Development of a preliminary environmental risk assessment system by using text mining for introducing alien crops.

Changes in worldwide crop trends and climate change has increased the introduction of alien crops. However, there are always potential side effect issues related to introduced crops, such as the introduced crop becoming a nuisance at the new country or bringing insect pests or microorganisms with the introduced crops. In this study, we developed a crop introduction risk assessment system using text mining method to prevent this problem. First, we designed the "Preliminary Environmental Impact Assessment Index for Alien Crops" based on ecological researches to assess the risks of introduced crops to the natural environment. The questionaries evaluate the target alien crop with previous cases reporting the target crops' adverse effects on the environment, the potential of target crops' direct or indirect damage on the environment. The index has sixteen questions with allocated scores that are divided into 4 categories. The detailed rationales of the questionaries and the assessment index are discussed in main text. Second, we assessed 67 crop species that were introduced or scheduled to be introduced to South Korea with this Preliminary Assessment Index. The literature and data were collected with JabRef, search engines, and from the documents of six international institutions. Finally, based on the preliminary assessment results of selected species, we developed the protocols and a manual for the preliminary environmental risk assessment of introduced species. Final evaluation scores for risk evaluation for introducing crops are suggested (over 70 total score for 'danger' and over 50 points for 'caution required', and under 50 points for 'low expected impact'). Presented crop introduction risk assessment system is effective to identify potential problem making crop species. The protocols and a manual that we provide in this study could be applied to other countries which have similar climate and environmental conditions, or after being adequately modified to their environmental factors such as climate, neighboring countries, major crops according to eating habits, and major vegetation.

Assessment of the potential risk of 1,2-hexanediol using phytotoxicity and cytotoxicity testing.

1,2-Hexanediol is commonly used in the cosmetic industry as a preservative, an emollient, and a moisturizing agent. However, studies on the scientific toxicity of 1,2-hexanediol are limited. In this study, we evaluated the potential toxic effects of 1,2-hexanediol using phytotoxicity and cytotoxicity testing methods. Phytotoxicity tests using Brassica campestris subsp. napus and Latuca sativa L. showed that 1,2-hexanediol significantly inhibited seed germination and root elongation at the lowest concentration (0.1%). Additionally, plants treated with 1,2-hexanediol failed to survive. In cytotoxicity tests, RAW 264.7 and HK-2 cells treated with 1.0% 1,2-Hexanediol showed a significant decline in viability, followed by death. Since most personal care products contain >2% 1,2-hexanediol, it is highly likely that 1,2-hexanediol is toxic to humans. Moreover, if 1,2-hexanediol enters the human body either via oral intake or through an open wound, it could have critical effects. Furthermore, upon release into the environment, 1,2-hexanediol could cause considerable damage to plants and other organisms. Therefore, further investigation of 1,2-hexanediol is required to prevent toxicity to humans and other living organisms.

Mowing: A cause of invasion, but also a potential solution for management of the invasive, alien plant species Erigeron annuus (L.) Pers.

Erigeron annuus is one of the major invasive, alien plants in Korea, and therefore research to manage (control) this invasive plant is essential. In this research, studies were conducted to determine the mechanisms by which E. annuus became the dominant plant at a landfill site and to develop management strategies for this alien plant. Because the seeds and seedling stage did not have superior adaptations to disturbed soil, demonstrate allelopathy, outcompete other species, or show rapid growth, the disturbance from mowing was likely the primary reason for the dominance of E. annuus. The areas without mowing showed a significant decrease in the coverage of E. annuus, whereas the mowed (managed) areas showed a significant increase. Additionally, mowing once increased the weight of reproductive organs by 50% and suppressed the growth of native species. Thus, the primary factor in the invasion of the alien species E. annuus was mowing, and, to control such an invasion, areas should be protected from mowing. Additionally, with selective mowing that targeted only E. annuus, mowing three times produced only approximately 10% of the reproductive organ biomass compared with that of the control. Because the flower stalk of E. annuus was relatively tall compared with that of native species in early summer, selective mowing might also provide a solution to control invasions of E. annuus. Therefore, with improved ecological understanding of the site and species, mowing of the right target during the optimal season and at an appropriate frequency is an environmental friendly solution to the management of E. annuus.

Post-remediation use of macrophytes as composting materials for sustainable management of a sanitary landfill.

To increase the remediation ability and life expectancy of a leachate channel in a sanitary landfill, the plants used for remediation were composted as a post-remediation management technique. Phragmites australis or Typha angustifolia used for phytoremediation in a landfill leachate channel was harvested and used as a co-composting material with sewage sludge. The macrophyte compost was applied to the slope of a landfill on which plants were introduced for revegetation and to plants grown in pots to test for acute effects of the compost. The compost of the macrophytes successfully increased soil moisture and nutrient contents both on the landfill slope and in the soil of the pot experiment. Additionally, the rates of photosynthesis and the nutrient contents increased for plants grown in macrophyte compost. Thus, the revegetation or restoration management of the landfill would improve with the macrophyte compost used as a soil conditioner. The harvest of the macrophytes has the additional benefit of improving the remediation function of the leachate channel. Therefore, to sustainably manage both the leachate channel and the landfill, the composting of post-remediation macrophytes is an environmentally friendly and economically affordable method.

Microcosm investigation of growth and phytoremediation potential of Azolla japonica along nitrogen gradients.

Although Azolla species are among the most promising plants for use in phytoremediation, more studies on their growth and nitrogen (N) uptake along the N gradients of growing media are required. In this study, N concentration-dependent growth in growing media and phosphorus (P) and N accumulation by Azolla japonica were studied by estimating direct N uptake from media by molybdenum-iron proteins. The doubling time of A. japonica was less than a week, regardless of the N concentration (0, 5, and 25 mg N/L) present in the growth media, indicating that this plant is suitable for remediation. Plants showed a high uptake of P, probably via plant-bacteria symbiosis, indicating their potential for effective P remediation. A. japonica also showed more than 4% N content regardless of the treatment and accumulated more than 40 mg of N per microcosm in 3 weeks. iron and molybdenum levels in plants were strongly associated with N fixation, and N uptake from media was estimated to be more than 25 mg per microcosm in 3 weeks, indicating that A. japonica has N remediation potential. As A. japonica is a rapidly growing plant, capable of efficient P and N remediation, it has great potential for use in phytoremediation of nutrient-enriched waters such as agricultural or urban wastewater and eutrophicated aquatic ecosystems.

From phytoaccumulation to post-harvest use of water fern for landfill management.

We examined the potential of Azolla japonica as a remediating plant for leachate channels and post-accumulation use as fertilizer for landfill slope. The harvested biomass of Azolla after one month grown in leachate was 254% that of the initial biomass and the predicted annual harvestable biomass of Azolla using a growth model was 32 times that of the initial biomass. Na, Fe, Mn, Mg, and P were accumulated in Azolla at very high concentrations. Such rapid increase of biomass and high accumulation rates suggest that this plant could be an excellent remediating plant. The post-harvest use of Azolla as compost was studied for the management and use of phytoaccumulating Azolla. Metal contents of Azolla compost were below permissible limits for co-composting material. Nitrogen, organic matter, P, and Mg content of the Azolla compost improved the soil condition of the landfill and enhanced ecophysiological responses of the plants. The application of Azolla compost can improve management of sanitary landfills, including the restoration of vegetation. Considering its ease of harvesting, high accumulation rates, harvestable biomass and suitability for composting, Azolla can provide a suitable solution for sustainable management of leachate channels and landfill slopes.

Halolamina sediminis sp. nov., an extremely halophilic archaeon isolated from solar salt.

An extremely halophilic archaeal strain, halo-7T, was isolated from brine sediment of the Gomso solar saltern, Republic of Korea. Cells of strain halo-7T were pleomorphic, stained Gram-negative, lysed in distilled water and formed red-pigmented colonies. Strain halo-7T grew in the range of 25-45°C (optimum 37-40°C), pH 6.5-9.5 (optimum pH 7.0-8.0), 15-30% (w/v) NaCl (optimum, 20-25%), and 0.05-0.5 M MgCl2 (optimum 0.1-0.3 M). The minimal NaCl concentration to prevent cell lysis of strain halo-7T was 10% (w/v). The major polar lipids of the isolate were phosphatidylglycerol, phosphatidylglycerolphosphate methyl ester, an unidentified phospholipid, an unidentified lipid, and two unidentified glycolipids. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain halo-7T is closely related to the members of the genus Halolamina, Halolamina salina WSY15-H3T (98.7% 16S rRNA gene sequence similarity), Halolamina pelagica TBN21T (98.2%) and Halolamina rubra CBA1107T (97.4%). The genomic DNA G+C content determined for strain halo-7T (68.0 mol%) was slightly higher than those of H. salina JCM 18549T and H. rubra CBA1107T. DNA-DNA hybridization values between strain halo-7T and reference strains were < 25%. Based on phenotypic, chemotaxonomic and phylogenetic properties, we describe a novel species of the genus Halolamina, represented by strain halo-7T, for which we propose the name Halolamina sediminis sp. nov. The type strain is halo-7T ( = JCM 30187T = CECT 8739T).

Effects of three fire-suppressant foams on the germination and physiological responses of plants.

Suppressant foams used to fight forest fires may leave residual effects on surviving biota that managers need to consider prior to using them. We examined how three fire-suppressant foams (FSFs) (Forexpan S, Phos-Chek-WD881, and Silv-ex) affected seed germination and physiological responses of three plant species. Exposure to FSFs, whether in diluted concentrations or those typical in the field, reduced final germination percentages of seeds grown in petri dishes and within growth chambers. However, the FSFs did not cause total germination failure in any treatment. Inhibition of germination increased with longer exposure times, but only to diluted FSF solutions. Unlike in the laboratory experiments, none of the three FSFs affected seedling emergence when tested in field conditions. Further, we found no evidence of long-term phytotoxic effects on antioxidant enzyme activity nor chlorophyll content of the plant saplings. Therefore, although the three FSFs showed evidence of phytotoxicity to plants in laboratory tests, their actual impact on terrestrial ecosystems may be minimal. We suggest that the benefits of using these FSFs to protect plants in threatened forest ecosystems outweigh their minor risks.

Functional analyses of nanoparticle toxicity: a comparative study of the effects of TiO2 and Ag on tomatoes (Lycopersicon esculentum).

Engineered nanoparticles (NPs), increasingly used in industry, enter and migrate through biological ecosystems. NPs may create some acute toxicity, but their overall effects on living organisms remain largely unknown. In particular, the behavior of NPs in natural conditions and their consequent ecological effects are still poorly understood. In this study, we developed methods to test the phytotoxicity of two distinctly different NPs, one aerosol (nano-TiO2), and the other colloidal silver (AgNP), by specifically considering their tendencies to agglomerate and form precipitates. First we examined effects of these NPs on germination and root elongation. While exposure to neither of these NPs resulted in acute toxicity on germination, silver NPs caused significantly decreased root elongation at every concentration we tested. We found that the hydrodynamic diameters of AgNPs were much smaller than those of nano-TiO2, which induced higher uptake and phytotoxicity. Based on the agglomeration behavior of the NPs, greenhouse trials were run using commercial soil, for nano-TiO2, and Hoagland's solution, for AgNP. Phytotoxicity of silver NPs in the mature plants was demonstrated by lower chlorophyll contents, higher superoxide dismutase activity and less fruit productivity, while nano-TiO2 resulted in higher superoxide dismutase activity at the highest concentration (5000mg/kg). Both nano-TiO2 and AgNPs were taken up into plant stems, leaves and fruits. Our results suggest that further studies of the ecological effects of nanoparticles and steps to mitigate appropriate management strategies are required.

Recycling of Anti-COVID-19 Filtering Facepiece Respirators for Use as Preliminary Water Filters.

Although the United Nations has set sustainable management of water as an important worldwide goal, methods to supply clean water to underdeveloped countries are generally lacking. The ongoing COVID-19 pandemic as increased the worldwide use of filtering facepiece respirators (FFRs), resulting in enormous amounts of plastic waste. The present study tested whether FFRs could be recycled for use as preliminary water filters. Filtering of contaminated water with FFRs significantly reduced its turbidity, as well as concentrations of total organic carbon and major pollutants such as P, K, Mg, and Fe. Most of the filtered samples satisfied the drinking water quality standards of the World Health Organization. The additional use of FFRs decontamination process with hydrogen peroxide or ultraviolet germicidal irradiation, and sterilization with water purification tablets can eliminate disease-causing microorganisms and further reduce turbidity that would make water suitable for drinking. Recycling anti-COVID-19 FFRs for use as preliminary water filters is an effective and sustainable method for solving both drinking water problems and waste due to FFRs. Supplementary Information: The online version contains supplementary material available at 10.1007/s41742-023-00526-w.

Assessing phytotoxicity of microplastics on aquatic plants using fluorescent microplastics.

Although studies on microplastics are increasing every year, still very little is known about their toxicity. Especially for plant species, even studies of uptake of microplastics are only few, not to mention phytotoxicity of microplastics. Therefore, we conducted a pilot study on the phytotoxicity of 1-µm-sized fluorescent microplastics (FMPs) on the free-floating aquatic plants Spirodela polyrhiza and Salvinia natans and the emergent aquatic plant Phragmites australis using 0.1% and 0.01% FMP treatment. Furthermore, uptake of FMPs by plants was verified by detecting fluorescence of FMPs by laser. A free-floating aquatic plant S. polyrhiza and emergent aquatic plant P. australis showed significantly decreased harvested biomass after 3 weeks indicating phytotoxicity of FMPs, but S. natans did not show any differences of harvested biomass or chlorophyll contents among treatments. Detection of fluorescence from plant leaves provided evidence of active FMPs uptake by plants. The emission spectra of plant leaves in 0.1% FMP treatment showed similar peaks to those of free fluorescent microplastics, providing a firm evidence of FMPs uptake by plants. This study is one of the pioneering studies to explore fluorescent microplastic uptake and toxicity in aquatic plants and therefore provides a baseline for further studies.

Effects of land-use types and the exotic species, Hypochaeris radicata, on plant diversity in human-transformed landscapes of the biosphere reserve, Jeju Island, Korea.

Land-use and plant invasion influence biodiversity. Understanding the effects of land-use types and invasive plants on the ecosystem is crucial for better management and the development of strategic plans for increasing biodiversity in Jeju Island, Korea, a designated Biosphere Reserve by the United Nations Education, Scientific, and Cultural Organization. The effect of the most dominant invasive exotic species, Hypochaeris radicata, on the four land-use types of Jeju Island was investigated. Plant composition, soil characteristics, and plant diversity among four land-use types (cropland, green space, neglected land, and residential) were compared. Among the land-use types, croplands had the most diverse plant composition and the highest richness in exotic and native plant species. Croplands, such as tangerine orchards, which are widely distributed throughout Jeju Island, showed the highest plant diversity because of medium intensity disturbance caused by weed removal. The relative cover of H. radicata did not differ between land-use types. However, H. radicata invasion was negatively related with plant species richness, making this invasive species a threat to the biodiversity of native herbs present in land-use areas. H. radicata adapts to areas with a broad range of soil properties and a variety of land-use types. Therefore, it is crucial to monitor land-use types and patterns of plant invasion to guide the implementation of consistent management and conservation strategies for maintaining ecosystem integrity of the transformed habitat in Jeju Island.

Responses of two invasive plants under various microclimate conditions in the Seoul metropolitan region.

The possible consequences of global warming on plant communities and ecosystems have wide-ranging ramifications. We examined how environmental change affects plant growth as a function of the variations in the microclimate along an urban-suburban climate gradient for two allergy-inducing, invasive plants, Humulus japonicus and Ambrosia artemisiifolia var. elatior. The environmental factors and plant growth responses were measured at two urban sites (Gangbuk and Seongbuk) and two suburban sites (Goyang and Incheon) around Seoul, South Korea. The mean temperatures and CO(2) concentrations differed significantly between the urban (14.8 °C and 439 ppm CO(2)) and suburban (13.0 °C and 427 ppm CO(2)) sites. The soil moisture and nitrogen contents of the suburban sites were higher than those at the urban sites, especially for the Goyang site. The two invasive plants showed significantly higher biomasses and nitrogen contents at the two urban sites. We conducted experiments in a greenhouse to confirm the responses of the plants to increased temperatures, and we found consistently higher growth rates under conditions of higher temperatures. Because we controlled the other factors, the better performance of the two invasive plants appears to be primarily attributable to their responses to temperature. Our study demonstrates that even small temperature changes in the environment can confer significant competitive advantages to invasive species. As habitats become urbanized and warmer, these invasive plants should be able to displace native species, which will adversely affect people living in these areas.

Forest litter and shrubs act as an understory filter for the survival of Quercus mongolica seedlings in Mt. Kwan-ak, South Korea.

Forest succession from Pinus to Quercus has often been observed in temperate forest, although the succession mechanism is not clearly understood. This study investigated factors that affect the succession of forests from pine to oak, using forest vegetation inventory data at plots at Kwan-ak mountain in Korea. Analyses of understory canopy coverage, light intensity, and tree numbers and ages in P. densiflora forests indicate that Q. mongolica can only invade these forests before understory shrub establishment. The results from analyses of all environmental factors indicate that similar adverse effects from environmental factors occur in established P. densiflora and Q. mongolica forests that inhibit Q. mongolica seedling survival. However, the observed survival rate of Q. mongolica seedlings under P. densiflora during winter were much higher than Q. mongolica seedlings under Q. mongolica trees, and it is due to accumulated snow over Q. mongolica forest litter which breaks or inhibits the emergence of Q. mongolica seedlings. Protecting seedlings with plastic cups significantly increased the survival rate which confirms that forest floor litter acts as a filter for the regeneration and succession of Q. mongolica forests. This paper thus concludes that understory shrubs and forest litter affect the succession dynamics of P. densiflora and Q. mongolica forests.

Phytotoxicity and accumulation of zinc oxide nanoparticles on the aquatic plants Hydrilla verticillata and Phragmites Australis: leaf-type-dependent responses.

The phytotoxicity and accumulation of zinc oxide nanoparticles (ZnO NPs) on aquatic plant Hydrilla verticillata and Phragmites australis were investigated using mesocosms. The percentage of dissolved Zn in the ZnO NP treatment solutions was measured along with plant shoot growth, antioxidant enzyme activity, chlorophyll content, and Zn content. The dissolution rate of ZnO NPs in Hoagland solution was inversely related to the concentration. The submerged aquatic plant H. verticillata, growth was reduced during the early stages of the experiment when exposed to the highest ZnO NP concentration (1000 mg/L), whereas the emerged aquatic plant P. australis began to show significantly reduced growth after a few weeks. The measurements of chlorophyll content, antioxidant enzyme activity, and Zn accumulation showed that P. australis was adversely affected by NPs and absorbed more Zn than H. verticillata. The results indicated that physiological differences among aquatic plants, such as whether they use leaves or roots for nutrient and water uptake, led to differences in nanoparticle toxicity. Overall, High ZnO NP concentrations caused significant phytotoxicity on aquatic plants, and low concentrations caused unpredictable phytotoxicity. Therefore, the use and disposal of zinc oxide nanoparticles should be carefully monitored.

Functional analysis of TiO2 nanoparticle toxicity in three plant species.

Titanium dioxide nanoparticles (nano-TiO2) are manufactured and used worldwide in large quantities. However, phytotoxicity research on nano-TiO2 has yielded confusing results, ranging from strong toxicity to positive effects. Therefore, in this research, the effects of nano-TiO2 on the germination and root elongation of seed and seedlings were studied. Additionally, the uptake and physiological responses of mature plants were investigated. Physical chemistry data were analyzed to assess the availability of nano-TiO2. Finally, a hydroponic system designed to overcome nano-TiO2 precipitation was used to reproduce the environmental conditions of actual fields. Nano-TiO2 did not have any effect on seed germination or on most of the plant species tested. Nano-TiO2 had positive effects on root elongation in some species. No physiological differences in enzyme activities or chlorophyll content were detected, even though the plants absorbed nano-TiO2. Physical chemistry data showed that nano-TiO2 agglomerated rapidly and formed particles with much bigger hydrodynamic diameters, even in distilled water and especially in a hydroponic system. Furthermore, agglomerated nano-TiO2 formed precipitates; this would be more severe in an actual field. Consequently, nano-TiO2 would not be also readily available to plants and would not cause any significant effects on plants. Our results and other reports suggest that titanium itself is not phytotoxic, even though plants absorb titanium. In conclusion, nano-TiO2 is not toxic to the three plant species, in vitro or in situ.