Pharmaceutical pollution of the world's rivers.

Environmental exposure to active pharmaceutical ingredients (APIs) can have negative effects on the health of ecosystems and humans. While numerous studies have monitored APIs in rivers, these employ different analytical methods, measure different APIs, and have ignored many of the countries of the world. This makes it difficult to quantify the scale of the problem from a global perspective. Furthermore, comparison of the existing data, generated for different studies/regions/continents, is challenging due to the vast differences between the analytical methodologies employed. Here, we present a global-scale study of API pollution in 258 of the world's rivers, representing the environmental influence of 471.4 million people across 137 geographic regions. Samples were obtained from 1,052 locations in 104 countries (representing all continents and 36 countries not previously studied for API contamination) and analyzed for 61 APIs. Highest cumulative API concentrations were observed in sub-Saharan Africa, south Asia, and South America. The most contaminated sites were in low- to middle-income countries and were associated with areas with poor wastewater and waste management infrastructure and pharmaceutical manufacturing. The most frequently detected APIs were carbamazepine, metformin, and caffeine (a compound also arising from lifestyle use), which were detected at over half of the sites monitored. Concentrations of at least one API at 25.7% of the sampling sites were greater than concentrations considered safe for aquatic organisms, or which are of concern in terms of selection for antimicrobial resistance. Therefore, pharmaceutical pollution poses a global threat to environmental and human health, as well as to delivery of the United Nations Sustainable Development Goals.

Impact of anthropogenic activities on the occurrence and distribution of toxic metals, extending-spectra ß-lactamases and carbapenem resistance in sub-Saharan African urban rivers.

The occurrence and dissemination of toxic metals, antibiotic resistant bacteria and their resistance genes (ARGs) in the aquatic ecosystems of sub-Saharan African countries are still understudied, despite their potential to threat human health and aquatic organisms. In this context, the co-contamination and seasonal distribution of toxic metals and ARG in river sediments receiving untreated urban sewages and hospital effluents from Kinshasa, the capital city of the Democratic Republic of the Congo were investigated. ARGs including ß-lactam resistance (blaCTX-M and blaSHV), carbapenem resistance (blaVIM, blaIMP, blaKPC, blaOXA-48 and blaNDM) and total bacterial load were quantified by using quantitative polymerase chain reaction (qPCR) in total DNA extracted from sediment. The amount of toxic metals in sediments was quantified using Inductively Coupled Plasma Mass Spectrometry (ICP-MS). The results highlight high abundance of 16S rRNA and ARGs copy numbers in sediment samples. Strong pollution of rivers by toxic metals was found, with max values (mg kg-1) of 81.85(Cr), 5.09(Co), 33.84(Ni), 203.46 (Cu), 1055.92(Zn), 324.24(Pb) and 2.96(Hg). Results also highlight the high abundance of bacterial markers (8.06 × 109-2.42 × 1012 16S rRNA/g-1 DS) as well as antibiotic resistance genes (up to 4.58 × 108 ARG. g-1 DS) in the studied rivers. Significant correlations were observed between (i) metals (except Cd and Hg) and organic matter (R > 0.60, p < 0.05); and (ii) ARGs (except blaNDM) and 16S rRNA (R > 0.57, p < 0.05) suggesting a tight link between (i) metal contamination and anthropogenic pressure and (ii) microbial contamination of river and dissemination of antibiotic resistance. Results demonstrated that multi-diffuse pollution originating from human activity contribute to the spread of toxic metals and ARGs into the aquatic ecosystems.

Hospital wastewaters: A reservoir and source of clinically relevant bacteria and antibiotic resistant genes dissemination in urban river under tropical conditions.

The occurrence and dissemination of antibiotic resistant genes (ARGs) that are associated with clinical pathogens and the evaluation of associated risks are still under-investigated in developing countries under tropical conditions. In this context, cultivable and molecular approaches were performed to assess the dissemination of bacteria and the antibiotic resistance genes in aquatic environment in Kinshasa, Democratic Republic of the Congo. Cultivable approach quantified ß-lactam, carbapenem resistant, and total Escherichia coli and Enterobacteriaceae in river sediments and surface waters that receive raw hospital effluents. The molecular approach utilized Quantitative Polymerase Chain Reaction (qPCR) to quantify the total bacteria and the richness of relevant bacteria (Escherichia coli, Enterococcus, and Pseudomonas), and antibiotic resistance genes (ARGs: blaOXA-48, blaCTX-M, blaIMP, blaTEM) in sediment samples. Statistical analysis were employed to highlight the significance of hospital contribution and seasonal variation of bacteria and ARGs into aquatic ecosystems in suburban municipalities of Kinshasa, Democratic Republic of the Congo. The contribution of hospitals to antibiotic resistance proliferation is higher in the dry season than during the wet season (p < 0.05). Hospital similarly contributed Escherichia coli, Enterococcus, and Pseudomonas and ARGs significantly to the sediments in both seasons (p < 0.05). The organic matter content correlated positively with E. coli (r = 0.50, p < 0.05). The total bacterial load correlated with Enterococcus, and Pseudomonas (0.49 < r < 0.69, p < 0.05). Each ARG correlated with the total bacterial load or at least one relevant bacteria (0.41 < r < 0.81, p < 0.05). Our findings confirm that hospital wastewaters contributed significantly to antibiotic resistance profile and the significance of this contribution increased in the dry season. Moreover, our analysis highlights this risk from untreated hospital wastewaters in developing countries, which presents a great threat to public health.

Heavy metals and persistent organic pollutants contamination in river, estuary, and marine sediments from Atlantic Coast of Democratic Republic of the Congo.

The pollution assessment and the evaluation of potential risks in the Atlantic Coastal Region of the Democratic Republic of the Congo are still very limited. Consequently, the present study investigates for the first time the concentrations of heavy metals and persistent organic pollutants (organochlorine pesticides (OCPs), polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), and polycyclic aromatic hydrocarbons (PAHs)) in river, estuary, and marine sediments from this area. The results highlighted high concentrations of Cr, Zn, As, and Pb exceeding the probable effect level (PEL) on aquatic life. Zn was the most dominant element detected at a range of 180-480 mg kg-1 in marine sediment, 132-382 mg kg-1 in estuary sediment, and 121-687 mg kg-1 in river sediment. Total PCBs (∑7 × 4.3) ranged from 1995 to 20,156 µg kg-1, 2013-12,058 µg kg-1, and 1861-36,417 µg kg-1 in marine, estuary, and river sediments, respectively. Total PCBs (∑7 × 4.3) were above PEL for all sediments, suggesting potential adverse effects on benthic organisms. The OCP, PBDE, and PAH levels were low to moderate for all sediments. Taking into consideration, the concentrations of Zn, Pb, PCBs, and DDTs, probable environmental risks, are present.

High levels of faecal contamination in drinking groundwater and recreational water due to poor sanitation, in the sub-rural neighbourhoods of Kinshasa, Democratic Republic of the Congo.

In many urban and peri-urban areas of developing countries, shallow wells and untreated water from urban rivers are used for domestic purposes, including drinking water supply, population bathing and irrigation for urban agriculture. The evaluation and monitoring of water quality are therefore necessary for preventing potential human risk associated with the exposure to contaminated water. In this study, physicochemical and bacteriological parameters were assessed in an urban river (named Kokolo Canal/Jerusalem River) draining the municipality of Lingwala (City of Kinshasa, Democratic Republic of the Congo) and in two shallow wells used as drinking water supplies, during the wet and dry seasons in order to estimate the seasonal variation of contamination. The faecal indicator bacteria (FIB) isolated strains (Escherichia coli (E. coli) and Enterococcus (ENT)) from water and surface sediment, were characterized for human-specific bacteroides by molecular approach. The results revealed very high faecal contamination of water from the shallow wells, and of water and sediments from the river, during both wet and dry seasons. During the wet season, E. coli reached the values of 18.6 × 105 and 4.9 × 105 CFU 100 mL-1 in Kokolo Canal and shallow wells, respectively; and Enterococcus reached the values of 7.4 × 104 and 2.7 × 104 CFU 100 mL-1. Strong mutually positive correlation was observed between E. coli and ENT, with the range of R-value being 0.93 < r < 0.97 (p-value < 0.001, n = 15). The PCR assays for human-specific Bacteroides indicated that more than 98% of 500 isolated FIB strains were of human origin, pointing out the effect of poor household sanitation practices on surface water but also on groundwater contamination. The water samples from the shallow wells and Kokolo Canal were highly polluted with faecal matter in both seasons. However, the pollution level was significantly higher during the wet season compared to the dry season. Physicochemical analysis revealed also very high water electrical conductivity, with values much higher than the recommended limits of the World Health Organization guideline for drinking water. These results highlight the potential human health risk associated with the exposure to water contamination from shallow wells and Kokolo Canal, due to the very high level of human FIB. Rapid, unplanned and uncontrolled population growth in the city of Kinshasa is increasing considerably the water demand, whereas there is a dramatic lack of appropriate sanitation and wastewater facilities, as well as of faecal sludge (and solid waste) management and treatment. The lack of hygiene and the practice of open defecation is leading to the degradation of water quality, consequently the persistence of waterborne diseases in the neighbourhoods of sub-rural municipalities, and there is a growing threat to the sustainability to water resources and water quality. The results of this study should encourage municipality policy and strategy on increasing the access to safely managed sanitation services; in order to better protect surface water and groundwater sources, and limit the proliferation of epidemics touching regularly the city.

High contamination in the areas surrounding abandoned mines and mining activities: An impact assessment of the Dilala, Luilu and Mpingiri Rivers, Democratic Republic of the Congo.

Abandoned mines and mining activities constitute important sources of toxic metals and Rare Earth Elements (REEs) affecting surrounding environmental compartments and biota. This study investigates the contamination degree and distribution of toxic metals and REEs in contrasting sediment, soil and plant samples surrounding rivers in the African copperbelt area characterized by the presence of numerous abandoned mines, artisanal and industrial mining activities. ICP-MS results highlighted the highest concentration of Cu, Co and Pb in sediments reaching values of 146,801, 18,434 and 899 mg kg-1, respectively. In soil, the values of 175,859, 21,134 and 1164 mg kg-1 were found for Cu, Co and Pb, respectively. These values are much higher than the sediment guidelines for the protection of aquatic life and international soil clean-up standards. Enrichment factor and geoaccumulation index results indicated important contribution of mining activities to the study sites pollution in addition to natural background. Highest metal accumulation in leaves of Phalaris arundinacea L., was observed, reaching values of 34,061, 5050 and 230 mg kg-1 for Cu, Co, and Pb, respectively. The ∑REE concentration reached values of 2306, 733, 2796 mg kg-1 in sediment, soil and plant samples, respectively. The above results were combined with geographical information including satellite imagery, hydrography and mining concessions. Maps were produced to present the results in a comprehensive and compelling visual format. The results will be disseminated through an innovative mapping online platform to simplify access to data and to facilitate dialogue between stakeholders.

Microbiological quality of water in a city with persistent and recurrent waterborne diseases under tropical sub-rural conditions: The case of Kikwit City, Democratic Republic of the Congo.

The availability of safe drinking water in sub-Saharan countries remains a major challenge because poor sanitation has been the cause of various outbreaks of waterborne disease due to the poor microbiological quality of water used for domestic purposes. The faecal indicator bacteria (FIB) used in the present study included Escherichia coli (E. coli) and Enterococcus (ENT). FIB and aerobic mesophilic bacteria (AMB) were quantified during July 2015 (dry season) and November 2015 (rainy season) in order to assess the quality of drinking water from wells (n=3; P1-P3), and two rivers, the River Lukemi (RLK, n=3) and River Luini (RLN, n=2) in the city of Kikwit, which is located in the province of Kwilu in the Democratic Republic of the Congo. Kikwit is well known for its outbreaks of persistent and recurrent waterborne diseases including Entamoeba, Shigella, typhoid fever, cholera, and Ebola Viral Hemorrhagic Fever. Consequently, E. coli, ENT, and AMB were quantified in water samples according to the standard international methods for water quality determination using the membrane filtration method. The FIB characterization was performed for human-specific Bacteroides by PCR using specific primers. The results obtained revealed high FIB concentrations in river samples collected during both seasons. For example, E. coli respectively reached 4.3×104 and 9.2×104 CFU 100mL-1 in the dry season and the wet season. ENT reached 5.3×103 CFU 100mL-1 during the dry season and 9.8×103 CFU 100mL-1 in the wet season. The pollution was significantly worse in the wet season compared to the dry season. Surprisingly, no faecal contamination was observed in well water samples collected in the dry season while E. coli and ENT were detected in all wells in the wet season with values of 6, 7, and 11CFUmL-1 for E. coli in wells P1-P3, respectively and 3, 5, 9 CFU mL-1for ENT in the same wells. Interestingly, the PCR assays for human-specific Bacteroides HF183/HF134 indicated that 97-100% captured in all analyses of isolated FIB were of human origin. The results indicate that contamination of E. coli, ENT, and AMB in the studied water resources increases during the wet season. This study improves understanding of the microbiological pollution of rivers and wells under tropical conditions and will guide future municipal/local government decisions on improving water quality in this region which is characterised by persistent and recurrent waterborne diseases. Although the epidemiology can be geographically localised, the effects of cross border transmission can be global. Therefore, the research results presented in this article form recommendations to municipalities/local authorities and the approach and procedures can be carried out in a similar environment.

The impact of hospital and urban wastewaters on the bacteriological contamination of the water resources in Kinshasa, Democratic Republic of Congo.

Although the United Nations General Assembly recognized in 2010 the right to safe and clean drinking water and sanitation as a human right that is essential to the full enjoyment of life and all other human rights, the contamination of water supplies with faecal pathogens is still a major and unsolved problem in many parts of the world. In this study, faecal indicator bacteria (FIB), including Escherichia coli (E. coli) and Enterococcus (ENT), were quantified over the period of June/July 2014 and June/July 2015 to assess the quality of hospital effluents (n = 3: H1, H2 and H3) and of rivers receiving wastewaters from the city of Kinshasa, Democratic Republic of Congo. The water and sediment samples from the river-receiving systems were collected in, upstream and downstream of the hospital outlet pipe (HOP) discharge. The analysis of E. coli and ENT in water and sediment suspension was performed using the cultural membrane filter method. The FIB characterization was performed for general E. coli, Enterococcus faecalis(E. faecalis) and human-specific Bacteroides by PCR using specific primers. The results revealed very high FIB concentration in the hospital effluent waters, with E. coli reaching the values of 4.2 × 10(5), 16.1 × 10(5) and 5.9 × 10(5) CFU 100 mL(-1), for the hospital effluents from H1, H2, and H3, respectively; and Enterococcus reaching the values of 2.3 × 10(4), 10.9 × 10(4) and 4.1 × 10(4) CFU 100 mL(-1), respectively. Interestingly, the FIB levels in the water and sediment samples from river-receiving systems are spatially and temporally highly variable and present in some samples with higher values than the hospital effluents. The PCR assays for human-specific Bacteroides HF183/HF134 further indicate that more than 98% of bacteria were from human origin. The results of this research therefore confirm the hypothesis of our previous studies, indicating that in developing countries (e.g., Democratic Republic of Congo and South India), the hospital effluent waters can be a significant source of the deterioration of the bacteriological quality for urban rivers. The approach used in this investigation can be further used to decipher the pollution of water resources by human faecal contamination. The results of this research will help to better understand the microbiological pollution problems in river-receiving systems and will guide municipality decisions on improving the urban water quality.

Leachates draining from controlled municipal solid waste landfill: Detailed geochemical characterization and toxicity tests.

Management of municipal solid wastes in many countries consists of waste disposal into landfill without treatment or selective collection of solid waste fractions including plastics, paper, glass, metals, electronic waste, and organic fraction leading to the unsolved problem of contamination of numerous ecosystems such as air, soil, surface, and ground water. Knowledge of leachate composition is critical in risk assessment of long-term impact of landfills on human health and the environment as well as for prevention of negative outcomes. The research presented in this paper investigates the seasonal variation of draining leachate composition and resulting toxicity as well as the contamination status of soil/sediment from lagoon basins receiving leachates from landfill in Mpasa, a suburb of Kinshasa in the Democratic Republic of the Congo. Samples were collected during the dry and rainy seasons and analyzed for pH, electrical conductivity, dissolved oxygen, soluble ions, toxic metals, and were then subjected to toxicity tests. Results highlight the significant seasonal difference in leachate physicochemical composition. Affected soil/sediment showed higher values for toxic metals than leachates, indicating the possibility of using lagoon system for the purification of landfill leachates, especially for organic matter and heavy metal sedimentation. However, the ecotoxicity tests demonstrated that leachates are still a significant source of toxicity for terrestrial and benthic organisms. Therefore, landfill leachates should not be discarded into the environment (soil or surface water) without prior treatment. Interest in the use of macrophytes in lagoon system is growing and toxic metal retention in lagoon basin receiving systems needs to be fully investigated in the future. This study presents useful tools for evaluating landfill leachate quality and risk in lagoon systems which can be applied to similar environmental compartments.

Occurrence of Antibiotic Resistance Genes and Bacterial Markers in a Tropical River Receiving Hospital and Urban Wastewaters.

The occurrence of emerging biological contaminants including antibiotic resistance genes (ARGs) and Faecal Indicator Bacteria (FIB) is still little investigated in developing countries under tropical conditions. In this study, the total bacterial load, the abundance of FIB (E. coli and Enterococcus spp. (ENT)), Pseudomonas spp. and ARGs (blaTEM, blaCTX-M, blaSHV, blaNDM and aadA) were quantified using quantitative PCR in the total DNA extracted from the sediments recovered from hospital outlet pipes (HOP) and the Cauvery River Basin (CRB), Tiruchirappalli, Tamil Nadu, India. The abundance of bacterial marker genes were 120, 104 and 89 fold higher for the E. coli, Enterococcus spp. and Pseudomonas spp., respectively at HOP when compared with CRB. The ARGs aadA and blaTEM were most frequently detected in higher concentration than other ARGs at all the sampling sites. The ARGs blaSHV and blaNDM were identified in CRB sediments contaminated by hospital and urban wastewaters. The ARGs abundance strongly correlated (r ≥ 0.36, p < 0.05, n = 45) with total bacterial load and E. coli in the sediments, indicating a common origin and extant source of contamination. Tropical aquatic ecosystems receiving wastewaters can act as reservoir of ARGs, which could potentially be transferred to susceptible bacterial pathogens at these sites.

A kinetic study of the enhancement of solution chemiluminescence of glyoxylic acid oxidation by manganese species.

In order to study the mechanism of the enhancement of solution chemiluminescence, the kinetics of the decay of the oxidant and the chemiluminescence emission were followed for oxidations by permanganate, manganese dioxide sol and Mn(3+) (aq) of glyoxylic acid, using stopped-flow spectrophotometry. Results are reported for the glyoxylic acid oxidized under pseudo first-order conditions and in an acidic medium at 25 °C. For permanganate under these conditions, the decay is sigmoidal, consistent with autocatalysis, and for manganese dioxide sol and Mn(3+) it is pseudo first order. The effects of the presence of aqueous formaldehyde and Mn(2+) were observed and a fit to a simple mechanism is discussed. It is concluded that chemiluminescent enhancement in these systems is best explained by reaction kinetics.