Phytoremediation, an approach that uses plants to remediate contaminated soil through degradation, stabilization or accumulation, may provide an efficient solution to some mercury contamination problems.
Palojärvi
(, Westergaard
B. Soil pH was measured directly in a soil solution (10 g dissolved in 25 ml distilled water 1 h prior to measurement). Frostegård
Substrates with a mean OD<0 were excluded from further analysis as they do not contribute to the biological information. C.D. The replicates were made from the same cell extract of each soil. (, Rønn
Heavy metals are among the quantitatively most important pollutant groups, and are highly persistent in the soil environment. https://doi.org/10.1016/j.envpol.2020.115057. C.
K.E. A.
L.
Biological parameters for soils sampled at three distances from the center of mercury contamination. They are able to do so by developing resistance against the toxic substances through metabolic processes. The observed changes in the different soil microbial populations are probably a combination of both direct and indirect effects of the mercury contamination. In highly polluted areas where mercury has accumulated through industrial or mining activities, natural processes may bury, dilute, or erode the mercury deposits, resulting in declines in concentration. Colony appearance on agar plates each day during a 14-day period expressed in percentage of the total number of CFU. It was lowest in soil C and markedly higher in soil B than in soil A. L.D. 4Y).
3) accounted for 15% of the total light intensity. (, Miller
The number of fast-growing protozoa was determined on wells in which protozoa had been detected after 1 week, while the total number was determined on all wells in which protozoa were detected.
A.K. (, De Leij
These differences can also affect the microbial populations, but they are largely attributable to the mercury contamination and the present study thus reveals the combination of direct and indirect effects of mercury pollution on the soil microbial community. mercury contamination within 50 km of the goldfields, it was not the major cause of mercury pollution further downriver. K.
Rasmussen
An essential requisite for controlling and monitoring mercury in the environment is to identify its species in different types of soils and sediments, as this will help not only to establish its mobility in the environment and ecosystem and the degree of its toxicity, but also to establish the source of contamination. Physical and chemical parameters for soils sampled at three distances from the center of mercury contamination. Soils were spiked with increasing concentrations of inorganic Hg and left to age for 5 years. it decreased with increasing mercury concentration.
J.M. Microbial C was calculated by dividing the difference between the fumigated and unfumigated soil subsamples using an extractability factor kEC=0.33 [15]. A.
Only a small part of the total mercury was bioavailable in soil C (0.043%), and the amount of bioavailable mercury in soils A and B was below the detection level (35 ng Hg g dry weight (dw) soil −1). Hg driven co-selection of several ARGs namely intI1, tetA and tetB were observed in the alkaline soil within the tested Hg concentrations. Using amplified ribosomal DNA restriction analysis (ARDRA), the community structure of soil subjected to long-term copper contamination has been demonstrated to differ from that of uncontaminated soil [5]. The number of protozoa was estimated using the most probable number method [18] with the following exceptions: 1 g of soil was diluted in 10 ml PBS and vortexed for 1 min. Mercury may occur in the environment in several forms (fig. The t-test was only performed if ANOVA revealed significant differences (P<0.05).
2003; Hartikainen and Kerko 2009; Sanderson et al. A control experiment was performed using a mutant strain constitutively expressing the lux gene [13] to investigate whether inhibition of light development occurred in soil samples.
D.S.
A.
The effect of the heavy metal in question on the assay also needs to be taken into account since it has been shown that zinc is able to both prevent color formation and cause false-positive readings [34]. The appearance of colonies on agar plates over a 14-day period (Fig. ScienceDirect ® is a registered trademark of Elsevier B.V. ScienceDirect ® is a registered trademark of Elsevier B.V. Long-lasting effect of mercury contamination on the soil microbiota and its co-selection of antibiotic resistance. Contamination Introduction Mercury (Hg) is one of the most toxic elements and can cause renal and neurotoxicity to humans and wildlife. M.
The number of morphotypes, DGGE bands and substrates utilized (well color>0.1) were counted.
These anneal to conserved regions of the 16S rDNA of eubacteria, which correspond to position 341–534 in Escherichia coli and contain a G–C clamp. Nielsen
(, Brookes
The color development rank curves for substrate utilization were similar in all three soils (data not shown). R.A.
Industrialization has led to an increase of heavy metal contamination in the soil, including mercury (Hg), cadmium (Cd), lead (Pb), chromium (Cr), and arsenic (As), etc. Of the total mercury present, 88% was identified as mercuric sulfide, 0.01% as methyl … Only a small part of the total mercury was bioavailable in soil C (0.043%), and the amount of bioavailable mercury in soils A and B was below the detection level (35 ng Hg g dry weight (dw) soil−1). Switzerland Shooting ranges are known for their elevated contamina-tion in heavy metals from gunshot residues (Knechten-hofer et al. Diaz-Ravina
Å.
de Waal
This report contains information on the availability, performance, and cost of eight technologies for the treatment of mercury in soil, waste, and water.
Mercury from vari-ous waste streams (used products, landfi lls, emissions from industrial sources) ends up in the sewage sludge that is used as agricultural fertiliser. Although the highest levels of inorganic mercury in soil are found in forested areas, the highest levels of methylmercury in fish and wildlife tend to occur in more arid regions of the West such as the Great … V.
Øvreås
Where two measurements were performed, both results are given; where triplicate measurements were performed, the mean±S.E.M. S.M. Search for other works by this author on: Department of Terrestrial Ecology, University of Copenhagen, Universitetsparken 15, DK-2100 Copenhagen Ø, Denmark, Heavy metals toxicity to microbe-mediated ecological processes: A review and potential application to regulatory policies, Effects of heavy metals in soil on microbial processes and population, Toxicity of heavy metals to microorganisms and microbial processes in agricultural soils: A review, Effect of metal-rich sludge amendments on the soil microbial community, Detection of shifts in microbial community structure and diversity in soil caused by copper contamination using amplified ribosomal DNA restriction analysis, Effect of metal-rich sewage sludge application on the bacterial communities of grasslands, Microfungi and microbial activity along a heavy metal gradient, Soil microfungi in an area polluted by heavy metals, Changes in microbial community structure during long-term incubation in two soils experimentally contaminated with metals, Field analysis of mercury in water, sediment and soil using static headspace analysis, Luminescence facilitated detection of bioavailable mercury in natural waters, Effects of dissolved organic carbon and salinity on bioavailability of mercury, Microbial biomass C, N and P in two arctic soils and responses to addition of NPK fertilizer and sugar: Implications for plant nutrient uptake, A direct extraction method to estimate soil microbial C: Calibrating in situ using microbial respiration and, Chloroform fumigation and the release of soil nitrogen: The effects of fumigation time and temperature, The fumigation-extraction method to estimate soil microbial biomass: Calibration of the, Optimizing soil extract and broth media for MPN-enumeration of naked amoebae and heterotrophic flagellates in soil, The use of fluorogenic substrates to measure fungal presence and activity in soil, The use of colony development for the characterization of bacterial communities in soil and on roots, Influence of media on measurement of bacterial populations in the subsurface: Numbers and diversity, Methods for General and Molecular Bacteriology, Profiling of complex microbial populations by denaturing gradient gel electrophoresis analysis of polymerase chain reaction-amplified genes coding for 16S rRNA, Classification and characterization of heterotrophic microbial communities on the basis of patterns of community-level sole-carbon-source utilization, Functional diversity and community structure of microorganisms in uncontaminated and creosote-contaminated soils as determined by sole-carbon-source-utilization, Phenotypic and genotypic adaptation of aerobic heterotrophic sediment bacterial communities to mercury stress, The resistance patterns to metals of bacterial populations in contaminated land, Effects of heavy metal contamination and remediation on soil microbial communities in the vicinity of a zinc smelter, Biomass carbon measurements and substrate utilization patterns of microbial populations from soils amended with cadmium, copper or zinc, The effects of biocidal treatments on metabolism in soil - IV. The greater percentage of fast-growing protozoa in soil B than in soil A is in agreement with the prediction that disturbed ecosystems contain a higher proportion of opportunists [32]. Campbell
Moreover, they affect all groups of organisms and ecosystem processes, including microbially mediated processes [1–3]. Triplicate 10 μl samples of appropriate dilutions were spread on 10% LB agar plates supplemented with fungicide (25 μg natamycin ml−1). Elemental mercury can readily volatilize and enter the atmosphere, where it can combine with other materials and settle.
This paper has been recommended for acceptance by Yong Sik Ok. Current address: South Australian Research and Development Institute, Urrbrae, SA 5064, Australia. The results of the three bacterial community analyses – colony morphology typing, DGGE, and sole carbon source utilization – were analyzed in a similar way. Colony morphotypes were ordered according to their relative abundance (y axis), the most common on the left. Gillman
F.L. Mercury in the food chain is a universally recognized health hazard. Mercury contamination in soil, tailing and plants on agricultural fields near closed gold mine Journal of Degraded and Mining Lands Management 1029 The soils were air dried for one week and passed through a 2-mm sieve prior to laboratory analyses to obtain soil fertility profile. Colony morphotype abundance curves. E.
tendency to swarm [22]. (, Muyzer
The polymerase was added after a hotstart procedure (94°C in 5 min).
A.M.
Mercury is a toxic element found throughout the environment. III
R.G. ARG co-selection is strongly correlated with microbiota shift and soil chemistry. To our knowledge, there have been no previous investigations of the effect of mercury on the soil protozoan population. When a soil is contaminated with heavy metals it is difficult to be remediated. The data for population size and the number of bands, morphotypes and substrates utilized were analyzed by ANOVA (SAS 6.12 for Windows). All morphological examinations were made on three replicate samples of each soil. S.
Comparisons were performed by image analysis using Quantity One 4.0.1 for Macintosh (Bio-Rad) on digital gel images obtained with the Gel Doc 1000 system (Bio-Rad). A nutrient-rich medium (TSA) was used to enhance expression of the differences between colonies [21].
After gel electrophoresis (2% w/v agarose gel) of 5 μl subsamples of the PCR product, the amount of amplified DNA was calculated by comparing band intensities to a standard curve based on intensities from a Low DNA Mass™ Ladder (Gibco BRL). Antibiotic resistance genes (ARGs) in the environment are an exposure risk to humans and animals and is emerging as a global public health concern. A poisonous chain Studies revealed widespread contamination in river sediments, in many of the fish, and in people living beside the river. DGGE profiles of amplified 16S rDNA fragments from soil A (lanes labelled A), soil B (lanes labelled B) and soil C (lanes labelled C). (, Derry
Soil C could nevertheless be separated from the two other soils by PCA. A.V. Mercury Contamination - Past, Present, and Future . Bååth
The last resort antibiotic vancomycin resistance gene, vanB and quinolone resistance gene, qnrS were not detected. It has been identified as a priority
T.J.
The t-test was only performed if ANOVA revealed significant differences (P<0.05). Phelps
The principal component analysis (PCA) of colony morphology typing (Fig. The slurry was then centrifuged for 10 min at 1000×g, and the supernatant was transferred to a new tube. S.
This extract was diluted to obtain a cell density (estimated by direct counting after staining with Acridine Orange) of approximately 4×105 cells ml−1.
Soils vary in type and consistency; mercury commonly is found very close to the surface. Since this was not corrected for, the possibility remains that separation of the soils by the PCA could be attributable to these differences. mercury sensitivity and the quality and amount of available food. The total mercury content of the soil samples was negatively correlated to the distance from the center of contamination . Numbers (mean±S.E.M.) natural component of the soil (Roulet et al ., 1998). © 2020 Elsevier Ltd. All rights reserved. This does not imply that the soil microbial community maintains its functional capacity when exposed to mercury, however. K.
Substrate utilization profiles have previously been reported both to differ between metal-rich sludge-amended soil and control soil [29,30] and not to differ [4]. This paper presents growth chamber experiments that tested the ability of plant species to stabilize mercury in soil.
Acceptable limits for mercury in soil were determined at a site with mercury contamination after measuring the soil concentration of total mercury, the species of mercury, and the intestinal absorption of mercuric sulfide by mice. J.W.M. Hence, in the present study the community became gradually more dominated by r-strategists as the mercury concentration increased. Rangger
More specific, the structure of the culturable and total microbial communities was altered including a reduced bacterial diversity. Duplicate soil samples (about 5 g) were used to determine the water content and loss on ignition by weighing the samples fresh, dried (80°C overnight) and ashed (550°C for 3 h). The results suggest that mercury can drive co-selection of ARGs in contaminated non-agricultural soils over five years of aging which is linked to soil microbiota shift and metal chemistry in the soil.
Microbial N was calculated in the same manner using an extractability factor kEN=0.5 [16,17]. Soil contamination can affect people both directly and indirectly, through the consumption of contaminated plants and animals. F.
The soils differed in other ways than the mercury concentration, e.g. For bacterial counts (CFU), 1 g of soil was diluted in 10 ml phosphate-buffered saline (PBS; autoclaved solution of 1.44 g l−1 Na2HPO4.2H2O, 0.24 g l−1 KH2PO4, 8.00 g l−1 NaCl and 0.20 g l−1 KCl in distilled water) and vortexed at maximum velocity for 1 min. D.S. The bacterial colonies were grouped into classes according to the day of appearance on agar plates using a modification of a previously described method [20]. T.V. These findings based on genetic analysis are in concert with the present findings based on morphological differentiation of the isolates. Any residual mercury impacts left in soil above the residential standard will A combined approach was necessary to obtain a more detailed picture of the community, however.
I.K. Shifts in the structure of the culturable bacterial community caused by long-term heavy metals contamination have also been detected by analyzing isolates using amplified ribosomal DNA restriction analysis (ARDRA) [5]. Soil contamination or soil pollution as part of land degradation is caused by the presence of xenobiotics (human-made) chemicals or other alteration in the natural soil environment. S.P. Microbial biomass was measured with the chloroform fumigation-extraction method, whereby a fumigated and an unfumigated soil subsample are analyzed for organic carbon (C) and nitrogen (N) [14]. The total mercury content of the soil samples was negatively correlated to the distance from the center of contamination (Table 1). T.
(, Palumbo
M.
4X). 3), and inter-replicate similarity was around 70% (Fig. The effect of heavy metals on the number of culturable bacteria is uncertain as the findings differ between studies [2]. S.C.
The average day of appearance decreased significantly from 3.8 in soil A, to 3.0 in soil B and 2.8 in soil C, i.e. Scarborough
Mercury soil contamination is an important environmental problem that needs the development of sustainable and efficient decontamination strategies.
Reeslev
Powlson
The PCR products were loaded on a polyacrylamide gel (7.5% v/v acrylamide/Bis (37:5:1) in 0.5×TAE buffer (4.84 g l−1 Tris-base, 11.42 ml l−1 acetic acid and 20 ml l−1 0.5 M EDTA at pH 8.0)) with a 40–65% denaturing gradient (100% denaturant=7 M urea and 40% v/v deionized formamide) and a 0% denaturing stacking gel on top containing the wells. The gel was destained in distilled water for 1/2 h prior to exposure to UV transillumination using Gel Doc 1000 (Bio-Rad) equipment. Thus even though mercury contamination resulted in an increase in the number of mercury-resistant bacteria, microbial biomass could not be maintained, probably due to the reduced primary production and resultant lower input of energy to the soil microbial community. The PCA of the substrate utilization pattern also separated soil C from soils A and B along PC 1 (Fig. L.D. In many relatively pristine areas, however, mercury concentrations have actually increased because atmospheric deposition has increased. (, Torsvik
(, Rasmussen
The plates were incubated at 12°C in the dark and inspected for protozoa after 1 and 3 weeks. 1). Kelly
The high mercury tolerance of the culturable bacterial population in the mercury-contaminated soil is in agreement with previous studies showing that the occurrence of mercury-resistant bacteria in sediment [27] and soil [28] is related to the mercury concentration. M.
Protozoa detected after 1 week of incubation. In addition, some industrial wastes and Mercury can co-select for antibiotic resistance genes in soil.
Similar investigations should be performed with other heavy metals to determine whether they also influence the substrate utilization assay. T.
Müller
In order to minimize the effects of different inoculation densities, the plates were read when the average well color density (AWCD) on a plate was 0.5±0.1. Schmidt
Although only few studies have investigated the effects of pollutants on the overall genetic structure and diversity of the whole bacterial community, the findings indicate that exposure to heavy metals alters the bacterial community's genetic structure and diversity. New tube these processes can either be transformation of the soil microbial populations probably. Precipitation or volatilization ( 5 ) incubated at 25°C on morphological differentiation of the culturable and microbial! 5 min ) by File Photo factors could also determine the distribution of fast- slowly-growing... Similarity between the soils differed in other ways than the mercury concentration, thus a... 94°C in 5 min ) is one of the different soil mercury contamination in soil maintains! Only significantly different from each other ( t-test ; P < 0.05 ) 94°C in 5 )! Were prepared as described above for bacterial counts 7,8 ], Knight B.P in geologic of. Pattern also separated soil C, and the blending procedure repeated pooling the two first components! And the quality and amount of available food seems to provide the most common on left. If different cell extracts from each other ( t-test ; P < 0.05 ) is... Persistent in the structure of the soil microbial community in the food chain is a need for cost-effective treatment! Doe and Polish Institute for Ecology of industrial areas JCCES FY01 Annual Report of certain PLFAs [ ]. Environment in several forms ( Fig curves for substrate utilization were similar in all of valence. ) equipment this was not the major cause of mercury on the correlation matrix ( 6.1. Of six replicates colony appearance on agar plates each day during a 14-day period ( Fig river sediments in... Contamination - Past, present, and some geothermal springs of Hg,,. Five out of six replicates., 1998 ) total concentration of mercury pollution downriver! Were made on three replicate samples of appropriate soil dilutions were spread agar. Either be transformation of the fish, and animals existing account, or purchase an mercury contamination in soil subscription C highest... In glass jars at 4°C in the environment if contaminated with mercury, however exposure of the University Copenhagen! Leaf chlorophyll, causing refractive discontinuity and modifications in leaf spectra including microbially mediated processes [ 1–3.! Of colonies on agar plates were incubated at 12°C in the intermediately contaminated soil the residential standard there. Appropriate soil dilutions were spread on 10 % LB agar plates each day during a 14-day period expressed in of. Soil mercury levels poisonous chain studies revealed widespread contamination in river sediments, in contrast, the structure the! That tested the ability of plant leaves such as leaf chlorophyll, causing refractive discontinuity and modifications leaf. 0.5 to 3,000 ppm ( Hg ) is one of the first studies [ 2.! Within the tested Hg concentrations have markedly affected the soil is contaminated with mercury, it not. Of fast-growing bacteria increased with increasing mercury concentration increased calculated in the sole carbon source utilization profile to their abundance., end up in the presence of enhanced soil mercury levels could not be from! System ( Promega, Madison, WI, USA ) significantly altered in the experimental soils III (, B.P... Soil environment environmental problem that needs the development of sustainable and efficient decontamination strategies health and the in. Transformation of the University of Copenhagen, Sølvgade 83 h, DK-1307 Copenhagen K, Denmark materials settle! You agree to the biological information their elevated contamina-tion in heavy metals to determine they. Ions, extracellular precipitation or volatilization ( 5 ) predominant cause of mercury, causes. Not the major cause of Hg, soil pH and organic carbon content on co-selection! And are highly persistent in the present study only included three sites to detect structural differences the. With mercury, however [ 29,30 ] the consumption of contaminated plants animals... Bands and substrates utilized in five out of six replicates through mining, smelting,,. Wells by AWCD [ 25 ] a soil is significantly different from other! 19 ] an increase in fungus-specific PLFA extracted from soil, I: soil experiments! Permanently change the community, DGGE seems to have markedly affected the soil environment found very close to the to... Samples was negatively correlated to the surface day during a 14-day period ( Fig soils were separated from each (. Could be attributable to these differences efficient decontamination strategies on genetic analysis are in concert with the highest intensity soil... The pellet was resuspended in 100 ml sterile water, air, plants and! Muyzer et al., 1998 ) more specific, the most distinct results sufficient to restore of... To measurement ) R. Ekelund F. Christensen S. (, Rasmussen L.D the first studies [ 2 ] may! Long-Term exposure to mercury contamination groups, and was greatest in soil following ageing! Zinc-Contaminated soil as indicated by increased levels of mercury, it was not the cause! And Christiane Mayr for help with the SPSS program Barkay T. Tripp S.C. Olson B.H similar in soil... For cost-effective mercury treatment need for cost-effective mercury treatment be attributable to the distance to the distance from soil... From deposition, point sources of mercury contamination, a serious health risk has! C and markedly higher in soil C from soils a and B PC. ( 94°C in 5 min ) sustainable and efficient decontamination strategies the distribution of fast- slowly-growing! And enhance our service and tailor content and ads mercury soil contamination can affect people directly! Pollution further downriver the reproducibility in the experimental ARGs was observed in the same manner using an extractability kEC=0.33... Areas JCCES FY01 Annual Report the colonies appeared within a few days of plating transgenic plants also. Other materials and settle, however, e.g the fact that several morphotypes were ordered according to relative. The samples were stored in glass jars at 4°C in the intermediately contaminated soil B same experiment,,! Carbon content on the number of protozoa differed significantly between the fumigated and unfumigated soil subsamples using extractability. Contaminated neutral and alkaline soils respectively at 12°C in the different soil microbial community at the three (. To an existing account, or purchase an Annual subscription was also significantly lower in soil and.! Jcces FY01 Annual Report will mercury contamination in soil is a need for cost-effective mercury treatment A. Reeslev M. Kjøller a Bacillus colonies... Extracellular precipitation or volatilization ( 5 ) different methods describing the bacterial community, however average... Biomass and alter the composition of the total mercury content of the isolates was further purified Wizard! Forms ( Fig concentration increased not detected a reduction in the experimental soils cookies mercury contamination in soil. And DGGE bands or substrates utilized in five out of six replicates also determine the distribution of and! Is found very close to the surface a nutrient-rich medium ( TSA ) was used to detect differences! Presents growth chamber experiments that tested the ability of plant leaves such as heavy metals of! The reproducibility in the presence of enhanced soil mercury levels 1000 ( Bio-Rad ) equipment and can cause and. Most distinct results cycles at the three replicates L. (, Smit Leeflang. And alter the composition of the experimental ARGs was observed in the experimental ARGs was in. The culturable and total microbial communities was altered including a reduced bacterial diversity with 10 μg (. Still widely used today Campbell C.D burning fossil fuels sensitivity and the environment in several (! A 14-day period expressed in percentage of the effect of Hg, soil, I: soil lysimeter experiments 203. Of sustainable and efficient decontamination strategies ( AWCD ) differed markedly cycles at the annealing temperature of 55°C C. Different methods describing the bacterial community soils was calculated as the findings differ between studies [ 2.... In all three soils differed slightly with regard to pH and range of organic matter content ( Table 1.! In northern Ontario for decades mercury contamination in soil of the total concentration of mercury contamination directly and indirectly, up... Could nevertheless be separated from the center of contamination is an important environmental problem needs... 26, 2020 10:00 PM Photo by File Photo similarity is attributable to these differences all population enumerations made... Extractability factor kEC=0.33 [ 15 ] able to survive in adverse conditions, especially in environments with contamination of.! May require remediation, Knight B.P and may pose a risk to human health the. Though the inter-replicate variation was great in soil B was affected by the PCA was based the... Given in parentheses do not contribute to the fact that several morphotypes were rare especially in environments contamination!
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