Browsing by Author "Skaare, J. U."

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Brominated flame retardants (BFRs) in breast milk and associated health risks to nursing infants in Northern Tanzania
(Elsevier, 2015-12-23) Müller, M. B.; Polder, A.; Brynildsrud, O. B.; Lie, E.; Løken, K. B.; Manyilizu, W. B.; Mdegela, R. H.; Mokiti, F.; Murtadha, M.; Nonga, H. E.; Skaare, J. U.; Lyche, J. L.
Themain aim of this studywas to assess brominated flame retardants (BFRs) in breastmilk in the Northern parts of Tanzania. Ninety-five colostrum samples from healthy, primiparous mothers at Mount Meru Regional Referral Hospital (MMRRH), Arusha Tanzania, were analyzed for polybrominated diphenyl ethers (PBDEs), hexabromocyclododecane (HBCD), 1,2-bis(2,4,6-tribromophenoxy) ethane (BTBPE), hexabromobenzene (HBB), (2,3-dibromopropyl) (2,4,6-tribromophenyl) ether (DPTE), pentabromoethylbenzene (PBEB) and 2,3,4,5,6- pentabromotoluene (PBT). The Ʃ7PBDE (BDE 28, 47, 99, 100, 153, 154, 183) ranged from below level of detection (bLOD) to 785 ng/g lipid weight (lw). BDE 47, 99, 100 and 153 were the dominating congeners, suggesting recent and ongoing exposure to banned, commercial PentaBDE mixture. Amultiple linear regressionmodel revealed that mothers eating clay soil/Pemba during pregnancy had significantly higher levels of BDE 47, 99, 100 and 153 in their breast milk than mothers who did not eat clay soil/Pemba. Infant birth weight and birth length were significantly correlated with the levels of BDE 47, 99, 100 and 153. The estimated daily intake (ng/kg body weight/day) of BDE 47 and 99 exceeded the US EPA Reference doses (RfD) in four and eight mothers, respectively, suggesting a potential health risk to the nursing infants.
Cyanobacteria and cyanobacterial toxins in the alkaline-saline Lakes Natron and Momela, Tanzania
(African Journal Online, 2016-12-05) Nonga, H. E.; Mdegela, R. H.; Sandvik, M.; Lie, E.; Miles, C. O.; Skaare, J. U.
Physicochemical parameters, phytoplankton communities, microcystin (MC) concentrations and potential MC-producing cyanobacteria were investigated in Lakes Natron and Momela, Tanzania. In Lake Big Momela, concentrations of soluble reactive phosphorus, nitrate and ammonia were 7.1, 2.6 and 0.9 μg/L, respectively, while dissolved oxygen, salinity, conductivity and pH were 9.4 mg/L, 19‰, 30 mS/cm and 9.7, respectively. The concentrations of soluble reactive phosphorus, nitrate and ammonia in Lake Natron were 129.4, 8.1 and 58 μg/L, respectively, while dissolved oxygen, conductivity and pH were 8 mg/L, 52 mS/cm and 9.5 respectively. The phytoplankton communities in both lakes were dominated by cyanobacteria, particularly Arthrospira fusiformis. Navicula and Nitzschia diatoms, and Chlorella, Chlorococcum and Scenedesmus green algae were common in Lakes Momela and Natron. Liquid chromatography–mass spectrometry (LC-MS) analysis phytoplankton detected four microcystin variants namely MC-RR, -YR, -LR and -RY. The total MC concentrations in Lake Natron were 0.1–4.5 μg/mL of phytoplankton scum and in Lake Momela were below quantifiable levels. Polymerase chain reaction analysis of phytoplankton revealed presence of Microcystis and the Microcystis mcyB gene in some samples. Finding of potential MC-producing cyanobacteria and MCs in study lakes poses a health risk to Lesser Flamingo which feed on cyanobacteria.
Dioxins, PCBs, chlorinated pesticides and brominated flame retardants in free-range chicken eggs from peri-urban areas in Arusha, Tanzania: Levels and implications for human health
(Elsevier, 2016-02-03) Polder, A.; Müller, M. B.; Brynildsrud, O.B.; de Boer, J.; Hamers, T.; Kamstra, J. H.; Lie, E.; Mdegela, R. H.; Moberg, H.; Nonga, H. E.; Sandvik, M.; Skaare, J. U.; Lyche, J. L.
The environment in the northern part of Tanzania is influenced by rapid population growth, and increased urbanization. Urban agriculture is common and of economic value for low income families. In Arusha, many households sell eggs from free-ranging backyard chicken. In 2011, 159 eggs from different households in five different locations in Arusha were collected, homogenized, pooled into 28 composite samples and analyzed for a wide selection of POPs. Levels of POPs varied widely within and between the locations. The levels of dieldrin and ΣDDT ranged between 2 and 98,791 and 2 and 324 ng/g lipid weight (lw), respectively. EUMRLs of 0.02 mg/kg dieldrin for eggs were exceeded in 4/28 samples. PCBs, HCHs, chlordanes, toxaphenes and endosulfanes were found at lower frequency and levels. Brominated flame retardants (BFRs), e.g polybrominated diphenylethers (PBDEs), hexabromocyclododecane (HBCD) and 1,2-bis(2,4,6-tribromphenoxy)ethane (BTBPE) were present in 100%, 60% and 46% of the composite samples, respectively. Octa-and deca-BDEs were the dominating PBDEs and BDE 209 levels ranged between bLOQ (limit of quantification) – 312 ng/g lw. Dioxins were measured using the DRLUC bio-assay and found in levels of bLOQ – 20 pg bio-TEQs/g lw. Four samples (13%) exceeded the maximum level of 5 pg/g total WHO-TEQs for hen eggs set by the Commission Regulation (EU) No 1259/2011. The daily/weekly intake was calculated and risk was characterized for all compounds comparing with available toxicity reference values (TRVs) such as the provisional tolerable intake (PTDI) or Reference Doses (RfDs). In one sample dieldrin exceeded the PTDI (100 ng/kg bw/day). Correlation was found between bio-TEQs and lipid adjusted levels of ΣPBDEs, suggesting similar sources. Open fires in backyards may be one of the sources for contamination of eggs with BFRs and dioxins.
Influence of 17a-ethynylestradiol on CYP1A, GST and biliary FACs responses in male African sharptooth catfish (Clarias gariepinus) exposed to waterborne Benzo[a]Pyrene
(Springer Science+Business Media,, 2006-11-01) Mdegela, R. H.; Braathen, M.; Correia, D.; Mosha, R. D.; Skaare, J. U.; Sandvik, J.
Dose dependent effects of Benzo[a]pyrene (BaP) on cytochrome P4501A (CYP1A), glutathione- S-transferase (GST) and fluorescent aromatic compounds (FACs) metabolites biomarker responses were studied in African sharptooth catfish (Clarias gariepinus) following 24 h of waterborne exposures. Based on biomass of C. gariepinus in different tanks, BaP concentrations of 1.60, 3.44, and 18.21 lg/L that corresponded to 0.5, 1.0, and 5.0 mg/kg body weight were used. Significant induction of EROD activities in gill filaments was observed at all doses and the accumulation of FACs metabolites in bile was significantly different between groups. Accumulation of FACs metabolites in bile strongly correlated (r2 = 0.99) with BaP doses. Hepatic EROD activities were undetectable and no effect on GST activities was observed. The highest dose of BaP from the dose dependent study was further studied to assess the interactive and temporal responses of C. gariepinus on CYP1A, GST, and FACs metabolites biomarkers following exposure to either BaP alone, 17a-ethynylestradiol (EE2) alone or a combination of both compounds at concentrations of 54.17 lg/L for BaP, 51.38 lg/L for EE2 and 54.44 lg/L for each of both compounds. Based on biomass in each tank, these concentrations corresponded to 5 mg/kg body weight. While a group of six fish was sacrificed on day 0 from the control tank only, other groups of six fish were sacrificed after 1, 3, and 6 days of exposure from the control and exposed groups. Maximum induction of gill filament and hepatic EROD activities was observed after 1 day of exposure. Both EROD activities in gill filaments and liver were significantly induced by exposure to BaP alone or co-administration with EE2. Gill filament EROD induction was significantly inhibited (50%) by co-administration of BaP and EE2 compared to administration of BaP alone. Levels of FACs in bile for BaP and BaP + EE2 exposed groups were significantly different from the control at all doses and time points. A significant induction of GST activities was observed in fish exposed to BaP and BaP + EE2 after 3 days. Exposure to EE2 alone caused significant induction of this enzyme after day 6. This study reports for the first time the significant antagonistic influence of EE2 on BaP in gills of fish following waterborne exposures. The results also indicate that chemical mixtures may affect biomarker responses differently from compounds administered alone and that the sensitivity of CYP1A to interactive chemicals is different in gills and liver.
Levels and patterns of persistent organic pollutants (POPs) in tilapia (Oreochromis sp.) from four different lakes in Tanzania: Geographical differences and implications for human health
(Elsevier, 2014-04-22) Lie, Elisabeth; Polder, A.; Müller, M. B.; Lyche, J. L.; Mdegela, R. H.; Nonga, H. E.; Mabiki, F.; Mbise, T. J.; Skaare, J. U.; Sandvik, M.; Skjerve, E.; Lie, E.
In Tanzania fish is one of the most important protein sources for the rapidly increasing population. Wild fish is threatened by overfishing and pollution from agriculture, industries, mining, household effluents and vector control. Tomonitor possible implications for public health, the geographical differences of the occurrence and levels of persistent organic pollutants (POPs) in tilapia fish (Oreochromis sp.) from four different Tanzanian lakes were investigated in 2011. Concentrations of organochlorine pesticides (OCPs), polychlorinated biphenyls (PCBs), polybrominated diphenyls (PBDEs) and hexabromocyclododecane (HBCDD) were determined in pooled samples of tilapia muscle from Lake (L) Victoria, L. Tanganyika, L. Nyasa (also called L. Malawi) and L. Babati in Tanzania in 2011. Levels of Σ-DDTs (274 ng/g lipid weight (lw)) and sum of 7 indicator PCBs (Σ-7PCBs) (17 ng/g lw) were significantly higher in tilapia from L. Tanganyika compared to the other lakes. The highest levels of Σ-endosulfan (94 ng/g lw) were detected in tilapia from L. Victoria. Toxaphenes were detected in low levels in fish from L. Tanganyika and L. Babati. Results revealed a geographic difference in the use of DDT and endosulfan between L. Victoria and L. Tanganyika. Low ratios of DDE/DDT in tilapia from L. Tanganyika indicated an on-going use of DDT in the area. Median levels of ΣBDEs, including BDE-209, were highest in L. Victoria (19.4 ng/g lw) and BDE- 209 was present in 68% of the samples from this lake. The presence of BDE-209 indicates increasing influence of imported products from heavy industrialized countries. The measured POP levels in the studied tilapia were all below MRLs of EU or were lower than recommended levels, and thus the fish is considered as safe for human consumption. They may, however, pose a risk to the fish species and threaten biodiversity.
Organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs) in human breast milk and associated health risks to nursing infants in northern Tanzania
(Elsevier, 2017-01-25) Müller, M. B.; Polder, A.; Brynildsrud, O. B.; Karimi, M.; Lie, E.; Manyilizu, W. B.; Mdegela, R. H.; Mokiti, F.; Murtadha, M.; Nonga, H. E.; Skaare, J. U.; Lyche, J. L.
This is the first study to report organochlorines (OCs), including chlorinated pesticides (OCPs) and polychlorinated biphenyls (PCBs) in human milk from Tanzania. The main aims of this study were to assess the level of contamination and the possible health risks related to OC exposure in nursing infants from the Northern parts of Tanzania. Ninety-five healthy mother-infant couples attending Mount Meru Regional Referral Hospital (MMRRH), Arusha, Tanzania, were assessed for associations between maternal/infant characteristics, i.e. mother's age, BMI, gestational weight gain, occupation, residence and fetal growth parameters and breast milk levels of OCPs, such as dichlorodiphenyltrichloroethane (DDT) and its metabolites, dieldrin and PCBs. p,p′-DDE and p,p′-DDT were detected in 100% and 75% of the breast milk samples, respectively, and ranged between 24 and 2400 ng/g lipid weight (lw) and < LOD and 133 ng/g lw, respectively. Dieldrin was detected in 66% of the samples in levels up to 937 ng/g lw. Σ7PCBs ranged between < LOD and 157 ng/g lw. Other OCPs were detected in low levels. For assessment of health risks, the Hazard Quotient (HQ) was calculated by comparing estimated daily intakes of OCPs and PCBs with health based guidance values. The estimated daily intake (ng/kg body weight/day) of ΣDDTs, dieldrin and nondioxin-like PCBs (Σ6PCBs) exceeded the provisional tolerable daily intake (PTDI) in two, six and forty-eight of the nursing infants, respectively, suggesting potential health risks. In addition, head circumference were negatively associated with p,p´-DDE in female infants, suggesting that OC exposure during pregnancy may influence fetal growth.
Socio-economic values of wetland resources around lake Manyara, Tanzania: assessment of environmental threats and local community awareness on environmental degradation and their effects
(Journal of Wetlands Ecology, 2010-12-05) Nonga, H. E.; Mdegela, R. H.; Lie, E.; Sandvik, M.; Skaare, J. U.
Understanding local people’s socio-economic values of wetlands and traditional mechanisms of managing natural resources forms the basis of conserving them. Wetlands have frequently been developed for short-term economic gains that destroy their ecological values and environmental services in the long term. A study was carried out to assess socio-economic values of the wetland resources, environmental threats around Lake Manyara and local community awareness on causes of environmental changes, degradation in the wetlands and their effects using 80 respondents. Field surveys, interviews, questionnaires and direct observation were used in data collection. It was found that local community was aware on the ecosystem services accrued from the wetlands which were unsustainably used. However, environmental degradation due to unsustainable agriculture, overgrazing, deforestation, urbanization and mining was rampant which had resulted to soil erosion, reduced water availability, wildlife mortality and frequent dry up of Lake Manyara and rivers. In order to protect the lake basin; controlled human activities, land use and water resources within the catchment are to be done in cooperation between the government departments, local authorities and the general local community around.