building design.
... The ornamental plants have the ability to absorb, distribute, and/or transport organic pollutants through mechanisms such as rhizosphere biodegradation (by microorganisms), phytoextraction (plant-liquid extraction), stomatal uptake (plant-gas extraction), phytodegradation (via enzymatic catalysis inside tissues), and phytovolatilization (directly by evaporation from leaves or indirectly by plant transpiration) (Soreanu et al. 2013). The bioremediation capability of different pollution abatement plants such as Dieffenbachia compacta (Formaldehyde) (Aydogan and Montoya 2011), Sansevieria trifasciata (Benzene) (Treesubsuntorn and Thiravetyan 2012), Chlorophytum comosum, Dracaena deremensis, Philodendron domesticum (Benzene, formaldehyde, trichloroethylene) (Wolverton et al. 1989), and Schefflera actinophylla (Toluene, Xylene) (Kim et al. 2016) has been well reported. This recognition has contributed to a rise in the selling of indoor plants. ...
Deterioration of indoor air quality (IAQ) has become a serious concern as people spend lots of time indoors and prolonged pollution exposure can result in adverse health outcomes. Indoor plants can phytoremediate a wide variety of indoor contaminants. Nonetheless, few experiments have demonstrated their efficacy in real-time environments. Therefore, the present study aims to experimentally assess the efficiency of Areca palm potted plants in phytoremediation of primary indoor air pollutant viz. total volatile organic compounds (TVOCs), carbon dioxide (CO2), and carbon monoxide (CO) levels from real-world indoor spaces, for the first time. Four discrete naturally ventilated experimental sites (I-IV) situated at the Council of Scientific and Industrial Research- Institute of Himalayan Bioresource Technology (CSIR-IHBT) were used. For over a period of 4 months, the sites were monitored using zero plants as a control (1–4 week), three plants (5–8 week), six plants (9–12 week), and nine plants (13–16 week), respectively. Present results indicate that Areca palm potted plants can effectively reduce the TVOCs, CO2, and CO levels by 88.16% in site IV, 52.33% and 95.70% in site III, respectively. The current study concluded that Areca palm potted plants offer an efficient, cost-effective, self-regulating, sustainable solution for improving indoor air quality and thereby human well-being and productivity in closed and confined spaces.
- Using phytoremediation to purify indoor air pollutants such as formaldehyde, benzene, and ammonia.
- Phytoremediation uses plant roots, leaves, and associated microorganisms to clean the pollutant.
- Integrating indoor plants offers an eco-friendly and sustainable approach to creating healthy spaces for living.
With growing awareness of how dependent humans are on nature and how ecosystems can address societal issues at all scales, the concept of “Nature-based Solutions” (NbS) has emerged. NbS is viewed as a more promising strategy for increasing city sustainability and resilience over typical gray solutions globally. There are numerous spatial scales and settings in and around cities where nature-based solutions for urban resilience can be implemented. Examples include smaller green areas on buildings, bioswales, and green corridors beside streets and bodies of water; urban parks and forests with wetlands inside city limits, which protect cities from flooding and enhance the quantity and quality of water available. NbS are becoming more popular in business and international policy discussions. Additionally, incorporating NbS as a solution to both the climate and biodiversity problems necessitates a systems-thinking paradigm that considers numerous ecosystem services. It requires shifting from a dependence on never-ending economic growth to an understanding that the energy and material flows required for human well-being must remain within safe biophysical limits. This chapter focuses on various NbS for adaptation into planning and policy, looks at the financing options for these initiatives, and highlights implementation progress and lessons discovered.
Air pollution is a growing environmental concern worldwide, which is closely associated with climate variation and change as well as global warming whose effects are deleterious. Phytoremediation describes a technique of using plants and plant-based microbes to detoxify air pollutants and is a promising technique to reverse the current pollution state. This book chapter explores on the various subsets of phytoremediation and their applicability in detoxifying air of pollutants such as particulate matter, volatile organic compounds, and inorganic pollutants. Findings based on literature show that the method is widely used and attracting contemporary scientific research due to its viability and eco-friendly nature. Several examples of microbes and their host plants used in this process as well as the pollutants they decontaminate are provided herein. In conclusion, the application of the technique should be enhanced and optimized through further research.
Environmental issues are a pressing concern for modern societies, and the increasing levels of atmospheric CO2 have led to global warming. To mitigate climate change, reducing carbon emissions is crucial, and carbon sequestration plays a critical role in this effort. Technologies for utilising CO2 can be divided into two major categories: direct use and conversion into chemicals and energy, and indirect use as a carbon source for plants. While plants’ ability to absorb and store CO2 makes them the best CO2 sink, finding suitable urban areas for significant green spaces is a challenge. Green walls are a promising solution, as they require less land, provide more ecosystem services than horizontal systems do, and can contribute to reducing environmental problems. This study evaluates the conceptual potentials and limitations of urban biomass circulation in terms of energy production, food production, and CO2 consumption, focusing on growth-promoting bacteria, urban agriculture, and vertical systems. The aim of this research is discovering new methods of carbon sequestration using multi-purpose green walls to achieve sustainable urban development and CO2 reduction strategies to contribute to a more sustainable future.
Indoor air quality (IAQ), specifically after the COVID-19 pandemic, has become an international issue, as humans spend 80–90% of their time in indoor microenvironments. Poor IAQ has been related to the sick-building syndrome, nasal and ocular irritations, allergies, and respiratory dysfunction, including premature deaths. Phytoremediation is a novel strategy to absorb, adsorb, assimilate or transfer/reduce air pollutants and improve the IAQ using plants. Hence, the current review aims to explore indoor plants' role in improving indoor air quality, including their purification capabilities. There is increasing evidence that various plant species (e.g., Ficus benjamina, Chlorophytum comosum, Draceana) or their parts can reliably reduce the concentration of numerous air pollutants in the indoor microenvironment and promote human wellbeing. However, the indoor air pollutants removal efficiency depends on the species of plant, various plant characteristics such as leaf size, thickness, area, photosynthetic activity, light intensity and part of plant involved, i.e., roots, leaves, wax, cuticle and stomata. Using indoor plants is one of the most cost-effective and reliable methods of making a healthier indoor environment. Better public health can be maintained at a lower cost, with less strain on the health care system, if more emphasis is placed on creating a biophilic atmosphere and increasing the use of indoor plants. However, there are no established criteria for the best indoor plants and the impact of indoor plants on various factors such as interior ventilation, temperature, humidity, etc. Therefore, further experimental research is needed that simulates the interior environment to monitor the impacts of indoor plants on factors such as humidity, temperature, ventilation, etc., in improving the microenvironment of a closed space/room.
Phytoremediation has become a popular technology due to its low cost, sustainability, and environmentally friendly use for removing particulate matter (PM) and volatile organic compound (VOC) pollution. However, pollution is detrimental to plant growth under stressful conditions and can even cause plant death. Physiology and proteomics approaches were used to explain a comprehensive stress response mechanism to provide better knowledge of plants' response to PM and VOC stress. In this study, Sansevieria trifasciata, a typical air phytoremediation plant, was exposed to PM and VOC stress conditions generated from cigarette smoke in a 15 L chamber for six cycles, with the fifth cycle being a recovery period (30 days without smoke). Plant physiological stress responses were examined, such as chlorophyll, carotenoid, and malondialdehyde (MDA) content. Exposure to PM and VOCs increased plant MDA content by cycles three and four but not chlorophyll and carotenoid. The exposure continuously caused plant stress, while the recovery period of 30 days relieved the stress. The proteomics results showed that plants might activate brassinosteroid signalling under PM and VOCs, which initiated the photosynthesis and antioxidant system. The plant might use an alternate carbon metabolism pathway through the folate cycle to provide carbon sources for synthesising other metabolites. This study is the first proteomics approach to show the response of proteins under PM and VOC stress in S. trifasciata. Understanding the plant stress response may enable a guideline to provide well-being conditions for phytoremediation.
Phytoremediation is the application of plant–microbe interactions for the bioremediation of toxic chemicals present in the environment. The application of phytoremediation has emerged as a prospective tool in the last three decades. Plants can be applied for the volatilization, degradation, extraction, and solubilization of pollutants. Plants and their associated microorganisms are able to remove both organic and inorganic pollutants from soils. However, the exact mechanism of the removal of pollutants from the environment with a plant–microbe association is still not known. Therefore, this chapter covers the knowledge about phytoremediation and its application for a sustainable environment.
Nowadays, air pollutants such as particulate matter, volatile organic compounds, carbon monoxide (CO), nitrogen dioxide (NO2), and sulfur dioxide (SO2) can have significant effects on human health and environment. Air pollutants can harm to the human respiratory system; alter the heart rate; enhance blood coagulation; and decrease lung function, chronic obstructive pulmonary diseases, lung cancer mortality, and cardiovascular problems. Therefore, air pollutants can be managed by using conventional physical and chemical technologies depending on the type of pollutants. Phytoremediation is an alternative method based on green technology that can decrease global warming and is environmentally friendly. Phytoremediation is a technology that uses plants to degrade organic pollutants and use them as a carbon source. In nature, plants are always associated with microorganisms, and they help each other to deal with pollutants by increasing hormones and antioxidant enzymes in the plant cell. Understanding of how plant-microbes remove the pollutants can be used to create an active living wall/botanical biofilter to solve the problem of air pollutants. In order to solve air pollution problems, forested areas should be created in the cities/industrial areas.
Air pollution is a major cause of concern globally. The origin of airborne pollutants is attributed to the industrial revolution and large‐scale use of fossil fuels. There are numerous evidences from epidemiologic research on the adverse effects of air pollutants on human health, such as chronic obstructive pulmonary diseases, lung cancer, premature mortality. Current mitigation strategies focus mostly on specific technical measures and are not sufficient to meet the challenges posed by the deteriorating environment. Despite several measures undertaken cities like Delhi are severely polluted throughout the year. Ambient air pollution is composed of a high variety of pollutants, mainly including particulate matter (PM), volatile organic compounds (VOCs) like benzene, formaldehyde, and inorganic pollutants (NO x , SO 2 , O 3 ). Many of these outdoor air pollutants are also found indoor, in concentrations that often can be higher than the outdoors. Phytoremediation is an effective plant‐based, environmentally friendly biotechnology to remediate indoor and outdoor air pollutants. Plants are known to scavenge significant amounts of air pollutants via processes like phytostabilisation, phytoaccumulation, phytodegradation phytovolatilisation, and rhizodegradation. Several plant enzymes such as nitroreductase, dehalogenase, laccase, and peroxidase aid these processes. Plants are known to be associated with symbiotic microbes such as fungi and bacteria that alleviate abiotic and biotic stresses in them and enhance their growth. Plant–microbe mutualism also plays an important role during phytoremediation by degrading, detoxifying, or sequestrating the pollutants. Plants and associated microorganisms maintain biodiversity and ecological sustainability of urban green infrastructures, and studies on this symbiosis are imperative for human health and environmental sustainability. The incorporation of green areas comprising plants remediating air pollution among concrete jungles would have a substantial positive influence on the health of urban dwellers. In cities, the uses of plants improve the microclimate and alleviate side effects of climate change, for example, by blocking excessive sun radiation during summer. In addition, plants can also be exploited to intensively reduce carbon footprint by absorbing CO 2 and provide long‐term carbon sequestration. Phytoremediation of air pollutants is still an emerging concept and the potential and suitability of individual species for specific pollutants require basic as well as applied research. The selection of the plant–soil–microbe system would vary depending on the abiotic factors of the region. Phytoremediation is a slow removal process, hence attempts should be made to combine it with other remediation strategies to achieve enhanced rates of decontamination. Policies must be executed to incorporate urban forestry with city planning, particularly for the rapidly urbanising cities of the developing world.
Phytoremediation is an eco-friendly and economical technology in which plants are used for the removal of contaminants presents in the urban and rural environment. One of the challenges of the technique is the proper destination of the biomass of plants. In this context, the use of ornamental plants in areas under contamination treatment improves landscape, serving as a tourist option and source of income with high added value. In addition to their high stress tolerance, rapid growth, high biomass production, and good root development, ornamental species are not intended for animal and human food consumption, avoiding the introduction of contaminants into the food web in addition to improving the environments with aesthetic value. Furthermore, ornamental plants provide multiple ecosystem services, and promote human well-being, while contributing to the conservation of biodiversity. In this review, we summarized the main uses of ornamental plants in phytoremediation of contaminated soil, air, and water. We discuss the potential use of ornamental plants in constructed buffer strips aiming to mitigate the contamination of agricultural lands occurring in the vicinity of sources of contaminants. Moreover, we underlie the ecological and health benefits of the use of ornamental plants in urban and rural landscape projects. This study is expected to draw attention to a promising decontamination technology combined with the beautification of urban and rural areas as well as a possible alternative source of income and diversification in horticultural production.
Graphical abstract
Many indoor plants can remove benzene, a common volatile organic compound that has been classified as a human carcinogen. Light intensity and initial benzene concentration may affect the removal efficacy of the plants. Cordyline terminalis (L.) Kunth 'Baby Doll' is widely used for indoor decorations as this delicate potted plant can tolerate a wide range of irradiances and generates prolific branches when pinched. Potted plants of 'Baby Doll', with root-zone wrapped, were placed under light intensity of 20, 40, 60, 80, and 100 μmol．m^(-2)．s^(-1) photosynthetic photon flux (PPF) in chambers containing an initial 5 μL．L^(-1) benzene for four days. In all treatments, benzene concentration in the chambers declined as analyzed with gas chromatography. Plants under 20 or 40 μmol．m^(-2)．s^(-1) PPF had lower stomatal conductance, net photosynthetic rate, and benzene removal rate per leaf area than those under 80 or 100 μmol．m^(-2)．s^(-1) PPF. Carbon dioxide removal rate during lighting period of day 1 increased linearly as light intensity increased. Potted plants of 'Baby Doll' were placed within chambers containing various initial concentrations of benzene under 80 μmol．m^(-2)．s^(-1) PPF. Results showed that benzene removal rate of the plant increased linearly with the initial benzene concentration increased from 5 to 25 μL．L^(-1). Initial benzene concentration did not affect the CO_2 uptake and evolution of the plants. Benzene concentration did not alter leaf Fv/Fm, ranged between 0.79 and 0.81, after all treatments for five days.
Indoor air pollution is a significant problem today because the release of various contaminants into the indoor air has created a major health threat for humans occupying indoors. Volatile Organic Compounds (VOCs) are pollutants released into the environment and persist in the atmosphere due to its low boiling point values. Various types of indoor activities, sources, and exposure to outdoor environments enhance indoor VOCs. This poor indoor air quality leads to adverse negative impacts on the people in the indoor environment. Many physical and chemical methods have been developed to remove or decompose these compounds from indoors. However, those methods are interrupted by many environmental and other factors in the indoor atmosphere, thus limit the applications. Therefore, there is a global need to develop an effective, promising, economical, and environmentally friendly alternatives to the problem. The use of the plant and associated microflora significantly impact reducing the environmental VOC gases, inorganic gases, particulate matter, and other pollutants contained in the air. Placing potted plants in indoor environments not only helps to remove indoor air pollutants but also to boost the mood, productivity, concentration, and creativity of the occupants and reduces stress, fatigue, sore throat, and cold. Plants normally uptake air pollutants through the roots and leaves, then metabolize, sequestrate, and excrete them. Plant-associated microorganisms help to degrade, detoxify, or sequestrate the pollutants, the air remediation, and promote plant growth. Further studies on the plant varieties and microorganisms help develop eco-friendly and environmentally friendly indoor air purifying sources.
Air pollution by particulate matter (PM) and volatile organic compounds (VOCs) is a major global issue. Many technologies have been developed to address this problem. Phytoremediation is one possible technology to remediate these air pollutants, and a few studies have investigated the application of this technology to reduce PM and VOCs in a mixture of pollutants. This study aimed to screen plant species capable of PM and VOC phytoremediation and identify plant physiology factors to be used as criteria for plant selection for PM and VOC phytoremediation. Wrightia religiosa removed PM and VOCs. In addition, the relative water content in the plant and ethanol soluble wax showed positive relationships with PM and VOC phytoremediation, with a high correlation coefficient. For plant stress responses, several plant species maintained and/or increased the relative water content after short-term exposure to PM and VOCs. In addition, based on proteomic analysis, most of the proteins in W. religiosa leaves related to photosystems I and II were significantly reduced by PM2.5. When a high water content was achieved in W. religiosa (80% soil humidity), W. religiosa can effectively remove PM. The results suggested that PM can reduce plant photosynthesis. In addition, plants might require a high water supply to maintain their health under PM and VOC stress.
Monitoring of air quality and the application of strategies for its improvement are perceived as key areas for reducing environmental pollution. The research on Nature Based Solutions for the mitigation of pollutant concentrations in the air has increasingly developed in the last twenty years. The purpose of this review is to evaluate whether the current knowledge about Nature-Based Solutions provides a quantitative answer of the real benefits of air phytoremediation. To address this question, the literature on air phytoremediation over the last twenty years was analyzed. Altogether, 52 variables were selected, grouped into six categories, to briefly characterize the contents, methodology and outcome of the peer-reviewed articles. Altogether, 413 plant species found in the analyzed studies were recorded. The results show the trends about the most studied pollutants and on the methodologies mostly applied, in relation to the study outcomes. The analysis demonstrated that particulate matter (PMx) was the most frequently examined pollutant, most studies on NBS are based on experiments with exposure chambers, and scaling up the results with models has been limited. Although effective reductions in pollutant concentrations have been shown in the majority of studies, there is a strong fragmentation of the approaches, most studies have looked at a single pollutant and detailed information for model parameterization is only available for a few species. Thus, the review highlights that studies of Nature Based Solutions in air phytoremediation require unification of methodologies, and should consider a broader range of pollutants and plant organisms useful for mitigating the impacts of air pollutants in indoor and outdoor human environments.
Indoor air quality is of emerging importance due to the rapid growth of urban populations that spend the majority of their time indoors. Amongst the public, there is a common perception that potted-plants can clean the air of pollutants. Many laboratory-based studies have demonstrated air pollution phytoremediation with potted-plants. It has, however, been difficult to extrapolate these removal efficiencies to the built environment and, contrary to popular belief, it is likely that potted-plants could make a negligible contribution to built environment air quality. To overcome this problem, active green walls have been developed which use plants aligned vertically and the addition of active airflow to process a greater volume of air. Although a variety of designs have been devised, this technology is generally capable of cleaning a variety of air pollutants to the extent where comparisons against conventional air filtration technology can be made. The current work discusses the history and evolution of air phytoremediation systems from potted-plants through to practical botanical air filtration.
There is a global need to use plants to restore the ecological environment. There is no systematic review of phytoremediation mechanisms and the parameters for environmental pollution. Here, we review this situation and describe the purification rate of different plants for different pollutants, as well as methods to improve the purification rate of plants. This is needed to promote the use of plants to restore the ecosystems and the environment. We found that plants mainly use their own metabolism including the interaction with microorganisms to repair their ecological environment. In the process of remediation, the purification factors of plants are affected by many conditions such as light intensity, stomatal conductance, temperature and microbial species. In addition the efficiency of phytoremediation is depending on the plants species-specific metabolism including air absorption and photosynthesis, diversity of soil microorganisms and heavy metal uptake. Although the use of nanomaterials and compost promote the restoration of plants to the environment, a high dose may have negative impacts on the plants. In order to improve the practicability of the phytoremediation on environmental restoration, further research is needed to study the effects of different kinds of catalysts on the efficiency of phytoremediation. Thus, the present review provides a recent update for development and applications of phytoremediation in different environments including air, water, and soil.
Air phytoremediation technology has been reported as a high potential technology for indoor air pollution treatment. Since 1996, NASA has supported this technology for application in the international space station. However, changes in plant physiology and hormone levels under microgravity (μG) conditions might affect air phytoremediation efficiency, especially changes of auxin hormone transportation in plants. In this study, the application of Chlorophytum comosum, high benzene removal plant species, to remove 100 ppm gaseous benzene under μG condition was studied. The experiment was operated for three days in a random positioning machine generate 6.44 × 10⁻⁴ G within 1 h. The results showed that under μG, benzene removal efficiency by C. comosum was significantly increased, with a remove more than 80% within three days under both 24 h light and dark conditions. In contrast, C. comosum growing under normal gravity (1G) can remove about 75% and 50% benzene under 24 h light and 24 h dark conditions, respectively. Surprisingly, μG conditions seem to maintain open stomata of a plant open under both 24 h light and dark conditions, and this plant will normally have closed stomata in the dark. In this case, shoot auxin hormone in the form of Indole-3-acetic acid was highly increased in the plant growing under μG. This result suggested that under μG, auxin hormone might be accumulated in the shoot part of plant. This auxin accumulation effect of maintaining open plant stomata can enhance benzene phytoremediation efficiency since stomata are the major benzene uptake pathway. Therefore, this study is the first report presenting the possibility of applying air phytoremediation technology under μG conditions.
Studies of indoor air quality have prompted serious concerns of occupant's health and human well-being, which might not be fully achieved solely by current ventilation strategies. Environmental exposures to indoor contaminants such as volatile organic compounds (VOCs), and Carbon Dioxide emissions (CO2) levels remain problematic issues that might not be fully addressed through increased levels of ventilation rate only. Living media where plants are able to remove indoor contaminants can provide an effective passive strategy that impact occupant's health, well-being, as well as building's ventilation system efficacy. Despite many studies on horticultural biotechnologies for improving indoor air quality in laboratory settings, active botanical biofilters or functional green walls seem to perform differently in actual indoor spaces rather than being assessed in closed experimental chambers. By introducing the idea of incorporating active botanical green wall systems as an air filtration strategy into double skin facades, a dual benefit might be achieved to improve indoor air quality and the building's energy saving potential by improving thermal performance of the building's envelope. This paper aims at evaluating previous results of biofiltration, botanical air filters, and potted plants by comparing their removal efficiencies to their air chamber volumes based on a meta-analysis of published results. Results are presented through specific defined metrics in which independent variables in the form of, plant species, leaf areas, time, air volume, and chamber geometry are computed to present spatial and technical influences of different experimental conditions in reducing indoor air contaminants. The paper concludes that plants show higher removal efficiencies when placed in enclosed spaces with higher ratio of leave areas to chamber volumes which also increases the rate of filtration. Although plants' latent heat might improve the envelope thermal insulation, air volume and stratification are more significant variables at improving the envelope thermal properties. Further studies are needed to test the impact of enclosed botanical biofilters in field studies and under different climatic and building types to determine the suitability and optimization potential of this strategy for the design of high-performance envelopes.
Phytoremediation is a sustainable remedial approach for removing benzene from environment. Plant associated bacteria could ameliorate the phytotoxic effects of benzene on plant, although the specificity of these interactions is unclear. Here, we used proteomics approach to gain a better understanding of the mechanisms involved in plant-bacteria interactions. Plant associated bacteria was isolated and subsequently inoculated into the sterilized Helianthus annuus, and the uptake rates of benzene by these inoculated plants were evaluated. At the end of the experiment, leaves and roots proteins were analyzed. The results showed inoculated H. annuus with strain EnL3 removed more benzene than other treatments after 96 hr. EnL3 was identified as Enterobacter sp. according to 16S rDNA analysis. Based on the comparison of proteins, 62 proteins were significantly up or down regulated in inoculated leaves, while 35 proteins were significantly up or down regulated in inoculated roots. Furthermore, there were 4 and 3 identified proteins presented only in inoculated H. annuus leaves and roots, respectively. These proteins involved in several functions including transcription and translation, photosynthesis, and stress response. The network among anti-oxidant defense system, protein synthesis, and photosynthetic electron transfer are involved in collaboratively activate the benzene uptake and stress tolerance in plant.
Twenty-eight ornamental species commonly used for interior plantscapes were screened for their ability to remove five volatile indoor pollutants: aromatic hydrocarbons (benzene and toluene), aliphatic hydrocarbon (octane), halogenated hydrocarbon [trichloroethylene (TCE)], and terpene (-pinene). Individual plants were placed in 10.5-L gas-tight glass jars and exposed to 10 ppm (31.9, 53.7, 37.7, 46.7, and 55.7 mg·m –3) of benzene, TCE, toluene, octane, and -pinene, respectively. Air samples (1.0 mL) within the glass containers were analyzed by gas chromatography–mass spectroscopy 3 and 6 h after exposure to the test pollutants to determine removal efficiency by monitoring the decline in concentration over 6 h within sealed glass containers. To determine removal by the plant, removal by other means (glass, plant pot, media) was subtracted. The removal efficiency, expressed on a leaf area basis for each volatile organic compound (VOC), varied with plant species. Of the 28 species tested, Hemigraphis alternata, Hedera helix, Hoya carnosa, and Asparagus densiflorus had the highest removal efficiencies for all pollutants; Tradescantia pallida displayed superior removal efficiency for four of the five VOCs (i.e., benzene, toluene, TCE, and -pinene). The five species ranged in their removal efficiency from 26.08 to 44.04 µg·m–3·m–2·h–1 of the total VOCs. Fittonia argyroneura effectively removed benzene, toluene, and TCE. Ficus benjamina effectively removed octane and -pinene, whereas Polyscias fruticosa effectively removed octane. The variation in removal efficiency among species indicates that for maximum improvement of indoor air quality, multiple species are needed. The number and type of plants should be tailored to the type of VOCs present and their rates of emanation at each specific indoor location.
The quality of the indoor environment has become a major health consideration, since urban-dwellers spend 80-90% of their time indoors, where air pollution can be several times higher than outdoors. Indoor potted-plants can remove air-borne contaminants such as volatile organic compounds (VOCs), over 300 of which have been identified in indoor air. In this study a comparison was made of rates of removal of benzene, as model VOC, by seven potted-plant species/varieties. In static test-chambers, high air-borne doses of benzene were removed within 24 h, once the response had been stimulated (induced) by an initial dose. Removal rates per pot ranged from 12-27 ppm d–1 (40 to 88 mg m–3 d–1) (2.5 to 5 times the Australian maximum allowable occupational level). Rates were maintained in light or dark, and rose about linearly with increased dose. Rate comparisons were also made on other plant parameters. Micro-organisms of the potting mix rhizosphere were shown to be the main agents of removal. These studies are the first demonstration of soil microbial VOC degradation from the gaseous phase. With some species the plant also made a measurable contribution to removal rates. The results are consistent with known, mutually supportive plant/soil-micro-organism interactions, and developments in microbially-based biofilter reactors for cleaning VOC-contaminated air. The findings demonstrate the capacity of the potted-plant microcosm to contribute to cleaner indoor air, and lay the foundation for the development of the plant/substrate system as a complementary biofiltration system.
Indoor air-borne loads of volatile organic compounds (VOCs) are usually significantly higher than those outdoors, and chronic exposures can cause health problems. Our previous laboratory studies have shown that the potted-plant microcosm, induced by an initial dose, can eliminate high air-borne VOC concentrations, the primary removal agents being potting-mix microorganisms, selected and maintained in the plant/root-zone microcosm. Our office field-study, reported in the preceding paper, showed that, when total VOC (TVOC) loads in reference offices (0 plants) rose above about 100 ppb, levels were generally reduced by up to 75% (to < 100 ppb) in offices with any one of three planting regimes. The results indicate the induction of the VOC removal mechanism at TVOC levels above a threshold of about 100 ppb. The aims of this laboratory dose-response study were to explore and analyse this response. Over from 5 to 9 days, doses of 0.2, 1.0, 10 and 100 ppm toluene and m-xylene were applied and replenished, singly and as mixtures, to potted-plants of the same two species used in the office study. The results confirmed the induction of the VOC removal response at the lowest test dosage, i.e in the middle of the TVOC range found in the offices, and showed that, with subsequent dosage increments, further stepwise induction occurred, with rate increases of several orders of magnitude. At each dosage, with induction, VOC concentrations could be reduced to below GC detection limits (< 20 ppb) within 24 h. A synergistic interaction was found with the binary mixtures, toluene accelerating m-xylene removal, at least at lower dosages. The results of these two studies together demonstrate that the potted-plant microcosm can provide an effective, self-regulating, sustainable bioremediation or phytoremediation system for VOC pollution in indoor air.
Phytoremediation—using plants to remove toxins—is an attractive and cost effective way to improve indoor air quality. This study screened ornamental plants for their ability to remove volatile organic compounds from air by fumigating 73 plant species with 150 ppb benzene, an important indoor air pollutant that poses a risk to human health. The 10 species found to be most effective at removing benzene from air were fumigated for two more days (8 h per day) to quantify their benzene removal capacity. Crassula portulacea, Hydrangea macrophylla, Cymbidium Golden Elf., Ficus microcarpa var. fuyuensis, Dendranthema morifolium, Citrus medica var. sarcodactylis, Dieffenbachia amoena cv. Tropic Snow; Spathiphyllum Supreme; Nephrolepis exaltata cv. Bostoniensis; Dracaena deremensis cv. Variegata emerged as the species with the greatest capacity to remove benzene from indoor air.
Small, volatile hydrocarbons, including trichloroethylene, vinyl chloride, carbon tetrachloride, benzene, and chloroform, are common environmental pollutants that pose serious health effects. We have developed transgenic poplar (Populus tremula × Populus alba) plants with greatly increased rates of metabolism and removal of these pollutants through the overexpression of cytochrome P450 2E1, a key enzyme in the metabolism of a variety of halogenated compounds. The transgenic poplar plants exhibited increased removal rates of these pollutants from hydroponic solution. When the plants were exposed to gaseous trichloroethylene, chloroform, and benzene, they also demonstrated superior removal of the pollutants from the air. In view of their large size and extensive root systems, these transgenic poplars may provide the means to effectively remediate sites contaminated with a variety of pollutants at much faster rates and at lower costs than can be achieved with current conventional techniques.
• CYP2E1
• P450
• poplar
• trichloroethylene
• carbon tetrachloride
Plant uptake rate constants (k1) were determined for vapor-phase 2,3,7,8-TCDD using grass, azalea, spruce, kale and pepper foliage, and the fruit from apple, tomato and pepper. Plants were exposed to vapor-phase 3H-2,3,7,8-TCDD for 96 h, and the TCDD sorption rate constant for each plant species was determined from measured air and plant concentrations. Sorption rate constants for the different plant tissues, expressed on a fresh weight basis (k1FWt with units of gAir gFWt−1 h−1), varied by two orders of magnitude. The rate constants were normalized for the exposed plant surface area (SA) by dividing k1FWt by the SA/FWt ratio for each plant species. Normalizing the rate constants for exposed surface area resulted in significantly less variation between species (k1SA = 1.2 gAir cm2 −1 h−1 ± 0.2 SE). The cuticular wax content of the different plant species did not effect the short-term sorption kinetics of 2,3,7,8-TCDD.
The air-to-vegetation pathway may substantially contribute to human and food-chain exposure to organic chemicals since the surface area of the above-ground parts of vegetation by far exceeds the area the plants are growing on. A model for assessing the atmosphere-to-vegetation transfer of persistent organic chemicals is discussed. It is based on the fugacity concept and uses the 1-octanol/water and cuticle/water partition coefficients, aqueous solubility, and the saturation vapor pressure of the chemicals as input data. Equilibrium concentrations in plant tissues and air-to-vegetation bioconcentration factors can be estimated. Further, the model permits prediction of the compartment(s) in vegetation where a given chemical will preferentially accumulate. An approach for assessing semiquantitatively the potential for (re)volatilization of organics from leaves is also suggested. Various applications of the model are shown for reference compounds of widely differing physicochemical properties.
Photosystem II plays an especially important role in the response of photosynthesis in higher plants to environmental perturbations and stresses. The relationship between photosystem II and photosynthetic CO2 assimilation is examined and factors identified that may modulate photosystem II activity in vivo. Particular attention is given to non-photochemical quenching of excitation energy, photoinhibition, state transitions, protein phosphorylation and biogenesis of photosystem II.
Pine needles were used as passive samplers for monitoring polychlorinated biphenyls (PCBs) in the environment. A method for the determination of PCB in pine needle wax was developed. By applying an HPLC-based cleanup procedure to wax extracts of pine needles, a high selectivity toward PCB was obtained. High precision and accuracy was achieved, as well as high relative (91-108 +/- 4-8%) and absolute overall recoveries (81 +/- 14%). Pine needle wax from the central and northern parts of Europe were examined. High concentrations of PCBs with a profile shifted toward low molecular species were found in Western Germany (SIGMA 9 CBs = 47 ng/g of wax) when compared to the other investigated geographical sites (SIGMA 9 CBs = 4-7 ng/g of wax).
In this study, the leaves, roots, soil, and associated microorganisms of plants have been evaluated as a possible means of reducing indoor air pollutants. Additionally, a novel approach of using plant systems for removing high concentrations of indoor air pollutants such as cigarette smoke, organic solvents, and possibly radon has been designed from this work. This air filter design combines plants with an activated carbon filter. The rationale for this design, which evolved from wastewater treatment studies, is based on moving large volumes of contaminated air through an activated carbon bed where smoke, organic chemicals, pathogenic microorganisms (if present), and possibly radon are absorbed by the carbon filter. Plant roots and their associated microorganisms then destroy the pathogenic viruses, bacteria, and the organic chemicals, eventually converting all of these air pollutants into new plant tissue. It is believed that the decayed radon products would be taken up the plant roots and retained in the plant tissue.
The uptake of 14C from various 14C-labeled organic chemicals from different chemical classes by barley and cress seedlings from soil was studied for 7 days in a closed aerated laboratory apparatus. Uptake by roots and by leaves via the air was determined separately. Although comparative long-term outdoor studies showed that an equilibrium is not reached within a short time period, plant concentration factors after 7 days could be correlated to some physicochemical and structural substance properties. Barley root concentration factors due to root uptake, expressed as concentration in roots divided by concentration in soil, gave a fairly good negative correlation to adsorption coefficients based on soil organic carbon. Barley root concentration factors, expressed as concentration in roots divided by concentration in soil liquid, gave a positive correlation to the n-octanol/water partition coefficients. Uptake of chemicals by barley leaves via air was strongly positively correlated to volatilization of chemicals from soil. Both root and foliar uptake by barley could be correlated well to the molecular weight of 14 chemicals. Uptake of chemicals by cress differed from that by barley, and correlations to physicochemical substance properties mostly were poor.
Monocylic aromatic hydrocarbons (MAHs: benzene, toluene, ehtylbenzene and xylenes) were isolated from fruit and vegetables using a solvent extraction technique. GC-MS (with selected-ion monitoring mode) was applied for determination of the isolated pollutants. It was observed that uptake of MAHs depends on the species and takes place in different morphological parts of the biological material. The highest concentrations of MAHs were found in parsley leaves (m- and p-xylene) and in orange peel (toluene). Estimation of the daily human exposure to MAHs through eating contaminated fruit and vegetables was performed.
The [1-6(14)C]benzene and [1-(14)C]toluene vapors penetrate into hypostomatous leaves of Acer campestre, Malus domestica, and Vitis vinifera from both sides, whereas hydrocarbons are more intensively absorbed by the stomatiferous side and more actively taken up by young leaves. Benzene and toluene conversion in leaves occurs with the aromatic ring cleavage and their carbon atoms are mainly incorporated into nonvolatile organic acids, while their incorporation into amino acids is less intensive. Intact spinach chloroplasts oxidize benzene, and this process is strongly stimulated in light. Oxidation of benzene by spinach chloroplasts or by enzyme preparation from spinach leaves is almost completely inhibited by 8-oxyquinoline or sodium diethyldithiocarbamate, and slightly affected by alpha, alpha'-dipyridyl. Benzene oxidation by enzyme preparation is significantly stimulated by NADH and NADPH; in their presence, the benzene hydroxylation product, phenol, is formed in a determinable amount. It is supposed that the enzyme performing the first step of oxidative transformation of benzene in plant leaves contains copper as the prosthetic group.
In this study apple, blackberry and cucumber crops were exposed to elevated levels of benzene under controlled conditions. Benzene was retained in fruits of all crops, but only accumulated in leaves of blackberries and apples. The retention by cucumber fruits is suggested to result from the longer pathway for the desorption of benzene as a consequence of their increased tissue depth compared to leaves. The process of accumulation in blackberry and apple leaves is unknown. The ingestion of benzene via the food-chain pathway on the basis of this study is concluded not to be significant.
Organic xenobiotics absorbed by roots and leaves of higher plants are translocated by different physiological mechanisms. The following pathways of xenobiotic detoxication have been observed in higher plants: conjugation with such endogenous compounds as peptides, sugars, amino acids, and organic acids; oxidative degradation and consequent oxidation of xenobiotics with the final participation of their carbon atoms in regular cell metabolism. The small parts of xenobiotics are excreted maintaining their original structure and configuration. Enzymes catalyze oxidative degradation of xenobiotics from the initial hydroxylation to their deep oxidation. The wide intracellular distribution and inductive nature of oxidative enzymes lead to the high detoxication ability. With plant aging, transformation of the monooxygenase system into peroxidase takes place. Once in the cells, xenobiotics are incorporated into different cell organelles. All xenobiotics examined are characterized by a negative effect on cell ultrastructure. The penetration of high doses of xenobiotics into plant cells leads to significant deviations from the norm and, in some cases, even to the complete cell destruction and plant death.
The epidemiologic literature on benzene exposure and leukemia in the MEDLINE and TOXNET databases was examined through October 2004 using the keywords "benzene", "leukemia" and "adverse health effects". This search was complemented by reviewing the reference lists from extant literature reviews and criteria documents on benzene. Published studies were characterized according to the type of industry studied and design, exposure assessment, disease classification, and control for confounding variables. Study design consisted of either cohort studies or case-control studies, which were further categorized into population-based and nested case-control studies. Disease classification considered the source of diagnostic information, whether there was clinical confirmation from medical records or histopathological, morphological and/or cytogenetic reviews, and as to whether the International Classification of Diseases (ICD) or the French-American-British (FAB) schemes were used (no studies used the Revised European-American Lymphoma (REAL) classification scheme). Nine cohort and 13 case-control studies met inclusion criteria for this review. High and significant acute myeloid leukemia risks with positive dose response relationships were identified across study designs, particularly in the "well-conducted" cohort studies and especially in more highly exposed workers in rubber, shoe, and paint industries. Risks for chronic lymphocytic leukemia (CLL) tended to show elevations in nested case-control studies, with possible dose response relationships in at least two of the three studies. However, cohort studies on CLL show no such risks. Data for chronic myeloid leukemia and acute lymphocytic leukemia are sparse and inconclusive.
Chlorinated dioxins-volatilization from soil and bioconcentration in plant leaves A possible role for photosystem II in environmental perturbations of photosynthesis Benzene accumulation in horticultural crops
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Enhanced phytoremediation of volatile environmental pollutants with transgenic trees Supplementary Information for the Derivation of SGV for Benzene Deter-mination of monocyclic aromatic hydrocarbon in fruit and vegetables by gas chromatographyemass spectrometry
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Environmental monitoring of poly-chlorinated biphenyls using pine needles as passive samples. Environmental Science and Technology 28, 1320e1324. Fig. 4. The ratios (%) of benzene uptake by wax and stomata of D
- H Kylin
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- C Ostman
Kylin, H., Grimvall, E., Ostman, C., 1994. Environmental monitoring of poly-chlorinated biphenyls using pine needles as passive samples. Environmental Science and Technology 28, 1320e1324. Fig. 4. The ratios (%) of benzene uptake by wax and stomata of D. sanderiana at 72 h. C. Treesubsuntorn, P. Thiravetyan / Atmospheric Environment 57 (2012) 317e321
Which ornamental plant species effec-tively remove benzene from indoor air? Atmospheric Environment 41 Vapor-phase 2,3,7,8-TCDD sorption to plant foliage-a species comparison
- Y Liu
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Review of the literature on benzene exposure and leukemia subtypes The Potential Use of PAH Accumulation as a Marker of Exposure to Air Emission From Oil and Gas Flares Air Research Users Group
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Use of Living Pot-Plants to Cleanse Indoor Air e Research Review Factors affecting the uptake of 14C-labeled organic chemicals by plants from soil AireVegetationeSoil partitioning of toxic chemicals in environmental simulation modeling Uptake and transformation of benzene and toluene by plant leaves
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- Uts
- Po Box
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- Austral
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