Contribution has the study of the Impacts of industrial activities on the estuarine ecosystem of the Nunez River, Case of climatic parameters

 Corresponding author: Mamadou Bhoyi BALDÉ Copyright © 2025 Author(s) retain the copyright of this article. This article is published under the terms of the Creative Commons Attribution License 4.0. Contribution has the study of the Impacts of industrial activities on the estuarine ecosystem of the Nunez River, Case of climatic parameters Mamadou Bhoyi BALDÉ 1, *, Mamadou Dioulde SOW 2, Abdoulaye BAH 3 and Mamadou Tanou DIALLO 4 1 PhD. Sc. Environment, Researcher at the Department of Environmental Geology, Environmental Laboratory, Marine and Coastal Research Center of Guinea (CEREMAC-G) former Scientific Research Center of Conakry Rogbané (CERESCOR). 2 PhD. Sc. Environment, Researcher of the Department of Hydrobiology, Laboratory of Ichthyology of the Marine and Coastal Research Center of Guinea (CEREMAC-G) former Scientific Research Center of Conakry Rogbané (CERESCOR). 3 PhD. Sc. Environment, Department of Environmental Geology, Scientific Secretary of the Doctoral School of the Marine and Coastal Research Center of Guinea (CEREMAC-G) former Scientific Research Center of Conakry Rognonné (CERESCOR). 4 Researcher from the Department of Environmental Geology, Environmental Laboratory, of the Marine and Coastal Research Center of Guinea (CEREMAC-G) formerly the Scientific Research Center of Conakry Rogbané (CERESCOR). World Journal of Advanced Research and Reviews, 2025, 27(02), 1247-1258 Publication history: Received on 05 July 2025; revised on 12 August 2025; accepted on 14 August 2025 Article DOI: https://doi.org/10.30574/wjarr.2025.27.2.2834 Abstract Bauxite mining is a relevant source of economic and social development for countries that have this natural resource. It emerges from the findings and extensive literature reviews that this exploitation has direct impacts on estuarine ecosystems through the establishment of ports and mining industries, hence the opportunity of our study entitled " Contribution has the study of the impacts of industrial activities on the estuarine ecosystem of the Nunez River. The field observation indicates that despite the efforts made by the authorities through the competent institutions and investors, the reduction of environmental impacts caused by this mining often poses problems linked to a lack of capacity and means to deal with them, as revealed by our study carried out on the Nunez estuary. The hypothesis of our theme sufficiently proves that the negative effects of major pollutants in the Nunez River estuary due to the installation of industrial units, combined with the impacts linked to climate change affecting the locality, contribute to the dysfunction of the estuary, and consequently, to the reduction of opportunities and ecosystem services offered by the Nunez River. In addition, numerous studies have been conducted on air quality, the measurement of various physicochemical parameters (temperature, pH, electrical conductivity, salinity, turbidity, dissolved oxygen, nitrates, nitrites, suspended matter, dissolved solids and phosphate) as well as the identification and quantification of trace metal elements (Cu, Cd, Ni, Pb, and Zn) in the waters of the Nunez River. However, given the high variability of the recorded values of these physicochemical parameters, the concentrations and potential toxicity reported in the literature for these elements, it seemed necessary to study them while addressing the climatic context in which these pollution processes take place. The European Water Framework Directive has set a monitoring for metals such as cadmium, lead, nickel and mercury. However, we find it interesting to expand our research to the 5 most listed metals in environmental studies and the characteristic parameters of water in general. Thus our general objective is to study the level of pollution and its impact on the functioning of the estuarine ecosystem of the Nunez River due to the installation and operation of industrial units taking into account the evolution of the climatic characteristics of the study area. with the following specific objectives: 1) Evaluate the impact of pollution on the ecology of the Nunez estuary taking into account the evolution of climatic conditions; 2) Propose mitigation and adaptation measures in accordance with the level of pollution. ). Thus eleven sampling sites served as a study framework. These samples were analyzed at the CERE / UGANC laboratory, and at the Guinéo Allemand analysis laboratory in Landréah in Conakry. We used World Bank data for the analysis of climate variability in our study area for the period 1950-2020. The results of all these detailed analyses are presented in Chapter 3. A summary of the results, operational perspectives and possible research are also mentioned. World Journal of Advanced Research and Reviews, 2025, 27(02), 1247-1258 1248 Keywords: Industrial activities; Estuarine ecosystems; Environmental impacts; Pollution 1. Introduction ( Christophe , 2011) draws on the American experience to provide a contribution to understanding the functioning of integrated coastal and marine zone management (ICMZ) and the maritimization process, for which he notes a notable advance recorded by France. His reflection on ICMZ demonstrates the importance of this ecological zone, which is particularly sensitive to human activities. According to him, this zone contains the majority of the planet's biological diversity and more than 60% of the world's population is now living there, which represents approximately 3.8 billion individuals living in a strip of land that does not exceed 100 kilometers from the shoreline. According to this author, by extrapolating the data available in the countries that have made the calculation, it can be estimated that the number of kilometers of natural shoreline disappearing in the world due to development is on average between 5 and 10 kilometers each day. The marine zone is increasingly subject to human action every day. This very relevant general reality is similar to that of our area which is an integral part of the Guinean coastal zone. According to Christian Lévêque (2020), it was in 1960 that the environmental sensitivity of the population took off in view of human activities that have an impact on the environment. Rachel Carlson's book, "Silent Spring" (1962), denounces the consequences of the use of pesticides, in particular DDT, which has become emblematic. This position is often considered one of the founding acts of environmental thought. Burkina Faso is a country whose economy has always been fueled by the resources of agriculture as well as those of livestock, and this until 2009. Nowadays, the country is experiencing an unprecedented mining boom. The international context, but also the adoption of its new mining code in 2003 (Law No. 031-2003/AN of May 8, 2003), more favorable to private investment, are the main causes of this prowess of the country in the mining sector. Indeed, since 2009, gold has been Burkina Faso's leading export product; and this raises a lot of hope but also many concerns about the sustainable management of this resource. In such a context, the largest mine Essakane SA located in the far north of the country, can serve as a mirror to address these various questions. The interest in the context of our study is particularly focused on the impacts that mining activity could have on human and environmental health . West African coastal areas in general, and Guinean coastal areas in particular, are home to major industries, particularly in the mining, agribusiness and tourism sectors, as well as urban and coastal residences, which generate waste and pollution. Many coastal areas do not have adequate waste and wastewater treatment systems. As a result, large volumes of untreated wastewater and waste are discharged into the environment, polluting the soil and water. In Kamsar and its surroundings, wastewater discharges are largely responsible for the degradation of the coastal environmental quality. The immediate negative effect felt in the short term is the poor health of continental and marine fauna and flora. Fofana (et al, 2019) . According to Rachid A. (2011), 80% of marine pollution is attributable to human activities of land-based origin, navigation, and the introduction of invasive species (such as certain marine algae). Overexploitation of fisheries resources, degradation, fragmentation, and habitat loss are all factors responsible for the erosion of marine biodiversity. Exacerbated by climate change, this anthropization threatens to destroy the fragile balance of marine ecosystems and the biodiversity they contain. Eric D. M. ( 2019 ) teaches us that Climate change is recognized by most scientists and leaders. Far from being a simple increase in average temperatures, climate change is an alarming phenomenon. Among its most serious consequences are water shortages in certain regions, rising sea levels, changing precipitation patterns around the world, ocean acidification, and the emergence of numerous diseases. Fortunately, the timber industry and forest ecosystems are there to store greenhouse gases. However, these ecosystems may be vulnerable to climate change. This is why it is necessary to implement other strategies. For example, we should favor the most resistant species and modify practices, etc. In short, we must adapt to climate change. To mitigate it, it would be preferable to no longer resort to fossil fuels that use oil, coal, and gas. Indeed, their use not only causes the depletion of resources, but also results in significant CO2 emissions into the atmosphere, thus promoting global warming. In the face of future global climate change, the UNFCCC (United Nations Framework Convention on Climate Change ) has proposed to focus on two fundamental strategies for responding to climate change: mitigation and adaptation (UNFCCC, 2006; Niasse et al. 2004). While mitigation seeks to limit climate change by reducing greenhouse gas (GHG) emissions, adaptation aims to alleviate adverse impacts through a wide range of actions on specific systems (Füssel and Klein, 2002). F.Mara (2010) Forest management and maintaining soil quality are complementary. Sustainable forest management is essential for soils to continue producing organic matter or biomass. As a reminder, organic matter in forest soil plays a central role in the fight against climate change because it stores carbon. However, when it decomposes, this carbon is released. It World Journal of Advanced Research and Reviews, 2025, 27(02), 1247-1258 1249 can also be said that preserving soil quality is essential for preventing health problems that could affect humans. Also with a view to adapting to climate change, ecosystem biodiversity should be protected by implementing various measures. Coral reefs, rivers, streams, and mountains are threatened by climate change, according to a publication from the Secretariat of the Convention on Biological Diversity. Because of this phenomenon, many species have also been forced to change their migration patterns or seasonal activities. Among the biggest environmental challenges are those related to climate change, soil quality, and biodiversity. As for Mr. Diallo ( et al 2019) the Guinean coastline is characterized by the presence of 300 km of coastline, mangroves, marine protected areas and significant fishery biodiversity. It is the site of various socioeconomic activities, including the exploitation of fishery resources. However, these resources are threatened by the construction of numerous mineral ports. This situation risks causing serious damage to fishery biodiversity in the absence of an adequate impact assessment model to make an informed choice of environmentally friendly development scenario. Large -scale mining operations have the potential to contribute significantly to air pollution, particularly in the operational phase. US Environmental Protection Agency, 2009-title40-vol15 http://www.gpo.gov/fdsys/ . At the current stage of knowledge, the question that arises is how, in a context of climate change, industrial activities could contribute to the structural and functional modification of the estuarine ecosystem of the Nunez River. The negative effects of major pollutants in the Nunez River estuary due to the installation of industrial units, combined with the impacts of climate change affecting the locality, contribute to the dysfunction of the estuary, and consequently to the reduction of opportunities and ecosystem services offered by the Nunez River. Goals General objective To study the level of pollution and its impact on the functioning of the estuarine ecosystem of the Nunez River due to the installation and operation of industrial units, taking into account the evolution of the climatic characteristics of the study area. Specific objectives • Evaluate the impact of pollution on the ecology of the Nunez estuary, taking into account changes in climatic conditions. • Propose mitigation and adaptation measures in accordance with the level of pollution. 1.1. Presentation of the study area: The Republic of Guinea is located in the western part of the African continent . It is located between the 8th and 12th degrees of north latitude) and between the 8th and 15th degrees of west longitude. It is bordered to the north by Senegal, to the northwest by Guinea-Bissau, to the west by the Atlantic Ocean, to the south by Sierra Leone and Liberia, to the east by Ivory Coast and to the northeast by Mali. Its area is 245,857 km². Ecologically subdivided into four natural regions (Lower Guinea, Middle Guinea, Upper Guinea and Forest Guinea), it is characterized by a two-season climate: a dry season and a rainy season, the duration and distribution of which vary according to the natural regions from 3 months (in the North) to 9 months (in the Southeast). Rainfall varies from 4,000 mm (Coastal Region) to 1,300 mm (Upper Guinea); precipitation peaks everywhere in July and August. Guinea is characterized by heterogeneous soils and an abundant hydrographic network. The numerous rivers and streams that originate there water all the neighboring countries and make Guinea the water tower of the sub-region. Today, unfortunately, this water tower is threatened by the extent of the drought, which is the harmful consequence of human actions of various origins and climate change. Our study focuses on Lower Guinea or Maritime Guinea, which is home to our study area (Kamsar) located in the administrative region of Boké), this region covers all of Guinea's marine and coastal ecosystems. Maritime Guinea covers 15% of the country's total area (36,200 km 2 ) and includes a marshy coastal area behind which extends a plain rising slowly to the foot of the Foutah-Djallon hills. Its current population density is estimated at 29 inhabitants / km 2 and its population growth is estimated at 2.8%. (refer to DNS data] . World Journal of Advanced Research and Reviews, 2025, 27(02), 1247-1258 1250 Figure 1 Map of the Republic of Guinea Figure 2 Sight of the Nunez estuarine with different collecton points World Journal of Advanced Research and Reviews, 2025, 27(02), 1247-1258 1251 Table 1 Geographic coordinates of the sample collection points No. Sampling points Geographic coordinates 1 Port Nene 10407115 N / 14364304W 2 CBG GAC Terminal 10667914 N / 14607735W 3 Witness station 10636136 N / 14638576W 4 Taidy 10734779 N / 14543816W 5 Tissaly 10694131N / 14633022W 6 Dahomey 10749705 N / 14556970W 7 Kanfarandé 10826358 N / 14544165W 8 Legbane 10810252 N /14530271W 9 Diandiaya 10811442 N / 14531050W 10 Dougoula 10760490 N / 14554885W 11 Tarensa port 10734779 N / 14573818 W 1.2. Physical context The present study, which concerns the city of Kamsar and its surroundings, concerns an area with climatic, geological, geomorphological and oceanological characteristics. It therefore seems useful to us, before approaching the specific analyses, to present the general physical framework in order to realize all the natural conditions of the area which could undergo structural and functional modifications. 1.2.1. Climate The climate of our study area is that of maritime Guinea, therefore of the sub-Guinean type Maritime Guinea is characterized by a tropical and humid climate with two seasons: The dry season (mid-October to April) is characterized by hot, dry winds (the Harmattan) blowing from the east and northeast, carrying hot air and dust from the Sahara Desert to the Gulf of Guinea; and the rainy season (which lasts the rest of the year) which brings heavy monsoon rains, high humidity, and southwesterly winds. Average daily temperatures also vary only slightly throughout the year. There are no long-term climate stations in the vicinity of Kamsar or Sangarédi. Boké, located about 45 km inland, northeast of Kamsar, and 70 km southwest of Sangarédi, has long-term climate data. A summary of statistics based on data collected by the World Meteorological Organization is available upon request. Detailed historical data on weather and climate conditions are generally not available for Kamsar or Sangarédi. (ESIA of the CBG Mine Extension Project Chapter 2 Physical Environment Study , 2014 project number: 13ea0039). 1.3. Characterization of climatic parameters 1.3.1. Temperature Atmospheric temperature is the degree of specific heat of the air in a location at a given time. The temperature of the atmosphere depends on the amount of sunshine or solar radiation. ( https://www.aquaportail.com/definition-4925climat.html) 1.3.2. Data and processing methods In Sahelian Africa, major environmental and socio-economic problems are mainly linked, directly or indirectly, to soil degradation, deforestation of natural habitats, water shortages, recurring droughts, floods, poverty and lack of access to essential services. To understand these phenomena in the Nunez River estuary, we used, on the one hand, meteorological and hydrological data from the Boké Region collected by the World Bank. The analysis of these data was carried out using several methods including statistical analysis techniques (Kendall rate). World Journal of Advanced Research and Reviews, 2025, 27(02), 1247-1258 1252 1.3.3. Description of climate data The climate data series were provided by the World Bank. These provide other parameters such as minimum and maximum temperatures, relative humidity and evaporation not available from rainfall stations. The climate data analyzed correspond to daily rainfall. The periods covered by the observation series are 70 years (Guinea and Boké) and 30 years (Guinea and Boké). The analyses were carried out over the periods 1950-2020 and 1991-2020. The 1950-2020 climate normal was chosen as the reference for calculating anomalies. CCKP (https://climateknowledgeportal.worldbank.org/country/guinea) 1.3.4. Methods for processing and analyzing climate data Depending on the nature of the data, different statistical methods and tools were used for their processing and analysis. Multivariate analysis methods using regression and correlation were applied to the time series of precipitation and temperature in order to calculate rainfall indices on the one hand and to characterize the rainfall regime in time and space on the other. Definition and calculation of precipitation and temperature indices among the concerns related to climate change, whether in the Boké region or in Guinea, the possible modification of the frequency of extreme events, and not only gradual changes in the average characteristics of the climate, arouses major interest in the scientific community, given their anticipated effects on the natural and human environment. Despite their rarity, these events constitute important factors of vulnerability of populations (Houghton et al. 2001), particularly extreme precipitation events (or absence of precipitation, i.e. drought) in Guinea in general. To understand these phenomena, the use of indices development has been suggested as a relatively simple way to analyze changes in precipitation events potentially having an effect on the natural and human environment (Dubuisson and Moisselin, 2006; Gachon et al. 2005). Several international research groups have developed a standard methodology to calculate these indices, such as the ETCCDMI project (Expert Team Climate Detection Monitoring and Indices), or the European STARDEX project (STAtistical and Regional dynamical Downscaling of EXtremes for European regions). The CLIVAR CLImate VARiability and predictability group (Karl et al., 1996; Karl et al., 1999; Frich et al., ( 2002) of the WCRP (World Climate Research program) of the WMO (World Meteorological Organization) proposed a list of different indices calculated from the daily series of surface variables (precipitation and temperature). The use of these indices made it possible in our study to highlight the links between fluctuations in the intensity, frequency and duration of wet/dry sequences. From the time series of daily precipitation and atmospheric temperature of Boké and Guinea, the interannual fluctuations in average precipitation are analyzed over the period 1950-2020 using the data in the appendix: From Table E2, the moving average was calculated over the same period and graphically superimposed on the standardized interannual anomalies (Table E6). Intra-seasonal distribution and variability monthly cumulative precipitation. For analysis purposes, tables E1 and E3 containing the time series of monthly average precipitation from April to October were used to characterize the precipitation distribution pattern over the period 1991-2020 on an analysis of monthly average cumulative precipitation in order to assess the variability of their contribution compared to the climate normal In order to analyze the interannual variability of the indices and basic variables relative to the reference period of 19502020, standardized anomalies were calculated from the available data, using the following formula: 𝐴𝑗=(𝑋𝑦−𝑋𝑦 𝜎𝑦)……….(1) Where X is the variable considered Y= year 𝐴𝑗= anomaly of year j 𝑋𝑦= average of the variable in the year considered 𝑋𝑦 = average of the index (period considered, April to October) calculated over the reference period (1961 to 1990) or (1950 to 2020) 𝜎𝑦 = interannual standard deviation of the y index (April-October period) calculated over the reference period The indices are calculated for Guinea and Boké for each of the months from January to December (for each year covering the period from 1950 to 2020). B World Journal of Advanced Research and Reviews, 2025, 27(02), 1247-1258 1253 Precipitation: These are all forms of hydrometeor from atmospheric water in the form of clouds that fall to the earth's surface through precipitation (rain, snow, hail , etc.). https://www.aquaportail.com/definition-4925-climat.html Standardized Precipitation Index (SPI): The SPI is an index for measuring meteorological drought. It is a probability index based solely on precipitation. The probabilities are standardized so that an SPI of 0 indicates a median precipitation amount (relative to a 30-year average reference climatology). The index is negative for droughts, and positive for wet conditions (Mc Kee et al . 1993). The main advantages of SPI are: • It only requires monthly rainfall; • It can be compared for regions with different climates; • Normalization of the index makes it possible to determine the rarity of a drought. The use of this index is further recommended by the World Meteorological Organization. • SPI Values and Meaning: • SPI > 0: more precipitation than normal (wetter); • SPI < 0: less precipitation than normal (drier); • -0.99 < SPI < +0.99: precipitation close to normal; • SPI < - 2.0: extremely dry; • SPI > 2.0: extremely humid. http://www.drias-climat.fr/accompagnement/sections/183 2. Results, interpretations and discussions 2.1. Characterization of climatic parameters Here the climatic parameters are analyzed taking into account the climatic normal (1950-1990 or 1980-2020) which are mainly, temperature and rainfall) 2.2. Temperature Atmospheric temperature refers to the specific heat content of the air at a given location and time. The temperature of the atmosphere depends on the amount of sunshine or solar radiation. https://www.aquaportail.com/definition-4925climat.html 2.3. The precipitation Is any form of hydrometeor from atmospheric water in the form of clouds that fall to the Earth's surface by precipitation (rain, snow, hail , etc.). https://www.aquaportail.com/definition-4925-climat.html World Journal of Advanced Research and Reviews, 2025, 27(02), 1247-1258 1254 Figure 3 Seasonal cycle of average temperature and precipitation in Guinea from 1991 to 2020 Figure (3) shows the monthly climatology, or the average values for a specific month over a 30-year period. It allows us to put the seasons into context for a given location. As for the temperature curve, it starts with a minimum average of 24.06 o c in January and reaches a maximum average of 28.79 o c in April, before finally falling back to 23.88 o c in December. The coldest months are December and January (23.04 o c). The hottest month is April (28.80 o c) While for precipitation, it starts from almost 00mm in January (completely dry period) to peak at around 450 mm in August. Note that these two curves are opposite. When the temperature curve is at its highest point, it coincides with the relatively dry period (without rain) and vice versa. Historically, Guinea has experienced the most rainfall in August with an average rainfall of 438 mm and the lowest rainfall value is recorded in December (5.36 mm). As shown in Figure (4) Guinea is characterized by two seasons. A dry season that begins from December to April and a rainy season that runs from May to November. Figure 4 Seasonal cycle of minimum-mean-maximum temperature and average precipitation of Boké from 1991 to 2020 World Journal of Advanced Research and Reviews, 2025, 27(02), 1247-1258 1255 Figure 5 The seasonal evolution of temperature (minimum, average and maximum) and average rainfall in Boké for the period 1991-2020 (29 years) The climatic normal of precipitation indices and temperature over the period 1991-2020 from January to December for the Boké region. Regarding the minimum temperature curve, it starts from 18.85 o c for January, then 24.57 o c in May as the highest then drops to 23.05 o c in July, to rise to 24.46 o c in August, to finally gradually drop to 18.41 o c in December as the lowest for these periods. As for the average temperature curve and that of the maximum temperature, they have practically the same shape, only with the difference of the minimum, they peak in April (36.91 o c / 3040 o c) to drop in August (29.50 o c / 26.95 o c) then rise again; the lowest remains that of December 25.81 o c and then that of April 30.40 o c as being the highest. While for precipitation (blue bars) it starts from almost 0.08mm in January (completely dry period) to peak at 581.43mm in August. Note that these three temperature curves and the precipitation bars clearly indicate the dry and cool periods of the years identified . The observed historical climate data are generated by thousands of weather stations around the world, which collect temperature and precipitation data continuously. These observed data present the temperatures (minimum, average and maximum) and precipitation. This annual and seasonal climate information; December-January-February, March-April-May, June-July-August and SeptemberOctober-November are available and can be consulted. These observational data come from the Climatic Research Unit (CRU) at the University of East Anglia. Figure (6) shows the standardized temperature anomaly for the Boké region for the period 1950-2020. It starts from - 5.76 in 1950, rises sharply to -2.14 in 1953, and then falls back to -5.18 in 1954. Note that this anomaly evolves in a sawtooth pattern irregular below normal to reach -0.30 in 1990. Although it remains negative (cool periods) it has only evolved in the positive direction (increasingly hot periods, with the announcement of drought). From 1998 (0.97) it has evolved almost in the positive direction, increasingly higher until reaching 2.33 in 2020, thus reflecting the current state of the climate, characterized by this remarkable change in the variation recorded in these climatic parameters.