Suchergebnisse

Sediments from two rivers receiving animal farming wastewaters under tropical conditions in Kinshasa, capital city of the Democratic Republic of the Congo were investigated for microbial pollution. The total bacterial load, the abundance of relevant bacteria and ARGs via qPCR. The total bacterial load correlated with relevant bacteria and genes blaOXA-48, sul3, and tet(B) (P value<0.01). E. coli strongly correlated with 16S rDNA, Enterococcus, Pseudomonas spp., blaOXA-48, sul3, and tet(B) (P value<0.01) and with blaCTX-M, sul1, and sul2 at a lower magnitude (P value <0.05). The most abundant and most commonly detected ARGs were sul1, and sul2. In a similar manner, we investigated hospitals and toxic metals and persistent organic pollutants and their consequences on sustainable agriculture and the risk posed to the consumers.

Antibiotic resistant bacteria and genes which confer resistance to antibiotics from human/animal sources are currently considered a serious environmental and a public health concern. This problem is still little investigated in aquatic environment of developing countries according to the different climatic conditions. In this research, the total bacterial load, the abundance of relevant bacteria (Escherichia coli (E. coli), Enterococcus (Ent), and Pseudomonas), and antibiotic resistance genes (ARGs: blaOXA-48, blaCTX-M, sul1, sul2, sul3, and tet(B)) were quantified using Quantitative Polymerase Chain Reaction (qPCR) in sediments from two rivers receiving animal farming wastewaters under tropical conditions in Kinshasa, capital city of the Democratic Republic of the Congo. Human and pig host-specific markers were exploited to examine the sources of contamination. The total bacterial load correlated with relevant bacteria and genes blaOXA-48, sul3, and tet(B) (P value<0.01). E. coli strongly correlated with 16s rDNA, Enterococcus, Pseudomonas spp., blaOXA-48, sul3, and tet(B) (P value<0.01) and with blaCTX-M, sul1, and sul2 at a lower magnitude (P value <0.05). The most abundant and most commonly detected ARGs were sul1, and sul2. Our findings confirmed at least two sources of contamination originating from pigs and anthropogenic activities and that animal farm wastewaters didn't exclusively contribute to antibiotic resistance profile. Moreover, our analysis sheds the light on developing countries where less than adequate infrastructure or lack of it adds to the complexity of antibiotic resistance proliferation with potential risks to the human exposure and aquatic living organisms. This research presents useful tools for the evaluation of emerging microbial contaminants in aquatic ecosystems which can be applied in the similar environment.

AbstractThe co-occurrence of heavy metals, antibiotic-resistant bacteria (ARB) and antibiotic-resistance genes (ARGs) from hospital effluents spreading into the river receiving systems and evaluating associated risks are topics of scientific interest and still under-studied in developing countries under tropical conditions. To understand the selectors of the ARGs, we examined the occurrence of heavy metals (Cr, Co, Ni, Cu, Cd, Pb and Zn), associated ARB (β-lactam-resistant Escherichia coli, β-lactam-resistant Enterobacteriaceae, and carbapenem-resistant Enterobacteriaceae) and ARGs (blaOXA, blaCTX-M, blaIMP, blaTEM) in water and sediments from two sub-urban rivers receiving urban and hospital effluent waters in the Democratic Republic of the Congo (DRC). High abundances of ARB and ARGs were observed in all sediment samples. All the metal contents correlated negatively with grain size (− 0.94 ≤ r ≤  − 0.54, p < 0.05) except for Ni and positively with organic matter content and total copies of 16 s rRNA (0.42 ≤ r ≤ 0.79, p < 0.05), except for Ni and Zn. The metals had a significant positive correlation with the faecal indicator Enterococcus except for Ni and Cd (0.43 ≤ r ≤ 0.67, p < 0.05). Carbapenem-resistant Enterobacteriaceae correlated negatively with Zn (r =  − 0.44, p < 0.05) and positively with all the rest of toxic metals (0.58 ≤ r ≤ 1.0, p < 0.05). These results suggested that some metals had a great influence on the persistence of ARB and ARGs in sediments. Overall, this study strongly recommends the managing urban wastewater to preserve water resources used for human and agricultural purposes. Additionally, we recommend the utilizing biological indicators (faecal indicator bacteria, ARB, ARGs) when investigating urban wastewater pollutions.

The co-occurrence of heavy metals, antibiotic-resistant bacteria (ARB) and antibiotic-resistance genes (ARGs) from hospital effluents spreading into the river receiving systems and evaluating associated risks are topics of scientific interest and still under-studied in developing countries under tropical conditions. To understand the selectors of the ARGs, we examined the occurrence of heavy metals (Cr, Co, Ni, Cu, Cd, Pb and Zn), associated ARB (β-lactam-resistant Escherichia coli, β-lactam-resistant Enterobacteriaceae, and carbapenem-resistant Enterobacteriaceae) and ARGs (bla(OXA), bla(CTX-M), bla(IMP), bla(TEM)) in water and sediments from two sub-urban rivers receiving urban and hospital effluent waters in the Democratic Republic of the Congo (DRC). High abundances of ARB and ARGs were observed in all sediment samples. All the metal contents correlated negatively with grain size (− 0.94 ≤ r ≤ − 0.54, p < 0.05) except for Ni and positively with organic matter content and total copies of 16 s rRNA (0.42 ≤ r ≤ 0.79, p < 0.05), except for Ni and Zn. The metals had a significant positive correlation with the faecal indicator Enterococcus except for Ni and Cd (0.43 ≤ r ≤ 0.67, p < 0.05). Carbapenem-resistant Enterobacteriaceae correlated negatively with Zn (r = − 0.44, p < 0.05) and positively with all the rest of toxic metals (0.58 ≤ r ≤ 1.0, p < 0.05). These results suggested that some metals had a great influence on the persistence of ARB and ARGs in sediments. Overall, this study strongly recommends the managing urban wastewater to preserve water resources used for human and agricultural purposes. Additionally, we recommend the utilizing biological indicators (faecal indicator bacteria, ARB, ARGs) when investigating urban wastewater pollutions. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s11356-021-17115-z.

The co-occurrence of heavy metals, antibiotic-resistant bacteria (ARB) and antibiotic-resistance genes (ARGs) from hospital effluents spreading into the river receiving systems and evaluating associated risks are topics of scientific interest and still under-studied in developing countries under tropical conditions. To understand the selectors of the ARGs, we examined the occurrence of heavy metals (Cr, Co, Ni, Cu, Cd, Pb and Zn), associated ARB (β-lactam-resistant Escherichia coli , β-lactam-resistant Enterobacteriaceae, and carbapenem-resistant Enterobacteriaceae) and ARGs ( bla OXA , bla CTX-M , bla IMP , bla TEM ) in water and sediments from two sub-urban rivers receiving urban and hospital effluent waters in the Democratic Republic of the Congo (DRC). High abundances of ARB and ARGs were observed in all sediment samples. All the metal contents correlated negatively with grain size (− 0.94 ≤ r ≤ − 0.54, p < 0.05) except for Ni and positively with organic matter content and total copies of 16 s rRNA (0.42 ≤ r ≤ 0.79, p < 0.05), except for Ni and Zn. The metals had a significant positive correlation with the faecal indicator Enterococcus except for Ni and Cd (0.43 ≤ r ≤ 0.67, p < 0.05). Carbapenem-resistant Enterobacteriaceae correlated negatively with Zn ( r = − 0.44, p < 0.05) and positively with all the rest of toxic metals (0.58 ≤ r ≤ 1.0, p < 0.05). These results suggested that some metals had a great influence on the persistence of ARB and ARGs in sediments. Overall, this study strongly recommends the managing urban wastewater to preserve water resources used for human and agricultural purposes. Additionally, we recommend the utilizing biological indicators (faecal indicator bacteria, ARB, ARGs) when investigating urban wastewater pollutions.

The accumulation of toxic metals in food consumption has been identified as a serious human health risk. Ledermanniella schlechteri (LDMSC) is a genus of Podostemaceae plant family and is well known to grow naturally on rocks of rapid waters. LDMSC is rich in nutrients and one of the most consumed aquatic vegetables in Africa. However, there are not any studies performed to assess the level of toxic metals in this aquatic plant. Consequently, the aim of this study is to assess the concentration of toxic metals in LDMSC and to evaluate the potential health risk to the consumers. Plant samples were collected in Congo River at the rapid of Kinsuka-Mimosa, in the vicinity of Kinshasa, Capital City of the Democratic Republic of the Congo (DRC). Toxic metal (Cr, Cu, Zn, As, Cd and Pb) concentrations in LDMSC were determined using Inductively Coupled Plasma Mass Spectrometry whereas Hg analysis was performed using atomic absorption spectrophotometry. Metal levels in LDMSC were compared with international regulation for human consumption set by the Food and Agriculture Organization (FAO) and World Health Organization (WHO). Metal concentrations in LDMSC varied significantly according to sampling sites. The average values (in mg kg-1) ranging from 0.44 -9.1 (Cr), 0.14-4.52 (Ni), 5.5-78.4 (Cu), 336.14-1520.91 (Zn), 0.08-0.49 (As), 0.21-0.78 (Cd), 0.44-11.81 (Pb), and 0.02-0.24 (Hg). In all sampling sites, the average concentration of Zn, As, Cd, and Hg in plant samples exceeded the FAO/WHO permissible limits for human consumption. According to FAO/WHO regulation and the calculated values of targeted risk quotient, the impact on human health is likely to occur. On other hand, according to the metal levels in LDMSC, this plant can be used as bioindicator to evaluate the state of river pollution by toxic metals.

Oysters and shrimp are abundant and commonly consumed seafood by the indigenous population of the Kongo central region of the Democratic Republic of the Congo (DRC). Literature reviews suggest that no data were available for the metal concentrations in these species. Consequently, the purpose of this study is to determine the metal concentrations in tissues of oysters (Egeria congica) and shrimp (Macrobrachium spp., Parapenaeus spp., Penaeus spp.) collected in November 2017 from the Atlantic Ocean Coast of DRC in the territory of Muanda. Metal levels in the seafood species studied here were put into context using international regulation for human consumption set by the Food and Agriculture Organization (FAO), Canadian Food Inspection Agency (CFIA), European Union (EU), and World Health Organization (WHO). Our results demonstrated that the concentration of heavy metals varied considerably between sampling sites and analyzed species (P<0.05), with the values (in mg kg1) ranged between 0.05-0.41, 0.03-2.25,

The objective of the present research was to evaluate the contamination level and potential risks at a part of a large and important river in Central Africa, the Congo River. Surface sediments were collected from seven stations located in Maluku-Kinsuka section, at the vicinity of Kinshasa, capital city of Democratic Republic of the Congo. The concentration of toxic metals (Cr, Co, Ni, Cu, Zn, As, Cd and Pb) in sediment samples were determined using Inductive Coupled Plasma-Mass Spectroscopy (ICP-MS). The Hg analysis was carried out using Advanced Mercury Analyzer (AMA). The evaluation of the pollution degree was based on Sediment Quality Guidelines (SQGs), Enrichment Factor (EF), Geoaccumulation Index (Igeo), and using toxicity test based on exposing Ostracods to the sediment samples. The result revealed high metal concentrations in sediments from the 4 densely populated areas (Kinkole, Kauka fishermen, Demoulin, Chanic), reaching the values (mg kg-1) of of 95.5, 14.3, 37.1, 139.9, 281.5, 4.8, 6.6, 200.9 and 4.9 mg kg-1 for Cr, Co, Ni, Cu, Zn, As, Cd, Pb and Hg, respectively. These values are above SQGs and probable effect levels. In these sites, Igeo and EF values showed heavily to extremely polluted and severe enrichment to extremely severe enrichment for analysed metals. Additionally, Ostracods exposed to sediments resulted in 100% mortality rates after 6 days of incubation, demonstrating the sediment toxicity as well as potential risks for aquatic living organisms. The pollution in these sites may be explained by local intense human activities with various commercial, presence of uncontrolled landfills in riverbank and industrial settlements, as well as by the construction of boats for the regular navigation along the river. This research presents useful tools for evaluating sediments quality and risk, which can be applied to similar environments.

Oysters and shrimp are abundant and commonly consumed seafood by the indigenous population of the Kongo central region of the Democratic Republic of the Congo (DRC). Literature reviews suggest that no data were available for the metal concentrations in these species. Consequently, the purpose of this study is to determine the metal concentrations in tissues of oysters (Egeria congica) and shrimp (Macrobrachium spp., Parapenaeus spp., Penaeus spp.) collected in November 2017 from the Atlantic Ocean Coast of DRC in the territory of Muanda. Metal levels in the seafood species studied here were put into context using international regulation for human consumption set by the Food and Agriculture Organization (FAO), Canadian Food Inspection Agency (CFIA), European Union (EU), and World Health Organization (WHO). Our results demonstrated that the concentration of heavy metals varied considerably between sampling sites and analyzed species (P < 0.05), with the values (in mg kg(1)) ranged between 0.05-0.41, 0.03–2.25,

The urban agriculture in developing countries plays a huge important socioeconomic role in confronting the challenge of eradicating hunger, improving food security and the social daily life of the population. However, the quality evaluation of water used for urban agriculture irrigation as well as the accumulation of pollutants such as heavy metals in fresh produces are still largely unstudied. The purpose of this study was to investigate the concentration of metals (Cr, Co, Ni, Cu, Zn, As, Cd, Pb and Hg) in irrigation water from rivers, soil and Amaranthus viridis (A. viridis), in order to evaluate the potential human dietary risks. The research was conducted in eight sites characterized by intensive agriculture performed in watersheds in Kinshasa, capital of Democratic Republic of the Congo. The results showed high metal concentrations in A. viridis leaf varying considerably among sampling sites (P<0.05), reaching the values (in mg kg-1 wet weight) of 2.97 (Cr), 1.73 (Co), 12.30 (Ni), 16.11 (Cu), 652.91 (Zn), 0.10 (As), 1.62 (Cd), 8.91 (Pb), and 0.1 (Hg). These values exceeded safe limits set by Food and Agriculture Organization/World Health Organization for human consumption (WHO/FAO) for human consumption. The assessment of human health risks using the targeted risk quotient and estimated dietary intake showed potential health hazards to consumers due to the levels of Cd and Pb in leafy vegetables from several studied sites. The vegetable contamination can be explained by chemicals used to combat and prevent A. viridis diseases, and the vehicle and motorcycle emissions around. Thus, given the concentrations of metals in A. viridus leaf, human health implications are likely to occur on heavy continuous consumption.