Microbial leaching of heavy metals using Escherichia coli and evaluation of bioleaching mechanism

2020 ◽  
Vol 9 ◽  
pp. 100368 ◽  
Author(s):  
Shruti Vyas ◽  
Yen-Peng Ting
Keyword(s):  
Escherichia Coli ◽  
Heavy Metals ◽  
Microbial Leaching

Detection of heavy metal toxicity and genotoxicity in wastewaters by microbial assay

1994 ◽  
Vol 30 (10) ◽  
pp. 145-151 ◽  
Author(s):  
J. C. Codina ◽  
A. Pérez-García ◽  
A. de Vicente
Keyword(s):  
Escherichia Coli ◽  
Heavy Metals ◽  
Heavy Metal ◽  
Metal Toxicity ◽  
Ames Test ◽  
Deionized Water ◽  
Toxicity Tests ◽  
Water Solutions ◽  
Microbial Assay ◽  
Higher Sensitivity

The effect of wastewater on the sensitivity of toxicity and genotoxicity assays for the detection of heavy metals was evaluated. Five microbiological toxicity tests were used to compare the toxicity of cadmium, copper, chromium, mercury, nickel, and zinc, both in deionized water solutions and in wastewater. The toxicity assays employed were: Microtox®, two tests of growth inhibition using Pseudomonas fluorescens, and two spectrophotometric assays of the inhibition of respiration test using baker's yeast and P. fluorescens. Also, the genotoxic effect of the assayed metals was evaluated by using the Ames test, the Escherichia coli WP2 test, and the SOS test. The sensitivity to metals decreases in most of the toxicity and genotoxicity assays; in general, higher sensitivity thresholds (EC20) in wastewater than in water solutions were determined. Each test shows different sensitivities to each metal, which is related to different sensitivities of the organisms used in the assays, as well as to other factors.

Effect of pH on metal solubilization from sewage sludge: a neural-net-based approach

1994 ◽  
Vol 21 (5) ◽  
pp. 728-735 ◽  
Author(s):  
Y. G. Du ◽  
T. R. Sreekrishnan ◽  
R. D. Tyagi ◽  
Peter G. C. Campbell
Keyword(s):  
Heavy Metals ◽  
Sewage Sludge ◽  
Municipal Sewage ◽  
Municipal Sewage Sludge ◽  
Neural Net ◽  
Metals Removal ◽  
Complex Biological Process ◽  
System Temperature ◽  
Microbial Leaching ◽  
Metal Solubilization

Microbial leaching for heavy metals removal from municipal sewage sludge is a complex biological process. The ultimate metal solubilization achieved depends on the type of sludge involved (nondigested, aerobically digested or anaerobically digested sludge), the decrease in sludge pH as a result of the leaching operation, and the concentration of metals initially present in the sludge. In addition, the system temperature exerts an indirect but strong influence by its effect on the bacterial growth and acid production process. A neural-net-based model was developed to predict the solubilization of six heavy metals, Cd, Cr, Cu, Ni, Pb, and Zn, from sewage sludge using the bioleaching process. The only input parameters required are the type of sludge, initial metal concentrations in the sludge, and the sludge pH. The model yielded satisfactory predictions of metal solubilization when tested with a number of actual experimental data. Key words: heavy metals, microbial leaching, modelling, neural-net, sewage sludge.

Evaluation of Chemical and Microbiological Contaminants in Fresh Fruits and Vegetables from Peasant Markets in Cundinamarca, Colombia

2020 ◽  
Vol 83 (10) ◽  
pp. 1726-1737
Author(s):  
MANUEL PATIÑO ◽  
MARÍA FERNANDA VALENCIA-GUERRERO ◽  
EDWIN SAMIR BARBOSA-ÁNGEL ◽  
MARÍA JOSÉ MARTÍNEZ-CORDÓN ◽  
PILAR DONADO-GODOY
Keyword(s):  
Escherichia Coli ◽  
Heavy Metals ◽  
Listeria Monocytogenes ◽  
Fruits And Vegetables ◽  
Integrated Management ◽  
Management Strategies ◽  
Escherichia Coli O157 ◽  
Pathogenic Microorganisms ◽  
Maximum Residue Limit ◽  
Integrated Crop Management

ABSTRACT In this study, chemical and microbiological contaminants were detected in fresh fruits and vegetables in peasant markets in the Department of Cundinamarca to assess food safety. At least one pesticide was detected in 63% of the samples evaluated (n = 100, including fruits and vegetables), and in 41% of these, pesticides exceeded the maximum residue limit. Within the pesticides found, 60% do not use a registry from the Instituto Colombiano Agropecuario to be applied on the crops where they were detected and are included in the toxicological categories “highly toxic” (category IB) and “moderately toxic” (category II). Heavy metals were found in 45% of the samples, with cadmium (38%) and lead (14%) being the most frequent. The pathogenic microorganisms Escherichia coli O157:H7, Listeria monocytogenes, Salmonella, and Campylobacter sp. were detected in 4, 2, 1, and 0% of the samples, respectively. Factors concerning integrated crop management, contaminated inputs with chemicals and microorganisms, and the lack of hygiene in the postharvest stage favor the presence of pesticide residues, heavy metals, and the appearance of pathogenic microorganisms. The results suggest the need to strengthen the implementation of integrated management strategies that guarantee the safety of fresh fruits and vegetables in the country. HIGHLIGHTS

scholarly journals Enteropathogenic Escherichia coli in a treated effluent from Puebla City-Mexico, resistant to antibiotics and heavy metals

2020 ◽  
Vol 3 (3) ◽  
pp. 069-078
Author(s):  
Edith Chávez-Bravo ◽  
Claudia Cecilia Cordero-Arellano ◽  
Alejandro IA Alonso-Calderón ◽  
Antonio Rivera
Keyword(s):  
Escherichia Coli ◽  
Heavy Metals ◽  
Enteropathogenic Escherichia Coli ◽  
Treated Effluent

Retention of pharmaceutical residues and microorganisms at the Altendorf retention soil filter

2014 ◽  
Vol 70 (9) ◽  
pp. 1503-1509 ◽  
Author(s):  
E. Christoffels ◽  
F. M. Mertens ◽  
T. Kistemann ◽  
C. Schreiber
Keyword(s):  
Escherichia Coli ◽  
Heavy Metals ◽  
Giardia Lamblia ◽  
Microbial Contamination ◽  
Advanced Treatment ◽  
Organic Micropollutants ◽  
Combined Sewer Overflows ◽  
Efficient Removal ◽  
Pharmaceutical Residues ◽  
Combined Sewer

A study has been conducted on a retention soil filter (RSF) to test its effectiveness in removing pharmaceutical residues and microorganisms from combined sewer overflows (CSOs). Efficient removal of solids, nutrients and heavy metals has already been proven. The possibility that organic micropollutants and microorganisms are also retained by the use of RSFs has been identified, but data are lacking. Results obtained in this study, in which testing for removal by a RSF of numerous micropollutant substances was performed, are most promising. The pharmaceuticals diclofenac and ibuprofen are presented in detail as examples of such micropollutants. Both showed a reduction in positive samples of more than 55% as well as a significant reduction in median and maximum concentrations. For microorganisms such as Escherichia coli, coliphages and Giardia lamblia (cysts), an average reduction in concentrations by three logarithmic steps (99.9%) was achieved. These results add to the evidence that using a RSF in the advanced treatment of wastewater from CSOs reduces the exposure of watercourses to pharmaceutical residues and microbial contamination.

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