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1.
Chemosphere ; 254: 126916, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32957301

RESUMO

4-Nonylphenol (4-NP), a phenolic endocrine disruptor chemical (EDC), is known to have high toxicity to aquatic organisms and humans. The remediation of 4-NP-contaminated marine sediments was studied using red algae-based biochar (RAB) thermochemically synthesized from Agardhiella subulata with simple pyrolysis process under different temperatures of 300-900 °C in CO2 atmosphere. The RAB was characterized by XRD, Raman, FTIR spectroscopy, and zeta potential measurements. The calcium in RAB efficiently activated sodium percarbonate (SPC) to generate reactive radicals for the catalytic degradation of 4-NP at pH 9.0. The oxygen-containing functional groups reacted with H2O2, which increased the generation of reactive radicals under alkaline pH condition. Ca2+ ion was the active species responsible for 4-NP degradation. CaO/CaCO3 on RAB surface enhanced direct electron transfer, increased HO production, and 4-NP degradation in marine sediments. Langmuir‒Hinshelwood type kinetics well described the 4-NP degradation process. Remediation of contaminated sediments using RAB could be a sustainable approach toward closed-loop biomass cycling in the degradation of 4-NP contaminants.


Assuntos
Carvão Vegetal/química , Disruptores Endócrinos/análise , Recuperação e Remediação Ambiental/métodos , Sedimentos Geológicos/química , Fenóis/análise , Rodófitas/química , Poluentes Químicos da Água/análise , Biomassa , Carbonatos/química , Catálise , Humanos , Peróxido de Hidrogênio/química , Cinética
2.
Bull Environ Contam Toxicol ; 105(4): 639-644, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32955595

RESUMO

Arsenic (As) and cadmium (Cd) are common soil pollutants whose opposing geochemical behaviors must be taken into account in the development of cost-effective, environmentally friendly remediation strategies. In this study, a pot experiment with lettuce and a field experiment with wheat were performed to examine the impacts of zeolite, biochar, MnO2, zero-valent iron (ZVI) individually and in binary combinations thereof on As-Cd pollution. The results of the pot experiment showed that biochar, MnO2 and ZVI had good passivation effects on As and Cd when provided individually, but the effects of a combination of 0.2% ZVI/0.5% biochar or 0.2% MnO2/0.5% ZVI were even better. These amendments were further investigated in a field experiment, which confirmed the positive effect of 0.2% MnO2/0.5% ZVI. Therefore, ZVI/biochar and MnO2/ZVI mixtures may offer effective solutions to the remediation of farmland soil contaminated with both As and Cd.


Assuntos
Arsênico/química , Cádmio/química , Recuperação e Remediação Ambiental/métodos , Poluentes do Solo/química , Arsênico/análise , Cádmio/análise , Carvão Vegetal , Poluição Ambiental , Fazendas , Ferro , Alface , Compostos de Manganês , Óxidos , Solo , Poluentes do Solo/análise , Triticum
3.
Bull Environ Contam Toxicol ; 105(2): 283-290, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32734360

RESUMO

The current study investigated the efficiency of sepiolite (SE), sodium humate (HS), microbial fertilizer (JF) and SE combined with JF/HS in a ratio of 2:1 (w/w) (JF-2SE and HS-2SE) on Cd, Pb and As bioavailability in field trials with rice (Oryza sativa L.). The results showed that all the amendments remarkably decreased (p < 0.05) the contents of available Cd and available Pb in soil. Only JF-2SE treatment reduced available As concentration in soil. All the amendments were found to effectively reduce (p < 0.05) the contents of As in brown rice. Both JF-2SE and HS-2SE co-applications reduced the concentrations of Cd in brown rice to 0.108 and 0.135 mg kg-1, and that of Pb reduced to 0.2 and 0.175 mg kg-1, which met the national standard limit of China. Thus, the co-application of JF/HS-2SE can be a promising remediation strategy in Cd, Pb and As co-contaminated paddy soil.


Assuntos
Cádmio/química , Recuperação e Remediação Ambiental/métodos , Chumbo/química , Poluentes do Solo/química , Disponibilidade Biológica , Cádmio/análise , China , Poluição Ambiental , Fertilizantes , Chumbo/análise , Silicatos de Magnésio , Oryza , Solo/química , Poluentes do Solo/análise
4.
PLoS One ; 15(8): e0228477, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32756569

RESUMO

Coral reefs worldwide are degrading due to climate change, overfishing, pollution, coastal development, coral bleaching, and diseases. In areas where the natural recovery of an ecosystem is negligible or protection through management interventions insufficient, active restoration becomes critical. The Reef Futures symposium in 2018 brought together over 400 reef restoration experts, businesses, and civil organizations, and galvanized them to save coral reefs through restoration or identify alternative solutions. The symposium highlighted that solutions and discoveries from long-term and ongoing coral reef restoration projects in Spanish-speaking countries in the Caribbean and Eastern Tropical Pacific were not well known internationally. Therefore, a meeting of scientists and practitioners working in these locations was held to compile the data on the extent of coral reef restoration efforts, advances and challenges. Here, we present unpublished data from 12 coral reef restoration case studies from five Latin American countries, describe their motivations and techniques used, and provide estimates on total annual project cost per unit area of reef intervened, spatial extent as well as project duration. We found that most projects used direct transplantation, the coral gardening method, micro-fragmentation or larval propagation, and aimed to optimize or scale-up restoration approaches (51%) or provide alternative, sustainable livelihood opportunities (15%) followed by promoting coral reef conservation stewardship and re-establishing a self-sustaining, functioning reef ecosystems (both 13%). Reasons for restoring coral reefs were mainly biotic and experimental (both 42%), followed by idealistic and pragmatic motivations (both 8%). The median annual total cost from all projects was $93,000 USD (range: $10,000 USD-$331,802 USD) (2018 dollars) and intervened a median spatial area of 1 ha (range: 0.06 ha-8.39 ha). The median project duration was 3 years; however, projects have lasted up to 17 years. Project feasibility was high with a median of 0.7 (range: 0.5-0.8). This study closes the knowledge gap between academia and practitioners and overcomes the language barrier by providing the first comprehensive compilation of data from ongoing coral reef restoration efforts in Latin America.


Assuntos
Conservação dos Recursos Naturais/métodos , Recifes de Corais , Recuperação e Remediação Ambiental/métodos , Animais , Antozoários/crescimento & desenvolvimento , Região do Caribe , Mudança Climática , Ecossistema , Pesqueiros , Previsões , Humanos , América Latina , Oceano Pacífico
5.
PLoS One ; 15(8): e0230985, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32845879

RESUMO

Spearfishing is currently the primary approach for removing invasive lionfish (Pterois volitans/miles) to mitigate their impacts on western Atlantic marine ecosystems, but a substantial portion of lionfish spawning biomass is beyond the depth limits of SCUBA divers. Innovative technologies may offer a means to target deepwater populations and allow for the development of a lionfish trap fishery, but the removal efficiency and potential environmental impacts of lionfish traps have not been evaluated. We tested a collapsible, non-containment trap (the 'Gittings trap') near artificial reefs in the northern Gulf of Mexico. A total of 327 lionfish and 28 native fish (four were species protected with regulations) recruited (i.e., were observed within the trap footprint at the time of retrieval) to traps during 82 trap sets, catching 144 lionfish and 29 native fish (one more than recruited, indicating detection error). Lionfish recruitment was highest for single (versus paired) traps deployed <15 m from reefs with a 1-day soak time, for which mean lionfish and native fish recruitment per trap were approximately 5 and 0.1, respectively. Lionfish from traps were an average of 19 mm or 62 grams larger than those caught spearfishing. Community impacts from Gittings traps appeared minimal given that recruitment rates were >10X higher for lionfish than native fishes and that traps did not move on the bottom during two major storm events, although further testing will be necessary to test trap movement with surface floats. Additional research should also focus on design and operational modifications to improve Gittings trap deployment success (68% successfully opened on the seabed) and reduce lionfish escapement (56% escaped from traps upon retrieval). While removal efficiency for lionfish demonstrated by traps (12-24%) was far below that of spearfishing, Gittings traps appear suitable for future development and testing on deepwater natural reefs, which constitute >90% of the region's reef habitat.


Assuntos
Conservação dos Recursos Naturais/métodos , Recuperação e Remediação Ambiental/métodos , Espécies Introduzidas/tendências , Animais , Biomassa , Recifes de Corais , Ecossistema , Peixes/crescimento & desenvolvimento , Golfo do México , Perciformes/crescimento & desenvolvimento , Densidade Demográfica , Dinâmica Populacional , Comportamento Predatório
6.
Ecotoxicol Environ Saf ; 204: 111121, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32798754

RESUMO

Rice is easy to accumulate mercury (Hg), especially methylmercury (MeHg) with high toxicity, and this leads to a serious health risk for residents in some Hg-polluted areas of Asia. Thus, there is an urgent need to find soil remediation techniques that can both guarantee agricultural production and protect human health in these Hg-contaminated areas. In this study, montmorillonite (Mont) and medical stone (Med) were modified by a thiol-based material (-SH) and by chitosan to obtain modified clay mineral adsorbents. Pot experiments were then performed to explore their ability to reduce the levels of Hg and MeHg in rice and their reduction mechanisms. Compared with unmodified clay minerals, modified clay minerals had better Hg reduction efficiencies in rice. The amendment of SH-modified Med (Med-SH) had the highest THg and MeHg reduction efficiencies in rice, reaching up to 78% and 81%, respectively, and brought the THg concentration in the rice below China's health guidelines for rice (20 ng g-1). Not only did amendment of the SH-modified clay minerals reduce the exchangeable and specially adsorbed Hg in the soil, as did the other amendments, but they also significantly reduced the amount of oxide-bound Hg and MeHg in the soil, and greatly enhanced the retention of Hg and MeHg in soil, thus significantly reduced the concentration of Hg and MeHg in rice.


Assuntos
Recuperação e Remediação Ambiental/métodos , Mercúrio/análise , Poluentes do Solo/análise , Agricultura , China , Argila , Monitoramento Ambiental , Poluição Ambiental , Humanos , Compostos de Metilmercúrio , Minerais , Oryza , Solo
7.
Bull Environ Contam Toxicol ; 105(2): 261-269, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32666192

RESUMO

Persistence and sorption behaviour of flubendiamide in two different Indian soils as affected by maize stalk biochar was studied. The persistence was more in West Bengal soil (178.6 days) than Sikkim soil (165.3 days) at 10 µg g-1 fortification level. Biochar amendment addition to soil at 5% enhanced the degradation process and half-life (T1/2) values were 103.5 and 117.4 days, respectively for biochar amended Sikkim and West Bengal soil. Sorption study through batch equilibrium method resulted the 4 h equilibrium time with adsorption 6.22% ± 0.16% and 5.26% ± 0.16% in Sikkim and West Bengal soil, respectively. Biochar addition at 5% increased the adsorption of flubendiamide to 8.12% ± 0.16% and 5.88% ± 0.16% indicating a greater influence in this process. The adsorption was more in biochar amended Sikkim soil than West Bengal soil. The values of desorption was slower than adsorption indicating a hysteresis effect having hysteresis coefficient (H1) ranges between 0.025 and 0.151 in two test soils.


Assuntos
Benzamidas/química , Carvão Vegetal/química , Recuperação e Remediação Ambiental/métodos , Poluentes do Solo/química , Sulfonas/química , Adsorção , Benzamidas/análise , Biomassa , Carvão Vegetal/economia , Solo , Poluentes do Solo/análise , Sulfonas/análise , Zea mays
8.
Bull Environ Contam Toxicol ; 105(2): 250-254, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32666193

RESUMO

Polychlorinated biphenyls (PCBs) are a class of persistent organic pollutants that pose a threat to environment and human health. Aiming at predicting PCBs risk in actual soil ecosystem, this study was conducted by chemical and biological methods to assess the bioavailability of PCBs in spiked soil, and in field-contaminated soils before or after remediation. The three chemical methods were Soxhlet, n-butanol and hydroxypropyl-ß-cyclodextrin (HPCD). Results were compared to actual PCB bioaccumulation in earthworms (Eisenia fetida). HPCD extraction was the best to predict the actual PCB bioaccumulation in all soils. The results suggest that HPCD could be an effective alternative method to earthworm toxicity test. This study provides strategy to understand the toxicity assessment in contaminated soil and soil after remediation.


Assuntos
Recuperação e Remediação Ambiental/métodos , Oligoquetos/efeitos dos fármacos , Bifenilos Policlorados/toxicidade , Poluentes do Solo/toxicidade , Solo/química , 1-Butanol/química , 2-Hidroxipropil-beta-Ciclodextrina/química , Animais , Bioacumulação , Disponibilidade Biológica , China , Ecossistema , Fertilizantes/análise , Oligoquetos/química , Bifenilos Policlorados/análise , Solo/normas , Poluentes do Solo/análise , Testes de Toxicidade
9.
Nat Commun ; 11(1): 3668, 2020 07 22.
Artigo em Inglês | MEDLINE | ID: mdl-32699271

RESUMO

Restoration is becoming a vital tool to counteract coastal ecosystem degradation. Modifying transplant designs of habitat-forming organisms from dispersed to clumped can amplify coastal restoration yields as it generates self-facilitation from emergent traits, i.e. traits not expressed by individuals or small clones, but that emerge in clumped individuals or large clones. Here, we advance restoration science by mimicking key emergent traits that locally suppress physical stress using biodegradable establishment structures. Experiments across (sub)tropical and temperate seagrass and salt marsh systems demonstrate greatly enhanced yields when individuals are transplanted within structures mimicking emergent traits that suppress waves or sediment mobility. Specifically, belowground mimics of dense root mats most facilitate seagrasses via sediment stabilization, while mimics of aboveground plant structures most facilitate marsh grasses by reducing stem movement. Mimicking key emergent traits may allow upscaling of restoration in many ecosystems that depend on self-facilitation for persistence, by constraining biological material requirements and implementation costs.


Assuntos
Adaptação Fisiológica , Recuperação e Remediação Ambiental/métodos , Hydrocharitaceae/fisiologia , Áreas Alagadas , Zosteraceae/fisiologia , Plásticos Biodegradáveis , Biomimética/métodos , Ecologia/métodos , Recuperação e Remediação Ambiental/instrumentação , Florida , Países Baixos , Água do Mar , Suécia , Clima Tropical , Índias Ocidentais
10.
Chemosphere ; 260: 127576, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-32688317

RESUMO

In this study, a hydrocarbon-contaminated marine sediment was treated applying ex-situ thermal desorption (ESTD) at bench-scale. Temperatures up to 280 °C and heating times (t) in the 5-30 min range were investigated. Results revealed that temperatures in the range 200-280 °C led to Total Petrol Hydrocarbon (TPH)-removal efficiency (RE) from 75 to 85% (t = 10 min). The maximum RE of 89% was obtained at 200 °C for 30 min. However, a shorter remediation time of 5 min (or lower temperatures of 160 and 180 °C with longer times) is needed to reach the TPH standard limit. Data also demonstrated the selectivity of the treatment in TPH fraction removal. The modelling of the TPH removal kinetics and desorption isotherm jointly with activation energy calculation (>30 kJ mol-1) indicated that ESTD process is quite unfavorable for marine sediments. This is due to the fact that ESTD is regulated by chemisorption processes and occurred in two distinct TPH removal phases: evaporation and boiling vaporization. This depends on the strong affinity of the TPH with the fine sediment particles, as well as on the high initial water, salinity, organic matter and sulfides content. However, the comparison between alternative processes has shown that ESTD is the most feasible treatment process for TPH-contaminated marine sediment remediation. Obtained results also add relevant information that can be used as a basis for future scaling-up investigations of ESTD for hydrocarbon-contaminated marine sediments.


Assuntos
Recuperação e Remediação Ambiental/métodos , Sedimentos Geológicos/química , Hidrocarbonetos/química , Poluição por Petróleo , Cinética , Mar Mediterrâneo , Salinidade , Temperatura , Poluentes Químicos da Água/química
11.
Chemosphere ; 260: 127590, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-32679376

RESUMO

A new treatment method using a deep eutectic solvent embedded melamine sponge (DES-MS) was studied for the removal of organic pollutants from water and soil samples. Five organophosphorus pesticides (OPPs) consisting of azinphos-methyl (AZP), parathion-methyl (PRT), fenitrothion (FNT), diazinon (DIZ) and chlorpyrifos (CPF), and two dyes including acid blue 29 (AB29) and malachite green (MG) were used as the model pollutants. DESs were easily prepared from tetrabutylammonium bromide (TBABr) and various fatty acids. The synthesised DESs were loaded into the sponge before being utilized for the removal of the studied pollutants. After the removal, the residual OPPs or dyes in the supernatant was quantified by high performance liquid chromatography or derivative spectrophotometry, respectively. The proposed method was simple, rapid, environmentally friendly and effective with the removal efficiency higher than 70% for various samples. Moreover, the removal of various dyes was successfully achieved with the efficiency greater than 65% under the optimum condition.


Assuntos
Corantes/análise , Praguicidas/análise , Resinas Sintéticas/química , Poluentes do Solo/análise , Solventes/química , Triazinas/química , Poluentes Químicos da Água/análise , Recuperação e Remediação Ambiental/métodos , Limite de Detecção , Solo/química , Águas Residuárias/química , Purificação da Água/métodos
12.
Artigo em Inglês | MEDLINE | ID: mdl-32615055

RESUMO

The effect of the presence of minerals in natural soil polluted with lead (II) was investigated to verify the efficiency of the electrokinetic remediation method. Natural soil "Sebkha of Oran" containing high calcite minerals and characterized by high salinity was used in experimental studies. This study investigates the effects of alkaline soil pH conditions on the transport and removal of lead by the electrokinetic treatment. XRD analyses were performed on the soil sample before and after electrokinetic treatment to determine any changes in mineral phases. Mathematical models using experimental data are developed to describe the mobility and diffusion coefficient of lead ions through the soil. Mathematical models were generated based on the physicochemical parameters characterizing the movement of cations and anions.


Assuntos
Técnicas Eletroquímicas/métodos , Recuperação e Remediação Ambiental/métodos , Chumbo/análise , Modelos Teóricos , Poluentes do Solo/análise , Solo/química , Ânions , Cátions , Minerais/química
13.
Ecotoxicol Environ Saf ; 202: 110865, 2020 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-32570103

RESUMO

Crop production in acid soils is facing enormous challenges due to low soil quality associated with an increase in the acidification rate and aluminum toxicity. Despite comprehensive prior work with biochar application on nutrient availability and crop productivity in acid soils, little information is available about the recommendation or standardization of biochar application rates that are more suitable for soil fertility improvement under different soil environments (physico-chemical properties) for maximizing the benefits of biochar applications and minimizing the potential environmental risk. Thus, the objective of this study was to investigate the effectiveness of poultry litter (PL) and poultry litter biochar (PLB) in ameliorating the fertility of acid soils through incubation and pot experiments. The soil was amended with different materials as follows; lime (1 g kg-1), PL (5, 10 and 15 g kg-1) and PLB (5, 10 and 15 g kg-1) along with control (non-amended). A pot experiment was also conducted using similar treatments to observe the responses of maize crop to the different amendments. The results indicated an increase in the pH and a decrease in exchangeable acidity in lime, PL and PLB amended soils. Lower soil pH, base cations and soil available phosphorus (P), and higher exchangeable acidity were found in control than the amended soils. Compared to PL and lime, PLB achieved greater increase rate in soil pH and reduction rate in soil exchangeable acidity with increased soil exchangeable base cations. An increase in soil available calcium (Ca) was observed in the lime treatment, while in PL and PLB treatments, there was an increase in soil available Ca, magnesium (Mg), potassium (K) and P. Application of the amendments increased availability of nitrogen (N), P, K, Ca and Mg relative to the control for maize in the pot experiment. When PL and PLB amendments were compared, it was found that the PLB was the best choice for the amelioration of acid soils as well as nutrient uptake by maize plants. It is suggested that application of PLB at the rate of 15 g kg-1 is suitable for maize growth in acid soils.


Assuntos
Carvão Vegetal , Recuperação e Remediação Ambiental/métodos , Zea mays/fisiologia , Ácidos , Animais , Cálcio , Compostos de Cálcio , Magnésio , Nitrogênio , Óxidos , Fósforo , Potássio , Aves Domésticas , Solo/química , Poluentes do Solo/análise , Zea mays/crescimento & desenvolvimento
14.
Chemosphere ; 257: 127309, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32535363

RESUMO

Soil degradation due to heavy metal contamination and acidification has negative effects on soil health and crop growth. Many previous studies have tried to improve the growth of crops and decrease their metal uptake. The recovery of soil health, however, has rarely been focused in soil remediation. In this study, a pot trial was conducted with lettuce (Lactuca sativa L.) growing in heavy metal contaminated and acidic soils, to examine the effects of alkaline amendments (limestone, LS; calcium magnesium phosphate fertilizer, Pcm) and organic amendments (cow manure compost, CMC; biochar, BC) on the growth of lettuce and on the availability of heavy metals, enzyme activities, and bacterial community structures in the soils. The results showed that, in comparison with the CMC and BC treatments, LS and Pcm were more effective at improving lettuce growth and reducing metal concentrations in shoots. Urease and catalase activities in LS and Pcm amended soils were consistently higher than in those with CMC and BC. Additionally, the alkaline amendments dramatically improved the bacterial diversity and shaped more favorable bacterial community structures. Proteobacteria and Gemmatimonadetes were predominant in soils amended with alkaline treatments. The beneficial bacterial genera Gemmatimonas and f_Gemmatimonadaceae, which are vital for phosphate dissolution, microbial nitrogen metabolism, and soil respiration, were also enriched. The results suggest that alkaline amendments were superior to organic amendments, and thus may be useful for the future recovery of soil functions and health under heavy metal contamination and low pH.


Assuntos
Recuperação e Remediação Ambiental/métodos , Metais Pesados/análise , Poluentes do Solo/análise , Animais , Carbonato de Cálcio , Bovinos , Carvão Vegetal , Compostagem , Produtos Agrícolas/metabolismo , Fertilizantes , Concentração de Íons de Hidrogênio , Alface/crescimento & desenvolvimento , Solo/química , Microbiologia do Solo , Urease
15.
Ecotoxicol Environ Saf ; 201: 110807, 2020 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-32505762

RESUMO

In order to investigate the decrease in total metal contents and to mitigate the availability and toxicity of metals from farmland near a lead mining area, a combination of two effective soil washing and eco-friendly stabilization technologies was applied in current research. The pre-treatment was performed with three types of agents including Ethylenediaminetetraacetic acid (EDTA), citric acid (CA), and mixture of hydroxylamine hydrochloride and citric acid (HA)) and the post-treatment stabilization was adopted using four rich-carbon organic waste amendments (cow manure compost (CMC), vermicompost (VC), urban sewage sludge (SS), and sludge-derived biochar (BIO)). Furthermore, the fate of residual metals (leachability, plant-availability, bioaccessibility, and chemical distribution), soil quality indicators (phytotoxicity and enzyme activities), and some soil physicochemical properties were examined before and after the two-steps remediation. The soil washing, especially using HA and CA agents, dramatically increased the labile metals and negatively changed the soil microbial activity. The two-month stabilization with SS, BIO, and VC resulted in a significant control of the leachability and plant-availability of residual Zn and Pb. However, the post-treatment was only slightly immobilized of Cd. The amendments affected the restoration of soil pH and organic carbon as well as the improvement of available nutrients. Compared to the other amendments that caused restrictions, the SS significantly restored the enzyme activities. With the exception of CMC, the SS, VC, and BIO, indicated higher germination rate and growth of wheat were also obtained. This study reveal the ability of the complementary role of stabilization with soil washing to reduce metal toxicity and confirm the usefulness of municipal and animal wastes in enhancing soil and environmental qualities.


Assuntos
Recuperação e Remediação Ambiental/métodos , Fertilizantes/análise , Metais Pesados/análise , Mineração , Poluentes do Solo/análise , Solo/química , Animais , Bovinos , Carvão Vegetal/química , Ácido Cítrico/química , Compostagem , Ácido Edético/química , Esterco/análise , Metais Pesados/metabolismo , Plantas/metabolismo , Esgotos/química
16.
Bull Environ Contam Toxicol ; 105(2): 277-282, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32556688

RESUMO

A bulky waste, oyster shell (OS), was calcinated at 400-800°C to produce Ca-rich products (OS400-OS800) to reduce the human health risk of soil cadmium (Cd) and arsenic (As). Thermogravimetric analysis, X-ray diffraction (XRD), scanning electron microscopy (SEM), and BET method were used to characterize OS and its calcined products. OS and OS400-OS700 removed little Cd and As from water, whereas OS800 removed 1508 mg Cd or 514 mg As per kg of OS800 from solutions of 1032 mg Cd/L or 257 mg As/L via adsorption and precipitation. Adding OS800 at a 2% dose to a Cd- and As-contaminated soil lowered its exchangeable Cd from 60% to 27%, and reduced Cd content in the edible part of vegetable Bok Choy from 2.80 to 0.048 mg/kg and As from 1.73 to 0.47 mg/kg. Converting OS to soil amendment has the dual benefits to soil remediation and sustainable oyster aquaculture.


Assuntos
Exoesqueleto , Cádmio/química , Recuperação e Remediação Ambiental/métodos , Poluentes do Solo/química , Adsorção , Agricultura , Animais , Arsênico/análise , Cádmio/análise , Carbonato de Cálcio , Humanos , Ostreidae , Solo , Poluentes do Solo/análise , Verduras
17.
Chemosphere ; 257: 127226, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32512332

RESUMO

In washing soils contaminated with toxic metals, the replacement of recalcitrant EDTA with biodegradable chelators has gained high expectations. Herein we investigated the feasibility of using EDTA and biodegradable GLDA, EDDS and IDS under conditions pertinent to operational remediation technology, in a pilot-scale experiment. GLDA and IDS did not precipitate from process solutions, which lessened their recyclability. In other process parameters, chelator supplement, Na-saturation of process solutions and processing time, EDTA outperformed biodegradable chelators. Treatment with EDTA was also the most effective in total Pb and Zn removal and least impacted soil properties. GLDA was slightly better in Cd removal. EDDS and IDS were inefficient. All chelators effectively removed easily-available Pb, Zn and Cd from the exchangeable soil fraction. EDTA was the most efficient chelator in reducing the bioaccessibility of Pb and GLDA in reducing the bioaccessibility of Cd from simulated human gastrointestinal tract. Treatment with GLDA had an edge in reducing plant bioaccessibility of toxic metals, but induced worrying leachability of Pb. This was 8.3-times higher than with the process with EDTA and 3.4-times higher than in original soil. In general, our results demonstrate the advantage of EDTA over tested biodegradable chelators in process and remediation efficiency and environmental safety.


Assuntos
Ácido Edético/química , Recuperação e Remediação Ambiental/métodos , Poluentes do Solo/química , Animais , Quelantes , Estudos de Viabilidade , Isópodes , Metais Pesados/análise , Reciclagem , Solo , Poluentes do Solo/análise
18.
Chemosphere ; 257: 127207, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32505949

RESUMO

Mechanochemical methods with co-milling reagents have been widely used to degrade organic pollutants. In this study, calcium oxide and persulfate were employed as co-milling reagents in a mechanochemical process that showed highly effective degradation of hexachlorobenzene in contaminated soil. The influences of soil particle size and organic matter content were also investigated. The interaction between different factors was analyzed by response surface methodology, and a multi-variate regression equation was obtained relating the soil-to-oxidant mass ratio, rotation speed and organic matter content. The existence of SO4- and OH during the mechanochemical reaction was proved by the indirect detection of benzoquinone and p-hydroxybenzoic acid for the first time, providing a new method for testing free radicals in solid-phase reactions. Finally, a possible activation mechanism and hexachlorobenzene degradation pathway were proposed. This study successfully presents a mild degradation method in the field of hexachlorobenzene contaminated site remediation.


Assuntos
Recuperação e Remediação Ambiental/métodos , Hexaclorobenzeno/análise , Poluentes do Solo/análise , Compostos de Cálcio , Hexaclorobenzeno/química , Oxirredução , Óxidos , Solo/química
19.
Chemosphere ; 258: 127281, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32540545

RESUMO

Development of Alberta's oil sands requires large volumes of water, leading to the abundance of oil sands process affected water (OSPW) that must be remediated prior to discharge or reuse. OSPW contains a variety of dissolved organic compounds, however naphthenic acids (NAs) have been found to contribute significantly to the toxicity of OSPW. A fungus, Trichoderma harzianum, isolated directly from OSPW, has previously demonstrated a high tolerance and capacity for growth in the presence of commercial NAs. This study conducted microcosm experiments to elucidate and characterize the capacity of T. harzianum to degrade labile commercial NAs (Merichem), and OSPW-sourced naphthenic acid fraction compounds (NAFCs). Additionally, two model NA compounds, the simple single ring cyclohexane carboxylic acid (CHCA) and complex diamondoid 1-adamanatane carboxylic acid (ADA), were utilized to determine the influence of NA structure on degradation. T. harzianum degraded 14% of CHCA, 13% of ADA, and 23-47% of Merichem NAs. Additionally, Orbitrap mass spectrometry revealed a large change in Z-series within NAFCs. This removal and shift in composition correlated to a 59% and 52% drop in toxicity as per Microtox, for Merichem NAs and NAFCs respectively. This proof of concept experiment confirms that the fungal species T. harzianum can contribute to the biodegradation of complex dissolved organics found in OSPW, including cyclic and diamondoid structures.


Assuntos
Ácidos Carboxílicos/metabolismo , Recuperação e Remediação Ambiental/métodos , Campos de Petróleo e Gás , Trichoderma/metabolismo , Águas Residuárias/microbiologia , Poluentes Químicos da Água/metabolismo , Adamantano/química , Adamantano/metabolismo , Alberta , Biodegradação Ambiental , Ácidos Carboxílicos/química , Cicloexanos/química , Cicloexanos/metabolismo
20.
Chemosphere ; 258: 127374, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32554021

RESUMO

Photocatalysis is extensively investigated as a green, efficient and promising technique for environmental remediation. In this study, a series of template free In-doped BiOBrxI1-x photocatalysts have been successfully prepared at room temperature and characterized by various methods. Complete degradation of negatively charged methyl Orange, positively charged Rhodamine B and Methylene Blue organic dyes, and neutral and colorless non-dye organic compound of furfural was attained. The flat band potential offered the possibility of reduction of dissolved O2 to O2.- in the conduction band while the trapping experiment identified the (O2.-)is the main radical species followed by h+ for the photodegradation. In-BiOBrI-0.4 had an excellent photocatalytic degradation activity which could be due to the synergetic effect between metal ion doping and solid solution formation. It further promotes visible light-harvesting ability and photoinduced charge carrier separation efficiency. The order of the reaction rate was determined and the mechanism was proposed. This work can lay a base for the design of effective photocatalyst toward environmental remediation.


Assuntos
Bismuto/química , Corantes/análise , Poluentes Ambientais/análise , Recuperação e Remediação Ambiental/métodos , Índio/química , Compostos de Iodo/química , Nanoestruturas/química , Fotólise , Compostos Azo/análise , Catálise , Luz , Azul de Metileno/análise , Rodaminas/análise , Propriedades de Superfície , Temperatura
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