Browsing by Author "Mwakalapa, Eliezer B."

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    Accumulation and Distribution of Mercury in Agricultural Soils, Food Crops and Associated Health Risks: A Case Study of Shenda Gold Mine-Geita Tanzania
    (ELSEVIER, 2023) Sanga, Tumikia R.; Maseka, Kenneth K.; Ponraj, Mohanadoss; Tungaraza, Clavery; Mng’ong’o, Marco E.; Mwakalapa, Eliezer B.
    Contamination of the environment and foodstuffby potentially harmful elements (PHEs) has become a serious concern due to the associated health risks to the population. In the present study total mercury (Hg) levels in soil and food crops from farms around Shenda gold mine in Geita Tanzania was determined by Cold Vapor Atomic Fluorescence Spectrometry (CVAFS). Generally, it was found that there was significant different of Hg content in soil and food crops ( P < 0.05) among studied sites. The total Hg concentrations determined were in the ranges of; soils (0.003-0.1220 mg/kg), rice (0.0752-0.1587 mg/kg) and vegetables (0.0556-0.3439 mg/kg) all measurement were based on dry weight basis (dw). Total Hg levels in soil were compared with the maximum allowable concentration (MAC) set by Tanzania Bureau of Standards (TBS) and United Kingdom (UK). All studied soil samples were within acceptable range (2 mg/kg) set by TBS and UK (1 mg/kg). Total Hg contents in food crop samples were compared with Chinese MAC of Hg (0. 01 and 0.02 mg/kg for leafy vegetables and grains respectively in a fresh weight basis). It was observed that Hg contents in potato leaves, pumpkin leaves and Chinese cabbage were within the MAC while Hg levels in cassava leaves and rice grains exceeded the MAC. In addition, Hg associated health risks to consumers of contaminated foods for residents around Shenda gold mine were estimated. The estimated weekly intake (EWI) of Hg due to consumption of rice grain was above the provisional tolerable weekly intake (PTWI) set by FAO/WHO (1.6 mg/kg bw/week) while the EWI due to consumption of leafy vegetables were below the PTWI. Target hazard quotient (THQ) was < 1 due to consumption of vegetables while THQ value for rice was > 1, indicating a potential non-carcinogenic risk to adult population from the consumption of rice grain from the study area. Therefore, people living near Shenda goldmine might be potential victim of Hg accumulation in soil and food crops, thus necessary management options have to be in place
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    Impacts of Emerging Infrastructure Development on Wildlife Species and Habitats in Tanzania
    (Journal of Wildlife and Biodiversity, 2024) Ojija, Fredrick; Swai, Everlyn E.; Mwakalapa, Eliezer B.; Mbije, Nsajigwa E.J.
    The loss of wildlife species due to habitat deterioration and pollution represents a major threat to biodiversity conservation. This is compounded by the rapid development of infrastructure i.e., expansion of roads, railways, harbours, construction of industries, human settlements and agricultural infrastructure. A few studies have explored the significant effects of emerging infrastructure development on wildlife species and habitats particularly in developing countries like Tanzania. We reviewed 58 research articles and reports, to highlight the significant impacts of emerging infrastructure on both aquatic and terrestrial species and habitats in Tanzania. We show that despite the role it plays in the development, the infrastructure contributes significantly to the loss of wildlife species. For instance, habitat loss, edge effects, population isolation, road mortality, and increased human access are among the effects of highways across the Serengeti, Mikumi, and Katavi National Parks in Tanzania. Effects on the health of aquatic species, pollution and loss of habitat have been pointed out as impacts due to the construction of hotels and industries upstream and along the coasts, expansion of harbours and agricultural activities. Environment effects i.e., reduction of forest, ecosystem services, and riverine habitat, and loss of species are anticipated due to the construction of Stiegler's Gorge Hydroelectric Dam, across the Rufiji River in eastern Tanzania. Though infrastructure development undoubtedly offers opportunities to boost economic growth and reduce poverty in developing nations, it should be planned to have the least possible negative effects on biodiversity. Well–planned infrastructure development could lessen human pressure on wildlife species and habitats. This paper would be useful to policymakers and politicians in developing nations to avoid the implementation of infrastructure development in biodiversity– rich or protected areas as their decision may jeopardize the integrity of wildlife species and future generations.
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    Mercury in Air and Soil on an Urban-Rural Transect in East Africa
    (Royal Society of Chemistry, 2022) Nipen, Maja; Jørgensen, Susanne J.; Bohlin-Nizzetto, P.; Borg˚a, Katrine; Breivik, Knut; Mmochi, Aviti J.; Mwakalapa, Eliezer B.; Quant, M. I.; Schlabach, Martin; Vogt, Rolf D.; Wania, Frank
    There are large knowledge gaps concerning concentrations, sources, emissions, and spatial trends of mercury (Hg) in the atmosphere in developing regions of the Southern Hemisphere, particularly in urban areas. Filling these gaps is a prerequisite for assessing the effectiveness of international regulation and for enabling a better understanding of the global transport of Hg in the environment. Here we use a passive sampling technique to study the spatial distribution of gaseous elemental Hg (Hg(0), GEM) and assess emission sources in and around Dar es Salaam, Tanzania's largest city. Included in the study were the city's main municipal waste dumpsite and an e-waste processing facility as potential sources of GEM. To complement the GEM data and for a better overview of the Hg contamination status of Dar es Salaam, soil samples were collected from the same locations where passive air samplers were deployed and analysed for total Hg. Overall, GEM concentrations ranged between <0.86 and 5.34 ng m 3 , indicating significant local sources within the urban area. The municipal waste dumpsite and e-waste site had GEM concentrations elevated above the background, at 2.41 and 1.77 ng m 3 , respectively. Hg concentrations in soil in the region (range 0.0067 to 0.098 mg kg 1 ) were low compared to those of other urban areas and were not correlated with atmospheric GEM concentrations. This study demonstrates that GEM is a significant environmental issue in the urban region of Dar es Salaam. Further studies from urban areas in the Global South are needed to better identify sources of GEM.
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    Persistent Organic Pollutants (Pops) And Per- and Polyfluoroalkyl Substances (Pfass) in Liver from Wild and Farmed Tilapia (Oreochromis Niloticus) from Lake Kariba, Zambia: Levels and Geographic Trends and Considerations in Relation to Environmental Quality Standards (Eqss)
    (ELSEVIER, 2023) Simukoko, Chalumba K.; Mwakalapa, Eliezer B.; Muzandu, Kaampwe; Mutoloki, Stephen; Evensen, Øystein; Ræder, Erik M.; Müller, Mette B.; Polder, Anuschka; Lyche, Jan L.
    The current study was carried out to investigate a wide variety of persistent organic pollutants (POPs) in wild and farmed tilapia (Oreochromis niloticus) in Lake Kariba, Zambia, and assess levels of POPs in relation to Environ- mental Quality Standards (EQSs). Concentrations of organochlorine pesticides (OCPs), polychlorinated biphenyls (PCBs), polybrominated diphenyls (PBDEs), and perfluoroalkyl substances (PFASs) were determined in liver samples of tilapia. PFASs compounds PFOS, PFDA and PFNA were only detected in wild fish, with the highest median PFOS levels in site 1 (0.66 ng/g ww). Concentrations of POPs were in general highest in wild tilapia. The highest median ∑DDTs (93 and 81 ng/g lw) were found in wild tilapia from sites 1 and 2, respectively 165 km and 100 km west of the fish farms. Lower DDE/DDT ratios in sites 1 and 3 may indicate relatively recent exposure to DDT. The highest median of ∑17PCBs (3.2 ng/g lw) and ∑10PBDEs (8.1 ng/g lw) were found in wild tilapia from sites 1 and 2, respectively. The dominating PCB congeners were PCB-118, -138, 153 and 180 and for PBDEs, BDE-47, -154, and 209. In 78% of wild fish and 8% of farmed fish ∑6PBDE concentrations were above EQSbiota limits set by the EU. This warrants further studies.
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    Seasonal Rainfall Affects Occurrence of Organohalogen Contaminants in Tropical Marine Fishes and Prawns from Zanzibar, Tanzania
    (ELSEVIER, 2021) Haarra, Ane; Mwakalapa, Eliezer B.; Mmochi, Aviti J.; Lyche, Jan L; Ruuse, Anders; Othman, Halima; Larsen, Martin M.; Borgå, Katrine
    Seasonal differences in precipitation may affect contaminant dynamics in tropical coastal regions due to terrestrial runoff of contaminants to the marine environment after the rainy seasons. To assess the effect of seasonal rainfall on occurrence of organohalogen contaminants in a coastal ecosystem, marine fishes and prawns were collected off the coast of Zanzibar, Tanzania in January and August 2018, representing pre- and post-rainy season, respectively. Samples were analyzed for organochlorine pesticides (OCPs), polychlorinated biphenyls(PCBs),brominatedflameretardants(BFRs),includingpolybrominateddiphenyl ethers (PBDEs) and emerging BFRs, as well as the dietary descriptors stable isotopes of carbon (δ13C) and nitrogen (δ15N). Across all species and seasons, mean contaminant concentrations ranged frombelowlimitofdetection(LOD)to129ng/glipidweight(lw)ΣPCBs;5.6–336ng/glwΣOCPs;and increaseinlowerhalogenated,moremobilePCBandPBDEcongeners,comparedtohigherhalogenatedcon geners with lower mobility, between January and Augustaligns with a signal and effect of terrestrial runoff followingtherainyseason
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    Spatial Trends of Chlorinated Paraffins and Dechloranes in Air and Soil in A Tropical Urban, Suburban, and Rural Environment
    (ELSEVIER, 2021) Nipen, Maja; Vogt, Rolf D.; Bohlin-Nizzetto, Pernilla; Borgå, Katrine; Mwakalapa, Eliezer B.; Borgen, Anders R.; Jørgensen, Susanne J.; Ntapanta, Samwel Moses; Mmochi, Aviti J.; Schlabach, Martin; Breivik, Knut
    There are large knowledge gaps concerning environmental levels and fate of many organic pollutants, particu- larly for chemicals of emerging concern in tropical regions of the Global South. In this study, we investigated the levels of chlorinated paraffins (CPs) and dechloranes in air and soil in rural, suburban, and urban regions in and around Dar es Salaam, Tanzania. Samples were also collected near the city’s main municipal waste dumpsite and an electronic waste (e-waste) handling facility. In passive air samples, short chain CPs (SCCPs) dominated, with an average estimated concentration of 22 ng/m3, while medium chain CPs (MCCPs) had an average estimated concentration of 9 ng/m3. The average estimated air concentration of ∑dechloranes (Dechlorane Plus (DP) + Dechlorane 602 + Dechlorane 603) was three to four orders of magnitudes lower, 2 pg/m3. In soil samples, MCCPs dominated with an average concentration of 640 ng/g dw, followed by SCCPs with an average con- centration of 330 ng/g dw, and ∑dechloranes with an average concentration of 0.9 ng/g dw. In both air and soil, DP was the dominating dechlorane compound. Urban pulses were observed for CPs and dechloranes in air and soil. CPs were in addition found in elevated levels at the municipal waste dumpsite and the e-waste handling facility, while DPs were found in elevated levels at the e-waste handling facility. This suggests that waste handling sites represent important emission sources for these pollutants. Investigations into seasonal trends and environmental fate of CPs and dechloranes showed that monsoonal rain patterns play a major role in governing air concentrations and mobility, particularly for the less volatile MCCPs and dechloranes. This study is the first to report levels of CPs in air from sub-Saharan Africa, and DP, Dechlorane 602, and Dechlorane 603 in soil from sub-Saharan Africa.