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1.
J Hazard Mater ; 421: 126757, 2022 01 05.
Artigo em Inglês | MEDLINE | ID: mdl-34352522

RESUMO

Inhalation exposure and beryllium (Be) toxicity are well-known, but research on bioaccessibility from soils via different exposure pathways is limited. This study examined soils from a legacy radioactive waste disposal site using in vitro ingestion (Solubility Bioaccessibility Research Consortium [SBRC], physiologically based extraction test [PBET], in vitro gastrointestinal [IVG]), inhalation (simulated epithelial lung fluid [SELF]) and dynamic two-stage bioaccessibility (TBAc) methods, as well as 0.43 M HNO3 extraction. The results showed, 70 ±â€¯4.8%, 56 ±â€¯16.8% and 58 ±â€¯5.7% of total Be were extracted (gastric phase [GP] + intestinal phase [IP]) in the SBRC, PBET, and IVG methods, respectively. Similar bioaccessibility of Be (~18%) in PBET-IP and SELF was due to chelating agents in the extractant. Moreover, TBAc-IP showed higher extraction (20.8 ±â€¯2.0%) in comparison with the single-phase (SBRC-IP) result (4.8 ±â€¯0.23%), suggesting increased Be bioaccessibility and toxicity in the gastrointestinal tract when the contamination derives from the inhalation route. The results suggested Be bioaccessibility depends on solution pH; time of extraction; soil reactive fractions (organic-inorganic); particle size, and the presence of chelating agents in the fluid. This study has significance for understanding Be bioaccessibility via different exposure routes and the application of risk-based management of Be-contaminated sites.


Assuntos
Arsênio , Poluentes do Solo , Arsênio/análise , Berílio/toxicidade , Disponibilidade Biológica , Poluição Ambiental , Solo , Poluentes do Solo/análise , Poluentes do Solo/toxicidade
2.
Sci Total Environ ; 802: 149899, 2022 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-34464792

RESUMO

A mass of tailings left by mineral exploitation have caused serious environmental pollution. Although many studies have shown that soil microorganisms have the potential to remediate environmental pollution, the interaction mechanism between microorganisms and the surrounding environment of tailings is still unclear. In this study, 15 samples around pyrite mine tailing were collected to explore the ecological effects of environmental factors on bacterial community. The results showed that most of the samples were acidic and contaminated by multiple metals. Cadmium (Cd), copper (Cu), nickel (Ni) migrated and accumulated to into downstream farmlands while chromium (Cr) was the opposite. Proteobacteria, Chloroflex and Actinobacteria were the dominant phyla. Soil pH, total phosphorus (TP), total nitrogen (TN), available potassium (AK), available phosphorus (AP), the bacteria abundance and diversity all gradually increased with the increase of the distance from the tailing. Invertase, acid phosphatase, total organic carbon (TOC), pH, TP and Cr were the main influencing factors to cause the variation of bacterial community. This work could help us to further understand the changes in soil microbial communities around pollution sources.


Assuntos
Metais Pesados , Poluentes do Solo , China , Monitoramento Ambiental , Poluição Ambiental , Metais Pesados/análise , Solo , Microbiologia do Solo , Poluentes do Solo/análise , Poluentes do Solo/toxicidade
3.
Chemosphere ; 286(Pt 1): 131570, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34293559

RESUMO

The increase in pollution increased the threat level of living organisms in the environment. Municipal Solid Waste is one of the most important wastes which contribute to polluted sites affecting livelihood. They pollute the water stream, marine environment ecology, soil fertility, and agriculture production. This, in turn, reduces the microflora of the marine environment, agricultural soil, and fertility. This could be analyzed by setting up a Winogradsky column using dumpsite soil samples. The current work was designed to study the municipal solid wastes from different dumpsite soil. Soil characterization revealed that the pH of Kodungaiyur and Otteri was 7.3 and 6.4. The bulk density was 0.067 g/cm3 and 0.069 g/cm3. The Porosity resulted to be 0.511 particle/volume and 0.513 particle/volume for Kodungaiyur and Otteri. The Kodungaiyur soil containing contaminants supplied with natural sources showed a 100% germination index, and Otteri soil containing contaminants supplied with natural sources showed a maximum vigour index. The presence of medicinal strips in the collected soil samples led to the study on Acetaminophen degradation. HB1 showed to be 79 ± 0.005% at optimum pH 5 containing 100 mg/L of Acetaminophen at day four among the isolated bacterial strains. Further, the intermediate formation was determined using FTIR and GC-MS. The isolated HB1 bacterial strain was identified as Staphylococcus hominis, which is heterotroph.


Assuntos
Poluentes do Solo , Solo , Acetaminofen/toxicidade , Agricultura , Poluentes do Solo/análise , Poluentes do Solo/toxicidade , Resíduos Sólidos/análise
4.
Chemosphere ; 286(Pt 1): 131599, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34315084

RESUMO

In this study, 11 low/uncontaminated (including Lufa 2.2) and 9 contaminated field soils with varying geophysical and physicochemical characteristics were evaluated for toxicities based on oxygen consumption of sulfur-oxidizing bacteria (SOB). Oxygen consumption of the low/uncontaminated soils ranged between 7.9 mL and 9.5 mL, while contaminated soils ranged between 0.4 mL and 5.4 mL. Inherent test variability (CVi), variation due to soil natural properties (CVns) and minimal detectable difference (MDD) values ranged 1.2%-3.9%, 3.5%-16.9%, and 2.1%-4.3%, respectively. The toxicity threshold of 20% was established for soil toxicity based maximal tolerable inhibition (MTI). All the contaminated soils were found to be toxic and showed inhibition between 42% and 100% above the 20% threshold value. Increased proportions of clay and slit enhanced the of inhibitory effect of contaminants on SOB by reducing the oxygen consumption. Current study provides a suitable method for the rapid toxicity assessment of contaminated field soils with the advantages of ease of handling and rapidity without employing elutriates and sophisticated equipments and tools.


Assuntos
Poluentes do Solo , Solo , Bactérias , Bioensaio , Oxirredução , Poluentes do Solo/análise , Poluentes do Solo/toxicidade , Enxofre/toxicidade
5.
Chemosphere ; 287(Pt 4): 132406, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34597649

RESUMO

Being analogue to arsenic (As), phosphorus (P) may affect As dynamics in soil and toxicity to plants depending upon many soil and plant factors. Two sets of experiments were conducted to determine the effect of P on As fractionation in soils, its accumulation by plants and subsequent impact on growth, yield and physiological characteristics of sunflower (Helianthus annuus L.). Experimental plan comprised of two As levels (60 and 120 mg As kg-1 soil), four P (0-5-10-20 g phosphate rock kg-1 soil) and three textural types (sandy, loamy and clayey) with three replications. Among different As fractions determined, labile, calcium-bound, organic matter-bound and residual As increased while iron-bound and aluminum-bound As decreased with increasing P in all the three textural types. Labile-As percentage increased in the presence of P by 16.9-48.0% at As60 while 36.0-68.1% at As120 in sandy, 19.1-64.0% at As60 while 11.5-52.3% at As120 in loamy, and 21.8-58.2% at As60 while 22.3-70.0% at As120 in clayey soil compared to respective As treatment without P. Arsenic accumulation in plant tissues at both contamination levels declined with P addition as evidenced by lower bioconcentration factor. Phosphorus mitigated the As-induced oxidative stress expressed in term of reduced hydrogen peroxide, malondialdehyde while increased glutathione, and consequently improved the achene yield. Although, P increased As solubility in soil but restricted its translocation to plant, leading to reversal of oxidative damage, and improved sunflower growth and yield in all the three soil textural types, more profound effect at highest P level and in sandy texture.


Assuntos
Arsênio , Helianthus , Poluentes do Solo , Arsênio/análise , Arsênio/toxicidade , Fósforo , Solo , Poluentes do Solo/análise , Poluentes do Solo/toxicidade
6.
Chemosphere ; 287(Pt 4): 132416, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34600014

RESUMO

The healthcare community acknowledged that bio-medical wastes (BMWs) have reached a colossal level across the globe. The recent pandemic (COVID-19) has brought a deluge of contaminated waste which calls for an urgent need of treatment technology for its safe disposal. BMW generally undergoes a conservative treatment approach of incineration which in turn generates potentially toxic ash known as BMW ash. BMW ash, if directly dumped in landfill, leaches and further pollutes both land and groundwater. The present study deployed Brassica juncea [Indian Mustard (IM)], Chrysopogon zizanioides [Vetiver Grass (VG)], and Pistia stratiotes [Water Lettuce (WL)] to remediate toxicity of potentially toxic elements (PTEs) i.e., Cd, Al, Pb, Cu, Mn, Co and Zn in BMW ash both in the presence and absence of chelate with an increased dosage of toxicity. The phyto-assessment results showed that IM extracted 202.2 ± 0.1-365.5 ± 0.02, 7.8 ± 0.03-12.5 ± 0.3, 132.1 ± 0.1-327.3 ± 0.1 and >100 mg kg-1 of Al, Cd, Pb and Zn, respectively without the assistance of a chelating agent. The VG accumulated heavy metals in greater concentration up to 10.5 ± 0.1 and 290.1 ± 0.05 mg kg-1 of Cd and Zn, respectively, and similar trends were observed in the WL set-up. However, the application of an ethylene diamine tetraacetic acid (EDTA) had also increased the efficiency on an average by 20-30% for IM, 35-45% for VG, and 25-35% for WL. The experimental set-up shows that the BCF for IM, VG and WL was found to be greater than 1 for most of the PTEs. The higher value of BCF resulted in a better ability to phytoextract the heavy metals from the soil. The results suggested that IM, VG and WL have the potential to phytoextract PTEs both in the absence and presence of chelating agents.


Assuntos
Araceae , COVID-19 , Vetiveria , Poluentes do Solo , Biodegradação Ambiental , Quelantes , Humanos , Mostardeira , SARS-CoV-2 , Poluentes do Solo/análise , Poluentes do Solo/toxicidade
7.
Environ Pollut ; 292(Pt A): 118242, 2022 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-34600067

RESUMO

Multigenerational tests provide a comprehensive assessment of the long-term toxicity of pollutants. Here, the multigenerational effects of soil metal contamination on Folsomia candida were investigated over five generations (generations 1-5: F1-F5). Nine soils with varying physicochemical properties and degrees of metal pollution were studied. The selected endpoints were survival, reproduction, body size and body metal concentrations. F. candida was cultured only up to the fifth generation with high reproduction in contaminated acid soils where reproduction was at least 5 times that in neutral soils and 20 times that in calcareous soils. Correlation analysis indicated that soil pH (68.9% contribution) and cation exchange capacity (CEC, 15.4% contribution) were more important factors than pollution level affecting the reproduction of F. candida. No significant difference was observed in adult survival or adult length over five generations. The highest collembolan body Cd concentrations in soils A1-A3 were 3.15, 2.93 and 3.23 times those in F1, with similar results for body Pb. A similar trend in reproduction and juvenile length was observed with an initial decrease (p < 0.05) and then an increase (p < 0.05) over the generations in each acid soil; the opposite trend occurred in the changes in body cadmium (Cd) and lead (Pb) concentrations which increased initially (p < 0.05) and then decreased (p < 0.05) compared to the original concentrations of the first generation. The results indicate that F. candida can adapt to soil metal stress during multigenerational exposure and the adaption energy may be related to a tradeoff between reproduction or growth of juveniles and the detoxification of metals accumulated in the body. Soil properties, especially pH and CEC, had a substantial influence on the long-term survival of the collembolan in the metal-polluted soils.


Assuntos
Artrópodes , Poluentes do Solo , Animais , Poluição Ambiental , Metais/toxicidade , Solo , Poluentes do Solo/toxicidade
8.
Chemosphere ; 286(Pt 2): 131768, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34426129

RESUMO

Novel green technologies for soil remediation have been focusing on altering soil properties and improving soil health. Hydrothermally-altered feldspar (HYP, HydroPotash), recently developed, is being related as both an efficient amendment to immobilize heavy metals in soils and a plant nutrients source, consisting in a promising technology for revegetation of contaminated sites. In order to evaluate the effectiveness of using HYP for phytostabilization programs, two different soils (Technosol and Oxisol) collected from a smelting site were amended with increasing doses of HYPs (HYP-1 and HYP-2): 15, 30, 60, and 120 Mg ha-1. For comparison, a control (soil without amendment) and a soil amended with zeolite (clinoptilolite) were also included as treatments. After 90 days of incubation, HYPs decreased up to 83.8 % of Cd availability and reduced exchangeable Al up to 100 %. HydroPotash increased pH, cation exchange capacity, and contents of potassium, calcium, and phosphorus, as well as microbial biomass carbon, and fluorescein diacetate hydrolysis of soils. Andropogon gayanus, Eucalyptus grandis, and Heterocondylus vitalbae started growing from the dose of 15 Mg ha-1 HYPs in the Oxisol and 60 Mg ha-1 HYPs in the Technosol. Principal component analysis indicates that plant shoot dry weight was negatively correlated with extractable Cd and Zn and positively with pH, CEC, and Ca content. Besides promoting plant growth, HYPs reduced heavy metals (Cd and Zn) absorption by plants, indicating that HYP has potential use as an amendment in phytostabilization programs.


Assuntos
Metais Pesados , Poluentes do Solo , Silicatos de Alumínio , Metais Pesados/análise , Metais Pesados/toxicidade , Compostos de Potássio , Solo , Poluentes do Solo/análise , Poluentes do Solo/toxicidade
9.
Chemosphere ; 286(Pt 2): 131707, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34365170

RESUMO

2-Pentanone is an excellent organic solvent and extractant, which is widely used in industrial production. 2-Pentanone is harmful to soil organisms when it enters the soil. However, current studies have not clarified the response of the antioxidant enzyme superoxide dismutase (SOD) to 2-Pentanone and its mechanism. In this study, the response of earthworm antioxidant enzyme SOD to 2-Pentanone and its molecular mechanism was investigated at organism molecular levels. The results showed that the SOD activity of earthworms under 2-Pentanone stress was significantly inhibited, and the inability of superoxide anion radicals (·O2-) to be scavenged in time might be one of the reasons for the increase of lipid peroxidation. Under 2-Pentanone exposure conditions, catalase (CAT), an antioxidant enzyme closely related to SOD, and the total antioxidant capacity (T-AOC) of earthworms were activated to resist oxidative damage. On the other hand, the observation of earthworm microstructure provided evidence of a direct risk of 2-Pentanone on earthworm body wall tissues. Molecular-level assays have shown that 2-pentanone altered the secondary structure of SOD, which further led to the loosening of the SOD backbone structure and the extension of the polypeptide chain. On the other hand, 2-pentanone quenched the endogenous fluorescence of SOD in the form of static quenching and formed the 2-pentanone/SOD complex. Molecular simulation results suggested that 2-pentanone tended to bind on the surface of SOD rather than close to the active site, and it is speculated that the alteration of SOD structure is the key reason for the change in its activity. This study enriches the toxicological data of 2-Pentanone on soil organisms, thus responding to the current concerns about its ecological risk.


Assuntos
Oligoquetos , Poluentes do Solo , Animais , Catalase/metabolismo , Malondialdeído , Oligoquetos/metabolismo , Estresse Oxidativo , Pentanonas , Poluentes do Solo/toxicidade , Superóxido Dismutase/metabolismo
10.
J Hazard Mater ; 421: 126694, 2022 01 05.
Artigo em Inglês | MEDLINE | ID: mdl-34332483

RESUMO

Although the compound pollution of microplastics and arsenic (As) in paddy soil can affect the growth and quality of rice, relevant research on this phenomenon was limited. Therefore, we combined a pot experiment with computational chemistry to explore the effects and mechanism of polystyrene (PSMP) and polytetrafluoroethylene (PTFE) microplastics on As bioavailability. PSMP and PTFE interacted with rice root exudates through van der Waals forces, approached the rice root system, inhibited root activity, reduced the relative abundance of Geobacteria and Anaeromyxobacter, and consequently reduced the iron plaques on the root surfaces. Consequently, As uptake by the rice was inhibited. PSMP and PTFE reduced the hemoglobin content by directly destroying its tertiary structure, thereby retarding rice growth. In contrast, As increased the hemoglobin content by inducing reactive oxygen species in rice. Under the influence of PSMP, PTFE, and As, the activities of soluble starch synthase and pyrophosphorylase in rice grains were inhibited, and starch accumulation decreased. Thus, PSMP, PTFE, and As reduced rice biomass and yield owing to their physiological toxicity and adverse impacts on root activity. Grain yields in soil with an As content of 86.3 mg·kg-1, 0.5% small particle-sized PSMP, and 0.5% small particle-sized PTFE decreased by 30.7%, 20.6%, and 19.4%, respectively, compared to the control. This study determined the comprehensive mechanism through which PSMP and PTFE affect As bioavailability, which is critical for managing rice biomass and low yields in As and microplastic co-contaminated soil.


Assuntos
Arsênio , Oryza , Poluentes do Solo , Arsênio/análise , Arsênio/toxicidade , Microplásticos , Plásticos/toxicidade , Solo , Poluentes do Solo/análise , Poluentes do Solo/toxicidade
11.
J Hazard Mater ; 421: 126826, 2022 01 05.
Artigo em Inglês | MEDLINE | ID: mdl-34396963

RESUMO

Plant roots can accumulate organic chemicals, including PCBs, and this could be relevant in spreading chemicals through the food chain. To estimate such uptake, several equations are available in the literature, mostly developed in lab conditions, to obtain the root concentration factor (RCF). Here, a long-term (18 months) greenhouse experiment, using an aged, contaminated soil, was performed to reproduce root uptake in field-like conditions and to account for the ecological variability of exposure during the entire life cycle. Specific growth strategies (i.e., annual vs. perennial), root development (e.g., timing of root production and decaying), and soil parameters (e.g., dissolved organic carbon (DOC), and the particulate organic carbon (POC)) may interfere with the uptake of contaminants into the roots of plants. In this study, we investigate the effects of these factors on the RCF, obtained for 79 PCBs. New predictive equations were calculated for 5 different plants species at four different growth times (from few months to 1.5 years) and stages (growing vs maturity). The relationships highlighted a species-specific and time-dependent accumulation of PCB in plants roots, with higher RCFs in summer than in fall for some species, and the relevant influence of DOC and POC in affecting root uptake.


Assuntos
Bifenilos Policlorados , Poluentes do Solo , Animais , Carbono , Estágios do Ciclo de Vida , Raízes de Plantas/química , Bifenilos Policlorados/análise , Bifenilos Policlorados/toxicidade , Solo , Poluentes do Solo/análise , Poluentes do Solo/toxicidade
12.
Sci Total Environ ; 805: 150115, 2022 Jan 20.
Artigo em Inglês | MEDLINE | ID: mdl-34818763

RESUMO

Gypsum (calcium sulfate dihydrate, CaSO4 ·2H2O) is commonly applied to improve soil quality and nutrient supply. Previous studies also suggested it is a cost-effective soil amendment in alleviating cadmium (Cd) toxicity and accumulation in plants. The aim of this study was to investigate how this is achieved. We used pak choi as our research material because it is a popular vegetable in Asia, and as a leafy vegetable, it accumulates higher Cd level than other types of vegetable. Under Cd stress, application of CaSO4 promoted pak choi seedling growth, decreased the oxidative stress in roots, reduced Cd accumulation, and enhanced the photosynthesis in shoots. We revealed the inhibition of Cd2+ absorption by CaSO4 is largely due to the competition between Ca2+ and Cd2+ for ion channels or transporter. Moreover, under Cd stress, CaSO4 facilitated the sulphate assimilation, increased the biosynthesis of phytochelatins, and activated the expression of transporters for vacuolar sequestration. Together, CaSO4 could benefit plant growth and enhance Cd tolerance by suppressing Cd root uptake and lowering the Cd content in cytoplasm.


Assuntos
Plântula , Poluentes do Solo , Cádmio/análise , Cádmio/toxicidade , Sulfato de Cálcio , Raízes de Plantas/química , Plântula/química , Solo , Poluentes do Solo/análise , Poluentes do Solo/toxicidade
13.
Chemosphere ; 287(Pt 2): 132116, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34492419

RESUMO

Biochar application as a soil amendment has attracted worldwide attention. Nevertheless, polycyclic aromatic hydrocarbons (PAHs) formed during biochar production might enter into ecosystems and threaten human health after application to soil. Continuous pyrolysis systems tend to cause an accumulation of PAHs in biochar owing to short residence time and rapid cooling. This study conducted a comprehensive assessment regarding potential risk of PAHs in biochars produced by a continuous pyrolysis system based on bioavailability, leaching behavior, toxic equivalent quantity, health risk and phytotoxicity of PAHs. Results showed that the concentrations of total PAHs in biochars were in the range of 93.40-172.40 mg/kg, exceeding the European Biochar Certificate standard. 3-rings PAHs were the predominant groups. The percentages of total freely dissolved and leachable PAHs were lower than 1%. RH contained the least bioavailable and leachable PAHs concentration and phytotoxicity compared with CS and PS, which might attribute to the characteristic of three biochars. CS and PS were acidic and exhibited high levels of DOC and VFAs, while RH was strongly alkaline and presented greater aromaticity and higher surface area, which might have resulted in high adsorptive capacity and decreased bioavailability of PAHs. When the biochar application rate was higher than 0.6 t/ha, the incremental lifetime cancer risk value for human exposure to biochar-borne PAHs through the biochar-amended soil was over 10-6, suggesting carcinogenic risks. Germination index values of biochars ranged from 25.66 to 88.95%. Phytotoxicity mainly was caused by bioavailable PAHs and dissolved organic compounds. Overall, these findings highlighted that although the percentage of bioavailable PAHs was low, the potential health risk and phytotoxicity of PAHs in biochars produced by a continuous pyrolysis system was of a great concern. High biochar application rates should be avoided without processing both for soil safety and human health.


Assuntos
Hidrocarbonetos Policíclicos Aromáticos , Poluentes do Solo , Disponibilidade Biológica , Carvão Vegetal , Ecossistema , Humanos , Hidrocarbonetos Policíclicos Aromáticos/análise , Hidrocarbonetos Policíclicos Aromáticos/toxicidade , Pirólise , Solo , Poluentes do Solo/análise , Poluentes do Solo/toxicidade
14.
Chemosphere ; 287(Pt 3): 132252, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34555583

RESUMO

The presence of engineered nanoparticles (ENPs) in soil gradually increases, among others due to the nano-agrochemicals application. So far, the co-existence of different ENPs in soil is poorly examined. Here, the metal extractability and toxicity of soils spiked (300 mg kg-1) singly and jointly with Zn- and Cu-based ENPs or metal salts were tested. The samples were aged for 1 and 90 days. The predicting available metal component of ENPs concentrations were determined by different methods including soil pore water collection and batch extractions with H2O, CaCl2 or DTPA. Survival and reproduction of Folsomia candida were also evaluated. The combined effect of ENPs on the extractability of metals was mainly found with DTPA characterized by the highest leaching capacity among the used extractants. In fresh soil, the mixtures of ENPs differentiated only DTPA-extractable Cu level, while aging resulted in changes in both Zn and Cu concentrations leached by CaCl2 or DTPA. However, the character of the combined effect was an ENPs- and soil type-dependent, whereas the mixtures of metal salts mostly provided higher Zn and Cu recovery than the individual compounds. The pattern of co-toxicity of metal-oxide ENPs was also time-dependent: the antagonistic and synergistic effect was observed in the samples after 1 and 90 days, respectively. However, the toxicity was weakly related with extractable concentrations in both single and joint treatment of metal compounds. The distinct joint effect patterns of ENPs imply the need for more in-depth investigation of mechanisms of activity of ENPs mixtures in soil.


Assuntos
Artrópodes , Nanopartículas Metálicas , Nanopartículas , Poluentes do Solo , Animais , Cobre/toxicidade , Nanopartículas Metálicas/toxicidade , Nanopartículas/toxicidade , Solo , Poluentes do Solo/análise , Poluentes do Solo/toxicidade , Zinco
15.
Chemosphere ; 287(Pt 1): 131957, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34450367

RESUMO

An increase in technological interventions and ruthless urbanization in the name of development has deteriorated our environment over time and caused the buildup of heavy metals (HMs) in the soil and water resources. These heavy metals are gaining increased access into our food chain through the plant and/or animal-based products, to adversely impact human health. The issue of how to restrict the entry of HMs or modulate their response in event of their ingress into the plant system is worrisome. The current knowledge on the interactive-regulatory role and contribution of different physical, biophysical, biochemical, physiological, and molecular factors that determine the heavy metal availability-uptake-partitioning dynamics in the soil-plant-environment needs to be updated. The present review critically analyses the interactive overlaps between different adaptation and tolerance strategies that may be causally related to their cellular localization, conjugation and homeostasis, a relative affinity for the transporters, rhizosphere modifications, activation of efflux pumps and vacuolar sequestration that singly or collectively determine a plant's response to HM stress. Recently postulated role of gaseous pollutants such as SO2 and other secondary metabolites in heavy metal tolerance, which may be regulated at the whole plant and/or tissue/cell is discussed to delineate and work towards a "not so heavy" response of plants to heavy metals present in the contaminated soils.


Assuntos
Metais Pesados , Poluentes do Solo , Biodegradação Ambiental , Humanos , Metais Pesados/análise , Metais Pesados/toxicidade , Plantas , Solo , Poluentes do Solo/análise , Poluentes do Solo/toxicidade
16.
Chemosphere ; 287(Pt 1): 132059, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34474392

RESUMO

Bioremediation of fuel-contaminated soils largely depends on microbial activities, which might be stimulated using (in)organic amendments. Attenuation of a diesel-biodiesel blend (B12) was investigated in microcosms during 93 days. Soil was spiked with B12 (5%, m m-1) and, in addition to contaminated Controls (unamended), soils received compost (COB), soybean hulls (SHB), or NPK fertilizer (IB) to reach a ~20:1 carbon-to-nitrogen (C:N) ratio regarding B12-carbon content. Effects of treatments on B12 attenuation, soil respiration, heterotrophic and B12-utilizing bacteria, pH, organic-C, nitrogen contents, and phytotoxicity, were evaluated. After 20 days, diesel range organics analysis indicated 58, 48, 45, and 43% attenuation in Controls, SHB, IB, and COB, respectively. Final dissipation reached 90, 86, 72, and 60% in Controls, COB, IB, and SHB. Compost and soybean hulls appeared as preferential substrates for microorganisms. Although microbial activity (soil respiration) was 39 and 22% higher than Controls in COB and SHB, amendments postponed attenuation. Amendments transiently affected bacterial numbers as compared to Controls; however, these effects were not related to attenuation levels. pH of the contaminated soils (~7.0) dropped to 6.1 in IB, whereas pH values were between 6.7 and 7.6 in other treatments. Organic-N and Kjeldahl-N decreased during incubations, indicating net N mineralization and subsequent nitrification, although N losses could occur. Organic-C, initially higher in SHB and COB, decreased in all treatments; however, more prominent losses in COB and SHB suggest amendments were preferentially used by microorganisms. Phytotoxicity was improved in Controls; however, it was not associated with attenuation levels in amended treatments, possibly owing to formation of toxic products and B12 sorption/desorption. In IB, decreased microbial activity, delayed attenuation, and remarkable phytotoxicity were due to excessive fertilization. Therefore, intrinsic soil conditions were adequate for B12 attenuation, without the need for nutritional inputs. Results also demonstrate that toxicity bioindicators are relevant to monitor remediation.


Assuntos
Poluentes do Solo , Solo , Biodegradação Ambiental , Biocombustíveis , Microbiologia do Solo , Poluentes do Solo/análise , Poluentes do Solo/toxicidade
17.
Chemosphere ; 287(Pt 1): 132082, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34523456

RESUMO

Knowledge is insufficient on feasible remediation techniques to agricultural soils contaminated by multiple heavy metal(loid)s with elevated concentrations and extreme acidy from acid mine drainages (AMD). We aimed to elucidate the effect of integrated biochar (BC) and soil replacement on improving the mining soil properties and then alleviating the phytotoxicity of As, Pb, Cd, Cu, and Zn on radish (Raphanus sativus L.)-soya bean (Glycine max Merr.) -amaranth (Amaranthus tricolor L.) rotation and the potential risk of crops to human health. Biochar and soil replacement showed outstanding effects on improving soil properties by increasing soil pH values, reducing available metal(loid)s, and enhancing the activity of catalase, urease and acid phosphatase. Also, the integrated technique regulated the physiological disorders of crops caused by metal(loid)s, specifically increasing chlorophyll content and reducing malondialdehyde (MDA) in the three crops, and reducing the content of metal(loid)s in edible parts of plants. The combination of biochar and soil replacement exhibited better remediation effect than the single application of biochar or soil replacement, which played different roles in remediating mining farmland. Biochar exhibited efficacy in soil pH amelioration, metal stabilization and soil enzyme activity enhancement, while soil replacement alleviated metal(loid)s stress through the dilution effect. Among the 8 treatments, only biochar combined with 35% (S35BC) and 50% (S50BC) of replaced soil could achieve the safe production of the three crops under the three-season crop rotation.


Assuntos
Metais Pesados , Raphanus , Poluentes do Solo , Carvão Vegetal , Humanos , Metais Pesados/análise , Metais Pesados/toxicidade , Solo , Poluentes do Solo/análise , Poluentes do Solo/toxicidade , Soja
18.
Environ Pollut ; 291: 118215, 2021 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-34740293

RESUMO

Laboratory experiments in which earthworms were exposed to four different Sb spiked agricultural soils (acidic, neutral, alkaline and calcareous alkaline soil) were conducted in a climate-controlled room. The study surveyed the toxicity of Sb to the Eisenia fetida at the individual (mortality, growth inhibition, Sb accumulation), physiological (enzymatic activities), subcellular and tissue levels (histological damage), and for the induction of an avoidance response of Sb. The results showed that earthworms clearly avoided Sb spiked soil, and the avoidance response tended to be correlated to the exposure dose. The EC50 values of the net avoidance response in the four soils were as followed: S1 (acidic soil, 135 ± 37 mg kg-1) < S3 (alkaline soil, 430 ± 114 mg kg-1) < S4 (calcareous alkaline soil, 455 ± 29 mg kg-1) < S2 (neutral soil, 946 ± 151 mg kg-1). Different toxic effects of Sb to earthworms cultivated in the four types of soils were observed. Antimony was more toxic in a sandy alkaline soil than that in the other three soils tested. The LC50 of the 28 d mortality ranged as follows: S3 (22.2 ± 0.1 mg kg-1) < S2 (372 ± 177 mg kg-1) < S4 (491 ± 140 mg kg-1) < S1 (497 ± 29 mg kg-1). Changes in oxidative stress and the subcellular distribution of Sb in earthworms induced by Sb exposure differed between soil types. Additionally, histological damage in earthworm's epidermis and intestine were observed under Sb stress. Mortality, growth inhibition and Sb accumulation in the earthworms tended to increase with Sb exposure regardless of soil type and were all significantly correlated with the exposure dose. The growth inhibition and Sb concentration in tissues of earthworms were sensitive indicators of Sb bioavailability. The relatively comprehensive toxicological data provided herein can contribute to the toxicity threshold and assessment of bioavailability of Sb contaminated agricultural soil, and then to the ecological risk assessments.


Assuntos
Oligoquetos , Poluentes do Solo , Animais , Antimônio/toxicidade , Disponibilidade Biológica , Solo , Poluentes do Solo/análise , Poluentes do Solo/toxicidade
19.
Environ Monit Assess ; 193(11): 762, 2021 Nov 02.
Artigo em Inglês | MEDLINE | ID: mdl-34727237

RESUMO

Plant species exhibiting heavy metal tolerance are instrumental in phytoremediation of metalliferous sites. Most of the time, variations in plant functional traits (PFTs) are overlooked while identifying hyperaccumulators. However, investigating morphological, physiological, and phenological variations can contribute to our knowledge about stress tolerance, and aid in identifying potential hyperaccumulators. In the present study, we investigated variation in morpho-functional traits in Solanum nigrum, a known hyperaccumulator, under lead (Pb) stress. Twenty-one PFTs including 9 above-ground (leaf count, leaf area, specific leaf area, leaf dry matter content, leaf thickness, leaf dry mass, shoot length, stem dry mass, stem diameter), 3 below-ground (root length, root dry mass, and root diameter), 4 reproductive (flower bud count, fruit count, flower count, and fruit dry mass), and 5 photosynthetic traits (total chlorophyll, total carotenoid, chlorophyll a, chlorophyll b, and photosynthetic efficiency) under varying Pb concentrations (500-2000 mg kg-1) were assessed. Pillai's trace test (MANOVA) depicted significant variations in above-ground, below-ground, and photosynthetic traits, whereas reproductive traits did not vary significantly with progressive metal concentration. However, most of the studied traits except flower count, fruit dry mass, and chlorophyll b varied significantly under Pb stress. The study depicts that enhanced PFT's plasticity enables S. nigrum to grow in Pb-contaminated soil effectively without impacting plant fitness. Plasticity of morpho-functional traits, therefore, establishes itself as a resourceful approach in successful identification of phytoremediation capacity of a plant.


Assuntos
Poluentes do Solo , Solanum nigrum , Biodegradação Ambiental , Clorofila A , Monitoramento Ambiental , Folhas de Planta , Poluentes do Solo/toxicidade
20.
Artigo em Inglês | MEDLINE | ID: mdl-34639452

RESUMO

The collaborative assessment and health risk evaluation of heavy metals (HMs) enrichment in soils and tea leaves are crucial to guarantee consumer safety. However, in high soil HM geochemical background areas superimposed by human activities, the health risk associated with HMs in soil-tea systems is not clear. This study assessed the HMs concentration (i.e., chromium (Cr), cadmium (Cd), arsenic (As), and lead (Pb)) in tea leaves and their relationship with soil amounts in the southwest region of China to evaluate the associated health risk in adults. The results revealed that the average soil concentration of Cr was the highest (79.06 mg kg-1), followed by Pb (29.27 mg kg-1), As (14.87 mg kg-1), and Cd (0.18 mg kg-1). Approximately 0.71, 4.99, 7.36, and 10.21% of soil samples exceeded the threshold values (NY/T 853-2004) for Pb, Cr, As, and Cd, respectively. Furthermore, the average concentration of Pb, As, and Cd in tea leaves was below the corresponding residue limits, but Cr was above the allowed limits. Correlation analysis revealed that the Pb, Cr, As, and Cd amounts in tea leaves were positively correlated to their soil amounts (p < 0.01) with an R2 of 0.203 **, 0.074 **, 0.036 **, and 0.090 **, respectively. Additionally, approximately 40.38% of the samples were found to be contaminated. Furthermore, spatial distribution statistical analysis revealed that Lancang was moderately contaminated, while Yingjiang, Zhenkang, Yongde, Zhenyuan, Lüchun, Jingdong, Ximeng, and Menglian were slightly contaminated areas. The target hazard quotients (THQ; health risk assessment) of Pb, Cr, As, and Cd and the hazard index (HI) of all the counties were below unity, suggesting unlikely health risks from tea consumption.


Assuntos
Metais Pesados , Poluentes do Solo , Adulto , China , Monitoramento Ambiental , Humanos , Metais Pesados/análise , Metais Pesados/toxicidade , Folhas de Planta/química , Medição de Risco , Solo , Poluentes do Solo/análise , Poluentes do Solo/toxicidade , Chá
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