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1.
Am J Trop Med Hyg ; 108(4): 755-767, 2023 04 05.
Article in English | MEDLINE | ID: mdl-36848892

ABSTRACT

Metropolitan Santo Domingo has accounted for a majority of reported malaria cases in the Dominican Republic in recent years. To inform malaria control and elimination efforts, a cross-sectional survey of malaria knowledge, attitudes, and practices collected 489 adult household-level questionnaires across 20 neighborhoods in the city's two main transmission foci, Los Tres Brazos (n = 286) and La Ciénaga (n = 203), in December 2020. Overall, most residents (69%) were aware of the problem of malaria in Santo Domingo, but less than half knew that mosquitos transmit the disease (46%) or took any correct preventative measure (45%). More residents of Los Tres Brazos, where malaria incidence is higher than in La Ciénaga, said that they had never been visited by active surveillance teams (80% versus 66%, respectively; P = 0.001), did not link mosquitos with malaria transmission (59% versus 48%, P = 0.013), and did not know medication can cure malaria (42% versus 27%, P = 0.005). Fewer residents of Los Tres Brazos said that malaria was a problem in their neighborhoods (43% versus 49%, P = 0.021) and fewer had mosquito bed nets in their homes (42% versus 60%, P < 0.001). The majority (75%) of questionnaire respondents in both foci did not have enough mosquito nets for all household residents. These findings demonstrate gaps in malaria knowledge and community-based interventions and highlight the need to improve community engagement for malaria elimination in affected areas of Santo Domingo.


Subject(s)
Health Knowledge, Attitudes, Practice , Malaria , Adult , Humans , Dominican Republic/epidemiology , Cross-Sectional Studies , Malaria/epidemiology , Surveys and Questionnaires
2.
Polymers (Basel) ; 15(1)2022 Dec 31.
Article in English | MEDLINE | ID: mdl-36616553

ABSTRACT

Polyurethane (PU) is a widely used polymer with a highly complex recycling process due to its chemical structure. Eliminating polyurethane is limited to incineration or accumulation in landfills. Biodegradation by enzymes and microorganisms has been studied for decades as an effective method of biological decomposition. In this study, Tenebrio molitor larvae (T. molitor) were fed polyurethane foam. They degraded the polymer by 35% in 17 days, resulting in a 14% weight loss in the mealworms. Changes in the T. molitor gut bacterial community and diversity were observed, which may be due to the colonization of the species associated with PU degradation. The physical and structural biodegradation of the PU, as achieved by T. molitor, was observed and compared to the characteristics of the original PU (PU-virgin) using Fourier Transform InfraRed spectroscopy (FTIR), Thermal Gravimetric Analysis (TGA), and Scanning Electron Microphotography (SEM).

3.
J Hazard Mater ; 389: 121820, 2020 05 05.
Article in English | MEDLINE | ID: mdl-31836370

ABSTRACT

In this manuscript we studied in the laboratory the bioremediation effects of a biostimulant obtained from okara by enzymatic hydrolysis processes in a soil polluted with used motor-car oil at a rate of 1 % (w/w) over an 89-day period. The biostimulant was added to the soil 6 times during the incubation period at a rate of 2 %. Dehydrogenase activity and the evolution of polycyclic aromatic hydrocarbons (PAHs) and pseudo total heavy metals in soil were studied. The successive applications of the biostimulant to the polluted soil gradually increased PAHs degradation during the experimental period. Thus, at the end of the experiment, the application of the biostimulant decreased the concentration of naphthalene in soil by 74 %, while PAHs with 3, 4, 5 and 6 aromatic rings had been reduced by around 58 %, 44 %, 30 % and 23 %, respectively. This degradation is possibly due to the high number of low molecular weight peptides (<300 Da) in the biostimulant which are readily available for PAHs-tolerant soil microorganisms that accelerate the degradation of the said toxins. The concentration of heavy metals in the oil used was not very high and consequently the dehydrogenase activity was not negatively affected.


Subject(s)
Fuel Oils/analysis , Polycyclic Aromatic Hydrocarbons/analysis , Soil Microbiology , Soil Pollutants/analysis , Automobiles , Biodegradation, Environmental , Fertilizers/analysis
4.
Heliyon ; 5(6): e01958, 2019 Jun.
Article in English | MEDLINE | ID: mdl-31294110

ABSTRACT

This work presents a new bioprocess process for the extraction of bioactive components from soy pulp by-product (okara) using an enzymatic technology that was compared to a conventional water extraction. Okara is rich in fiber, fat, protein, and bioactive compounds such as isoflavones but its low solubility hampers the use in food and fertilizer industry. After the enzymatic attack with endoproteases half of the original insoluble proteins were converted into soluble peptides. Linked to this process occured the solubilization of isoflavones trapped in the insoluble protein matrix. We were able to extract up to 62.5% of the total isoflavones content, specially aglycones, the more bioactive isoflavone forms, whose values rose 9.12 times. This was probably due to the increased solubilization and interconversion from the original isoflavones. In conclusion, our process resulted in the formulation of a new functional product rich in aglycones and bioactive peptides with higher antioxidant potency than the original source. Therefore, we propose that the enzymatic extraction of okara bioactive compounds is an advantageous tool to replace conventional extraction.

5.
Environ Technol ; 40(3): 399-406, 2019 Jan.
Article in English | MEDLINE | ID: mdl-29037122

ABSTRACT

In this manuscript, we study the manufacture and effect on soils of different edaphic biostimulants/biofertilizers (BS) obtained from sewage sludge using Bacillus licheniformis as biological tool. These BS consist of different combinations of organic matter, bacteria and enzymes that were subjected to several treatments. These BS were applied in soil in order to observe their influence on the biochemical properties (enzymatic activities and ergosterol content). Dehydrogenase, urease, ß-glucosidase, phosphatase activities and ergosterol content were measured at different incubation days. Only dehydrogenase activity and ergosterol content were significantly stimulated after the application of BS1 and BS4. Rest of the extracellular activities were not stimulated probably because B. licheniformis practically has digested all organic substrates during fermentation process.


Subject(s)
Soil Pollutants , Soil , Fermentation , Sewage , Soil Microbiology
6.
Environ Technol ; 40(16): 2073-2084, 2019 Jul.
Article in English | MEDLINE | ID: mdl-29400642

ABSTRACT

In this work okara (OK), a by-product of soy milk manufacturing, is submitted to an enzymatic hydrolysis and a fermentative process to produce different soil biostimulants (BS): EH, hydrolysate obtained by the enzymatic process; FHEB, fermentation broth with Bacillus licheniformis and the enzymes secreted during the fermentation; FHE, fermentation broth without bacteria and FH, the FHE hydrolysate in which enzymes were denatured. Enzymatic hydrolysates showed a different chemical composition compared with fermented hydrolysates and OK. It had a higher protein concentration as well as C, P and K. The proteins of OK were converted into peptides with a lower molecular weight, the fermented hydrolysates being those with the lowest molecular weight profile. The influences of hydrolysates and OK were tested in soil, finding that ß-glucosidase, phosphatase and dehydrogenase activities were stimulated by every treatment. However, it was observed that EH produced a greater stimulation of dehydrogenase and phosphatase than both OK and fermented BS. The bacterial and fungal phospholipid fatty acids were also higher in soils amended with BS than those of the control and soils with OK. It has also been found that ß-glucosidase, phosphatase and microbial biomass were dose-dependent in every treatment, but dehydrogenase only was dose-dependent in EH and OK treatments.


Subject(s)
Bacillus licheniformis , Soil , Fermentation , Hydrolysis , Soil Microbiology
7.
J Hazard Mater ; 322(Pt B): 334-347, 2017 Jan 15.
Article in English | MEDLINE | ID: mdl-27776866

ABSTRACT

The use of pesticides in agriculture is essential because it reduces the economic losses caused by pests, improving crop yields. In spite of the growing number of studies concerning the development and application of controlled release formulations (CRFs) of pesticides in agricultural soils, there are no studies about the effects of such formulations on the biochemical properties. In this paper the dissipation of diuron and alachlor in three agricultural soils for 127days, applied either as commercial or CRFs, was determined as well as their concomitant effects on soil biochemical properties. Dehydrogenase, urease, ß-glucosidase and phosphatase activities were measured thought the experimental period. The application of alachlor as CRF increases its half-life time in soils, whereas no differences were noticed between diuron formulations due to its slower degradation, which takes longer than its release from the CRF. At the end of the incubation period, the enzymatic activities were the same after the use of diuron either as commercial or CRF, recovering the soil previous status. For alachlor formulations, no differences in enzymatic activities were again observed between both formulations, but their levels in soils were enhanced. Therefore, the use of these CRFs does not adversely affect the soil biochemical properties.


Subject(s)
Acetamides/analysis , Diuron/analysis , Herbicides/analysis , Pesticide Residues/analysis , Soil/chemistry , Acetamides/administration & dosage , Agriculture , Aluminum Silicates , Clay , Diuron/administration & dosage , Enzymes/analysis , Herbicides/administration & dosage , Phosphatidylcholines
8.
J Hazard Mater ; 300: 235-242, 2015 Dec 30.
Article in English | MEDLINE | ID: mdl-26188866

ABSTRACT

We studied in the laboratory the bioremediation effects over a 100-day period of three edaphic biostimulants (BS) obtained from sewage sludge (SS) and from two different types of chicken feathers (CF1 and CF2), in a soil polluted with three polycyclic aromatic hydrocarbons (PAH) (phenanthrene, Phe; pyrene, Py; and benzo(a)pyrene, BaP), at a concentration of 100 mg kg(-1) soil. We determined their effects on enzymatic activities and on soil microbial community. Those BS with larger amounts of proteins and a higher proportion of peptides (<300 daltons), exerted a greater stimulation on the soil biochemical properties and microbial community, possibly because low molecular weight proteins can be easily assimilated by soil microorganisms. The soil dehydrogenase, urease, ß-glucosidase and phosphatase activities and microbial community decreased in PAH-polluted soil. This decrease was more pronounced in soils contaminated with BaP than with Py and Phe. The application of the BS to PAH-polluted soils decreased the inhibition of the soil biological properties, principally at 7 days into the experiment. This decrease was more pronounced in soils contaminated with BaP than with Py and Phe and was higher in polluted soils amended with CF2, followed by SS and CF1, respectively.


Subject(s)
Benzo(a)pyrene/metabolism , Phenanthrenes/metabolism , Pyrenes/metabolism , Soil Pollutants/metabolism , Animals , Biodegradation, Environmental , Chickens , Feathers , Sewage/microbiology , Soil Microbiology
9.
Environ Technol ; 36(17): 2217-26, 2015.
Article in English | MEDLINE | ID: mdl-25732482

ABSTRACT

We studied the influence of six edaphic biostimulants/biofertilizers (BSs) manufactured by the pH-stat method from different sewage sludge (SS): SS1 (an anaerobic mature sludge, one year old), SS2 (an aerobic young sludge, without maturation) and SS3 (an aerobic mature sludge, four months old), not previously autoclaved (A) and autoclaved (B), by analysing their effects on soil biological properties. Soil enzymatic activities were measured at 1, 3, 5, 7, 15, 30 and 60 days of the incubation period, whereas the 16S rDNA-DGGE profiles were determined at 0, 5 and 60 days. The enzymatic activities were significantly stimulated. The highest stimulation was found in the B2 treatment followed by B3, A2, A3, B1 and A1 treatments. Increasing the number of lower molecular weight proteins in the BS enhances the stimulation of soil enzymatic activities. The application of BS caused at 5 days of the incubation period temporal variations in the soil bacterial community structure.


Subject(s)
Bacteria/drug effects , Fertilizers/microbiology , Sewage/microbiology , Soil Microbiology , Bacteria/enzymology , Bacteria/metabolism , Fertilizers/analysis , Sewage/analysis
10.
Bull Environ Contam Toxicol ; 94(5): 622-6, 2015 May.
Article in English | MEDLINE | ID: mdl-25820376

ABSTRACT

We studied the effect of mefenoxam on soil biochemical properties. Soil was mixed with three rates of mefenoxam (0.5, 1 and 2 L ha(-1)) and incubated for 83 days. Fungicide was applied to the soil four times during the experiment, according to the manufacturer's instructions. Soil ergosterol, dehydrogenase, urease, ß-glucosidase, and phosphatase activities were measured during the experiment. Compared to controls, soils with the highest doses of mefenoxam demonstrated decreased ergosterol and dehydrogenase activities by 81 and 27 %, respectively; whereas, urease, ß-glucosidase, and phosphatase activities increased. These results suggest that mefenoxam may possibly have consequences for agronomic crop production due to the negative effect on soil fungal populations and stimulation of the growth of soil bacterial activity.


Subject(s)
Alanine/analogs & derivatives , Bacteria/drug effects , Fungi/drug effects , Fungicides, Industrial/pharmacology , Soil Microbiology , Alanine/pharmacology
11.
Arch Environ Contam Toxicol ; 69(1): 8-19, 2015 Jul.
Article in English | MEDLINE | ID: mdl-25604921

ABSTRACT

We performed a laboratory study into the effect of cypermethrin insecticide applied to different concentrations on biological properties in two soils [Typic Xerofluvent (soil A) and Xerollic Calciorthid (soil B)]. Two kg of each soil were polluted with cypermethrin at a rate of 60, 300, 600, and 1,200 g ha(-1) (C1, C2, C3, and C4 treatments). A nonpolluted soil was used as a control (C0 treatment). For all treatments and each experimental soil, soil dehydrogenase, urease, ß-glucosidase, phosphatase, and arylsulphatase activities and soil microbial community were analysed by phospholipid fatty acids, which were measured at six incubation times (3, 7, 15, 30, 60, and 90 days). The behavior of the enzymatic activities and microbial population were dependent on the dose of insecticide applied to the soil. Compared with the C0 treatment, in soil A, the maximum inhibition of the enzymatic activities was at 15, 30, 45, and 90 days for the C1, C2, C3, and C4 treatments, respectively. However, in soil B, the maximum inhibition occurred at 7, 15, 30, and 45 days for the C1, C2, C3, and C4 treatments, respectively. These results suggest that the cypermethrin insecticide caused a negative effect on soil enzymatic activities and microbial diversity. This negative impact was greater when a greater dose of insecticide was used; this impact was also greater in soil with lower organic matter content. For both soils, and from these respective days onward, the enzymatic activities and microbial populations progressively increased by the end of the experimental period. This is possibly due to the fact that the insecticide or its breakdown products and killed microbial cells, subsequently killed by the insecticide, are being used as a source of energy or as a carbon source for the surviving microorganisms for cell proliferation.


Subject(s)
Insecticides/toxicity , Pyrethrins/toxicity , Soil Microbiology , Soil Pollutants/toxicity , Biodiversity , Carbon/analysis , Oxidoreductases/analysis , Soil/chemistry , Urease/analysis
12.
Environ Sci Pollut Res Int ; 21(18): 11027-35, 2014 Sep.
Article in English | MEDLINE | ID: mdl-24859703

ABSTRACT

We studied the behaviour of oxyfluorfen herbicide at a rate of 4 l ha(-1) on biological properties of a Calcaric Regosol amended with two edaphic biostimulants/biofertilizers (SS, derived from sewage sludge; and CF, derived from chicken feathers). Oxyfluorfen was surface broadcast on 11 March 2013. Two days after application of oxyfluorfen to soil, both biostimulants/biofertilizers (BS) were also applied to the soil. An unamended soil without oxyfluorfen was used as control. For 2, 4, 7, 9, 20, 30, 60, 90 and 120 days of the application of herbicide to the soil and for each treatment, the soil dehydrogenase, urease, ß-glucosidase and phosphatase activities were measured. For 2, 7, 30 and 120 days of the application of herbicide to the soil and for each treatment, soil microbial community was determined. The application of both BS to soil without the herbicide increased the enzymatic activities and soil biodiversity, mainly at 7 days of beginning the experiment. However, this stimulation was higher in the soil amended with SS than for CF. The application of herbicide in organic-amended soils decreased the inhibition of soil enzymatic activities and soil biodiversity. Possibly, the low-molecular-weight protein content easily assimilated by soil microorganisms is responsible for less inhibition of these soil biological properties.


Subject(s)
Feathers/chemistry , Halogenated Diphenyl Ethers/chemistry , Herbicides/chemistry , Sewage/microbiology , Soil Microbiology , Animals , Bacterial Proteins/chemistry , Biodegradation, Environmental , Biodiversity , Chickens , Microbiota , Oxidoreductases/chemistry , Soil/chemistry , Soil Pollutants/analysis , Urease/chemistry
13.
J Hazard Mater ; 273: 207-14, 2014 May 30.
Article in English | MEDLINE | ID: mdl-24742665

ABSTRACT

We performed a laboratory study on the effect of oxyfluorfen at a rate of 4lha(-1) on biological properties of a soil amended with four organic wastes (two biostimulants/biofertilizers, obtained from rice bran, RB1 and RB2; municipal solid waste, MSW; and sheep manure, SM). Soil was mixed with SM at a rate of 1%, MSW at a rate of 0.52%, RB1 at a rate of 0.39% and RB2 at a rate of 0.30%, in order to apply the same amount of organic matter to the soil. The enzymatic activities and microbial community in the soil were determined during the incubation times. The application of RB1 and RB2 to soil without oxyfluorfen increased the enzymatic activities and biodiversity, peaking at day 10 of the incubation period. This stimulation was higher in the soil amended with RB2 than in that amended with RB1. In SM and CF-amended soils, the stimulation of enzymatic activities and soil biodiversity increased during the experiment. The application of herbicide in organic-amended soils decreased the inhibition of soil enzymatic activities and soil biodiversity. Possibly the low molecular weight protein content easily assimilated by soil microorganisms and the higher fat content in the biostimulants/biofertilizers are responsible for the lower inhibition of these soil biological properties.


Subject(s)
Halogenated Diphenyl Ethers/toxicity , Herbicides/toxicity , Proteins/pharmacology , Soil Microbiology , Soil Pollutants/toxicity , Animals , Bacteria/drug effects , Bacteria/metabolism , Fatty Acids/metabolism , Fungi/drug effects , Fungi/metabolism , Halogenated Diphenyl Ethers/analysis , Herbicides/analysis , Manure , Oryza , Oxidoreductases/metabolism , Phosphoric Monoester Hydrolases/metabolism , Sheep , Soil Pollutants/analysis , Solid Waste , Urease/metabolism , beta-Glucosidase/metabolism
14.
Arch Environ Contam Toxicol ; 65(3): 449-57, 2013 Oct.
Article in English | MEDLINE | ID: mdl-23703122

ABSTRACT

We investigate the use of Allolobophora molleri as a biomarker of arsenic (As)-polluted soils and study the influence of A. molleri on the metabolic activity and microbial biodiversity of soil polluted with As. Because there are no experimental data available regarding the effect of the pollutant rate of As on A. molleri, we determined the LC50 that was 143.5 mg As kg(-1). Sodium arsenite was added at two rates, equivalent to 143.5 and 71.8 mg As kg(-1) soil, to a soil that was then maintained with and without worms for 120 days. In addition, a nonpolluted soil without and with earthworms was used as the control. The As concentration in the soil was measured after 7 and 120 and the worm weight and As concentration after 120 days of exposure. Soil enzymatic activities and the structure of the soil microbial community, by analysis of phospholipid fatty acids, were determined. At the end of the experiment, the highest earthworm As contents were found in soils polluted with the highest rate of As. Earthworm weights significantly decreased in soil polluted with 143.5 or 71.8 mg As kg(-1), by 49.9 and 29.8% of initial weight, because the worm consumption rate decreased. These results suggest that A. molleri can be used as a good biomarker of the As toxicity. The As available fraction decreased in polluted soil with worms because the metal was accumulated in worm tissues. However, this assimilation was lower than other worms such as L. rubbellus or L. terrestris. Soil enzymatic activities were decreased in As-polluted soils but were increased significantly by the presence of earthworms. The earthworms modified the soil microbial diversity. In this respect, A. molleri significantly increased (p < 0.05) the bacterial and fungal populations. Soil As pollution decreased microbial biodiversity but to a lesser extent in the presence of A. molleri.


Subject(s)
Arsenic/metabolism , Microbiota/drug effects , Oligochaeta/drug effects , Soil Microbiology , Soil Pollutants/metabolism , Animals , Arsenic/analysis , Biodegradation, Environmental , Dose-Response Relationship, Drug , Oligochaeta/metabolism , Soil Pollutants/analysis , Spain , Spectrophotometry, Atomic
15.
Ecotoxicol Environ Saf ; 74(7): 2075-81, 2011 Oct.
Article in English | MEDLINE | ID: mdl-21813178

ABSTRACT

The sorption capacity of both an organic municipal solid waste by-product (MSW) and a cow manure (CM) in a soil polluted with chlorpyrifos, as well as its effect on soil microbial activity, and weight, reproductive parameters and glutathione-S-transferase activity of two earthworm species (Eisenia fetida and Lumbricus terrestris) were studied. Chlorpyrifos was added at the recommended application rate (5 L ha(-1); 768 mg chlorpyrifos kg(-1)) and treated with MSW at a rate of 10% and CM at a rate of 5.8% in order to apply the same amount of organic matter to the soil. An unamended polluted soil was used as control. Earthworm cocoon number, average weight of cocoon, and number of juveniles per cocoon were measured after 30 days of incubation, whereas soil enzymatic activities, earthworm weight, and glutathione-S-transferase activity of earthworms were measured after 3, 45 and 90 days. Soil enzymatic activities, reproductive and glutathione-S-transferase activity in both worms decreased in polluted soil. The inhibition percentage of soil enzymatic activities, reproductive and glutathione-S-transferase activity in both worms was lower in MSW-amended soil than for CM-amended soil. The toxic effect of chlorpyrifos on E. fetida was lowest compared to L. terrestris. This suggested that the addition of organic wastes with higher humic than fulvic acid concentration is more beneficial for remediation of soils polluted with chlorpyrifos.


Subject(s)
Chlorpyrifos/pharmacokinetics , Insecticides/pharmacokinetics , Oligochaeta/drug effects , Soil Microbiology , Soil Pollutants/pharmacokinetics , Animals , Biodegradation, Environmental , Biological Availability , Cattle , Environmental Pollution/analysis , Glutathione Transferase/metabolism , Manure , Oligochaeta/enzymology , Oligochaeta/physiology , Soil/chemistry , Waste Management
16.
Ecotoxicol Environ Saf ; 74(6): 1708-14, 2011 Sep.
Article in English | MEDLINE | ID: mdl-21596437

ABSTRACT

We studied in the laboratory the effect of Prochloraz fungicide on the biological properties (soil enzymatic activities and soil bacterial communities) of a Plaggic Anthrosol. Five hundred grams of soil (<2mm) was mixed with three dosages of Prochloraz (1, 2, and 4 l ha(-1)) for 83 days. A non-Prochloraz polluted soil was used as control. Following commercial recommendations, fungicide was applied four times during the incubation experiment. For all treatments, the soil ergosterol and levels of dehydrogenase, urease, ß-glucosidase, and phosphatase activity were measured at nine different times (0, 1, 21, 22, 41, 42, 62, 63, and 83 days). The 16S rDNA-DGGE profiles in all treatments were determined at the beginning and end of the incubation period. At the end of the experiment, a significant decrease in ergosterol by 72.3%, 80.8%, and 83.1%, compared with control soil, was observed when 1, 2, and 4 l ha(-1), respectively, was added. Soil enzymatic activities increased when the Prochloraz applied to the soil increased, possibly because the fungicide is used by bacterial communities as a source of energy and nutrients. The 16S rDNA-DGGE profiles indicated that the fungicide did not negatively affect soil bacterial biodiversity. These results suggested that the fungicide Prochloraz has a very interesting agronomic effect, possibly due to the negative effect on soil fungal population stimulating the growth of soil bacterial activity.


Subject(s)
Bacteria/drug effects , Fungicides, Industrial/toxicity , Imidazoles/toxicity , Soil Microbiology , Soil Pollutants/toxicity , Bacteria/classification , Bacteria/enzymology , Biodiversity , Cellulases/metabolism , Ergosterol/metabolism , Fungi , Oxidoreductases/metabolism , Phosphoric Monoester Hydrolases/metabolism , Soil/chemistry , Urease/metabolism , beta-Glucosidase/metabolism
17.
Talanta ; 84(3): 853-8, 2011 May 15.
Article in English | MEDLINE | ID: mdl-21482293

ABSTRACT

In this paper we studied the As content in natural contaminated soils, classified as Dystric Leptosol, Chromic Luvisol, Eutric Cambisol and Mollic Leptosol. In soil samples, sieved (<2mm), total As was determined by XRF and chemical speciation by sequential extraction. As-bearing minerals were concentrated from fine sand fraction of soil (200-20 µm) using heavy liquid. In this fraction, mineralogical speciation was studied by X-ray microfluorescence, XRD with Göbbel mirror and SEM-BEI-EDX. Total As contents ranging from 61.00 to 131.00 mg kg(-1). The results of the sequential extraction showed that As was, mainly, in the residual fraction (52.51-98.76 mg kg(-1)) and in the fraction bound to iron oxyhydroxides (0-36.5 mg kg(-1)). Mapping of As with X-ray microfluorescence show strongly relationship between Fe and As. Iron (III) oxyhydroxides (FeOHs) (lepidocrocite and goethite), scorodite, angelellite, schultenite and dussertite were identified by XRD analysis as most likely mineral phases. The contents of As, Fe, Pb and Ba obtained with EDX-microprobe, confirmed the results of XRD. The results of sequential extraction and X-ray microfluorescence indicate that As is strongly bound to the soils because the identified As-bearing mineral phases are very stable at the pH conditions of studied soils. Consequently, a low mobility of As can be assumed in these soils.

18.
Waste Manag Res ; 29(11): 1185-96, 2011 Nov.
Article in English | MEDLINE | ID: mdl-20921058

ABSTRACT

The objective of the present study was to study the effect of two vermicomposts [animal (VCD) and vegetal origin (VGF)] and a cotton gin compost (C) at rates of 1780 and 3560 kg fresh organic matter ha(-1) for 3 years on an Typic Xerofluvent located near Seville (Spain) on soil biological properties, nutrition (leaf N, P and K concentration, pigments and soluble carbohydrate concentrations) and yield parameters of maize (Zea mays cv. Tundra) crop. All organic waste materials had a positive effect on the soil biological properties, plant nutrition and crop yield parameters, although at the end of the experimental period and at the high organic matter rate, the soil microbial biomass and dehydrogenase, urease, ß-glucosidase, phosphatase and arylsulfatase activities increased more significantly in the VCD-amended soils (86.4, 85.8, 94.5, 99.3, 70.1 and 63.8%, respectively) respect to the control soil, followed by VGF-amended soils (84.8, 80.6, 92.7, 99.1, 68.3 and 61.6%, respectively) and CC-amended soils (80.5, 75.9, 89.7, 99, 65.7 and 59.9%, respectively). Leaf N, P and K contents and pigments and soluble carbohydrate contents were highest in VCD-amended soils, followed by VGF and CC treatments. Compared with the control soil, the application of VCD in soils at high doses increased the crop yield parameters, followed by VGF and CC treatments. This may have been due to a greater labile fraction of organic matter in the VCD than the VGF and CC, respectively.


Subject(s)
Organic Chemicals/analysis , Refuse Disposal/methods , Soil Pollutants/analysis , Soil , Waste Products , Zea mays/metabolism , Animals , Biomass , Cattle , Enzymes/metabolism , Hydrogen-Ion Concentration , Nitrogen/metabolism , Organic Chemicals/chemistry , Organic Chemicals/metabolism , Phosphorus/metabolism , Potassium/metabolism , Soil Pollutants/chemistry , Soil Pollutants/metabolism , Spain , Temperature , Time Factors
19.
J Hazard Mater ; 185(1): 204-11, 2011 Jan 15.
Article in English | MEDLINE | ID: mdl-20950939

ABSTRACT

The effects of adding municipal solid waste (MSW) or poultry manure (PM) on the biochemical properties of a soil polluted with Cr and Cd were studied. Soil was mixed with Cr(NO(3))(3) and Cd(NO(3))(2) to give three concentrations (0, 100, and 250 mg Cr kg(-1) and 0, 100, and 250 mg Cd kg(-1)) in the soil, which was then treated with MSW at a rate of 10% or PM at a rate of 7.6%. The pH and biochemical parameters were measured at 0 and 120 days. An unamended and no-polluted soil was used as control. Compared with the non-polluted soil, for the 250 mg Cd kg(-1) treatment the microbial biomass-C, dehydrogenase, urease, ß-glucosidase, phosphatase, and arylsulphatase activities decreases 23%, 26.2%, 36%, 34.8%, 18.4%, and 15.8%, respectively, whereas for 250 mg Cr kg(-1) treatment the biochemical parameters were slightly lowest than for 250 mg Cd kg(-1) treatment. For 250 mg Cr kg(-1) soil+250 mg Cd kg(-1) soil treatment, the inhibition percentages of the biochemical parameters increased. After the application of organic wastes in Cr+Cd polluted soil, the inhibition of biochemical properties was greater with the MSW amendment than with PM, possibly due to its higher humic acid concentration.


Subject(s)
Cadmium Compounds/toxicity , Chromium Compounds/toxicity , Industrial Waste , Nitrates/toxicity , Organic Chemicals/toxicity , Soil Pollutants/toxicity , Arylsulfotransferase/chemistry , Biomass , Hydrogen-Ion Concentration , Incineration , Manure/analysis , Oxidoreductases/chemistry , Phosphoric Monoester Hydrolases/chemistry , Poultry Products , Refuse Disposal , Soil Microbiology , Urease/chemistry , beta-Glucosidase/chemistry
20.
Ecotoxicol Environ Saf ; 74(4): 668-74, 2011 May.
Article in English | MEDLINE | ID: mdl-21112089

ABSTRACT

In this paper we studied the bioremediation effects of a soil artificially contaminated by benzo(a)pyrene with and without two organic wastes (organic municipal solid waste, MSW, and poultry manure, PM) and with and without worms (Eisenia fetida) over 90 days. For the organic treatments, soil samples were mixed with MSW at a rate of 10% or PM at a rate of 7.6%, in order to apply the same amount of organic matter to the soil. An unamended and non-polluted soil was used as control. Cellulase and glutathione-S-transferase activities in worms and the earthworms' weight were measured at four different incubation times (3, 15, 60 and 90 days). Cocoon numbers, average weight per cocoon and number of juveniles per cocoon were measured 30 days after the benzo(a)pyrene exposure. Extractable benzo(a)pyrene in soils and E. fetida was determined during the incubation period. To observe the effects of bioremediation of the contaminated soil, ATP, urease and phosphatase activities were measured. At the end of the incubation period and when compared with the polluted soil without worms and organic matter, the extractable benzo(a)pyrene decreased by 41.2% for the unamended polluted soil and without worms, by 45.8% for the organic-PM polluted soil and without worms, 48.3% for the organic-MSW polluted soil and without worms, 55.4% for the organic-PM polluted soil and with worms, and 66.3% for the organic-MSW polluted soil and with worms. This meant that worm hydrocarbon absorption was lowest in the contaminated soil amended with MSW and with worms, causing an increase in catabolic activity of the soil. These results suggested that the co-application of organic wastes and E. fetida for the bioremediation of benzo(a)pyrene polluted soil is potentially advantageous.


Subject(s)
Benzo(a)pyrene/metabolism , Oligochaeta/metabolism , Soil Pollutants/metabolism , Adenosine Triphosphate/metabolism , Animals , Benzo(a)pyrene/toxicity , Biodegradation, Environmental , Glutathione Transferase/metabolism , Hazardous Substances/metabolism , Hazardous Substances/toxicity , Manure , Oligochaeta/drug effects , Phosphoric Monoester Hydrolases/metabolism , Soil/chemistry , Soil Microbiology , Soil Pollutants/toxicity , Urease/metabolism
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