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1

Effects of the tide on the temporal and spatial physicochemical structure of the Kienké river estuary (South Atlantic Coast of Cameroon, Kribi) and its phytoplankton

Mama Anselme Crépin, Ghepdeu Gisele Flodore Youbouni, Fossi Tankoua Olivia, Bonga Manfred Desire, Abouga-Bodo Willy Karol, Mandeng Thérésa Irma, Owona-Edoa François Désiré, Tangko Noel Chuye, Ngoupayou-Ndam Jules Rémi

Oceanological and Hydrobiological Studies

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2023

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Vol. 52, No. 1

20--40

EN

The present work aimed to understand the physicochemical and phytoplanktonic structure of the Kienke estuary water in the urban area of Kribi town in relation to human activities and fluvial or oceanic influences. Field investigations and laboratory work were devoted to the sampling and measurement of some physicochemical and biological parameters, specific treatments and classical statistics (descriptive, multidimensional) of variables. Estuary water is characterised by an instability and spatio-temporal variations in its physicochemical parameters. The most sensitive parameters are as follows: a temperature ranging between 22.6°C and 31°C under the influence of atmospheric variations, electrical conductivity and salinity that are relatively high (0.22 < C. E < 49.70 mS cm-1; avg =16.56 mS cm-1; 0 < Sal < 29.32 PSU; avg = 11.51 PSU), and a pH that is overall acidic to basic (6 < pH < 8.86; avg = 7.75 ± 0.82). The nutrients variation (ammonium, nitrite, nitrate and orthophosphate) is very low in space and time, with a longitudinal distribution controlled by tidal flows, river flows and the biological pump. For the 64 samples collected, 167 phytoplankton taxa were identified. The most abundant (36.36%) were Chrysophyta Division, followed by Chlorophyta. Species richness is marked by brackish water taxa. According to this structure and the combination of both gradients, mineratilisation and organic matter enrichment is of a physicochemical typology, and the biotypology is hydrotypologically dependent.

2

Comparative Study of the Physico-Chemical and Metallic Quality of Waters and Sediments in the Larbaa Basin (Morocco) in the Dry and Wet Period

Afgane Rachida, Benjelloun Faiza, Lahrach Abderrahim, Daide Fatima

Journal of Ecological Engineering

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2021

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Vol. 22, nr 8

92--102

EN

The catchment area of Oued Larbaâ is located in the eastern prerif at the very eastern end of the large Innaouene basin, a stream of Oued Sebou [Lahrach. A et al., 1994]. The objective of the study was to establish a quality comparison of the watershed during the dry and wet seasons. Eight water and sediment samples were taken during the two seasons, all along the main channel of the Larbaa river, taking into account anthropogenic activities and the areas of confluence with its tributaries: Tarmasst, Taza, Larouireg, Defali and Jaouna. The physicochemical parameters (pH, EC, TDS, nitrates, sulfates, chlorides), as well as metal contamination (Al, Zn, Ni, Pb, Ag, Fe, Cd, Cr, Cu, Mg, Mn) were studied in summer. The results revealed the alkaline pH higher than 7, a significant electrical conductivity in several stations, but still conforming to the Moroccan standards. Laboratory analyses reflect that the waters of the basin have generally good quality, except for a few peaks that indicate metallic contamination in Fe and Al. In order to better assess whether there is an anthropogenic effect influencing these results, and to remove the relationships between the different parameters studied, a statistical analysis was carried out with the PCA tool. This analysis made it possible to indicate Cr, Ni and Al as indices of pollution in certain areas. Although the results obtained have been tolerant until now, it is necessary to put in place an action plan to control the areas at risk of contamination during the years.

3

Assessment of Inaouene River Pollution for Potable Water Supply, Northern Morocco

Laaraj Marouane, Benaabidate Lahcen, Mesnage Valérie

Journal of Ecological Engineering

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2020

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Vol. 21, nr 7

68--80

EN

Under hydrological uncertainty and to secure the potable water supply for the Fez city with more than one million and a half inhabitants, the competent authority intends to bring water from the Idriss 1st reservoir 30 km away, downstream the Inaouene watershed. The pollution risks as well as the contamination degree of surface water and sediments were assessed by monitoring the physicochemical characteristics of the water and sediment samples. The results revealed high values of chemical oxygen demand and chloride mainly linked to the uncontrolled liquid discharges. Calcium and magnesium showed also high concentrations that are due to the watershed geology, where carbonate rocks are dominant. The contents of some heavy metals remain relatively low and within the Moroccan standards. The metal contents in sediments show a low degree of the anthropogenic pollution. This led to conclude that the waters and sediments in the study area show relatively degraded quality and then could be used for water supply under continuous control.

4

Shaping changes in the ecological status of watercourses within barrages with hydropower schemes : literature review

Tomczyk Paweł, Wiatkowski Mirosław

Archives of Environmental Protection

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2020

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Vol. 46, no. 4

78--94

EN

Hydropower use of watercourses has tangible consequences for the environment, society and economy. Based on a literature review and their own research, the authors present current data on changes in the ecological status of waters within run-of-river and reservoir hydropower plants, i.e. changes in biological elements (benthic macroinvertebrates, plankton, ichthyofauna, macrophytes), as well as hydromorphological and physicochemical changes. Previous researchers have noted that the impact of hydropower use of rivers on ecological status of those rivers is extensive, consisting of, among others, changes in species structure and populations of macrophytes, benthic macroinvertebrates, plankton and ichthyofauna (positive as well as negative changes), algal blooms due to increased turbidity, constrained migration of water organisms, changes in temperature within hydroelectric power plants, the phenomenon of supersaturation, eutrophication, changes in hydrological conditions (e.g., increased amplitudes of diurnal water levels and their consequent annual reduction), and increased erosion below the damming and deposition of bottom sediments on the damming barriers. In addition to such changes in ecological status, hydropower use also has a visible impact on socio-economic conditions (e.g., living standards of the population) and the environment (e.g., quality of bottom sediments and biodiversity). The article offers an assessment of the impact of hydropower use of rivers on ecological status (biological, hydromorphological, physicochemical elements and hydrological conditions of such rivers), society, economy and environment; it also proposes a research scheme to assess the impact of hydropower structures.

5

Groundwater’s physicochemical and bacteriological assessment: Case study of well water in the region of Sedrata, North-East of Algeria

Malek Amina, Kahoul Mohamed, Bouguerra Hamza

Journal of Water and Land Development

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2019

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no. 41

91--100

EN

Drinking water is a possible source of humans’ illness when it contains chemicals and microorganisms especially from anthropogenic activities. The water supply from groundwater remains very important in Algeria. To assess the quality of groundwater in the region of Sedrata, analyses were carried out on 26 wells belonging to two neighbouring areas: one urban and the other rural. A study of physicochemical parameters has focused on the measurement of in situ temperature, electrical conductivity, pH and turbidity. Then the following parameters were analysed: hardness, and the elements: Ca2+, Mg2+, SO4 2–, PO4 3–, Cl–, NO2 –, NO3 –, NH4 + as well as metal trace elements Fe2+, Mn2+, Al3+. The samples taken for the bacteriological study were filtered and introduced into growth medium for the research and enumeration of total germs, faecal coliforms, faecal streptococci and sulphite reducing Clostridium. As a result, the contamination of the studied waters is almost general. Some of the most important obtained values are ranging from 4.8 to 76 mg∙dm–3 for nitrates, the recorded values for mesophilic germs vary from 1 to 1100 CFUs∙cm–3. Agricultural activity and livestock products on the one hand and the use of fertilizers on the other hand are the main sources of physicochemical and bacteriological pollution. Contaminated wells should be treated as soon as possible to limit contamination before spreading in the deep aquifers. In the future, it will be necessary not only to assess the health risks related to the level of contamination of these waters, but also to proceed with their treatment before supplying them to consumers.

PL

Woda pitna jest potencjalnym źródłem chorób, kiedy zawiera substancje chemiczne i mikroorganizmy pochodzące z działalności człowieka. Zaopatrzenie w wodę ze źródeł podziemnych odgrywa dużą rolę w Algierii. Aby ocenić jakość wód gruntowych w regionie Sedrata, przeprowadzono analizy w 26 studniach znajdujących się w dwóch sąsiadujących ze sobą obszarach – miejskim i wiejskim. Badania czynników fizycznych i chemicznych obejmowały pomiar in situ temperatury, przewodnictwa elektrolitycznego, pH i mętności wody. Analizowano także twardość, stężenie Ca2+, Mg2+, SO4 2–, PO4 3–, Cl–, NO2 –, NO3 –, NH4 + i metali śladowych Fe2+, Mn2+, Al3+. Próbki do badań bakteriologicznych sączono i wprowadzano na pożywkę w celu określenia stężenia całkowitej ilości mikroorganizmów, bakterii z grupy coli, fekalnych streptokoków i siarkowych bakterii Clostridium. Wyniki dowodzą, że zanieczyszczenie badanych wód jest powszechne. Spośród najbardziej znaczących wyników należy wymienić stężenie azotanów w zakresie od 4,8 do 76 mg∙dm–3 i mezofilnych bakterii od 1 do 1100 jtk∙cm–3. Rolnictwo, hodowla i chów zwierząt oraz stosowanie nawozów są głównymi źródłami fizycznego, chemicznego i bakteriologicznego zanieczyszczenia wód. Skażone studnie powinny być oczyszczane tak szybko, jak to możliwe, aby zapobiec rozprzestrzenianiu się zanieczyszczeń w całym poziomie wodonośnym. W przyszłości konieczna jest ocena ryzyka zdrowotnego w związku ze skażeniem wód, ale także ich uzdatnianie przed dostarczeniem tych wód do konsumentów.

6

Zastosowania wzorców z dziedziny fizykochemii

Żeberkiewicz A.

Metrologia i Probiernictwo : biuletyn Głównego Urzędu Miar

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2016

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nr 2 (13)

63--66

PL

W artykule omówione zostały zastosowania państwowych wzorców jednostek miar i wzorców odniesienia z dziedziny fizykochemii, utrzymywanych w Głównym Urzędzie Miar.

EN

The article discusses the application of national measurement standards and reference standards in the field of physical chemistry, maintaned in the Central Office of Measures.

7

Coupled thermal and physico-chemical analysis of multicomponent oxidic melt solidification

Journeau C., Sudreau F., Ramacciotti M., Cognet G.

Zeszyty Naukowe Politechniki Świętokrzyskiej. Mechanika

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1999

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Z. 67

265--274

EN

The solidification of multicomponent melts with large solidification ranges, such as corium-concrete mixtures is studied. A methodology to estimate relevant physical properties from a thermodynamical computation is presented and applied to an experiment performer in the VULCANO facility. A thermal analysis provides the orders of magnitude of the solidification kinetics for the observed microstructures. Various phenomena in which physico-chemistry is coupled with heat transfer are described : the corium rheology, which affects convection, depends on the physico-chemistry and on the cooling rate; the density gradients which cause natural convections are strongly dependent of the solidification rate; solidification at the substratum contact creates a large thermal contact resistance which reduces sharply heat transfer at this interface.