Hazard of heavy metal resistant bacteria in polluted water and soil Introduction (original) (raw)
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British microbiology research journal, 2016
Pollution of water is one of the major concerns for whole world. Heavy metals, toxic waste and various effluents from industrialization and anthropogenic sources causes pollution of river water. These pollutants have adverse effects on health of human and other living beings in terrestrial and aquatic environment and also affect the food chain. The present study was an attempt to evaluate the water quality of river Hasdeo at Sarvamangla Nagar, Korba (Chhattisgarh). Pollution level was measured by estimating the water quality parameters [physicochemical i.e. temperature, pH, DO, BOD, COD and Level of heavy metal pollutants]. Pollution of heavy metals were observed in following order [Fe>Pb>Cd>Zn]. In addition, the bacteriological analyses involved most abundant bacterial species tolerant to heavy metal pollution and isolation identification of these heavy metal resistant bacteria from the river water of Hasdeo. The bacteriological analyses showed the population density [in %] of most abundant metal resistant bacterial species were Pseudomonas sp. [38%], Bacillus sp. [27%], E. Coli [20%] and Enterobacter sp. [15%]., The results of the present investigation revealed that, the river Hasdeo water at Sarvamangla Nagar was highly contaminated with heavy metals and require suitable action for the removal of pollutant by using the these metal tolerant bacteria as bio-remediating heavy metal pollutant which are very harmful to human health and environment.
Heavy metal pollutants are commonly found in soils, sediments and waste water where they remain persistent, and become toxic to many species above certain threshold concentrations. Bacteria resistant to heavy metals can be used for detoxification and prevent further deterioration of contaminated sites. The incidence of bacteria resistant to heavy metals in soils collected from six contaminated sites in Lagos and Ota, Nigeria was assessed in this study. Heavy metal resistant bacteria were isolated from the soil samples following enrichment by growth on media amended with high concentrations of lead, cadmium and chromium, and identified based on cultural, morphological and biochemical characteristics. A total of 11 heavy metal resistant bacteria isolated from the soil samples were tentatively identified as Aeromonas sp (3), Arthrobacter sp. (1), Corynebacterium sp (4), Pseudomonas sp (1) and Streptococcus sp (2). The maximum tolerated concentrations of metals (in basal medium suppleme...
Contamination with various toxic metal ions has been detected in sediment and water samples of Paradip Port environment caused by various metal handling operations. Presence of chromium in the sediment and water samples has led to isolate Cr(VI) resistant marine bacteria from these environments. In total 44 chromate resistant bacteria were isolated from surface water, bottom water and sediment samples using nutrient agar medium supplemented with 50 mg/l Cr(VI) which were screened for their tolerance to increasing Cr concentrations in nutrient agar medium. The screening test has resulted in selection of 11 bacterial isolates tolerating Cr(VI) concentrations as high as 1500 mg/l. These 11 strains were then subjected to purification by two subsequent quadrant streak in nutrient agar plates and evaluated for determination of their minimum inhibitory concentration (MIC) towards Cr(VI) in nutrient broth by broth dilution method with further increasing concentrations from 1500 to 2500 mg/l of Cr(VI). Based on MIC test, a bacterium, CrRPSD40 isolated from marine sediment was selected because of very high tolerance towards Cr(VI) with MIC value of 2100 mg/l. This strain was found to exhibit multiple metal tolerance capacity when screened for tolerance towards other 6 toxic heavy metals such as Cd(II), Cu(II), As(III), Zn, Pb(II) and Ni in nutrient broth medium. Based on morphological and biochemical characterisation the bacterium was identified as a Brevibacillus sp. Identification of Brevibacillus sp as a high chromium resistant bacteria with multi-metal tolerance ability could be a potential candidate for bioremediation of chromium along with other metals from saline industrial waste effluents.
Heavy metal tolerance (Cr, Ag and Hg) in bacteria isolated from sewage
Brazilian Journal of Microbiology, 2012
Samples of sewage from a university hospital and a chemistry technical school were analysed for the percentage of bacterial tolerance to chromium (Cr), silver (Ag) and mercury (Hg). Additionally, we investigated the effect of these metals on pigmentation and on some enzymatic activities of the metal tolerant strains isolated, as well as antimicrobial resistance in some metal tolerant Enterobacteriaceae strains. Tolerance to Cr was observed mainly in Gram positive bacteria while in the case of Ag and Hg the tolerant bacteria were predominately Gram negative. Hg was the metal for which the percentage of tolerance was significantly higher, especially in samples from the hospital sewage (4.1%). Mercury also had the most discernible effect on color of the colonies. Considering the effect of metals on the respiratory enzymes, one strain of Ag-tolerant Bacillus sp. and one of Hg-tolerant P. aeruginosa were unable to produce oxidase in the presence of Ag and Hg, respectively, while the expression of gelatinase was largely inhibited in various Gram negative strains (66% by Cr). Drug resistance in Hg-tolerant Enterobacteriaceae strains isolated from the university hospital sewage was greater than 80%, with prevalence of multiple resistance, while the Agtolerant strains from the same source showed about 34% of resistance, with the predominance of monoresistance. Our results showed that, despite the ability of metal tolerant strains to survive and grow in the presence of these elements, the interactions with these metals may result in metabolic or phisiological changes in this group of bacteria.
Resistance of environmental bacteria to heavy metals
Bioresource Technology, 1998
Bacteria were isolated from different naturally polluted environments. Metal-resistant bacteria were selected and minimal inhibitory concentrations of heavy metals (MICs) for each isolate were determined. In addition, the mobility of the most important metallic cations (Cu, Zn, Cr, Cd, Co, Hg) was evaluated by comparing results obtained by two tests of toxicity in solid and liquid media. Results of the test of toxicity in solid media agreed with those in liquid, however, inhibitory concentrations in solid media were much higher than those in liquid. The range of metal concentrations tolerated in solid and liquid media yielded information on the capacity of adsorption and complexation of the metals. Mercury, and to a lesser degree copper, seemed to have a good capacity for adsorption and complexation and, consequently, had a limited diffusion in different naturally polluted environments. The presence of metals in the growth medium allowed us to maintain the tolerance of bacteria at a comparable level with that observed in naturally polluted environments. Cu and Cr were the best tolerated metals. Hg was the most toxic component for all bacteria, followed by Co and Cd. Pseudomonas aeruginosa (strain $6), with a relatively high MIC for metals and a large spectrum of antibiotic resistance appears to be a bacterial model for eco-toxicological studies.
Investigations on the Heavy Metal Resistant Bacterial Isolates in Vitro from Industrial Effluents
Heavy metals are widespread persistent inorganic pollutants and are not easily removable from the environment and are also indestructible, unlike many other organic pollutants that can be chemically or biologically degraded, hence, heavy metals constitute a global environmental problem. Heavy metal tolerable bacteria are currently favoured for their capacity to depollute the environment and hence regarded as instruments for bioremediation of metals. This study aimed to isolate heavy metal tolerant and antibiotic sensitive and resistant bacteria from industrial Effluent from Kanpur, U.P., India, Initially, a total of 28 isolates were screened from industrial effluent of which seven isolates were selected based on high level of heavy metal and antibiotic resistances. On the basis of cultural, morphological and biochemical analysis, the isolates were authentically identified as Pseudomonas spp. and Bacillus spp. maximum microbial tolerance of Bacillus spp. (B-2) was recorded to Cr (350 μg /ml) and lowest to Cu (240 μg/ml) whereas maximum microbial tolerance of Pseudomonas spp. (P-3) was recorded to Cr (300 μg/ml, and lowest to Pb and Cu. Thus, heavy metal tolerance test isolates showed maximum microbial tolerance to Cr and minimum tolerance to Pb and Cu. This study suggests that the isolated Bacillus spp. and Pseudomonas spp. have the properties to resist a wide range of heavy metals and antibiotics.
Investigation of heavy metal resistance in some bacterial strains isolated from industrial soils
2010
Soil samples were collected from an industrial area in Kazanli, Mersin, Turkey. Six heavy metals, Cr, Cu, Ni, Co, Cd, and Zn, were tested. ICP-AES analyses were carried out to detect the heavy metal levels of the soil samples. The analysis of test samples revealed high levels of Ni and Cr. A total of 272 Pseudomonas spp. and 161 Bacillus spp. strains were isolated from soils from 4 different sampling locations. The maximum tolerable metal concentrations (MTCs) of Cr, Cu, Ni, Co, Cd, and Zn for each isolate were determined. Resistance to Cr was found in 73.9% of the bacterial strains isolated from soil samples, whereas 26% of the isolates exhibited resistance to Ni, 18.4% to Zn, 11.5% to Cd, 9.2% to Co, and 7.3% to Cu. Observed maximum MTCs were 5 mM for Zn and Cu, 3 mM for Ni, and 2 mM for Cr. Plasmids of sizes 1.8, 2.1, and 28 kb were detected in most Pseudomonas spp. strains with resistance to Cu, Cr, Zn, and Ni.
Prevalence of heavy metal resistance in bacteria isolated from tannery effluents and affected soil
Environmental Monitoring and Assessment, 2011
In the present study, a total of 198 bacteria were isolated, 88 from the tannery effluents and 110 from agricultural soil irrigated with the tannery effluents. Tannery effluents and soils were analyzed for metal concentrations by atomic absorption spectrophotometer. The tannery effluents and soil samples were found to be contaminated with chromium, nickel, zinc, copper, and cadmium. All isolates were tested for their resistance against Cr6 + , Cr3 + , Ni2 + , Zn2 + , Cu2 + , Cd2 + , and Hg2 + . From the total of 198 isolates, maximum bacterial isolates were found to be resistant to Cr6 + 178 (89.9%) followed by Cr3 + 146 (73.7%), Cd2 + 86 (43.4%), Zn2 + 83 (41.9%), Ni2 + 61 (30.8%), and Cu2 + 51 (25.6%). However, most of the isolates were sensitive to Hg2 + . Among the isolates from tannery effluents, 97.8% were resistant to Cr6 + and 64.8% were resistant to Cr3 + . Most of the soil isolates were resistant against Cr6 + (83.6%) and Cr3 + (81.8%). All isolates were categorized into Gram-positive and Gram-negative bacteria. In a total of 114 Gram-positive isolates, 91.2% were resistant to Cr6 + followed by 73.7% to Cr3 + , 42.1% to Zn2 + , 40.4% to Cd2 + , and 32.5% to Ni2 + . Among Gram-negative isolates, 88.1% were found showing resistance to Cr6 + , 75.0% to Cr3 + , and 47.6% were resistant to Cd2 + . Majority of these metal-resistant isolates were surprisingly found sensitive to the ten commonly used antibiotics. Out of 198 isolates, 114 were found sensitive to all antibiotics whereas only two isolates were resistant to maximum eight antibiotics at a time. Forty-one and 40 isolates which constitute 20.7% and 20.2% were resistant to methicilin and amoxicillin, respectively.
Association of Antibiotic and Heavy Metal Resistant Bacteria Screened from Wastewater
International Journal of Environment, 2018
Wastewater treatment plant is a potential reservoir contributing to the evolution and spread of heavy metal and antibiotic resistant bacteria. The pollutants such as biocides, antibiotics, heavy metals are to be feared for as they have been known to evoke resistance in microorganisms in such polluted environment. The aim of this study was to the isolate bacteria from the treated wastewater and assess the resistance pattern of the isolates against antibiotics and heavy metals. Grab sampling was performed from April to June 2017, from the treated effluent from the secondary treatment plant. To assess the resistance pattern for antibiotic(s) and heavy metal(s), antibiotic susceptibility test and minimum inhibitory concentration by cup well method were performed respectively. Staphylococcus aureus, Enterococcus faecalis, Citrobacter freundii, Escherichia coli, Enterobacter aerogenes, Proteus mirabilis, P. vulgaris, Salmonella Typhi, Pseudomonas aeruginosa were isolated. Multi drug and h...
Journal of Tropical Microbiology and Biotechnology, 2008
Water pollution in Dhaka city, Bangladesh has been a serious problem for years and increasing urbanisation is worsening the situation. Water supply in Dhaka mainly depends on the rivers Buriganga, Turag, Shitalakhya and Balu, which in recent years have been polluted to such an extent that it is getting very difficult to cope up with the increasing demand of usable water. The pollution is both biological and chemical, resulting from sewerage lines dumplings and toxic wastes originating from different types of industries 1. In 2010, analysis of the heavy metal content of water in the Buriganga showed that concentrations of lead (Pb), Cadmium (Cd), Nickel (Ni), (Copper) Cu and Chromium (Cr) range from 58.17 to 72.45 µg/L, 7.08 to 12.33 µg/L, 7.15 to 10.32 µg/L, 107.38 to 201.29 µg/L and 489.27 to 645.26 µg/L, respectively 2. For most of these heavy metals this concentration exceed the acceptable level set by the Environmental Quality Standards (1997), Department of Environment, Government of the Peoples' Republic of Bangladesh 3 which is 50 µg/L for lead, 5 mg/L for cadmium, 1000 mg/L for copper, 100 µg/L for nickel and 50 mg/L for chromium and impose great risk to public health. Most of these heavy metals are toxic and carcinogenic for human and may lead to death in extreme cases. Among these, lead and hexavalent chromium are of particular concern due to their major impact on human and other forms of lives 4. In children, exposure to high concentration of lead and chromium can cause potentially permanent learning and behavior disorders. These metals are also toxic for adults, having deleterious effects on heart, bones, intestines, kidneys, reproductive and nervous systems and leading to death in extreme cases 4. Therefore, to ensure good public health, it is very important to remove these heavy metals from aquatic bodies in Bangladesh. There are limited strategies for removal of heavy metals from environment, most of which are physicochemical methods and possess several disadvantages, such as less affectivity, high costs, generation of toxic sludges as well as the problem of the safe disposal of the materials 5. As an alternative to the physicochemical removal methods, use of microorganism to reduce, eliminate or detoxify heavy metals has achieved growing attention in recent years 5-9. Additionally in several investigations, bacterial species have been isolated from several aquatic systems which were tolerant to different types of heavy metals and were also resistant to a variety of antibiotics, indicating to a strong correlation between metal resistance and antibiotic resistance among microbes 10-13. In a number of studies aerobic, gram positive, endospore forming multi-drug resistant Bacillus spp has been found to be associated with the bioremediation of heavy metals 6,7,10,13-14. It is possible that these bacteria utilize similar mechanisms to survive under metal and antibiotic stressed condition. Therefore, to understand the mechanism of heavy metal bioremediation by Bacillus spp, it is necessary to study the antibiotic resistance as well. This study therefore specifically focuses to isolate Bacillus spp with tolerance to increased concentration of lead and chromium from polluted water of the rivers Buriganga and Shitalkhya aiming to find out a solution to remove these pollutants from the river water. Materials and Methods Sampling sites The aim of this study is to isolate Bacillus spp with bioremediation capacity of heavy metals lead and Chromium. Therefore, aquatic environments heavily contaminated with industrial pollutant, especially pollutant from textile and tannery that would be enriched