Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 20
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
Chemosphere ; 262: 127788, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-33182082

RESUMO

Lead (Pb) interferes with various bodily functions. Although high blood Pb (Pb-B) levels in residents from Kabwe, Zambia have been reported, the accumulation pattern of other metals remains unknown. The study was designed to determine the Pb-B, blood cadmium (Cd-B), and zinc (Zn-B) values of 504 representative samples from Kabwe, as well as the potential associated adverse health effects. The Pb-B level ranged from 0.79 to 154.75 µg/dL and generally increased in areas near the mine. A significant elevation of Cd-B was observed in two areas (0.37 ± 0.26 and 0.32 ± 0.30 µg/L) where the two highest mean Pb-B levels were recorded. By contrast, the Zn-B values did not differ greatly with respect to area. Some blood biochemical parameters relating to hepatic and renal functions were out of the normal range in approximately 20-50% of studied adult participants. The δ-aminolevulinic acid dehydratase (δ-ALAD) activity was significantly inhibited in the two areas contaminated by Pb and Cd. A significant negative relationship was observed between metal levels and clinical parameters, e.g., between Pb-B and δ-ALAD for all the age categories and between Cd-B and the estimated glomerular filtration rate for all the age categories except 0-4 years. The elevated Cd-B in areas near the mine relative to the other areas suggested the potential adverse health effects of Cd and/or the interaction of Pb and Cd. A significant association of metal levels with clinical parameters also indicated the effects of metal exposure on hematopoietic, hepatic, and renal systems.


Assuntos
Exposição Ambiental/análise , Poluentes Ambientais/análise , Metais/análise , Adulto , Cádmio/análise , Coleta de Dados , Efeitos Colaterais e Reações Adversas Relacionados a Medicamentos , Exposição Ambiental/estatística & dados numéricos , Monitoramento Ambiental/métodos , Taxa de Filtração Glomerular , Humanos , Fígado/química , Registros , Valores de Referência , Adulto Jovem , Zâmbia , Zinco
2.
Sci Rep ; 10(1): 15092, 2020 09 15.
Artigo em Inglês | MEDLINE | ID: mdl-32934309

RESUMO

This study quantitatively assessed the population-wide lead poisoning conditions in Kabwe, Zambia, a town with severe lead pollution. While existing data have reported concerning blood lead levels (BLLs) of residents in pollution hotspots, the data representing the entire population are lacking. Further, selection bias is a concern. Given the lack of compulsory testing schemes, BLLs have been observed from voluntary participants in blood sampling surveys, but such data can represent higher or lower BLLs than the population average because of factors simultaneously affecting participation and BLLs. To illustrate the lead poisoning conditions of the population, we expanded the focus of our surveys and then econometrically estimated the BLLs of individuals representing the population, including those not participating in blood sampling, using background geographic, demographic, and socioeconomic information. The estimated population mean BLL was 11.9 µg/dL (11.6-12.1, 95% CI), lower than existing data because of our wide focus and correction of selection bias. However, the scale of lead poisoning remained immense and 74.9% of residents had BLLs greater than 5 µg/dL, the standard reference level for lead poisoning. Our estimates provide a deeper understanding of the problem and a foundation for policy intervention designs.

3.
Environ Res ; 188: 109759, 2020 09.
Artigo em Inglês | MEDLINE | ID: mdl-32554272

RESUMO

BACKGROUND: Lead (Pb) is a well-known toxic heavy metal which can have serious public health hazards. As of today, there is no safe threshold for Pb exposure, especially for children. Lead exposure has been associated with adverse health outcomes involving epigenetic mechanisms, such as aberrant DNA methylation. The objective of the present study was to elucidate the associations between blood lead levels (BLLs) and gene-specific promoter DNA methylation status in environmental Pb-exposed children from Kabwe, Zambia. METHODS: A cross-sectional study was conducted using 2 to 10-year-old children from high Pb exposed area (N = 102) and low Pb exposed area (N = 38). We measured BLLs using a LeadCare II analyzer and investigated the methylation status of the ALAD and p16 gene promoters by methylation-specific PCR. RESULTS: The mean BLLs were 23.7 µg/dL and 7.9 µg/dL in high Pb exposed and low Pb exposed children, respectively. Pb exposure was correlated with increased methylation of the ALAD and p16 genes. The promoter methylation rates of ALAD and p16 in high Pb exposed children were 84.3% and 67.7%, and 42.1% and 44.7% in low Pb exposed children, respectively. Significantly increased methylation was found in both genes in high Pb exposed children compared with low Pb exposed children (p < 0.05). Children with methylated ALAD and p16 genes showed an increased risk of Pb poisoning (odd ratio >1) compared to the unmethylated status. CONCLUSIONS: This study for the first time tries to correlate promoter methylation status of the ALAD and p16 genes in environmental Pb-exposed children from Kabwe, Zambia as a representative. The result suggests that Pb exposure increases aberrations in ALAD and p16 gene methylation, which may be involved in the mechanism of Pb toxicity.


Assuntos
Intoxicação por Chumbo , Chumbo , Criança , Pré-Escolar , Estudos Transversais , Metilação de DNA , Genes p16 , Humanos , Chumbo/toxicidade , Intoxicação por Chumbo/epidemiologia , Intoxicação por Chumbo/genética , Sintase do Porfobilinogênio/genética , Zâmbia
4.
Chemosphere ; 243: 125412, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31995873

RESUMO

Childhood lead (Pb) poisoning has devastating effects on neurodevelopment and causes overt clinical signs including convulsions and coma. Health effects including hypertension and various reproductive problems have been reported in adults. Historical Pb mining in Zambia's Kabwe town left a legacy of environmental pollution and childhood Pb poisoning. The current study aimed at establishing the extent of Pb poisoning and exposure differences among family members in Kabwe as well as determining populations at risk and identify children eligible for chelation therapy. Blood samples were collected in July and August 2017 from 1190 household members and Pb was measured using a portable LeadCare-II analyser. Participants included 291 younger children (3-months to 3-years-old), 271 older children (4-9-years-old), 412 mothers and 216 fathers from 13 townships with diverse levels of Pb contamination. The Blood Lead Levels (BLL) ranged from 1.65 to 162  µg/dL, with residents from Kasanda (mean 45.7  µg/dL) recording the highest BLL while Hamududu residents recorded the lowest (mean 3.3  µg/dL). Of the total number of children sampled (n = 562), 23% exceeded the 45  µg/dL, the threshold required for chelation therapy. A few children (5) exceeded the 100  µg/dL whereas none of the parents exceeded the 100  µg/dL value. Children had higher BLL than parents, with peak BLL-recorded at the age of 2-years-old. Lead exposure differences in Kabwe were attributed to distance and direction from the mine, with younger children at highest risk. Exposure levels in parents were equally alarming. For prompt diagnosis and treatment, a portable point-of-care devise such as a LeadCare-II would be preferable in Kabwe.


Assuntos
Exposição Ambiental/análise , Intoxicação por Chumbo/epidemiologia , Chumbo/sangue , Chumbo/toxicidade , Adulto , Criança , Pré-Escolar , Poluição Ambiental/análise , Pai , Feminino , Humanos , Lactente , Masculino , Mineração , Mães , Registros , Reprodução , Manejo de Espécimes , Zâmbia/epidemiologia
5.
J Parasit Dis ; 43(4): 624-632, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31749534

RESUMO

Tephrosia vogelii (T. vogelii) is a known tropical leguminous herb for fixing nitrogen in the soil and as pesticide properties. Its crude leaf extract was evaluated as a natural acaricide to control ticks on naturally infested traditionally reared cattle in selected areas of Monze District of Zambia. Experimental animals were selected from herds of cattle with poor or no history of any conventional tick control and were divided into six treatment groups of five animals per set which were sprayed with 5, 10, 20 and 40% w/v of T. vogelii leaf extract bio-acaricide solution. A negative control group of five animals were sprayed with ordinary water, while a positive group with a commercial acaricide (Amitraz®) at a recommended dosage of 1:500 dilution. Half-body tick counts then doubled were conducted on each animal, before and at twenty-four hourly intervals of: 24 (1 day), 48 (2 days), 96 (3 days), 192 (4 days), 384 (5 days) and 768 (6 days) after treatment. The observed tick reductions were found to be statistically significant at all treatment levels (p value < 0.001). With this performance, there was evidence to show that the herbal extract was effective against ticks. The results showed significant and sustained efficacy T. vogelii extract from day 2 to day 6 after treatment. There was no significant difference at 5, 10, 20 and 40 w/v in the observed efficacies between low and high concentrations of the bio-acaricide used. We conclude that T. vogelii could be used to spray animals against ticks, especially in low-income communities and also in setups where organic farming is practiced.

6.
Environ Pollut ; 252(Pt B): 1267-1276, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31252124

RESUMO

Metal pollution has been associated with anthropogenic activities, such as effluents and emissions from mines. Soil could be exposure route of wild rats to metals, especially in mining areas. The aim of this study was to verify whether soil exposure under environmentally relevant circumstances results in metal accumulation and epigenetic modifications. Wistar rats were divided to three groups: 1) control without soil exposure, 2) low-metal exposure group exposed to soil containing low metal levels (Pb: 75 mg/kg; Cd: 0.4), and 3) high-metal exposure group exposed to soil (Pb: 3750; Cd: 6). After 1 year of exposure, the metal levels, Pb isotopic values, and molecular indicators were measured. Rats in the high-group showed significantly greater concentrations of Pb and Cd in tissues. Higher accumulation factors (tissue/soil) of Cd than Pb were observed in the liver, kidney, brain, and lung, while the factor of Pb was higher in the tibia. The obtained results of metal accumulation ratios (lung/liver) and stable Pb isotope ratios in the tissues indicated that the respiratory exposure would account for an important share of metal absorption into the body. Genome-wide methylation status and DNA methyltransferase (Dnmt 3a/3b) mRNA expressions in testis were higher in the high-group, suggesting that exposure to soil caused metal accumulation and epigenetic alterations in rats.


Assuntos
Cádmio/análise , Metilação de DNA/efeitos dos fármacos , Poluição Ambiental/análise , Chumbo/análise , Poluentes do Solo/análise , Animais , Cádmio/toxicidade , DNA (Citosina-5-)-Metiltransferases/metabolismo , Chumbo/toxicidade , Masculino , Mineração , Ratos , Ratos Wistar , Solo/química , Poluentes do Solo/toxicidade
7.
Int J Mol Sci ; 18(7)2017 Jul 18.
Artigo em Inglês | MEDLINE | ID: mdl-28718783

RESUMO

Anthropogenic pollution with heavy metals is an on-going concern throughout the world, and methods to monitor release and impact of heavy metals are of high importance. With a view to probe its suitability as molecular biomarker of metal pollution, this study has determined a coding sequence for metallothionein of the African sharptooth catfish Clarias gariepinus. The gene product was recombinantly expressed in Escherichia coli in presence of Zn(II), Cd(II), or Cu, and characterised by Electrospray Ionisation Mass Spectrometry and elemental analysis. C. gariepinus MT displays typical features of fish MTs, including 20 conserved cysteines, and seven bound divalent cations (Zn(II) or Cd(II)) when saturated. Livers from wild C. gariepinus fish collected in all three seasons from four different sites on the Kafue River of Zambia were analysed for their metal contents and for MT expression levels by quantitative PCR. Significant correlations were found between Zn and Cu levels and MT expression in livers, with MT expression clearly highest at the most polluted site, Chililabombwe, which is situated in the Copperbelt region. Based on our findings, hepatic expression of MT from C. gariepinus may be further developed as a major molecular biomarker of heavy metal pollution resulting from mining activities in this region.


Assuntos
Biomarcadores/metabolismo , Peixes-Gato/metabolismo , Metalotioneína/química , Metalotioneína/metabolismo , Metais Pesados/metabolismo , Transcrição Genética , Poluição da Água , Sequência de Aminoácidos , Animais , Sequência de Bases , Peixes-Gato/genética , DNA Complementar/genética , Monitoramento Ambiental , Regulação da Expressão Gênica , Geografia , Fígado/metabolismo , Metalotioneína/genética , Modelos Moleculares , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Proteínas Recombinantes/metabolismo , Zâmbia
8.
Bull Environ Contam Toxicol ; 99(1): 108-116, 2017 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-28434067

RESUMO

Zambia's Kafue River receives wastes from various sources, resulting in metal pollution. This study determined the degree of contamination of 13 metals (Al, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Se, Cd, Hg and Pb) in Kafue River sediment and the associated ecological risks at six sites in three different seasons. The level of contamination for most metals showed significant site and seasonal differences. The contamination factor and pollution load index indicated that concentrations of most metals particularly copper (Cu), cobalt (Co), manganese (Mn) and arsenic (As) were very high at sites within the Copperbelt mining area. The geoaccumulation index showed an absence of anthropogenic enrichment with Cd and Hg at all the study sites and extreme anthropogenic enrichment with Cu at sites in the Copperbelt mining area. Potential ecological risk showed that Cu and As were likely to cause adverse biological effects to aquatic organisms in the Copperbelt mining region of the Kafue River.


Assuntos
Monitoramento Ambiental , Metais Pesados/análise , Rios/química , Poluentes Químicos da Água/análise , Arsênico , Ecologia , Sedimentos Geológicos/química , Mercúrio , Medição de Risco , Estações do Ano , Zâmbia
9.
Chemosphere ; 119: 941-947, 2015 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-25303652

RESUMO

Childhood lead poisoning is a serious public health concern worldwide. Blood lead levels exceeding 5 µg dL(-1) are considered elevated. In Kabwe, the capital of Zambia's Central Province, extensive Pb contamination of township soils in the vicinity of a Pb-Zn mine and posing serious health risk to children has been reported. We investigated BLLs in children under the age of 7 years in townships around the mine; where blood samples were collected and analyzed using an ICP-MS. All of the sampled children had BLLs exceeding 5 µg dL(-1). Children in these areas could be at serious risk of Pb toxicity as 18% of the sampled children in Chowa, 57% (Kasanda) and 25% (Makululu) had BLLs exceeding 65 µg dL(-1). Eight children had BLLs exceeding 150 µg dL(-1) with the maximum being 427.8 µg dL(-1). We recommend that medical intervention be commenced in the children with BLL exceeding 45 µg dL(-1).


Assuntos
Poluentes Ambientais/sangue , Intoxicação por Chumbo/sangue , Intoxicação por Chumbo/epidemiologia , Chumbo/sangue , Adolescente , Criança , Humanos , Mineração , Zâmbia/epidemiologia , Zinco
10.
Jpn J Vet Res ; 61 Suppl: S79-81, 2013 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-23631162

RESUMO

In order to assess the effects of metal contamination on wildlife, we collected wild black rats (Rattus sp.) from mining areas (Kabwe and Chingola) and a control area (Lusaka) in Zambia and compared metal and metallothionein (MT) levels in their tissues. Furthermore, we exposed metal-contaminated soil from Kabwe to laboratory Wistar rats (Rattus norvegicus) for one year in order to determine the accumulation factors and effects of metals caused by soil exposure. Results of both the field and laboratory studies suggested that metal-contaminated soil caused accumulation and biological responses such as elevation of MT-2 mRNA expression levels in rats.


Assuntos
Metais/química , Ratos , Poluentes do Solo/metabolismo , Poluentes do Solo/toxicidade , Animais , Animais Selvagens , Osso e Ossos/química , Encéfalo/metabolismo , Regulação Enzimológica da Expressão Gênica , Rim/química , Rim/metabolismo , Fígado/química , Fígado/metabolismo , Pulmão/química , Pulmão/metabolismo , Metaloproteinase 15 da Matriz/genética , Metaloproteinase 15 da Matriz/metabolismo , Tíbia
11.
Arch Environ Contam Toxicol ; 64(1): 119-29, 2013 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-23052357

RESUMO

The Copperbelt region, upstream of the Kafue River, including Lake Itezhi-tezhi (ITT), in Zambia has extensive copper (Cu) mines. In our field study, geographic information system analysis in lake sediment indicated that the northern part of the lake, i.e., the Copperbelt region, could be the source of Cu pollution. Concentrations of Cu in stomach contents between fish species were not significantly different. However, Oreochromis spp. liver showed significantly greater Cu concentrations than those in other fish species. Log liver [Cu], standard length, and nitrogen stable isotope ratio were positively correlated only in Oreochromis spp. In the laboratory study, O. niloticus and O. latipes were exposed to Cu for 4 days, and recovery phases ≤ 28 days were examined. O. niloticus showed significantly greater concentrations of Cu compared with O. latipes at all sampling points. Significantly greater concentrations of Hg in Schilbe intermedius liver than for other fish species were observed, whereas O. macrochir showed significantly greater concentrations of cadmium. In conclusion, the northern part of the lake could be the source of Cu pollution in Lake ITT. Diet may not be the reason for high Cu accumulation in Oreochromis spp. Results from both field and laboratory studies imply that Oreochromis spp. contain high concentrations of Cu under normal physiological conditions.


Assuntos
Ciclídeos/metabolismo , Cobre/análise , Monitoramento Ambiental/métodos , Sistemas de Informação Geográfica , Lagos/química , Poluentes Químicos da Água/análise , Animais , Cobre/metabolismo , Poluentes Químicos da Água/metabolismo , Zâmbia
12.
Environ Toxicol Chem ; 32(1): 189-92, 2013 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-23059509

RESUMO

Concentrations of Pb, Cd, and other metals in tissues of 17 free-range and 32 commercial broiler chickens from the Kabwe mining town in Zambia were determined. Mean concentrations of Pb and Cd exceeded maximum levels for human consumption in some organs including muscle (Pb only) in free-range chickens, in contrast to low levels in broiler chickens. Human consumers in Kabwe could be exposed to Pb and Cd in free-range chickens.


Assuntos
Galinhas/metabolismo , Exposição Ambiental/estatística & dados numéricos , Poluentes Ambientais/metabolismo , Metais/metabolismo , Mineração , Animais , Exposição Ambiental/análise , Chumbo , Zâmbia , Zinco
13.
Environ Monit Assess ; 185(6): 4907-18, 2013 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-23054276

RESUMO

The lead-zinc (Pb-Zn) mine in Kabwe City and the copper-cobalt (Cu-Co) mine in the Copperbelt Province are major mining areas in Zambia. To examine the effects of metal pollution on wildlife, wild black rats (Rattus rattus and Rattus tanezumi) were captured in Kabwe and Chingola (in the Copperbelt Province), and in Lusaka (a noncontaminated site). Wild black rats in Kabwe accumulated significantly higher concentrations of Pb and Cd in various organs than rats from Lusaka. In Chingola, significantly higher concentrations of Cu, Co, Pb, and Cd were accumulated in wild black rats than in rats from Lusaka. These results were in accordance with metal accumulation patterns in soil. From toxicological aspects, concentrations of Pb and Cd in rats were generally low. However, metallothionein-1 (MT-1) and metallothionein-2 (MT-2) mRNA expression levels in wild black rats from Kabwe were significantly higher than those in rats from Lusaka. A generalized linear model (GLM) showed that concentrations of Zn and Cu had positive effects on the MT-1 and MT-2 mRNA expression. These results suggest that wild black rats in Zambian mining sites were exposed to metals that accumulated in their organs, causing biological responses such as MT mRNA induction. GLM indicated that heme oxygenase-1 (HO-1) mRNA expression could be a marker for Cr exposure.


Assuntos
Monitoramento Ambiental , Poluentes Ambientais/metabolismo , Metais/toxicidade , Mineração , Animais , Poluentes Ambientais/toxicidade , Feminino , Masculino , Metais/metabolismo , Ratos , Zâmbia
14.
Parasit Vectors ; 5: 282, 2012 Dec 04.
Artigo em Inglês | MEDLINE | ID: mdl-23211002

RESUMO

BACKGROUND: Loop-mediated isothermal amplification (LAMP) is a novel strategy which amplifies DNA with high sensitivity and rapidity under isothermal conditions. In the present study, the performance of the repetitive insertion mobile element (RIME)-LAMP and human serum resistance-associated gene (SRA)-LAMP assays were evaluated using clinical specimens obtained from four male patients from Luangwa and Zambezi valleys in Zambia and Zimbabwe, respectively. FINDINGS: The cases reported in this preliminary communication were all first diagnosed by microscopy, through passive surveillance, and confirmed by both RIME-LAMP and SRA-LAMP. A good correlation between microscopy and LAMP was observed and contributed to staging and successful treatment of patient. RIME-LAMP and SRA-LAMP complimented each other well in all the cases. CONCLUSIONS: Both RIME-LAMP and SRA-LAMP were able to detect Trypanosoma brucei rhodesiense DNA in patient blood and CSF and hence confirmed HAT in the parasitaemic patients. Our study indicates that the LAMP technique is a potential tool for HAT diagnosis, staging and may be useful for making therapeutic decisions. However, no statistically significant conclusion may be drawn due to the limited sample size used in the present study. It is thus imperative to conduct a detailed study to further evaluate the potential of LAMP as a bedside diagnostic test for HAT.


Assuntos
Técnicas de Amplificação de Ácido Nucleico/métodos , Tripanossomíase Africana/diagnóstico , Tripanossomíase Africana/epidemiologia , Adulto , Doenças Transmissíveis Emergentes , Humanos , Masculino , Fatores de Tempo , Zâmbia/epidemiologia , Zimbábue/epidemiologia
15.
Environ Toxicol Chem ; 31(10): 2300-5, 2012 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-22821446

RESUMO

The Republic of Zambia is rich in mineral resources, such as zinc (Zn) and lead (Pb), and mining is a key industry in Zambia. A previous study of Pb pollution in Kabwe, one of the main mining areas, found that soil was contaminated with high levels of toxic metals over a substantial area. In the present study, the authors focus on toxic metal pollution in cattle, one of the most important domestic animals in Zambia. Blood samples from cattle in Kabwe and a control area (Lusaka) were tested for toxic metal content. They also measured mRNA expression of metal-responsive proteins and cytokines in white blood cells using real-time reverse transcriptase polymerase chain reaction. In the present in vitro study, The authors cultured peripheral blood mononuclear cells (PBMCs) from cattle, exposing them to Pb acetate for 24 h and analyzing mRNA expression of metal-responsive proteins and selected cytokines. Lead concentrations in cattle blood from Kabwe were significantly greater than those from Lusaka, as were the mRNA expressions of metallothionein-2 (MT-2), tumor necrosis factor-α (TNF-α), interferon-γ (IFN-γ), interleukin-1ß (IL-1ß), IL-6, and inducible nitric oxide synthase (iNOS). The present in vitro study demonstrated that Pb exposure led to an increase in the expressions of MT-2, TNF-α, IL-1ß, and iNOS, similar to those found in vivo. These results indicate the possibility of immune system modulations in cattle from the Kabwe area.


Assuntos
Bovinos/imunologia , Chumbo/toxicidade , Mineração , Poluentes do Solo/toxicidade , Animais , Bovinos/sangue , Células Cultivadas , Feminino , Heme Oxigenase-1/metabolismo , Interferon gama/metabolismo , Interleucina-1beta/metabolismo , Interleucina-6/metabolismo , Chumbo/sangue , Leucócitos Mononucleares/imunologia , Leucócitos Mononucleares/metabolismo , Metalotioneína/metabolismo , Óxido Nítrico Sintase Tipo II/metabolismo , Compostos Organometálicos/toxicidade , Fator de Necrose Tumoral alfa/metabolismo , Zâmbia , Zinco/sangue
16.
Ecotoxicol Environ Saf ; 80: 333-8, 2012 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-22521811

RESUMO

Hippopotami (Hippopotamus amphibius L) are large semi-aquatic mammals that can be exposed to metals and metalloid from both terrestrial and aquatic environments. Therefore, knowledge of metal and metalloid accumulation characteristics in hippopotami living in the national park is important from ecotoxicological point of view. Levels of toxic metals (Cd, Pb and Hg) and metalloid (As) in hippopotami liver from the South Luangwa National Park in Zambia were far lower compared to the established values of toxic levels in cattle. No temporal variations of metal levels in hippopotami were observed, probably because of good management condition and the lack of anthropogenic activities around the national park. However, hippopotami liver accumulated significantly higher concentrations of Hg compared to soil, sediment and their food (plants), most likely due to a process of biomagnification throughout a trophic chain. Moreover, hippopotami liver and land plants showed significantly higher Cd levels than those of soil. These results strongly suggest that hippopotami liver accumulate higher levels of these metals if surrounding environment is contaminated. Levels of Cr and Ni in hippopotami liver were higher compared to other toxic metals. Since this is the first report to show the Cr and Ni levels and bio-accumulation characteristics of Hg and Cd in hippopotami, we concluded that continuous monitoring and evaluation of toxic effects of these metals on hippopotami should be conducted.


Assuntos
Mamíferos/metabolismo , Metaloides/análise , Metais/análise , Plantas/química , Poluentes Químicos da Água/análise , Animais , Monitoramento Ambiental , Feminino , Sedimentos Geológicos/química , Masculino , Metaloides/metabolismo , Metais/metabolismo , Solo/química , Poluentes Químicos da Água/metabolismo , Zâmbia
17.
Trop Anim Health Prod ; 44(1): 179-83, 2012 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-21647772

RESUMO

A field investigation was conducted in the Sesheke District of Zambia along the Zambezi River to determine the fish species susceptible to epizootic ulcerative syndrome (EUS), a newly confirmed disease in Southern Africa. A total of 2,132 fishes were inspected for gross EUS-like lesions, of which 188 (8.82%; 95% CI=7.67-10.1%) were found with typical characteristic lesions of EUS. Of these 188 samples, 156 were found to have mycotic granulomas on histopathological analysis, representing 83.0% (95% CI=76.7-87.9%) of the initially identified in the laboratory through gross examination. The following 16 species of fish were examined and found with EUS lesions; Clarias ngamensis, Clarias gariepinus, Barbus poechii, Tilapia sparrmanii, Serranochromis angusticeps, Brycinus lateralis, Micralestes acutidens, Sargochromis carlottae, Hydrocynus vittatus, Phryngochromis acuticeps, Schilbe intermedius, Hepsetus odoe, Labeo lunatus, Oreochromis andersonii, Barbus unitaeniatus, and Barbus paludinosus. T. sparrmanii did not show any lesions, while the Clarias species were found to be the most afflicted with EUS. These results could be useful to fish farmers and organizations interested in improving aquaculture in the area.


Assuntos
Aphanomyces/fisiologia , Surtos de Doenças/veterinária , Doenças dos Peixes/patologia , Peixes/microbiologia , Infecções/veterinária , Dermatopatias/veterinária , Animais , Doenças dos Peixes/epidemiologia , Doenças dos Peixes/microbiologia , Peixes/classificação , Infecções/epidemiologia , Infecções/microbiologia , Infecções/patologia , Prevalência , Rios , Dermatopatias/epidemiologia , Dermatopatias/microbiologia , Dermatopatias/patologia , Zâmbia/epidemiologia
18.
Environ Pollut ; 159(1): 175-181, 2011 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-20971538

RESUMO

Metal (Cr, Co, Cu, Zn, Cd, Pb, Ni) and metalloid (As) accumulation was studied in roadside soil and wild rat (Rattus sp.) samples from near a Pb-Zn mine (Kabwe, Zambia) and the capital city of Zambia (Lusaka). The concentrations of the seven metals and As in the soil samples and Pb in the rat tissue samples were quantified using atomic absorption spectroscopy. The concentrations of Pb, Zn, Cu, Cd, and As in Kabwe soil were much higher than benchmark values. Geographic Information System analysis indicated the source of metal pollution was mining and smelting activity. Interestingly, the area south of the mine was more highly contaminated even though the prevailing wind flow was westward. Wild rats from Kabwe had much higher tissue concentrations of Pb than those from Lusaka. Their body weight and renal Pb levels were negatively correlated, which suggests that mining activity might affect terrestrial animals in Kabwe.


Assuntos
Metaloides/análise , Metaloides/metabolismo , Metais Pesados/análise , Metais Pesados/metabolismo , Mineração , Poluentes do Solo/análise , Poluentes do Solo/metabolismo , Animais , Cromo/análise , Cromo/metabolismo , Cobalto/análise , Cobalto/metabolismo , Cobre/análise , Cobre/metabolismo , Monitoramento Ambiental , Chumbo/análise , Chumbo/metabolismo , Níquel/análise , Níquel/metabolismo , Ratos , Zâmbia
19.
Arch Environ Contam Toxicol ; 59(2): 291-300, 2010 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-20162262

RESUMO

We measured the level of heavy metal accumulation in lake sediments, herbivorous (Oreochromis niloticus) and carnivorous (Serranochromis thumbergi) fish, and crayfish (Cherax quadricarinatus) from Lake Itezhi-tezhi (ITT) and Lake Kariba. We used atomic absorption spectrophotometry to quantify the levels of seven heavy metals (Cr, Co, Cu, Zn, Cd, Pb, and Ni). The sediment and the herbivorous fish O. niloticus accumulated a very high concentration of Cu in Lake ITT, most likely due to the discharge of Cu waste from a mining area 450 km upstream. The aquatic species we sampled in Lake Kariba had higher concentrations of Cr, Ni, and Pb relative to those in Lake ITT. This is most likely due to anthropogenic activities, such as the use of leaded petrol and antifouling agents in marine paints. Interestingly, we observed a negative correlation between the coefficient of condition (K) and Ni concentration in the crayfish hepatopancreas. Both O. niloticus and the crayfish had much higher biota-sediment accumulation factors (BSAF) for Cu, Zn, and Cd relative to Cr, Co, Pb, and Ni. The rank of BSAF values for O. niloticus (Cu>Cd>Zn) and C. quadricarinatus (Zn>Cd>Cu) differed from the expected ranks based on the general order of affinity of metals (Cd>>Zn>Cu).


Assuntos
Astacoidea/metabolismo , Ciclídeos/metabolismo , Monitoramento Ambiental , Sedimentos Geológicos/química , Poluentes Químicos da Água/análise , Animais , Água Doce/química , Hepatopâncreas/metabolismo , Fígado/metabolismo , Metais Pesados , Músculos/metabolismo , Zâmbia
20.
Jpn J Vet Res ; 54(2-3): 119-28, 2006 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-17201197

RESUMO

The study determined the types of pesticide/herbicide pollutants in water, sediment and fish from the Kafue River. A preliminary investigation of the oxidative stress from these pesticides/herbicides was also assessed by measurement of catalase activity. Water, sediment and fish samples were collected upstream, midstream and downstream the Kafue river in Chingola, Kitwe, Kafue National Park and Kafue Town. Water, sediment and fish muscle were sampled and analysed for pesticides using Gas chromatography. For catalase activity fish liver samples only were examined. The pesticides/herbicides detected in all samples collectively included: Heptachlor, pp'-DDE, Cypermethrin, Chlordane, Toxaphene, Terbufos, Kelthane, Endosulfan, Dieldrin, pp'-DDD, pp'-DDT, Atrazine, Disulfoton, d-trans-Allethrin and Endrin. On the other hand, catalase activity was detected in all fish liver samples from all sites. Its levels increased significantly from Chingola upstream to sites downstream with highest being in Kafue town. This study therefore, demonstrates that there is widespread contamination of the Kafue River with pesticides/ herbicides. It also demonstrates that organochlorides are found throughout the river especially in fish samples. The spectrum of pesticides/herbicides was much wider in fish probably due to bioaccumulation. It was also observed that fish are subjected to oxidative stress as determined by catalase levels. The stress is more pronounced downstream where the catalase levels were significantly higher than Chingola. The observation that more pesticide varieties are also found downstream may suggest a likely causative effect of the pesticides on oxidative stress although this needs further investigation. This study further tentatively highlights the potential dangers of these agro-related substances to dependants of the Kafue River water body and the need to carry out risk assessments and thereafter institute corrective measures to help reduce contamination and adverse effects.


Assuntos
Catalase/metabolismo , Peixes/metabolismo , Praguicidas/análise , Praguicidas/toxicidade , Rios/química , Poluentes Químicos da Água/análise , Animais , Sedimentos Geológicos/química , Japão , Fatores de Tempo , Poluentes Químicos da Água/toxicidade , Poluição Química da Água
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA