Browsing by Author "Nehemia, Alex N."

Now showing 1 - 1 of 1
  • No Thumbnail Available
    Item
    Commonly caught fish species as potential indicators of pollution along lake nyasa (lake Malawi), Tanzania
    (Royal Society of Chemistry, 2024) Mwakalesia, Alinanuswe J.; Nehemia, Alex N.
    The chapter presented the potential use of frequently caught fish species from Lake Nyasa as bioindicators of pollution that is likely to be a result of human activities. The effects of pollution can be magnified if proper and periodic assessments of risks associated with the pollution are not properly done. The sampling and analyses of pollutants accumulated in the sediments is always difficult. However, pollution induces stresses that can be detected through the molecular analysis of the fish. Thus, parameters such as genetic diversity, haplotype diversity (h), nucleotide diversity (π), observed heterozy- gosity (Ho) and unbiased expected heterozygosity can be used as potential indicators of the effects of pollution in aquatic systems. It is also possible for a pollutant contained in the aquatic systems to accu- mulate in the body tissues of the fish. The concentration of persistent and non-biodegradable heavy metals in fish increases with eating behaviour, age or rate of exposure. Thus, the concentration of heavy metals may vary from one fish species to another depending on the factors. The heavy metals accu- mulated in the body of the fish can be used to estimate potential risks that can be caused by pollution to human health. The toxicity of a pollutant highly depends on the chemical form in which it is present in the aqueous environment. For example, organic mercury is more toxic compared to inorganic mercury due to its ability to penetrate through various blood barriers and cause neurological damage. The chem- ical characteristics of a toxicant vary from one another. Thus, to estimate potential risks associated with a certain pollutant, the analysis of a specific chemical species is required. The use of fish as a potential bioindicator can be significantly more relevant, if these aspects are borne in mind during the chemical speciation analysis.