International Journal of Environment

Flour Mill Workers Occupational Noise Exposure in Chandrapur City, Central India

2019-02-16T16:58:29+00:00

Assessment of occupational noise exposure of flour mill workers in Chandrapur city of central India was carried out during November 2015-January 2016. Total 62 flour mills were selected for this study comprising one, two and three grinding machines operating in the shop floor. The sound level meter was used to measure sound level at 50 cm and 3 meters from grinding machines at receiver’s position during operation. Noise monitoring was also recorded when one, two and three machines were operating individually and simultaneously. The results showed that noise levels when one grinding machine in operation in close proximity (50 cm) was in the range of 80-97 dB(A). Comparison of these observations with that of 3 meters distance; it was observed that noise levels got reduced and in the range of 70-77 dB(A). In the case of two machines in operation, it was in the range of 95-118 dB(A) at 50 cm distance and reduced to 75-95 dB(A) at 3 meters distance. This reduction in noise level was due to the propagation of noise in the ambient environment. Furthermore, daily noise exposure points, exposure points job per task and exposure points per hour were computed by using noise exposure calculator developed by Health and Safety Executive (HSE), United Kingdom. The computation from this calculator revealed that these attributes were directly depended upon noise levels in flour mills and duration of noise exposure. A positive linear Pearson’s correlation (p<0.01) was observed between noise level and exposure points per hour. Of the 65 flour mill workers surveyed, 70.76% reported a hearing problem, 23.07% headache at work and out of which 7.69% workers headache remains after completion of work also. Remedial measures to control noise exposure to flour mill workers such as ear plugs, ear muff, semi-insert are recommended.

Efficiency of Polycyclic Aromatic Hydrocarbons (PAHs) Degrading Consortium in Resisting Heavy Metals During PAHs Degradation

2019-02-16T16:58:28+00:00

Polycyclic aromatic hydrocarbons (PAHs) comprised of many dangerous organic pollutants which affect human cell. The choice of phenanthrene and pyrene as model substrates was based on their classification among the most hazardous PAHs group by the US EPA where they belonged to low and high molecular weights PAHs respectively. Biodegradation of these PAHs is the best strategy that completely removes such pollutants in an environmentally friendly manner. However, the bacteria involved are challenged degradation difficulties as a result of PAHs inhibitory effects to the organisms. This research is aimed at formulating phenanthrene and pyrene degrading consortium that effectively perform best even in complex mixture with hazardous heavy metals. Different bacteria consortia were formulated using the compatibility testing and mathematical permutation approach and the best consortium selected. This selected consortium was then subjected to the degradation of both phenanthrene and pyrene separately in a combined mixture with the selected heavy metals from the inductively coupled plasma optical emission spectrophotometer (ICP-OES) analysis. Consortium composition of C. sakazakii MM045 (2%, v/v) and Enterobacter sp. MM087 (2%, v/v) were found to be much effective during phenanthrene (500 mg/L) and pyrene (250 mg/L) degradation. This consortium also resisted more than 6 mg/L each of Nickel (Ni), Cadmium (Cd), Vanadium (V) and Lead (Pb) in such complex degradation which was found to be more than the concentration in the natural habitat the consortium exists prior to isolation. Such performance makes the selected consortium to be an extremely efficient tool for the PAHs degradation application as many biodegradation agents were reported to be less effective when significant concentration of Ni, Cd, V and Pb are present.

Association of Antibiotic and Heavy Metal Resistant Bacteria Screened from Wastewater

2019-02-16T16:58:27+00:00

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 heavy metal resistant isolates were screened. Fisher’s exact test revealed that there is a significant association (p< 0.001) between antibiotic resistance pattern and resistance patterns at dilution of 2500 g/L (25%). Cramer’s V test revealed that the effect size of antibiotic resistance pattern and heavy metal resistance pattern at dilution 2500 g/L is medium. P. aeruginosa was able to resist the metal concentration up to 10000 g/L (100%) dilution of Fe⁺⁺. Heavy metal resistant bacteria can be safely used to lower chemical concentration in the environment once their harmful genes are edited, knocked etc. so that risks of evoking antibiotic resistance could be minimized.

Seasonal and Land Type Based Soil Chemical and Nutrient Status in Agricultural Lands of Coastal District, Bagerhat, Bangladesh

2019-02-16T16:58:26+00:00

The present study investigated the land type based seasonal status of agricultural topsoil chemical properties at Bagerhat district, Bangladesh. Because of relief and seasonal effect we hypothesized the changes of soil nutrient and chemical properties in topsoil. Composite soil samples were collected from fifteen purposive sampling points in pre-monsoon and post-monsoon period of 2016-2017. Soil digestion and analysis were performed following standard procedures. Topsoil pH was strongly alkaline to slightly alkaline (8.02-7.85) in pre-monsoon and post-monsoon with a significant variation. Seasonal OM status was below the optimum level (<3.4). Mean salinity status was very slightly saline in both seasons. Total nitrogen status was low in different lands in both seasons. Phosphorus status was very low (<0.06µg/g) in post-monsoon for upland and wetland crops. Sulfur status was very high (>45.0µg/g) in both seasons for upland and wetland crops. Seasonal mean status of B, Ca and Mg was very high in different lands. Status of Zinc was medium in both seasons having a deficiency (<9.0 µg/g) in some lands. Multivariate analysis showed that lowlands were rich in salinity, OM, K, Ca, total nitrogen and S comparing with medium lowland and medium highland (LL>MLL>MHL). Considering the above issues present study suggests to avoiding excessive use of chemical fertilizer and encourages organic fertilizer for sustainable management of these agricultural lands.

Growth Enhancement of Phragmites australis, Eichhornia crassipes and Saccharum officinarum for Rhizoremediation of Crude Oil

2019-02-16T16:58:25+00:00

P. australis, E. crassipes (in mangrove swamp) and S. officinarum (in rainforest) are capable of tolerating some levels of crude oil in soil. However, some important growth characteristics such speedy growths, extensive root system and increased biomass desirable for efficient rhizoremediation are depressed. To cushion this suppressive effects, plants were subjected to the following treatments: Plant + Soil (PS) (Control); Plant + Soil + Oil (PSO); Plant + Soil + Oil + Fertilizer (PSOF); Plant +Soil + Oil + Fertilizer + Microorganisms (PSOFM); and Plant + Soil + Fertilizer + Microorganisms + Solarization (PSOFMS). Treatments were monitored for 120 days to determine their effects on the following growth parameters: Germination, germination percentage, height, and root length, dry weight, and leaf area. Results indicated that treatments PSOF, PSOFM and PSOFMS enhanced all growth parameters over contaminated untreated soil (PSO) with the exception of germination in P. australis and S. officinarum; while root length, leaf area in E. crassipes were statistically the same for PS, PSO, PSOFM and PSOFMS (P ˂ 0.05). Overall, growth enhancement efficiencies of the applied treatments were in the order: PSOFM ˃ PSOF ˃ PSOFMS. Thus, growth of these plants can be enhanced in crude oil contaminated soil by the above treatments for efficient rhizoremediation.