Dataset Information

Trace Elements in Crustaceans, Mollusks and Fish in the Kenyan Part of Lake Victoria: Bioaccumulation, Bioindication and Health Risk Analysis.

ABSTRACT: This is the first comprehensive report on the accumulation of Cr, Ni, As, and Ag in the fish species Nile tilapia Oreochromis niloticus and Nile perch Lates niloticus from Lake Victoria, complemented with recent data on Cu, Zn, Cd, and Pb. This also is the first report on Cr, Ni, As, and Ag levels in invertebrates: the shrimp Caridina nilotica, gastropod Pila ovata, and bivalve Mutela bourguignati. The study was conducted at five sites in the Kenyan part of Lake Victoria: four sites in Winam Gulf influenced by various anthropogenic pressures, including a site near Kisumu City, and one in the main lake, with lesser direct anthropogenic influence. Apart from Cu and Ag, which were highest in O. niloticus liver, the invertebrates had higher levels of trace elements than fish. Contamination of the gulf with trace elements was best mirrored by the invertebrates, whose mobility is limited; they accumulated Cr, Cd, Ag, and Pb corresponding to the levels in the surface sediment. The accumulation of trace elements in fish species and their bioindicative potential corresponded to their habitats and feeding behaviour. The tissue contents of most trace elements were higher in the inshore-dwelling, omnivorous O. niloticus compared to the pelagic, piscivorous L. niloticus. Cu (465?±?689 mg/kg dw) and Ag (3.45?±?1.49 mg/kg dw) in the liver of O. niloticus were up to 10 and 119 times higher than in L. niloticus, respectively. Oreochromis niloticus therefore has bioindicative potential for Cu and Ag contamination. Both the invertebrates and fish showed positive correlations between Cu and Ag concentrations, indicating similar source and/or uptake route. The target hazard quotients (THQ) show that there is no human health risk associated with the consumption of these fish. However, the levels of Zn, Cd, and Pb in P. ovata surpassed maximum food safety limits and are hence potentially unsafe for human consumption.

SUBMITTER: Outa JO

PROVIDER: S-EPMC7136317 | biostudies-literature | 2020 May

REPOSITORIES: biostudies-literature

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Trace Elements in Crustaceans, Mollusks and Fish in the Kenyan Part of Lake Victoria: Bioaccumulation, Bioindication and Health Risk Analysis.

Outa James Omondi JO Kowenje Chrispin O CO Avenant-Oldewage Annemariè A Jirsa Franz F

Archives of environmental contamination and toxicology 20200204 4

This is the first comprehensive report on the accumulation of Cr, Ni, As, and Ag in the fish species Nile tilapia Oreochromis niloticus and Nile perch Lates niloticus from Lake Victoria, complemented with recent data on Cu, Zn, Cd, and Pb. This also is the first report on Cr, Ni, As, and Ag levels in invertebrates: the shrimp Caridina nilotica, gastropod Pila ovata, and bivalve Mutela bourguignati. The study was conducted at five sites in the Kenyan part of Lake Victoria: four sites in Winam Gul ...[more]

PMID: 32020255

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Project description:INTRODUCTION:Global efforts to end HIV by 2030 focus on reducing and eventually eliminating new infections in priority populations. Identifying these populations and characterizing their vulnerability factors helps in guiding investment of scarce HIV prevention resources to achieve maximum impact. We sought to establish HIV prevalence, spatial distribution and risk factors for HIV infection in the Kenyan fishing communities of Lake Victoria. METHODS:We conducted a cross-sectional survey of 2637 people from all the 308 fish-landing beaches on the Kenyan shore of Lake Victoria. The number of participants enrolled at each beach were weighted based on the size of the beach, determined by the number of functional registered boats. We used simple random sampling to select those to be approached for study participation. Consenting participants were privately interviewed about their socio-economic and demographic characteristics and sexual behavior, and were invited for HIV test using the Kenya rapid HIV testing protocol. We used descriptive statistics and multivariate logistic and linear regression for analysis. RESULTS:We found high HIV prevalence of 32% with significant differences between men (29%) and women (38%). Among men, having an HIV negative sexual partner, being circumcised, increasing number of condom protected sex acts in the preceding month, being younger and being a resident of Homa Bay, Kisumu, Siaya and Busia counties compared to Migori County reduced the risk of HIV infection. For women, being married, having more children with the current spouse, having an HIV negative sexual partner and being a resident of Busia compared to Migori County reduced the risk of HIV infection. We also found that longer distance from the beaches to the nearest public health facilities was associated with increasing cumulative HIV prevalence at the beaches. CONCLUSION:Fishing communities have high HIV prevalence and may greatly benefit from interventions such as wider ART coverage, couple HIV risk reduction counseling, PrEP use for HIV negative partner at substantial continuous risk, alongside other HIV prevention services that the Kenyan government is currently rolling out. This will additionally require adequate plans to synchronize the provision of these services with the population's routine schedules for all these options to be reasonably accessible to them.

Project description:BackgroundEfficient communication requires that signals are well transmitted and perceived in a given environment. Natural selection therefore drives the evolution of different signals in different environments. In addition, environmental heterogeneity at small spatial or temporal scales may favour phenotypic plasticity in signaling traits, as plasticity may allow rapid adjustment of signal expression to optimize transmission. In this study, we explore signal plasticity in the nuptial coloration of Lake Victoria cichlids, Pundamilia pundamilia and Pundamilia nyererei. These two species differ in male coloration, which mediates species-assortative mating. They occur in adjacent depth ranges with different light environments. Given the close proximity of their habitats, overlapping at some locations, plasticity in male coloration could contribute to male reproductive success but interfere with reproductive isolation.MethodsWe reared P. pundamilia, P. nyererei, and their hybrids under light conditions mimicking the two depth ranges in Lake Victoria. From photographs, we quantified the nuptial coloration of males, spanning the entire visible spectrum. In experiment 1, we examined developmental colour plasticity by comparing sibling males reared in each light condition. In experiment 2, we assessed colour plasticity in adulthood, by switching adult males between conditions and tracking coloration for 100 days.ResultsWe found that nuptial colour in Pundamilia did respond plastically to our light manipulations, but only in a limited hue range. Fish that were reared in light conditions mimicking the deeper habitat were significantly greener than those in conditions mimicking shallow waters. The species-specific nuptial colours (blue and red) did not change. When moved to the opposing light condition as adults, males did not change colour.DiscussionOur results show that species-specific nuptial colours, which are subject to strong divergent selection by female choice, are not plastic. We do find plasticity in green coloration, a response that may contribute to visual conspicuousness in darker, red-shifted light environments. These results suggest that light-environment-induced plasticity in male nuptial coloration in P. pundamilia and P. nyererei is limited and does not interfere with reproductive isolation.

Dataset Information

Trace Elements in Crustaceans, Mollusks and Fish in the Kenyan Part of Lake Victoria: Bioaccumulation, Bioindication and Health Risk Analysis.

Publications

Trace Elements in Crustaceans, Mollusks and Fish in the Kenyan Part of Lake Victoria: Bioaccumulation, Bioindication and Health Risk Analysis.

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