NRU :: Browsing by Author "Ssebugere, Patrick"

Browsing by Author "Ssebugere, Patrick"

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Bioconcentration and trophic transfer of polychlorinated biphenyls and polychlorinated dibenzo-p-dioxins and dibenzofurans in aquatic animals from an e-waste dismantling area in East China
(Environmental Science: Processes & Impacts, 2015) Zhu, Chaofei; Wang, Pu; Li, Yingming; Chen, Zhaojing; Li, Wenjuan; Ssebugere, Patrick; Zhang, Qinghua; Jianga, Guibin
Eight aquatic biota species were collected from an e-waste dismantling area in East China to investigate bioconcentration and trophic transfer of polychlorinated biphenyls (PCBs), polychlorinated dibenzo-pdioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs). The mean concentrations of PCBs varied widely from 6.01 104 to 2.27 106 pg per g dry weight (dw). The P25PCB concentrations in eels were significantly higher than those in other species. The levels of PCDD/Fs changed from 8.13 pg per g dw in toads to 617 pg per g dw in stone snails. World Health Organization-toxic equivalents (WHO2005-TEQs) ranged from 2.57 to 2352 pg WHO-TEQ per g dw with a geometric mean value of 64.7 pg WHO-TEQ per g dw, which greatly exceeded the maximum levels of 4 pg per g ww set by the European Commission. The log-transferred bioconcentration factors (BCFs) of 25 PCB congeners ranged from 1.0 to 6.6, with the highest value for CB-205 in crucian carp and the lowest value for CB-11 in frog. A parabolic correlation was observed between log BCF and log Kow (R2 ¼ 0.53, p < 0.001), where the maximum value occurred at a log Kow of approximately 7. A similar correlation was also found in the plot of log BCF against the number of chlorine atoms of PCBs (R2 ¼ 0.57, p < 0.001), indicating that mediumhalogenated congeners of PCBs are more easily accumulated by aquatic biota species. There were no significant correlations between the log-transferred concentrations and trophic levels of aquatic species, suggesting that trophic magnification for PCBs and PCDD/Fs was not observed in this study.
Comparative exposomics of persistent organic pollutants (PCBs, OCPs, MCCPs and SCCPs) and polycyclic aromatic hydrocarbons (PAHs) in Lake Victoria (Africa) and Three Gorges Reservoir (China)
(Science of the Total Environment, 2019) Omwoma, Solomon; Muendo Mbithi, Bonface; Pandelova, Marchela; Ssebugere, Patrick; Lalah, Joseph O.; Wang, Yawei; Bi, Yonghong; Henkelmann, Bernhard; Schramm, Karl-Werner
Exposomics is assessment of organism exposure to high priority environmental pollutants in an ecosystem using OMIC technologies. A virtual organism(VO) is an artificial property-tool (OMIC) reflecting exposomic process in compartments of real organisms. The exposomics of aquatic organisms inhabiting Lake Victoria (L.V.) and Three Gorges Reservoir (TGR) were compared using VOs. The two reservoirs are heavily depended on for food and water both in Africa and China. The target priority pollutants in the reservoirs were polyclic aromatic hydrocarbons (PAHs) and persistent organic pollutants such as polychlorinated biphenyls (PCBs), organochlorine pesticides (OCPs), medium chain chlorinated paraffins (MCCPs) and short chain chlorinated paraffins (SCCPs). The VOs showed that in a period of 28 days, aquatic organisms in TGR were exposed to total (Σ) PAHs of 8.71 × 10−6 mg/L, PCBs of 2.81 × 10−6 mg/L, OCPs of 2.80 × 10−6 mg/L, MCCPs of 8.9 × 10−10 mg/L and SCCPs of 1.13 × 10−7 mg/L. While in a period of 48 days, organisms in L. V. were exposed to total (Σ) PAHs of 7.45 × 10−6 mg/L, PCBs of 4.70 × 10−6 mg/L, OCPs of 3.39 × 10−8 mg/L,MCCPs of 4.6 × 10−10 mg/L and SCCPs of 3.6 × 10−9 mg/L. The exposomic levels in TGR after 28 dayswere higher than those in Lake Victoria after 48 days. In both reservoirs, bioaccumulation levels are above set standards for aquatic organisms. The sources of the pollutants into the reservoirswere diagnostically determined to originate fromanthropogenic processes such as petrogenic, diesel emissions, biomass burning, coal combustion, electronic wastes, traffic emissions and historic uses.
Concentrations and sources apportionment of polycyclic aromatic hydrocarbons in 1 sediments from the 2 Uganda side of Lake Victoria
(Environmental Science: Processes & Impacts, 2017) Kerebba, Nasifu; Ssebugere, Patrick; Kwetegyeka, Justus; Arinaitwe, Kenneth; Wasswa, John
This paper presents the levels and possible sources of selected polycyclic aromatic hydrocarbons (PAHs) in surface sediments from Napoleon Gulf and Murchison Bay of Lake Victoria. Sediment samples were extracted and cleaned up for PAHs using UNEP, 1992 and EPA method 3630C protocols, respectively. The analysis of sample extracts was done using a gas chromatograph coupled to a mass spectrometer. Fifteen congeners, mostly the high molecular weight PAHs (HPAHs) (4-6 rings) were detected. Total (Σ) concentrations varied from 44.2 to 80.2 ng g-1 dry weight (d.w.) at Napoleon Gulf while those at the Murchison Bay ranged from 17.0 to 55.0 ng g-1 d.w. Statistical analysis showed no significant difference in the concentrations of PAHs among sites (p <0.05, ANOVA). It was noted that the concentrations for most sampling sites were far below the lowest effect levels based on the Sediment Quality Guidelines except for one station at the Napoleon Gulf. Principal component analysis and diagonistic ratios indicated that PAHs of combustion and petroleum origin were dominant and brought mainly by atmospheric deposition.
DDT and metabolites in fish from Lake Edward, Uganda
(Chemosphere, 2009) Ssebugere, Patrick; Kiremire, Bernard T.; Kishimba, Michael; Wandiga, Shem O.; Nyanzi, Steven A.
This paper presents results based on determination of residue levels of 1,1,1-trichloro-2,2-bis[p-chlorophenyl]ethane (DDT) and its metabolites in five fish species from Rwenshama landing site on Lake Edward, Uganda. The residue levels were analysed by using a GC-ECD and confirmed by GC–MS. The DDT residues detected in fish samples from Lake Edward were p,p′-DDT, o,p′-DDT, p,p′-DDE, o,p′-DDE, p,p′-DDD and o,p′-DDD. All the analysed samples of fish presented mean DDT residues ranging from non-detectable levels to 68 μg kg−1 fresh weight. High levels of p,p′-DDT were detected in comparison to the metabolites (p,p′-DDE and p,p′-DDD). The detection of higher levels of p,p′-DDT than p,p′-DDE and p,p′-DDD, in most fish samples, suggests recent exposure of fish to DDT. Generally, most of the fish samples had residue levels below the maximum residue limits (MRL) recommended by FAO/WHO Codex Alimentarius Commission.
The endangered African Great Ape: Pesticide residues in soil and plants consumed by Mountain Gorillas (Gorilla beringei) in Bwindi Impenetrable National Park, East Africa
(Science of The Total Environment, 2021) Amusa, Chemonges; Odongo, Silver; Matovu, Henry; Ssebugere, Patrick; Baranga, Deborah
Bwindi Impenetrable National Park situated southwest of Uganda is a biodiversity hotspot that is home to about half of the world's endangered mountain gorilla (Gorilla beringei). Given its ecological significance and mounting pressures from agricultural activities such as tea growing, continuous monitoring of the levels of chemical toxins like pesticides in the park and surrounding areas is needed for effective conservation strategies. Furthermore, persistent organochlorine pesticides (OCPs) like DDT were used in agricultural gardens and indoor spraying in Kanungu district between the 1950s and 80s. The focus of this study was to explore the possible exposure of mountain gorillas to OCPs and cypermethrin used by the farmers in the areas near the park. Data from our interviews revealed that glyphosate is the most widely used pesticide by the farmers in areas surrounding the park, followed by cypermethrin, and mancozeb. Samples of leaves from plants consumed by mountain gorillas along the forest edges of the park and surficial soils (15–20 cm depths) were collected from three sites (Ruhija, Nkuringo and Buhoma) and analysed for the presence of cypermethrin and OCPs residues. Concentrations of total (∑) DDTs and ∑endosulfans were up to 0.34 and 9.89 mg/kg dry weight (d.w), respectively in soil samples. Concentrations of ∑DDTs and ∑endosulfans in samples of leaves ranged from 0.67 to 1.38 mg/kg d.w (mean = 1.07 mg/kg d.w) and 0.9 to 2.71 mg/kg d.w (mean = 1.68 mg/kg d.w), respectively. Mean concentration of ∑DDTs in leaves exceeded the European pharmacopeia and United States pharmacopeia recommended maximum residue limit values for DDTs in medicinal plants (1.0 mg/kg). In addition, calculated hazard indices for silverbacks (36.35), females (57.54) and juveniles (77.04) suggested potential health risks to the mountain gorillas. o,p′-DDT/p,p′-DDT ratios (0.5–0.63) in samples of leaves confirmed recent input of dicofol-DDT type in Bwindi rainforest.
The endangered African Great Ape: Pesticide residues in soil and plants consumed by Mountain Gorillas (Gorilla beringei) in Bwindi Impenetrable National Park, East Africa
(Science of The Total Environment, 2021) Amusa, Chemonges; Rothman, Jessica; Odongo, Silver; Matovu, Henry; Ssebugere, Patrick; Baranga, Deborah; Sillanpää, Mika
Bwindi Impenetrable National Park situated southwest of Uganda is a biodiversity hotspot that is home to about half of the world's endangered mountain gorilla (Gorilla beringei). Given its ecological significance and mounting pressures from agricultural activities such as tea growing, continuous monitoring of the levels of chemical toxins like pesticides in the park and surrounding areas is needed for effective conservation strategies. Furthermore, persistent organochlorine pesticides (OCPs) like DDT were used in agricultural gardens and indoor spraying in Kanungu district between the 1950s and 80s. The focus of this study was to explore the possible exposure of mountain gorillas to OCPs and cypermethrin used by the farmers in the areas near the park. Data from our interviews revealed that glyphosate is the most widely used pesticide by the farmers in areas surrounding the park, followed by cypermethrin, and mancozeb. Samples of leaves from plants consumed by mountain gorillas along the forest edges of the park and surficial soils (15–20 cm depths) were collected from three sites (Ruhija, Nkuringo and Buhoma) and analysed for the presence of cypermethrin and OCPs residues. Concentrations of total (∑) DDTs and ∑endosulfans were up to 0.34 and 9.89 mg/kg dry weight (d.w), respectively in soil samples. Concentrations of ∑DDTs and ∑endosulfans in samples of leaves ranged from 0.67 to 1.38 mg/kg d.w (mean = 1.07 mg/kg d.w) and 0.9 to 2.71 mg/kg d.w (mean = 1.68 mg/kg d.w), respectively. Mean concentration of ∑DDTs in leaves exceeded the European pharmacopeia and United States pharmacopeia recommended maximum residue limit values for DDTs in medicinal plants (1.0 mg/kg). In addition, calculated hazard indices for silverbacks (36.35), females (57.54) and juveniles (77.04) suggested potential health risks to the mountain gorillas. o,p′-DDT/p,p′-DDT ratios (0.5–0.63) in samples of leaves confirmed recent input of dicofol-DDT type in Bwindi rainforest.
Environmental levels and human body burdens of per- and polyfluoroalkyl substances in Africa: A critical review
(Science of the Total Environment, 2020) Ssebugere, Patrick; Sillanpää, Mika; Matovu, Henry; Wang, Zhanyun; Schramm, Karl-Werner; Omwoma, Solomon; Wanasolo, William; Chelangat Ngeno, Emily; Odongo, Silver
Per- and polyfluoroalkyl substances (PFASs) are known organic pollutants with adverse health effects on humans and the ecosystem. This paper synthesises literature about the status of the pollutants and their precursors, identifies knowledge gaps and discusses future perspectives on the study of PFASs in Africa. Limited data on PFASs prevalence in Africa is available because there is limited capacity to monitor PFASs in African laboratories. The levels of PFASs in Africa are higher in samples from urban and industrialized areas compared to rural areas. Perfluorooctane sulfonic acid (PFOS) and perfluorooctanoic acid (PFOA) are the dominant PFASs in human samples from Africa. Levels of PFOS and PFOA in these samples are lower than or comparable to those from industrialised countries. PFOA and PFOS levels in drinking water in Africa are, in some cases, higher than the EPA drinking water guidelines suggesting potential risk to humans. The levels of PFASs in birds’ eggs from South Africa are higher, while those in other environmental media from Africa are lower or comparable to those from industrialised countries. Diet influences the pollutant levels in fish, while size and sex affect their accumulation in crocodiles. No bioaccumulation of PFASs in aquatic systems in Africa could be confirmed due to small sample sizes. Reported sources of PFASs in Africa include municipal landfills, inefficient wastewater treatment plants, consumer products containing PFASs, industrial wastewater and urban runoff. Relevant stakeholders need to take serious action to identify and deal with the salient sources of PFASs on the African continent.
Hexabromocyclododecane in alpine fish from the Tibetan Plateau, China
(Environmental Pollution, 2013) Zhu, Nali; Fu, Jianjie; Gao, Yan; Ssebugere, Patrick; Wang, Yawei; Jiang, Guibin
Hexabromocyclododecanes (HBCDs) has just been listed into Stockholm Convention as a persistent organic pollutant recently. This paper studied the HBCDs in 79 wild fish from high mountain lakes and rivers of the Tibetan Plateau. ThePHBCDs in fish muscles ranged from non detectable levels to 13.7 ng/g lipid weight (lw) (mean value of 2.12 ng/g lw) with a high detection frequency of 65.8%. a-HBCD dominated among the isomers and accounted for 78.2% of the total burden. Concentrations of PHBCDs in the fish were significantly correlated with the lipid content. A decreasing trend was observed between a-HBCD and trophic level. Positive correlation was also noted between the HBCD levels in fish from lakes and the annual precipitation, and this implied the long-range atmospheric transport of HBCDs to the Tibet Plateau. This was the first work to widely explore HBCDs contamination in the aquatic ecosystems of the Tibetan Plateau.
Human and environmental exposure to PCDD/Fs and dioxin-like PCBs in Africa: A review
(Chemosphere, 2019) Ssebugere, Patrick; Sillanpaa, Mika; Matovu, Henry; Mubiru, Edward
This paper reviews literature for the last two decades with emphasis on levels, toxic equivalencies and sources of polychlorinated dibenzo-p-dioxins (PCDDs), dibenzofurans (PCDD/Fs) and dioxin-like polychlorinated biphenyls (dl-PCBs) in Africa. Further, we comprehensively analysed data, interpret differences and identify existing gaps with those from other continents.We observed that high levels of PCDD/ Fs and dl-PCBs were reported in environmental and biological samples near densely populated urban and industrialised areas compared to those in rural settings. In general, the concentrations of PCDD/Fs and dl-PCBs in the blood samples from Africa were in the same range as those from Asia but lower than those from Europe. The concentrations of dioxins and dioxin-like compounds in the atmosphere in Africa were comparable to and/or higher than those in developed countries. The reported sources of PCDD/Fs and dl-PCBs in Africa were industrial emissions, obsolete pesticide stockpiles, household heating, recycling of electronic waste, and incineration and combustion of domestic waste. Regional and intercontinental transport of dioxins could not be confirmed because of the lack of sufficient literature on them. Further data about the levels and sources of PCDD/Fs and dl-PCBs in Africa need to be generated to complete the chemical inventories for the continent and to facilitate the implementation of the Stockholm Convention on persistent organic pollutants. The reviewed literature shows that most analyses have been carried out in laboratories outside Africa because of the limited institutional capacity in Africa. More support needs to be given to laboratories in Africa to develop the capacity to accurately quantify dioxins on routine basis.
Lacustrine Cyanobacteria, Algal Blooms and Cyanotoxins in East Africa: Implications for Human and Ecological Health Protection
(Phycology, 2023) Omara, Timothy; Nagawa, Christine Betty; Kyarimpa, Christine; Böhmdorfer, Stefan; Lugasi, Solomon Omwoma; Matovu, Henry; Odongo, Silver; Ssebugere, Patrick
Advected cyanobacteria, algal blooms and cyanotoxins have been increasingly detected in freshwater ecosystems. This review gives an insight into the present state of knowledge on the taxonomy, dynamics, toxic effects, human and ecological health implications of cyanobacteria, algal blooms and cyanotoxins in the East African Community lakes. The major toxigenic microalgae in East African lakes include Microcystis, Arthrospira, Dolichospermum, Planktolyngbya and Anabaenopsis species. Anatoxin-a, homoanatoxin-a, microcystins (MCs), cylindrospermopsin and nodularin have been quantified in water from below method detection limits to 81 µg L−1, with peak concentrations characteristically reported for the wet season. In whole fish, gut, liver and muscles, MCs have been found at concentrations of 2.4 to 1479.24 μg kg−1, which can pose human health risks to a daily consumer. While there have been no reported cases of cyanotoxin-related poisoning in humans, MCs and anatoxin-a (up to 0.0514 μg kg−1) have been identified as the proximal cause of indiscriminate fish kills and epornitic mortality of algivorous Phoeniconaias minor (lesser flamingos). With the unequivocal increase in climate change and variability, algal blooms and cyanotoxins will increase in frequency and severity, and this will necessitate swift action towards the mitigation of nutrient-rich pollutants loading into lakes in the region.
Multiple persistent organic pollutants in mothers' breastmilk: Implications for infant dietary exposure and maternal thyroid hormone homeostasis in Uganda, East Africa
(Science of The Total Environmen, 2021) Matovu, Henry; Li, Zhong-Min; Henkelmann, Bernhard; Bernhöft, Silke; De Angelis, Meri; Schramm, Karl-Werner; Sillanpää, Mika; Drago Kato, Charles; Ssebugere, Patrick
Persistent organic pollutants (POPs) are ubiquitous contaminants with adverse health effects in the ecosystem. One of such effects is endocrine disruption in humans and wildlife even at background exposure concentrations. This study assessed maternal breastmilk concentrations of POPs; brominated flame retardants (BFRs), polychlorinated biphenyls (PCBs) and polychlorinated dibenzo-p-dioxins/furans (PCDD/Fs), and the potential health risks posed to the nursing infants. We also evaluated the association of these POPs with total 3,3′,5- triiodo-L-thyronine (T3), L-thyroxine (T4), and 3,3′,5′-triiodo-L-thyronine (rT3) levelsmeasured in human breast milk. Thirty breastmilk samples were collected from Kampala, Uganda between August and December 2018. Hexabromobenzene was not detected while the maximum level of 2,2′,4,4′,5,5′-hexabrombiphenyl was 64.7 pg/g lw. The median levels of total indicator PCBs, PBDEs, dioxin-like PCBs, and PCDD/Fs in the samples were 159 pg/g lw, 511 pg/g lw, 1.16 pg TEQ/g lw, and 0.4 pg TEQ/g lw, respectively. These levels were lower than those reported in other countries. Owing to their bio accumulative nature, PCBs −81, −169, andΣPCDD/Fs increased with increase in maternal age. Estimated dietary intakes for dioxin-like PCBs and PCDD/Fs were lower than those reported elsewhere but were higher than the WHO tolerable daily intakes suggesting potential health risks to nursing infants. In adjusted single pollutant models, PCB-126, PCB-169, andΣPCBTEQ were negatively associated with T3, while 1,2,3,4,5,7,8-HpCDF was positively associated with rT3. Although these associations did not persist in multi pollutant models, our findings suggest potential thyroid hormone disruption by POPs in mothers. This may reduce the levels of thyroid hormones transferred from the mother to the neonates and, hence, adversely influence infant growth. A temporal study with a bigger sample size is required to corroborate these findings
Organochlorine pesticide residues in sediments from the Uganda side of Lake Victoria
(Chemosphere, 2011) Wasswa, John; Kiremire, Bernard T.; Nkedi-Kizza, Peter; Mbabazi, Jolocam; Ssebugere, Patrick
Organochlorine (OC) residues were analysed in 117 sediment samples collected from four bays of the Uganda side of Lake Victoria. The sediments were collected with a corer at a depth of 0–20 cm, and extracted for OC residues using a solid dispersion method. The extracts were cleaned using gel permeation chromatography and analysed for pesticide residues using a gas chromatograph (GC) equipped with an electron capture detector. The results were confirmed using a GC equipped with a mass spectrometer (MS). A total of 16 OC residues, most of them persistent organic pollutants (POPs) were identified and quantified. The OC residue levels were expressed on an oven dry weight (d.w.) basis. Endosulphan sulphate, in the range of 0.82–5.62 lg kg 1 d.w., was the most frequently detected residue. Aldrin and dieldrin were in the ranges of 0.22–15.96 and 0.94–7.18 lg kg 1 d.w., respectively. DDT and its metabolites lay between 0.11–3.59 for p,p0-DDE, 0.38–4.02 for p,p0-DDD, 0.04–1.46 for p,p0-DDT, 0.07–2.72 for o,p0-DDE and 0.01–1.63 lg kg 1 d.w. for o,p0-DDT. The levels of c-HCH varied from 0.05 to 5.48 lg kg 1 d.w. Heptachlor was detected only once at a level of 0.81 lg kg 1 d.w., while its photo-oxidation product, heptachlor epoxide, ranged between non-detectable (ND) to 3.19 lg kg 1 d.w. Chlordane ranged from ND to 0.76 lg kg 1 d.w. Based on the threshold effect concentration (TEC) for fresh water ecosystems, aldrin and dieldrin were the only OCs that seemed to be a threat to the lake environment.
Organochlorine pesticides and their markers of exposure in serum and urine of children from a nodding syndrome hotspot in northern Uganda, east Africa
(Elsevier Ltd, 2024-08-28) Odongo, Silver; Ssebugere, Patrick; Spencer, Peter S.; Palmer, Valerie S; Angues, Raquel Valdes; Mwaka, Amos Deogratius; Wasswa, John
Nodding syndrome (NS) is a neurologic disorder of unknown etiology characterized by vertical head nodding that has affected children aged 5-18 years in East Africa. Previous studies have examined relationships with biological agents (e.g., nematodes, measles, and fungi), but there is limited data on the possible contributions of neurotoxic environmental chemicals frequently used as pesticides/insecticides to the development and progression of this disorder. We examined the levels of persistent organochlorine pesticides (OCPs) in children (5-18 years old) from Kitgum District, Northern Uganda. These children previously lived in internally displaced people's (IDP) camps, where they were exposed to various health risks, including contaminated food and water. Exposure to OCPs through contaminated food and water is postulated here as a potential contributor to NS etiology. We analyzed serum (n = 75) and urine (n = 150) samples from children diagnosed with NS, and from seizure-free household controls (HC), and community controls (CC). Samples were extracted using solid-phase extraction (SPE) and extracts were analyzed for OCPs using gas chromatography with a triple quadrupole mass spectrometry (GC-MS/MS). Mean levels of total (∑) ∑OCPs in serum samples from NS, HC and CC subjects were 23.3 ± 2.82, 21.1 ± 3.40 and 20.9 ± 4.24 ng/mL, respectively, while in urine samples were 1.86 ± 1.03, 2.83 ± 1.42, and 2.14 ± 0.94 ng/mL, respectively. Correlation and linear regression analysis indicated that potential markers for ∑hexachlorocyclohexanes (HCHs), ∑chlordane compounds (CHLs), ∑endosulfan and ∑dichlorodiphenyltrichloroethanes (DDTs) were γ-HCH, heptachlor-exo-epoxide, endosulfan-α and p,p'-DDD in NS cases while in controls were α -HCH, heptachlor, endosulfan-α and p,p'-DDE, respectively. Since, in some instances, higher OCP levels were found in controls vs. NS cases, we conclude that exposure to organochlorine pesticides is unlikely to be associated with the etiology of NS.Nodding syndrome (NS) is a neurologic disorder of unknown etiology characterized by vertical head nodding that has affected children aged 5-18 years in East Africa. Previous studies have examined relationships with biological agents (e.g., nematodes, measles, and fungi), but there is limited data on the possible contributions of neurotoxic environmental chemicals frequently used as pesticides/insecticides to the development and progression of this disorder. We examined the levels of persistent organochlorine pesticides (OCPs) in children (5-18 years old) from Kitgum District, Northern Uganda. These children previously lived in internally displaced people's (IDP) camps, where they were exposed to various health risks, including contaminated food and water. Exposure to OCPs through contaminated food and water is postulated here as a potential contributor to NS etiology. We analyzed serum (n = 75) and urine (n = 150) samples from children diagnosed with NS, and from seizure-free household controls (HC), and community controls (CC). Samples were extracted using solid-phase extraction (SPE) and extracts were analyzed for OCPs using gas chromatography with a triple quadrupole mass spectrometry (GC-MS/MS). Mean levels of total (∑) ∑OCPs in serum samples from NS, HC and CC subjects were 23.3 ± 2.82, 21.1 ± 3.40 and 20.9 ± 4.24 ng/mL, respectively, while in urine samples were 1.86 ± 1.03, 2.83 ± 1.42, and 2.14 ± 0.94 ng/mL, respectively. Correlation and linear regression analysis indicated that potential markers for ∑hexachlorocyclohexanes (HCHs), ∑chlordane compounds (CHLs), ∑endosulfan and ∑dichlorodiphenyltrichloroethanes (DDTs) were γ-HCH, heptachlor-exo-epoxide, endosulfan-α and p,p'-DDD in NS cases while in controls were α -HCH, heptachlor, endosulfan-α and p,p'-DDE, respectively. Since, in some instances, higher OCP levels were found in controls vs. NS cases, we conclude that exposure to organochlorine pesticides is unlikely to be associated with the etiology of NS. MEDLINE - Academic
Organochlorine pesticides in soils from south-western Uganda
(Chemosphere, 2010) Ssebugere, Patrick; Wasswa, John; Mbabazi, Jolocam; Nyanzi, Steven A.; Kiremire, Bernard T.; Marco, John A.M.
Organochlorine (OC) residues were analysed in soil samples collected from Kihiihi sub-county, Kanungu District, which is located in south-western Uganda. Mabira Central Forest Reserve which is located in central Uganda was used as a reference site in this study. The samples were collected at 15–20 cm depths below the soil surface and extracted with organic solvents. The extracts were cleaned using florisil, and were analysed using a gas chromatograph (GC) equipped with an electron capture detector (ECD). The results were confirmed using a GC equipped with a mass spectrometer (MS). The levels of the OC residues in soil from Kihiihi sub-county varied from non-detectable (ND) to 59 μg kg−1 dry weight. The frequencies of detection for p,p′-DDT, p,p′-DDE and p,p′-DDD in the total soil samples were 47%, 24% and 11%, respectively. The o,p′compounds were detected in the following frequencies: o,p′-DDT (23%), o,p′-DDE (19%) and o,p′-DDD (8%). The low p,p′-DDE/p,p′-DDT residue ratios (0.2–0.9) in Kihiihi samples suggest recent inputs of DDT in Kihiihi sub-county. The detection frequencies for dieldrin, endosulfan-α, -β and -sulphate in the soil samples were 21%, 26%, 31% and 19%, respectively. Mabira Forest Reserve soils showed detection frequencies of p,p′-DDT (5%) and p,p′-DDE (9% of the soil samples), varying from ND to 9 μg kg−1. Although the use of OCPs has been banned, our results show that they can still be detected in the environment. Their presence may be attributed to adulteration of pesticides which are not banned and also atmospheric deposition.
PCDD/Fs and dioxin-like PCBs in fish species from Lake Victoria, East Africa
(Chemosphere, 2013) Ssebugere, Patrick; Kiremire, Bernard T.; Henkelmann, Bernhard; Bernhöft, Silke; Kasozi, Gabriel N.; Wasswa, John; Schramm, Karl-Werner
Two commercially important fish species, Nile perch (Lates niloticus) and Nile tilapia (Oreochromis niloticus) belonging to different trophic levels were collected from the Napoleon Gulf and Thurston Bay in Lake Victoria. Polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs) and dioxinlike polychlorinated biphenyls (dl-PCBs) were extracted from the fish muscles and livers using the 13C isotope dilution method, followed by multiple column chromatography clean-up. Analysis was achieved by a high resolution gas chromatography coupled with a high resolution mass spectrometer. The concentrations of analytes ranged from 0.07 to 0.59 pg g 1 fresh weight (fw) and 0.3–19.0 pg g 1 in L. niloticus and 0.06–0.18 and 0.2–15.7 pg g 1 in O. niloticus, for PPCDD/Fs and Pdl-PCBs, respectively. Differences in congener concentrations were observed between the two fish species and study sites, and this was attributed to differences in feeding habits and trophic levels. World Health Organization-toxic equivalents (WHO-TEQs) were in the range 0.01–0.16 pg TEQ g 1 for the PCDD/Fs and 0.001–0.74 pg TEQ g 1 for the dl-PCBs. The TEQ values in the present study were lower compared to those of most fish samples reported in literature and were within permissible levels recommended by the European Union, implying that the fish was fit for human consumption.
PCDD/Fs and dioxin-like PCBs in surface sediments from Lake Victoria, East Africa
(Science of the total environment, 2013) Ssebugere, Patrick; Kiremire, Bernard T.; Henkelmann, Bernhard; Bernhöft, Silke; Wasswa, John; Kasozi, Gabriel N.; Schramm, Karl-Werner
Surface sediments (b60 cm) from the Napoleon Gulf and Thurston Bay on the northern shore of Lake Victoria were analyzed for polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs) and dioxin-like polychlorinated biphenyls (dl-PCBs). Fifteen PCDD/Fs and eleven dl-PCBs were found in 75.5% of the samples. The maximum concentrations of PCDD/Fs and dl-PCBs were 44.1 and 136 pg g−1 dry weight (dw), respectively. Octachlorodibenzo-p-dioxin was the predominant PCDD/F congener at the Napoleon Gulf and Thurston Bay area. Regarding the dl-PCBs, a variation in levels was observed between the mono-ortho PCBs and non-ortho PCBs, with the former having higher levels than the latter. The PCDD/F and dl-PCB levels, in the sediments of Napoleon Gulf, which is near urban centers and industrial areas were markedly higher (α ≤ 0.05) than those from the Thurston Bay, which is offshore, suggesting that human activities could be sources of the pollutants to the surrounding water resources. World Health Organization-toxic equivalency quotients (WHO-TEQs) lay in the range of 0.07–5.53 pg g−1 dw for PCDD/Fs and 0.01–0.23 pg g−1 dw for dl-PCBs. 23.1% of samples from the Napoleon Gulf had their results above the set WHOPCDD/Fs-TEQ value.
Polybrominated diphenyl ethers in mothers' breast milk and associated health risk to nursing infants in Uganda
(Science of The Total Environment, 2019) Matovu, Henry; Sillanpää, Mika; Ssebugere, Patrick
The aimof this studywas to investigate levels of polybrominated diphenyl ethers (PBDEs) in breast milk samples from healthy primiparous mothers who had lived in Kampala capital city (urban area) and Nakaseke district (a rural area) for the last five years. Fifty sampleswere collected between March and June 2018 andwere extracted by dispersive solid-phase extraction (SPE). Clean-up was performed on an SPE column and analysis was done using gas chromatography–mass spectrometry. Total (Σ) PBDEs (BDE 28, 47, 49, 66, 77, 99, 100,138,153, 154, 183 and 209) ranged from0.59 to 8.11 ng/g lipidweight (lw). The levels of PBDEs in samples fromKampala capital citywere significantly higher than those fromNakaseke (p b 0.01,Mann-Whitney U test). Themost dominant congenerswere BDE-209 and -47 (contributed 37.1% and 20.2%, respectively toΣPBDEs), suggesting recent exposure of mothers to deca-and penta-BDE formulations. Fish and egg consumption, plastics/e-waste recycling and paint fumes were associated with higher levels of BDE-47, -153 and -99, respectively, implying that diet and occupation were possible sources of the pollutants. Estimated dietary intakes (ng kg−1 body weight day−1) for BDE-47, -99 and -153 were below the US EPA reference doses for neurodevelopmental toxicity, suggestingminimal health risks to nursing infantswho feed on themilk. Generally, the risk quotients for BDE-47, -99 and -153 were b1 in majority (96%) samples, indicating that the breast milk of mothers in Uganda was fit for human consumption.
Polychlorinated biphenyls (PCBs) and polybrominated biphenyl ethers (PBDEs) in environmental samples from Ny-Ålesund and London Island, Svalbard, the Arctic
(Chemosphere, 2015) Zhu, Chaofei; Li, Yingming; Wanga, Pu; Chen, Zhaojing; Ren, Daiwei; Ssebugere, Patrick; Zhang, Qinghua; Jiang, Guibin
Polychlorinated biphenyls (PCBs) and polybrominated biphenyl ethers (PBDEs) were determined in environmental samples collected from Ny-Ålesund and London Island, Svalbard, the Arctic. Total PCB concentrations (P25PCBs) varied from 0.57 to 2.52 ng g 1 dry weight (dw) in soil, 0.30 to 1.16 ng g 1 dw in plants and 0.56 to 0.98 ng g 1 dw in reindeer dung. The non-Aroclor congener of CB-11 was predominant in most samples compared to other congeners, accounting for 16.0 ± 9.8% to theP25PCBs. TheP13PBDEs concentrations were 1.7–416, 36.7–495 and 28.1–104 pg g 1 dw in soil, plants and reindeer dung, respectively. The signature of enantioselective biotransformation was observed in all samples for chiral CB-95, whereas in parts of samples for other chiral PCBs. Bioaccumulation factors (BAFs) in six plant species varied within individual contaminant congeners and plant species, with BAFs less than 1 for PPCBs and higher than 1 forPPBDEs. BAF values decreased with increasing soil concentrations, suggesting that high background levels in soil restricted the accumulation of these contaminants by plants.
Polychlorinated biphenyls and hexachlorocyclohexanes in sediments and fish species from the Napoleon Gulf of Lake Victoria, Uganda
(Science of the Total Environment, 2014) Ssebugere, Patrick; Sillanpää, Mika; Kiremire, Bernard T.; Kasozi, Gabriel N.; Wang, Pu; Sojinu, Samuel O.; Otieno, Peter O.; Zhu, Nali; Zhu, Chaofei; Zhang, Haidong; Shang, Hongtao; Ren, Daiwei; Li, Yingming; Zhang, Qinghua; Jiang, Guibin
Polychlorinated biphenyls (PCBs) and hexachlorocyclohexanes (HCHs) were analyzed in surface sediments (b30 cm depth) and two fish species: Nile perch (Lates niloticus) and Nile tilapia (Oreochromis niloticus). The samples were collected from the Napoleon Gulf on the northern shore of Lake Victoria. The analysis was done using a gas chromatograph (GC) coupled to a high resolution mass spectrometer for PCBs and a GC equipped with an electron capture detector for HCHs. Total (Σ) PCBs in the muscles of fish varied widelywith mean values ranging from41 to 670 pg g−1 lipidweight (lw). The PCB levels in L. niloticuswere significantly greater than those in O. niloticus. The large variability observed in the datawas attributed to differences in feeding habits and trophic levels. While O. niloticus is a filter-eating fish species feeding mainly on phytoplankton and zooplankton, L. niloticus have predatory feeding behaviors and prefer a diet of live fish and, therefore, are more prone to bioaccumulate contaminants. The mean PCB concentrations in the sediments varied from 362 to 848 pg g−1 dry weight. Variations in PCB levels were observed from one study site to another, this was attributed to the nature and particle size of the sediments. HCH isomers were detected in fish at mean concentrations of up to 45,900 pg g−1 lw. The PCB and HCH concentrations were lower than those from previous studies elsewhere in literature and were below the maximum residue limits set by the European Commission and FAO/WHO Codex Alimentarius Commission, implying that the fish was fit for human consumption.
Polychlorinated biphenyls in sediments and fish species from the Murchison Bay of Lake Victoria, Uganda
(Science of the Total Environment, 2014) Ssebugere, Patrick; Sillanpää, Mika; Wang, Pu; Li, Yingming; Kiremire, Bernard T.; Kasozi, Gabriel N.; Zhu, Chaofei; Ren, Daiwei; Zhu, Nali; Zhang, Haidong; Shang, Hongtao; Zhang, Qinghua; Jiang, Guibin
Polychlorinated biphenyls (PCBs) were determined in sediments and two fish species collected from the Murchison Bay in Lake Victoria, using high resolution gas chromatography coupled to a high resolution mass spectrometer. Total PCB concentrations (Σ18PCBs) varied widely with mean values ranging from 777 to 4325 pg g−1 dry weight (dw) for sediments and 80 to 779 pg g−1 wet weight (ww) for fish. The PCB levels in the sediments were significantly higher at the station closest to Nakivubo channel, presumably due to effluents discharged by the channel, which may contain domestically produced commercial PCB mixtures. For fish, the concentrations in Nile perch (Lates niloticus) were significantly greater than those in Nile tilapia (Oreochromis niloticus) at all study stations, possibly due to dietary differences among species. World Health Organization-toxic equivalents (WHO2005-TEQs) for the dioxin-like PCBs were 0.04–0.64 pg g−1 dw and 0.01–0.39 pg g−1 ww for sediments and fish, respectively. The non-ortho PCBs exhibited the highest contribution to the Σ12TEQs (N75%) compared to themono-ortho PCBs in both fish species. The TEQs in the present study were lower than many reported worldwide in literature for fish and were within the permissible level recommended by the European Commission, implying that the fish did not pose health hazards related to PCBs to the consumers.

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