Influence of Paraquat on Four Rhizobacteria Strains: Pantoea agglomerans, Rhizobium nepotum, Rhizobium radiobacter and Rhizobium tibeticum

Background:Soil microorganisms are exposed to herbicides after treatment, which leads to their interaction. The result of this interaction may be the degradation of the herbicides by the microorganisms and by the way, they use the degradation products as an energy source for their own physiological processes, or herbicides have a toxic effect on these microorganisms. Herbicide toxicity becomes severe instantly after application when its concentration in soil is the highest. Paraquat is one of the most widely used herbicides in agriculture; inappropriate use of this herbicide represents an immense pollution problem for soil, therefore on microorganisms. However, the knowledge about the effect of paraquat on soil microorganisms has been limited.Objectives:The purpose of the current study was to determine the effect of paraquat application on four nitrogen-fixing bacteria:Pantoea agglomerans, Rhizobium nepotum, Rhizobium tibeticumandRhizobium radiobacter.Methods:Paraquat was applied as the sole source of carbon at a rate (0 g/L, 0.5 g/L, 1 g/L, 3 g/L, 6 g/L and 12 g/L). The effect of paraquat treatments was determined by agar diffusion method and the rate of the growth of bacterial colonies in each treatment.Results:In the agar diffusion method, the bacterial strains were inhibited by paraquat, in which the inhibition zone was wider with the increase of paraquat concentration; also, analysis of the Colony Forming Units (CFUs) mostly showed a declining in bacterial growth. In comparison with the control, the growth of the four strains was decreased by increasing the paraquat concentration. Comparing strains with each other,Pantoea agglomeransis the most resistant strain to paraquat.Conclusion:Our study has shown the impact of the irrational use of pesticide upon the beneficial bacteria in question. For that, the results of this research have a positive impact on the natural environment, which will have tangible social and economic impacts.

A Review of Medical Waste Management in South Africa

Background:Poor medical waste management has been implicated in an increase in the number of epidemics and waste-related diseases in the past years. South Africa is resource-constrained in the management of medical waste.Objectives:A review of studies regarding medical waste management in South Africa in the past decade was undertaken to explore the practices of medical waste management and the challenges being faced by stakeholders.Method:Published articles, South African government documents, reports of hospital surveys, unpublished theses and dissertations were consulted, analysed and synthesised. The studies employed quantitative, qualitative and mixed research methods and documented comparable results from all provinces.Results:The absence of a national policy to guide the medical waste management practice in the provinces was identified as the principal problem. Poor practices were reported across the country from the point of medical waste generation to disposal, as well as non-enforcement of guidelines in the provinces where they exit. The authorized disposal sites nationally are currently unable to cope with the enormous amount of the medical waste being generated and illegal dumping of the waste in unapproved sites have been reported. The challenges range from lack of adequate facilities for temporary storage of waste to final disposal.Conclusion:These challenges must be addressed and the practices corrected to forestall the adverse effects of poorly managed medical waste on the country. There is a need to develop a medical waste policy to assist in the management of such waste.

Environmental Degradation in the Ikorodu Sub-Urban Lagos - Lagoon Coastal Environment, Nigeria

Introduction:Human activities exert great pressures on the environment which in turn cause environmental stresses of various intensities depending on the factors involved and the sensitivity of the receiving environment.Objective:This study examines the effects of anthropogenic activities along the sub-urban lagoon fragile coastal ecosystem using DPSIR framework.Results:The results show that the study area has undergone a tremendous change between 1964 and 2015 with the built up area increasing to about 1,080 ha (17.87%) in 2015 from 224 ha (1.32%) in 1964 at an average growth rate of 16.78ha per annum. The nature of the degradation includes an increasing fragility of the ecosystem through the emergence and expansion of wetlands, flooding and erosion as well as a reduction in the benefits from the ecosystem services. Population growth, between 2006 and 2015 for Ikorodu LGA, estimated at 8.84% per annum serves as the most important driving force in reducing the quality of the environment. This is in addition to Pressures emanating from anthropogenic activities. The state of the environment shows continuous resource exploitation (fishing and sand mining) with the impacts of the pressures coming from water pollution, bank erosion, biodiversity loss and flooding. Although there has been a strong policy formulation response from the government, weak implementation is a major challenge.Recommendation:The study recommends public awareness campaigns and the implementation of existing policies to ensure a sustainable sub-urban lagoon coastal environment..

A Review of Landfill Gas Generation and Utilisation in Africa

This review evaluates the current Landfill Gas (LFG) utilisation technology across Africa and gives general overview on the global context. With the increase in global Municipal Solid Waste (MSW), the world has embraced landfilling to be its major way of MSW management. About 85% of the world’s MSW is deposited in landfills. This has brought increased concerns of gases emitted from landfill sites. These gases have contributed enormously to the global anthropogenic Greenhouse Gas (GHG) emission which are detrimental to the world’s environmental media. Although significant progress has been made on the utilization of landfill gases but this is limited to some developed countries, while in Africa, there has been limited strategies and control of LFG emissions. This review spotted several reasons that could have influenced the low development of LFG utilisation in Africa as ranging from lack of skilled expertise, inadequate knowledge of the technology involved, lack of political will, inadequate funding for LFG utilization projects and monopoly of the power sector among others. It is recommended that urgent attention should be given to LFG utilisation as it can aid in acquiring carbon credits, reduction in obnoxious smell and odours, and provide the much-needed energy which is crippling the economy in Africa as well as reducing the consequences associated with the release of greenhouse gases to the environment.

BOOK REVIEW: Environmental Zeolites and Aqueous Media: Examples on Practical Solutions

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Effects of Glyphosate and Polyoxyethylene Amine on Metabolic Rate and Energy Reserves of Procambarus clarkii Juveniles

P. clarkii juvenile crayfish were exposed during 60 days to sublethal concentrations of glyphosate (G), polyoxyehtylene amine (P) or a combination of both (G+P), together with a control group of aged tap water (C). At the end of the experiment, the following statistical differences were noted, with respect to control: 1) a lower metabolic rate in both G and G+P groups, 2) a higher glycemia in G group with no differences in hemolymphatic lactate levels, 3) a lower muscle glycogen levels in both P and G+P groups, 4) a lower level of protein muscle in the P group. Taken together, these results suggest that glyphosate may cause a metabolic arrest. Additionally, under chronic exposure conditions, polyoxyehtylene amine acts as a strong stressor, leading to the utilization of both muscle carbohydrate and protein reserves.

Methylmercury and Trace Element Distribution in the Organs of Stenella coeruleoalba Dolphins Stranded on the French Mediterranean Coast

The main objective of this study was to evaluate the contamination by mercury (Hg), methylmercury (Me-Hg), cadmium (Cd), selenium (Se), zinc (Zn), copper (Cu), iron (Fe) and manganese (Mn) in dolphins stranded on the French Mediterranean coast. The distributions of these contaminants in the organs of dolphins have also been studied. Overall, contamination levels varied according to the following sequence: liver > kidney > lung > muscle, except for cadmium (kidney > liver > lung > muscle). Size and sex of animals were also considered. Young dolphins were less impacted with trace elements than adults, except for copper. Among the studied parameters, the most important appeared to be the size of mammals. In addition, in the case of mercury and selenium, the sex of mammals seemed to be also relevant. The correlations between the concentrations of trace elements suggest the existence of detoxification processes. Since 1990s, using dolphins for tracing marine pollution, a slight reduction in the burden of the considered trace elements could be noted.

Environmental Standard, Quality Improvement, and Technology Transfer

With technology licensing on quality innovation becoming a general phenomenon in the industry, this study focuses on the impact of quality improvement under different environmental standards. We established a three-country model to analyze the actions taken by the domestic firm located in the home country with high quality technology, the foreign firm located in the foreign country with low quality technology, and the products they export to the third country. The importing country also decides on an environmental standard for reducing environmental pollution. Our major findings are: (1) A less strict environmental standard is preferable for the third country government in the beginning, but the government will become stricter with the increasing substitution of products in the long term. (2) In the aspect of licensing, the higher quality firm tends to provide an option to draw up a royalty licensing contract rather than a fixed-fee licensing contract. (3) The social welfare of the high quality firm is always higher than that of the low quality firm, but it will decrease with the increasing substitution of products. Coming from the increasing substitution of products, the excess profit that is created for the low quality firm is used as a cost for pollution abatement. Therefore, the social welfare of the foreign country does not change when the substitution of product changes. This model fully illustrates the real case of mainland China and enriches the field of technology licensing on quality innovation. JEL Codes: L11, L51, O13.