International Research in Environment, Geography and Earth Science Vol. 9

The present study investigated quantitatively the significance of HNLC (high-nutrient low-chlorophyll) regions and its grazing control with the improved iron fertilization for climate change. The limitation of iron (Fe) for phytoplankton growth in HNLC regions was confirmed by sulfur compounds (S) such as volcanic ash and hydrogen sulfide (H₂S) in batch cultures, whose chemical sediment of Fe₃S₄ showed 4.06 wt %. The technologies developed for iron fertilization since 1993 till now were not practical to provide sufficient amounts of bioavailable iron due to sedimentary iron sulfides induced by undersea volcanic sulfur compounds. The proposed technology for iron fertilization was improved to enhance the bioavailable iron to phytoplankton by keeping minimal sulfur compounds in HNLC regions. The low productivity of phytoplankton by grazing control in HNLC regions was 6% diatoms whose 52% was grazed by copepods and 42% by krill on the basis of data analysis in 2000 EisenEx Experiment at boundary of Antarctic and African tectonic plates. All of the previous iron fertilization experiments were conducted at volcanic sulfur compounds enriched HNLC regions. The present study revealed that the enhanced phytoplankton productivity in batch culture without sedimentary iron sulfides can be possible only if sulfur compounds are minimal, as is in Shag Rocks  of South Georgia in Scotia Sea in the Southern Ocean.

Underground accidental explosions are caused by the detonation of solid, liquid or gas explosive materials stored below the ground surface. Underground explosion can take place, broadly speaking, in sand as well as undrained clay with varying degrees of impact on underground structures. In this study, effects on underground pipes due to varying degrees of underground accidental explosions were studied using ABAQUS numerical code. Pipes buried in loose sand, dense sand and undrained clay at various depths below the ground surface were modelled. The material properties as revealed by several researchers were used. Pipe and soil materials were limited to linear, elastic, homogeneous and isotropic. The observed parameters are displacement, pressure, mises, stress and strain at the crown, invert and spring-line of vertically and horizontally buried underground pipes. The results showed that irrespective of the ground media, displacement increases linearly as the loading wave velocity increases while clay soil (i. e. undrained clay) is problematic. Even though there is wide variation in the results due to dilations and compressions caused by the transient stress pulse of compression wave, observed parameters increases as the loading wave velocity increases. This study has demonstrated that higher loading wave velocity would result to higher displacement which invariably would result to higher induced moment and stress if multiplied by the corresponding distances. As a result of this, there is need for accidental explosion resistant evaluation of underground installations like pipes in order to have an optimal design of underground structures like pipes that would resist the effects of underground accidental explosions.

The pattern of population distribution of the common hippopotamus was examined along the 165 km stretch of the Luangwa River in eastern Zambia. The rise and fall in population size create oscillations which have persisted in the last 40 years (1976-2015). The study area was divided between the upper (A - D) and lower (E - H) study blocks. Population data collected between 1976 - 2015 showed a significant difference in the pattern of density distribution between upper and lower study blocks. Upper blocks had higher density of 41/km than lower blocks 29/km. Length of study blocks and mortality were discounted as density was used to determine distribution pattern, while mortality applied to both river segments and was insignificant. These results suggest that primary production in each study block as influenced by river geomorphologic features such as river bends and confluences characterized higher hippopotamus density in the upper blocks. The present study also found that hippopotamus pasture was mainly restricted to the alluvial belt which had in some places vast grasslands such as the Nsefu Plains in the upper river segment. Further research is required to investigate other factors that may have interplayed with food (above ground grass biomass) and river meander features to separate upper and lower blocks.

The ten provinces of Zambia were surveyed to determine number and size of game ranches situated in these areas up to the end of 2012/early 2013. Three classes of game ranches were developed as: 1) ?500 hectares as game ranch proper, 2) ?50 - <500 hectares as game farm, and 3) <50 hectares as ornamental. A total of 200 game ranches keeping large mammals from the size of common duiker to eland were recorded with a growth rate of 6 per year for the period 1980-2012. The largest number was ornamental 98 (49%); large game ranches were 75 (38%) and the least was game farms 27 (14%). Thirty-seven species of large mammals were recorded, of which, 15 were the most abundant with impala topping the list with 21,000 individuals (34%). It was found that of the ten provinces, Luapula, Western and Northern Provinces despite being largely rural with low population densities except for Luapula did not have any game ranch. The provinces with the largest number were Lusaka 71(36%), Southern 59 (30%), Central 31(16%), Copperbelt 19 (10%), Eastern and Northwestern 9 (4.5% each) and Muchinga was the least with 2 (1%). The rapid increase in the number of ornamental categories is mainly attributed to the rise in the development of tourist accommodation facilities and high cost residential properties. This growth provides an opportunity to convert to game ranching schemes abandoned farmlands which are not currently useful to agriculture due to loss of fertility and other forms of land degradation. Similarly, parcels of land with natural ecological limitations should also be considered for such schemes. The game ranching sector in Zambia has the potential to increase as human population density is still low (17/km² in 2012). To achieve good growth rates in each province, there should be provision of technical information and services.  Rehabilitation of degraded land through ranching could also enhance carbon sequestration, a factor critical in minimizing carbon emissions and other greenhouse gases.

The population size of hippopotamus (Hippopotamus amphibius Linnaeus 1758) in Luangwa valley, Zambia was earlier assessed for the period 1976 -2008 and repeated 2009 -2015 and found to have reached and maintained carrying capacity K of 6000 individuals over a 165 km river stretch. This study covered the period 2009-2015 and used riverbank count method as in previous studies. In 1976, a stretch of 165 km was demarcated for intensive population monitoring using the same survey methods. Results of this monitoring showed that the population recorded high densities of up to 42 hippopotami/km during the period 1976 - 2008. The method involved counting individuals and taking GPS locations of hippopotamus schools. During the period 2009 -2015 the population had maintained irregular cycles oscillating above and below K of 6000 and was still within carrying capacity band of 3000 individuals. The highest population size was 7,862 hippopotami and density of 48/km reached in 2015, and the lowest was 4501 hippopotami and density of 27/km recorded in 1978. Between 1976-2008, and 2009-2015 the population still oscillated between 5000 - 8000 individuals, which is symptomatic of a population that had reached its asymptote. Plot of population size for the period 1976-2015 assumed a population model which was a hybrid between less accurate regulation and stable limit cycle. The slow-down in population growth at K and oscillations were attributed to environmental resistance. More studies are required to identify the impact of climate change on the population size and density fluctuations to determine whether K will rise or drop.

The public health problems in Benin come from various angles. Domestic water has a fundamental role in households, but these sources are exposed to contamination by biological and physico-chemical pollutants. As a solution, household water purification devices such as ceramic filters can be used. “Filtre Songhaï” is a ceramic filter, simple and easy to use, marketed in Benin. This study’s object is to analyze the use of the “Filtre Songhaï” in the treatment of water for domestic use in a peri-urban area in Porto-Novo (Benin). Collective well and a pond from in the 5th district of Porto-Novo served as a source of sample collection. The physico-chemical and bacteriological parameters were measured before and after filtration. The results showed that the use of filters has allowed for a reduction of 97.5% for total coliform in the well water and 99.05% for water from the lagoon. The reduction is 100% for Escherichia coli and fecal streptococci in both cases. Considering the reliability and accessibility due to the lifetime use of “filtre Songhai”, this device can be proposed to households for drinking water, particularly for children below five years old the most vulnerable to water-borne diseases. At the end of this study, it arises that the use of the “Filtre Songhaï” allows a significant improvement of the mi-crobiological properties of water. Later research is needed to improve the speed of filtration of the “Filtre Song-haï”. Research is still necessary to refine the filtration time of this device.

Water is an indispensable resource for life. In the district of Ahomadégbé in Benin, access of households to improved water sources is not a problem because a large part of the population has water.

However, people consume poor water quality which is a function of microbiological contamination during transport and storage. The objective of this research is to analyze the behavior, knowledge and practices of households relating drinking water treatment methods in the district of Ahomadégbé with a view to proposing adequate measures for improving the quality of drinking water.

As part of this research, the questionnaire was used to approach 377 residents individually and 82 participants were organized into eight focus groups to understand the behavior, knowledge and practices of population.

The results show that more than 65% of the population of the borough have knowledge of certain process of treating water at home.

But they find themselves limited in the application of these different water treatment methods and only 6.1% of the population used at least one home water treatment method, even if this is not always appropriated.

The water treatment methods residents used were Alum (KAl(SO₄)₂?12 H₂O, chemical decantation method), filtration on tissues, and disinfection by boiling. The populations resort to other techniques of water treatment at home such as the use of oil and cresol which prove ineffective.

The population is aware of water contamination during transport and storage. However, most residents interviewed do not treat water before consumption, and the few who treat it resort to unsuitable methods. Thus, households need to be sensitized on effective and suitable methods of water treatment for their well-being.

Although drinking water is readily available in Benin, a public health problem arises in terms of its quality. The district of Ahomadégbé in the commune of Lalo is characterized by several artesian wells. Unfortunately, anthropogenic factors negatively affect the drinking water quality in this area. This research aims to analyze the microbiological quality of drinking water in the Ahomadégbé district and to reassess household water treatment methods practiced by the local population. To achieve these goals thirty-five water samples were taken at water collection points, at selected points along the water transportation system and from water storage facilities, and microbiological parameters were measured. The qualitative aspect of the research allowed to approach key interlocutors for in-depth discussions on endogenous techniques for treating water at home.

The analysis of results permitted to note the high degree of microbiological pollution of drinking water in this district, particularly during the water transportation and storage stages where microbiological pollution is above the standards approved by the World Health Organization. Local residents are familiar with several household water treatment methods. However, they remain less effective due to their inappropriate application.

In addition to improving the quality of the drinking water resource itself, it is important to set up interventions relating to water treatment methods in local households.

In Benin, the coverage rate of improved water sources is high. But the majority of the population does not have a drinking water source at home. In the absence of a home piping system, population develop strategies to have drinking water available at home. So, water is drawn from the source, transported and stored. This strategy is not without consequences because it favors microbiological contamination of the water. Unfortunately, bacteria that indicate fecal contamination are often resistant to the majority of antibiotics. Regarding drinking water, fecal contamination indicator bacteria such as Escherichia coli and enterococci are now resistant to antibiotics; thus, several infections can no longer be effectively treated. This research aims to assess the effectiveness of commonly-used antibiotics on the germs responsible for the microbiological contamination of drinking water in the district of Ahomadégbé, in the municipality of Lalo, Benin.

Thirty-five (35) drinking water samples were obtained, and antibiotic efficacy was tested on Escherichia coli and Staphylococcus aureus strains isolated from these samples. Ciprofloxacin, Doxycycline, Gentamicin, Imipenem, and Pristinamycin exhibited full sensitivity in Escherichia coli strains. Isolated Staphylococcus aureus strains, on the other hand, were resistant to Cephalosporins, Cyclins, and Macrolides but sensitive to Pristinamycin (Streptogramins). Strains of Escherichia coli and Staphylococcus aureus are resistant to most common antibiotics. To mitigate the risk of infection of populations and limit the progression of resistance of microbial to antibiotics that can still act on these strains, it is urgent to make people aware of good hygiene practices, which are the most effective ways to reduce the risk of infection.

This work aims to evaluate the impact of climate change on the quantitative availability of the Aghien lagoon located in the north of the Abidjan district in Côte d'Ivoire. In first step, the semi-distributed SWAT (Soil and Water Assessment Tools) based physical model [1] was calibrated and validated at the monthly time step over the period 1960-1981, in the Mé watershed where flow rates data are available. SWAT was then applied on the watershed of the lagoon of Aghien which is ungauged but for which the challenges are considerable for the drinking water supply of the Abidjanese population. In a second step, the gross outputs (precipitation, temperatures) of six climate models of the CORDEX-Africa project under the "Representative Concentration Pathways" (RCP 4.5 and RCP 8.5) scenarios were corrected using the delta method. These corrected outputs were used at the SWAT model input to project the impact of climate change on the flow of the Aghien lagoon for horizons 2040 (2035-2056), 2060 (2057-2078) and 2080 (2079-2100). The projections made on these different horizons were compared with the simulated flow over the period 1960-1981. The results show a sensible decrease in the annual flow of the Aghien lagoon compared to the reference period (1960-1981). Under the medium assumption (RCP 4.5), the models predict a decrease in the annual discharge almost 10% on average. Under the pessimistic hypothesis (RCP 8.5), the average annual discharge should decrease by more than 17%. On a monthly basis, flows in August and September would increase by more than 80% and those in October and November would increase by more than 20% in both RCP scenarios.

The goal of this study was to characterise the anaerobic biodegradability potential of mango processing solid waste as well as its methane potential (measured as methane yield) using various mass ratios of mango peel and cow dung. Fruit and vegetable wastes are highly biodegradable wastes which represent a potential energy resource for producing biogas by biological process. A maximum methane yield of 3.581 m³ CH₄ / Kg VS _degraded was obtained at 8% TS and ratio of 1:10. The addition of cow dung speeded up the onset of biogas production and increased methane productivity. The reductions in volatile solids in the entire BMP test ranged from 96% to 98%. The specific gas production for mango peel was higher (5.3926 m³ biogas / Kg VS _added and 5.5093 m³ biogas / Kg VS _des) for the 1:10 ratio at 8% TS than for the 1:2 ratio 2.0342 m³ biogas / Kg VS _added and 2.4535 m³ biogas / Kg VS _des at 4% TS. As a result, when compared to other values, the specific gas production for the mango peel, co-digestion with cow dung for the 1:10 at 8% TS was higher.This result was compared to the anaerobic digestion capability of MP and cow dung on their own. The mango peel's organic waste comprises easily biodegradable organic materials, which contributed to a better biogas yield.