Environmental and natural resources management in the South

published in: 2019 - 2018 - 2017 - 2016


Numidian clay for ceramic tiles

Moussi B, Hajjaji W, Hachani M, Hatira N, Labrincha JA, Yans J, Jamoussi F. 2020. Numidian clay deposits as raw material for ceramics tile manufacturing. Journal of African Earth Sciences 164:103775. DOI: 10.1016/j.jafrearsci.2020.103775.

Tunisia has a growing industry of ceramic tiles. Several clays collected in the Numidian Flysch Formation (Upper Oligocene) at Tabarka, and Sejnane (Northern part of Tunisia) were tested for their potential use in ceramic manufacturing to provide a database that could be used by investors. The mineralogy composition of raw clays is dominated by kaolinite and illite and shows relatively high quartz content for the two sites of Tabarka and Sejnane. Chemical analyses highlight a significant richness in SiO2 which can be explained by the presence of clays and silica sand. Technological tests confirm the aptitude of these clays to be used in the manufacture of ceramic tiles on an industrial scale.

Fish production in Benin

Pèlèbè ROE, Imorou Toko I, Ouattara IN, Attakpa EY, Montchowui EH, Kestemont P. 2019. Fish production in cages and pens in the northern Benin water reservoirs. Livestock Research for Rural Development 31. http://www.lrrd.org/lrrd31/9/peleb31148.html

This study aims at assessing the production of Clarias gariepinus and Oreochromis niloticus reared for 120 days in cages and pens installed in the Batran water reservoir in the cotton basin and Songhaï water reservoir outside the cotton basin in northern Benin. For C. gariepinus, the final biomass and the production values are significantly higher in Batran-caged fish while the lowest values are obtained with the same infrastructure in Songhaï. Differences are significant between the two infrastructures only in Batran. With regard to O. niloticus, values obtained for these two parameters are about twice as high in Songhaï compared to Batran in both cages and pens. They are similar between the two infrastructures in each water reservoir. However, cages that do not promote fish contact with aquatic sediment would be more appropriate to avoid the health risks associated with agricultural pesticides in the water reservoir located at the cotton basin.

Deadly effect of insecticides on fish

Guedegba NL, Toko II, Agbohessi PT, Zoumenou B, Douny C, Mandiki SNM, Schiffers B, Scippo M-L, Kestemont P. 2019. Comparative acute toxicity of two phytosanitary molecules, lambda-cyhalothrin and acetamiprid, on Nile Tilapia (Oreochromis Niloticus) juveniles. Journal of Environmental Science and Health, Part B 54:580–589. DOI: 10.1080/03601234.2019.1616986.

This study compares the toxicity of two active ingredients for fish, a pyrethroid and a neonicotinoid, that are components of a commercial insecticide (Acer 35 EC) used in cotton crop in many West African countries. For 96 hours, the juveniles of Nile Tilapia (Oreochromis niloticus) were exposed to increasing concentrations of active ingredients or a mixture similar to Acer 35 EC. During the experiments, the behavioural responses (loss of balance, colour change, hyperactivity, etc.) that usually precede death were observed in the exposed fish. Fish mortality and lethal concentrations of each chemical were determined. All insecticides had profound impacts on Nile tilapia behaviour which confirm the neurotoxicity of each single active compound as well as of their mixture.

Reproductive biology of fish

Osombause JS, Mandiki SNM, Ulyel J-P, Micha J-C, Kestemont P. 2019. Ovarian activity and plasma sex steroid levels of Distichodus antonii in relation to environmental conditions in the upper basin of the Congo River. African Journal of Aquatic Science 0:1–10. DOI: 10.2989/16085914.2018.1555511.

 Distichodus antonii is an endemic fish species of the Congo River basin. Its wild populations are threatened due to overfishing. Understanding its reproductive biology helps in conservation and management efforts for the species. Ovarian activity and levels of steroid profiles in wild populations were investigated with respect to temperature and rainfall. These were synchronised in two annual reproductive seasons that correspond to the long (September and October) and short (May) rainy season.

Pesticides & Mekong aquaculture

Nguyen QT, Douny C, Tran MP, Brose F, Nguyen PT, Huong DTT, Kestemont P, Scippo M-L. 2019. Screening of quinalphos, trifluralin and dichlorvos residues in fresh water of aquaculture systems in Mekong Delta, Vietnam. Aquaculture Research 50:247–255. DOI: 10.1111/are.13890.

Pesticides are often used in rice farms in Vietnam, which risk to impact on integrated and alternative productions (rice in combination with shrimp or fish). This study developed and validated a method using gas chromatography & mass spectrometry to determine pesticide residues in water samples. One pesticide could be detected in rice field systems. Its concentration could be high in fish. The other two pesticides tested are banned and could not be found in the samples.

Insecticide & Cotton in Benin

Zoumenou BGYM, Aïna MP, Imorou Toko I, Igout A, Douny C, Brose F, Schiffers B, Gouda I, Chabi Sika K, Kestemont P, Scippo M-L. 2018. Occurrence of Acetamiprid Residues in Water Reservoirs in the Cotton Basin of Northern Benin. Bulletin of Environmental Contamination and Toxicology 102:7–12. DOI: 10.1007/s00128-018-2476-4.

Insecticides, such as Acetamiprid, a neonicotinoid, are frequently used in Benin to protect cotton crops. It is therefore expected that water reservoirs close to cotton fields are contaminated with acetamiprid residues via drift, runoff, leaching or drainage. The authors developed an Ultra performance liquid chromatography (UPLC)–UV method to determine acetamiprid residues in water samples. The levels found do not represent a risk for human consumption of this water nor for aquatic species. However, acetamiprid is often used in combination with other pesticides which could be more harmful.


Euphorbia as natural antioxidant

Bach LT, Dung LT, Tuan NT, Phuong NT, Kestemont P, Quetin-Leclercq J, Hue BTB. 2018. Antioxidant activity against hydrogen peroxide-induced cytotoxicity of Euphorbia hirta L. AIP Conference Proceedings 2049:030018. DOI: 10.1063/1.5082519.

Euphorbia hirta is an important plant in traditional medicine in tropical regions, especially used to treat asthma and diarrhoea. This study aimed to investigate the antioxidant capacities of plant extractions and some isolated compounds from E. hirta. Results showed that the plant can serve as natural antioxidative. Its further pharmacological potential should be tested to treat oxidative stress which may be related to neurodegenerative diseases.

Pesticides & Benin cotton fields

Gouda A-I, Imorou Toko I, Salami S-D, Richert M, Scippo M-L, Kestemont P, Schiffers B. 2018. Plant protection practices and pesticide exposure levels of Northern Benin cotton producers. Cahiers Agricultures 27. DOI: 10.1051/cagri/2018038.

The level to which cotton producers are exposed to pesticides is alarming. Since the majority never received any education nor instructions of use, 75% apply higher amounts than recommended and 80% do not protect themselves during mixing, loading and spraying. Empty pesticide containers are often left in cotton fields or even worse, used for domestic purposes.

Pikeperch production in the Caspian Sea

Falahatkar, B, Efatpanah, I, & Kestemont, P 2018, ‘Pikeperch Sander lucioperca production in the south part of the Caspian Sea: technical notes’, Aquaculture International, vol. 26, no.1, pp. 391–401, DOI: 10.1007/s10499-017-0222-2

Pikeperch (Sander lucioperca) is a popular food fish in the Caspian Sea basin. However, due to over-fishing in the early 20th century and destruction of natural spawning areas, wild populations have completely collapsed. From 1989, Iranian Fisheries Organization developed the artificial propagation and rearing activities for the rehabilitation of natural populations. This publication summarizes the developments concerning reproduction, stock rehabilitation, on-growing etc. in Iran.

Richelle, L, Visser, M, Bock, L, Walpole, P, Mialhe, F, Colinet, G & Dendoncker, N 2018, 'Looking for a dialogue between farmers and scientific soil knowledge: Learnings from an ethno-geomorphopedological study in a Philippine’s upland village' Agroecology and Sustainable Food Systems, vol 42, no. 1, pp. 2-27. DOI: 10.1080/21683565.2017.1322661

Thinh NQ, Phu TM, Douny C, Phuong NT, Huong DTT, Kestemont P, Scippo M-L. 2018. Bioconcentration and half-life of quinalphos pesticide in rice-fish integration system in the Mekong Delta, Vietnam. Journal of Environmental Science and Health, Part B 53:35–41. DOI: 10.1080/03601234.2017.1371551.


Pezzulo, C, Hornby, GM, Sorichetta, A, Gaughan, AE, Linard, C, Bird, TJ, Kerr, D, Lloyd, CT & Tatem, AJ 2017, 'Sub-national mapping of population pyramids and dependency ratios in Africa and Asia' Scientific Data, vol 4, 170089. DOI: 10.1038/sdata.2017.89

Schmitz, M, Baekelandt, S, Tran Thi, LK, Mandiki, R, Douxfils, J, Nguyen, TQ, Do Thi Thanh, H & Kestemont, P 2017, 'Osmoregulatory and immunological status of the pond-raised striped catfish (Pangasianodon hypophthalmus S.) as affected by seasonal runoff and salinity changes in the Mekong Delta, Vietnam' Fish Physiology and Biochemistry, vol 43, no. 1, pp. 39-49. DOI: 10.1007/s10695-016-0266-7

Schmitz, M, Ziv, T, Admon, A, Baekelandt, S, Mandiki, SNM, L'Hoir, M & Kestemont, P 2017, 'Salinity stress, enhancing basal and induced immune responses in striped catfish Pangasianodon hypophthalmus (Sauvage)' Journal of Proteomics, vol 167, pp. 12-24. DOI: 10.1016/j.jprot.2017.08.005


Bich Hang, BT, Nguyen, PT & Kestemont, P 2016, 'Oral administration of Escherichia coli lipopolysaccharide enhances the immune system of striped catfish, Pangasianodon hypophthalmus (Sauvage)' Aquaculture Research, vol 47, no. 4, pp. 1299-1308. DOI: 10.1111/are.12589