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

Stopped-Flow Kinetic Investigation of Manganese-based Chemiluminescence Oxidation Reactions

In order to better understand the mechanism of solution manganese-based chemilumines-cence, the kinetics of a number of chemiluminescent oxidations by manganese species were studied using stopped-flow spectrophotometry. Both the kinetics of the decay of the oxi-dant and the chemiluminescence emission were followed for oxidations by permanganate, manganese dioxide sol and Mn3+(aq) of a range of organic compounds. The most detailed studies were carried out on the oxidation of the relatively simple compounds including glyoxylic acid and glyoxal under pseudo first order conditions and an acidic medium at 25oC. For permanganate under these conditions, the decay is sigmoidal consistent with autocatalysis and for managanese dioxide sol and Mn3+ pseudo first order. Simple mechanisms are suggested and compared with the experimental kinetic data. For per-manganate CL system, the following chemical kinetic model was considered: MnO4- + xsR MnO2 (k1) MnO2 + xsR Mn3+ (k2) MnO4- + 3Mn3+ 4MnO2 (k3) Mn3+ + xsR (Mn2+)

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 Mn3+(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 Mn3+ it is pseudo first order. The effects of the presence of aqueous formaldehyde and Mn2+ 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 kinetic

Impact of anthropogenic activities on the occurrence and distribution of toxic metals, extending-spectra β-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 β-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>0.6, p0.57, p<0.05). Results demonstrated that multi-diffuse pollution originating from human activity contribute to the spread of toxic metals and ARGs into the aquatic ecosystems

Influence of watershed on the accumulation of heavy metals in sediments of urban rivers under tropical conditions: Case of N’djili and Lukaya rivers in Kinshasa Democratic Republic of the Congo

The contamination of freshwater resource by heavy metals is still a major environmental and human health concern globally. The release of these contaminants into the aquatic environment can lead to the pollution of water resources and generate risks for aquatic living organisms and human health. The sediments can act as reservoir for heavy metals, thereby they are used to assess the pollution status of the rivers. In the present investigation, surface sediments collected from two urban rivers named, N’djili and Lukaya draining through the city of Kinshasa, Democratic Republic of the Congo were characterized for grain size, organic matter (OM) and heavy metals. Additionally, Sediment Quality Guidelines for the protection of aquatic life (SQGs), enrichment factor (EF) and geoaccumulation index (Igeo) were performed to determine the river pollution status. The results highlight high concentrations of heavy metals in sediment samples mainly from N’djili River, reaching the values (mg kg−1) of 180.3 (Cu), 451.5 (Zn), 185.8 (Pb) and 4.1 (Hg). These values exceed the SQGs. Based on EF and Igeo values, the sediments from the two rivers have severe enrichment and polluted with Cu, Zn and Pb, and moderate enrichment of Cr and As. In general, the positive correlation was observed between some heavy metals and OM suggesting that these contaminants could have originated from common sources with a similar transport pathway. Based on the SQGs, EF and Igeo, N’djili River is considered as highly polluted with heavy metals indicating environmental and human health potential risks. The results of this study clearly indicate that the pollution of urban rivers in developing countries can be explained by several anthropogenic activities such as urban runoff, uncontrolled landfills in riverbanks, untreated wastewater from densely populated areas, anarchic commercial and industrial settlements, and heavy road traffic. The approaches used in this study represent a useful tool to assess the river sediment quality of urban river which can be applied to similar environment

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 little investigated in developing countries under tropical conditions. In this context, cultivable and molecular approaches were performed to assess the dissemination of bacteria and their antibiotic resistance genes in aquatic environment in Kinshasa, Democratic Republic of the Congo. Cultivable approach quantified β-lactam, carbapenem resistant, and total Escherichia coli (E. coli) and Enterbacteriaceae (Ent) 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 (E. coli), Enterococcus, and Pseudomonas (P. spp)), and antibiotic resistance genes (ARGs: blaOXA-48, blaCTX-M, blaIMP, blaTEM) in sediment samples. Statistical analysis (ANOVA method, principle component analysis, and correlation matrix) were used to explore the significance of hospital contribution and seasonal variation of bacteria and ARGs into explored 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 value<0.05). Hospital similarly contributed significantly fecal bacteria and Pseudomonas (P. spp) and ARGs to the sediments in both seasons (P value<0.05). The organic matter content correlated positively with E. coli (r=0.50, P value<0.05). The total bacterial load correlated with Enterococcus, and Pseudomonas (0.49<r<0.69, P value<0.05). Each ARG correlated with the total bacterial load or at least one relevant bacteria (0.41<r<0.81, P value<0.05). Our findings confirms that hospital wastewaters contributed significantly to antibiotic resistance profile and the significance of this contribution increased in dry season. Moreover, our analysis highlights this risk from untreated hospital wastewaters in developing countries, which presents a great threat to public health

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 18.6x105 and 4.9x105 CFU 100 mL-1 in Kokolo Canal and shallow wells, respectively; and Enterococcus reached the values of 7.4x104 and 2.7x104 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

Concentration of toxic metals and potential risk assessment in edible fishes from Congo River in urbanized area of Kinshasa, DR Congo

The objective of this research is to determine the concentration and potential health risks of toxic metals in six most consumed freshwater fish species (Auchenoglanis occidentalis, Bagrus ubangensi, Citharinus gibbosus, Distichondus fasciolatus, Marcusenius moorii and Schilbe mystus). A total of 126 samples of these fish species were collected from seven sites of Congo River in the vicinity of Kinshasa City, Democratic Republic of the Congo. Toxic metals (Cr, Co, Ni, Zn, Se, Ag, Cd, Sn, Sb and Pb) levels in fish muscle tissues were determined using Inductively Coupled Plasma Mass Spectrometry whereas Hg analysis was carried out using atomic absorption spectrophotometry. The maximum metal concentration (mg kg-1 wet weight) of Zn (59.72), Sb (5.98) and Pb (4.96) was detected in muscle tissues of Marcusenius moorii, Citharinus gibbosus and Distichondus fasciolatus respectively. Pb, Zn, and Hg values in many fish samples exceeded the permissible levels set by Food and Agriculture Organization and World Health Organization for human consumption. Given the concentrations of Pb in all fish species and Zn in Marcusenius moorii, human health implications are likely to occur on continuous consumption. Addition, the evaluation of potential health risks for fish consumers indicates that there may or not be adverse effects

Citizen sensing of solid waste disposals: crowdsourcing as tool supporting waste management in a developing country

Large sub-Saharan African cities are characterized by serious and persistent environmental problem of Solid Waste Management (SWM). The city of Kinshasa, in Democratic Republic of the Congo has a long lasting and major concern of SWM. More worryingly, with rapid population growth and urbanization, waste generation, both domestic and industrial, is expected to rise with great potential of health and environmental problems. Therefore, with an objective of bringing a possible solution that reduces the increasing problem of SWM, we explore in the present study the use of crowdsourcing as a possible mechanism to identify, localize, characterize solid waste landfills. The proposed approach allows (i) creating a spatial and temporal database through a participatory process to support data collection and information generation, and (ii) visualizing the spatial and temporal distribution of observations through an interactive map. Our database holds 187 observations of solid waste disposals across Kinshasa within two years with estimated volume of solid waste accounts of 587'920 m3. These observations include 61 public disposals (e.g., transit center), and 151 wild dumps, of which, 174 active and 3 inactive disposals. The approach developed in this study is a proof-of- concept and a successful implementation was achieved. Our conception and results provide new tool and mechanism to collect data and generate useful information on solid waste landfills in the city of Kinshasa that was not available before. The results of this study indicate that crowdsourcing can be a valuable mechanism to involve citizens in collecting data on solid waste landfills in the city of Kinshasa, which can be applied in similar urban cities

Effect of untreated urban effluents on the accumulation of toxic metals in river sediments under tropical conditions: Funa River, Kinshasa, Democratic Republic of the Congo

The objective of the present study was to assess the status of surface sediments from Funa River. Sediment samples were characterized for physicochemical parameters including grain size, organic matter and toxic metals. The result revealed high metal concentrations in river sediments, reaching values of 154.19, 186.00, 1105.34, 3.69, 548.02 and 5.45 mg kg-1 for Cr, Cu, Zn, Cd, Pb and Hg, respectively. A strong correlation was observed between analyzed metals and organic matter suggesting that these contaminants could have originated from common sources with a similar transport pathway. Based on the Sediment Quality Guidelines for the Protection of Aquatic Life (SQGs), Funa River is considered as highly polluted with toxic metals indicating the potential environmental and human health risk. The results of this research represent a useful tool to assess the sediment quality of urban river receiving system which can be applied to similar environment