The use of selected purple nonsulfur bacteria to remove heavy metals and salts from sediment and water collected from contaminated areas to decrease their phytotoxicity

The potential of the purple nonsulfur bacteria (PNSB), NW16 and KMS24, to remove heavy metals (HMs) and salts was investigated in a synthetic solution (62.63 Pb2+, 34.60 Cu2+, 58.5 Zn2+ and 0.75 Cd2 mg/L) containing 3% NaCl, sediment, and water collected from contaminated post cultured shrimp ponds and seed germination of 2 plants were used to assay their plant toxicities after bioremediation. Both light metal ions (85 mg/L Ca2+ and 160 mg/L Mg2+ to the synthetic HMs solution) significantly decreased the HMs removal efficiency and the mixed culture gave the highest efficiency to remove HMs (removal percentages; 85 Pb2+, 74 Cu2+, 47 Zn2+ and 28 Cd2+). The best set for the treatment of contaminated water from shrimp ponds (Cu2+, Zn2+; 0.043, 0.057 mg/L and salinity, 10.23%0) under the conditions of aerobicdark and microaerobic-light was a set of native with added mixed culture with a decrease of roughly 75, 31 and 77% for Cu2+, Zn2+ and salinity, respectively. For the sediment samples, a set of native with added mixed culture also produced the highest efficiency to remove HMs (initial concentrations in mg/kg dry weight; 23.15 Pb2+, 15.05 Cu2+, 22.16 Zn2+ and 0.29 Cd2+) and salinity (0.84%0) under aerobicdark conditions with the removal percentages of HMs; 84.29, 62.52, 43.33 and 40.95, and 100% salinity. Consequently, this set produced the most effective treatment as the germination index was 34.50 and 35.29% for rice seed (Oryza sativa) and water spinach (Ipomoea aquatic) respectively in the treated water and 115.70 and 139.33% for rice and water spinach respectively in the treated sediment.Keywords: Bioremediation, contaminated shrimp ponds, heavy metals, photosynthetic bacteria, salinity, seed germination indexAfrican Journal of Biotechnology Vol. 11(29), pp. 7434-7444, 10 April, 201

Are the existing guideline values adequate to protect soil health from inorganic mercury contamination?

© 2018 Elsevier Ltd Currently, data that guide safe concentration ranges for inorganic mercury in the soil are lacking and subsequently, threaten soil health. In the present study, a species sensitivity distribution (SSD) approach was applied to estimate critical mercury concentration that has little (HC 5 ) or no effect (PNEC) on soil biota. Recently published terrestrial toxicity data were incorporated in the approach. Considering total mercury content in soils, the estimated HC 5 was 0.6 mg/kg, and the PNEC was 0.12–0.6 mg/kg. Whereas, when only water-soluble mercury fractions were considered, these values were 0.04 mg/kg and 0.008–0.04 mg/kg, respectively

IS ELECTRONIC PAYMENT SUITABLE FOR ALL?

As the worldwide distribute and utilization a web and portable added towards the advancement of computerized installments as well as baking. There's the absence in terms of examination that gives far reaching union and investigation of variables influencing the utilization and reception of computerized banking and installment strategies in GCC nations. Consequently, the point due to this paper is to give anwriting survey also carry out weight and meta-examination. Through 46 audits examinations, that was observed that is excellent indicators in light of advanced installment as well as banking reception the GCCnations are believed, saw safety and saw helpfulness. In light of the broad writing audit, the reasonable of elements influencing reception computerized banking and installment techniques in Bay nations a model was put out that will set plan in the future examination

Niche breadth and overlap of spotted deer and domestic cattle with swamp deer in tropical region of Nepal

Background Knowledge about the niche overlap among wild species and domestic cattle is helpful to conserve and manage wildlife. We assessed the habitat niche breadth and overlap of sympatrically living spotted deer (Axis axis) and domestic cattle with swamp deer (Cervus duvaucelii) in Shuklaphanta National Park, Nepal during the dry season to explore the possibility of interspecific competition by studying the habitat use by these species. The assumption was made that the presence of pellets is proof of habitat used by species. Methods Grids of 2 km x 2 km have four subgrids, each with four sample plots, making a total of 16 plots (20 m x 20 m) in each grid. The size of each sub-grid was 200 m x 200 m and they were placed randomly inside the grid but at least 1 km apart from one another. The data was collected in a 96 plots in total. Levin's niche breadth and Morisita's overlap index were calculated to determine the niche breadth and the habitat overlap, respectively. Results The Levin's measure of niche breadth suggested that spotted deer had the highest acclimatization with an index value of 0.94, followed by domestic cattle at 0.50, and swamp deer at 0.33 in our study area. Thus, our findings supported the evidence that spotted deer are habitat generalists, whereas swamp deer are habitat specialists. The swamp deer had lower niche breadth and more overlap with domestic cattle. Conclusion Our study showed the least niche breadth of swamp deer in comparison to spotted deer and domestic cattle. The domestic cattle had the highest and least niche overlap with spotted deer and swamp deer, respectively, in terms of habitat use. Our study suggests that domestic cattle grazing should be stopped, and grassland management should be carried out for the benefit of ungulates. Similar studies should be conducted, including different seasons and places, prior to appropriate habitat management. In addition, further studies are needed to quantify the extent of interspecific competition by incorporating more species.Peer reviewe

Bioremediation of mercury: not properly exploited in contaminated soils!

© 2017, Springer-Verlag Berlin Heidelberg. Contamination of land and water caused by heavy metal mercury (Hg) poses a serious threat to biota worldwide. The seriousness of toxicity of this neurotoxin is characterized by its ability to augment in food chains and bind to thiol groups in living tissue. Therefore, different remediation approaches have been implemented to rehabilitate Hg-contaminated sites. Bioremediation is considered as cheaper and greener technology than the conventional physico-chemical means. Large-scale use of Hg-volatilizing bacteria are used to clean up Hg-contaminated waters, but there is no such approach to remediate Hg-contaminated soils. This review focuses on recent uses of Hg-resistant bacteria in bioremediation of mercury-contaminated sites, limitation and advantages of this approach, and identifies the gaps in existing research

A Study on Effect of Microbial Growth on Dentures in Relation to Denture Storage and Overnight Soaking of Dentures in Various Soaking Solutions -An In Vitro Study

Background: Denture hygiene is essential for preventing microbial growth and associated oral health issues in denture wearers. This in vitro study investigates the effect of denture storage conditions and overnight soaking in various solutions on microbial growth on denture surfaces. Methods: Standardized denture models were inoculated with Candida albicans, Streptococcus mutans, and Staphylococcus aureus and subjected to dry and moist storage conditions. Soaking solutions included commercial denture cleanser, sodium hypochlorite, hydrogen peroxide, and distilled water (control). Microbial assessments were conducted at specified intervals. Results: Moist storage significantly promoted microbial growth on dentures compared to dry storage. Soaking solutions, especially commercial denture cleanser, sodium hypochlorite, and hydrogen peroxide, demonstrated substantial reductions in microbial counts compared to distilled water. Conclusion: Denture storage conditions and choice of soaking solution significantly influence microbial growth on dentures. Moist storage and the use of antimicrobial solutions are effective strategies for reducing microbial colonization. Keywords: Denture hygiene, microbial growth, denture storage, soaking solutions, oral health

Isolation of purple nonsulfur bacteria for the removal of heavy metals and sodium from contaminated shrimp ponds

In order to determine whether waters used for the shrimp cultivation contained toxic levels of heavy metals (HMs) and sodium (Na), analysis was carried out on 31 shrimp ponds in areas of southern Thailand. Purple nonsulfur bacteria (PNB) were also isolated from the same ponds to investigate if they could be used for bioremediation of the above contaminants. The highest HMs concentrations of the sediment samples in mg/kg dry weight were found as follows: 0.75 cadmium (Cd), 62.63 lead (Pb), 34.60 copper (Cu) and 58.50 zinc (Zn). However, all sediment samples met Hong Kong standards for dredged sediment. In contrast, contamination of Cu (9-30 µg/L) and Zn (140-530 µg/L) exceeding the standard guidelines for marine aquatic animal set by the Pollution Control Department, Thailand, were found in 32 and 61% of water samples, respectively. Two metal resistant PNB isolates, NW16 and KMS24, were selected from the 120 PNB isolates obtained. Both isolates reduced the levels of HMs by up to 39% for Pb, 20% for Cu, 7% for Cd, 5% for Zn and 31% for Na from water that contained the highest levels of HMs found and 3% NaCl when cultured with either microaerobic-light or aerobic-dark conditions. The isolate NW16 removed a greater percentage of the HMs than the isolate KMS24, but the isolate KMS24 was able to survive better under a greater variety of environmental conditions. Both strains were therefore suitable to use for further investigating their abilities to remediate water contaminated with HMs and Na

Isolation of purple nonsulfur bacteria for the removal of heavy metals and sodium from contaminated shrimp ponds

In order to determine whether waters used for the shrimp cultivation contained toxic levels of heavy metals (HMs) and sodium (Na), analysis was carried out on 31 shrimp ponds in areas of southern Thailand. Purple nonsulfur bacteria (PNB) were also isolated from the same ponds to investigate if they could be used for bioremediation of the above contaminants. The highest HMs concentrations of the sediment samples in mg/kg dry weight were found as follows: 0.75 cadmium (Cd), 62.63 lead (Pb), 34.60 copper (Cu) and 58.50 zinc (Zn). However, all sediment samples met Hong Kong standards for dredged sediment. In contrast, contamination of Cu (9-30 \u3bcg/L) and Zn (140-530 \u3bcg/L) exceeding the standard guidelines for marine aquatic animal set by the Pollution Control Department, Thailand, were found in 32 and 61% of water samples, respectively. Two metal resistant PNB isolates, NW16 and KMS24, were selected from the 120 PNB isolates obtained. Both isolates reduced the levels of HMs by up to 39% for Pb, 20% for Cu, 7% for Cd, 5% for Zn and 31% for Na from water that contained the highest levels of HMs found and 3% NaCl when cultured with either microaerobic-light or aerobic-dark conditions. The isolate NW16 removed a greater percentage of the HMs than the isolate KMS24, but the isolate KMS24 was able to survive better under a greater variety of environmental conditions. Both strains were therefore suitable to use for further investigating their abilities to remediate water contaminated with HMs and Na

Bioaccumulation and Tolerance Indices of Cadmium in Wheat Plants Grown in Cadmium-Spiked Soil: Health Risk Assessment

Farmers use wastewater for irrigation in many developing countries, for example Bangladesh, India, China, Sri Lanka and Vietnam because they have limited access to clean water. This study explored cadmium (Cd) bioaccumulation in two spring wheat cultivars (cv. Mustang and Lancer), which were grown in different concentrations of Cd (0,1, 2, 4, and 8 mg kg−1) in agricultural soils. The half maximum inhibitory concentration (IC50) values were 4.21 ± 0.29 and 4.02 ± 0.95, respectively, whereas the maximum health risk index (HRI) was 3.85 ± 0.049 and 5.33 ± 0.271, respectively, for Mustang and Lancer. In other words, the malondialdehyde content increased significantly in Mustang (around five-fold) and Lancer (around four-fold) compared with the control treatment. Results revealed that Cd content was well above the acceptable limit (HRI >1) in the two cultivars when exposed to different levels of Cd stress. The tolerant cultivar (Mustang) has potential to chelate Cd in the nonedible parts of plants in variable fractions and can be used efficiently to improve growth and macro- and micro-nutrients content while reducing Cd concentration in plants in Cd-contaminated soil. It can also diminish the HRI, which may help to protect humans from Cd risks. The two cultivars’ nutrient availability and sorption capacity significantly shape their survival and adaptability under Cd stress. Based on what is documented in the current study, we can conclude that Mustang is more tolerant and poses fewer health hazards to people than Lancer because of its capacity to maintain grain macro- and micro-nutrients under Cd stress

Phytotoxicity of Class B aqueous firefighting formulations, Tridol S 3 and 6% to Lemna minor

Phytotoxicity of Class B aqueous firefighting concentrates, Tridol-S 3%, and Tridol-S 6% to Lemna minor were studied using the parameters such as the frond number, biomass production in terms of dry weight, chlorophyll content and proline accumulation. Decrease in fresh weight, dry weight, and chlorophyll pigments; increase in proline content suggested that both the firefighting concentrates are potentially toxic to L. minor. Relative growth rate (RGR) also showed a similar pattern of toxicity with the corresponding increase in test concentrations of both the compounds. The EC50 values show Tridol-S 3% was more toxic than Tridol-S 6% in terms of frond number and dry weight. From our findings, it is clear that L. minor is highly sensitive to the exposure of firefighting foams, and is suitable for its use as an indicator organism for assessing the aquatic toxicity of aqueous firefighting foams. This study clearly suggests that the migration of Tridol AFFF into aquatic environments is likely to have detrimental effects on the aquatic flora. To the best of our knowledge, this study constitutes the first report on the phytotoxicity of firefighting concentrates, Tridol-S 3% and Tridol-S 6% to Lemna minor L