Biomass-based biomimetic-oriented Janus nanoarchitecture for efficient heavy-metal enrichment and interfacial solar water sanitation

Interfacial solar steam generation(ISSG),involving the use of solar energy to evaporate water at the water-to-vapor interface,has presented prospects for the desalination and purification of water due to high energy conversion efficiency and low-cost freshwater generation.Herein,inspired by the aligned nanostructure of plants for efficiently transporting nutrient ions,we optimally design and construct a biomass-based Janus architecture evaporator with an oriented nanostructure for ISSG,using the ice template method,followed by biomimetic mineralization with the resource-abundant and low-cost biomass of the carboxymethyl cellulose and sodium alginate as the raw materials.Taking advantage of the oriented nanostructure allowing efficient transportation of water and coordination capacity of sodium alginate for effective enrichment of heavy-metal ions,the biomass-based Janus architecture shows much lower thermal conductivity and an ultrahigh steam regeneration rate of 2.3 kg m−2 h−1,considerably surpassing those of previously reported oriented biomass-based evaporators.Moreover,the biomass precursor materials are used for this Janus evaporator,guaranteeing minimum impact on the water ecology and environment during the regeneration process of clean drinking water.This study presents an efficient,green,and sustainable pathway for ISSG to effectively achieve heavy-metal-free drinking water.

DID YOU KNOW...? Facts and figures on water and sanitation

Water-related diseases,including diarrhea,are a leading cause of death in children of developing countries.However,they can be prevented and controlled by improving access to safe drinking water and sanitation,

Anthropogenic Activities and the Degradation of the Environmental Quality in Poor Neighborhoods of Abidjan,Cote d’Ivoire:Abia Koumassi Village

This study deals with the degradation of the quality of the water environment in the village of Abia Koumassi, due to the pollution that has risen in Abidjan. The method used in this study is based on piezometric measurements, the physico-chemical and microbiological analysis. The results were processed using statistical and hydrochemical methods. The groundwater in the village is shallow, with a piezometric average level 0.55 m. The groundwater flows from the north of the village to the south. The Water resources have a neutral pH that varies between 6.8 and 7.43. Water temperature varies from 27.7°C to 29.8°C. The Water is highly mineralized, with electrical conductivity ranging from 585 μS/cm to 1310 μS/cm. The groundwater contains high levels of nitrate (116.81 mg·L-1) greater than the WHO standard for drinking water. High levels of Metallic Trace Elements (Ni, Zn, Co, Cr, Pb, Fe, Cu and Cd) are found in the water. Microbiological analysis shows that the water contains important levels of Escherichia coli, faecal streptococci, Clostridium perfringens and thermo tolerant coliform. These microorganisms create microbiological pollution in the water from the area. The Water resources of the village are facing a recent faecal pollution of human origin. This pollution comes from anthropogenic activities taking place in the area.

Environment and Awareness Influencing Food Safety in the Western Area, Sierra Leone

Food safety, nutrition, health and wellbeing are inextricably linked. This study investigated the environmental, awareness and practices amongst both food vendors and consumers in and around Freetown the capital of Sierra Leone. The population of the area has vastly out-grown the infrastructure laid down before and since independence. De-centralization of authority to local councils as recommended post-war has only been partial. The role of local versus central government in the planning and maintenance of water, sanitation and market-infrastructure and related policies was explored. This is a qualitative study that used semi-structured interviews with vendors, consumers and 29 key informants. Amongst an estimated population of 5386 actors in food services a sample size of 309 vendors, consumers in and around the 12 busiest market hubs in Western Area Urban and Rural Districts were sampled. Most of the respondents described “food safety” as “good-to-eat, well taken care-off, and free from germs”. The respondents cited that main causes to unsafe food are poor hygienic practices: 38%, contamination by flies: 28%, uncovered food/ improper handling/poor personal hygiene: 21%, and environmental factors, such as improper refuse disposal: 11%. Respondents expressed that consuming unsafe foods can lead to diarrhoea: 34%, food poisoning: 24%, vomiting: 17%, stomach ache/pain: 16%, or typhoid: 9%. Various measures to improve food safety were cited as hand washing: 60%, cleaning surroundings: 57%, covering food: 56%, washing utensils: 52%, covering hair: 42% and using a face mask: 32%. However almost 76% of food vendors interviewed were trading near gutters, where muddy/dirty water settled, with slippery floors, discarded plastic waste, flies and inadequate water, sanitation, and/or storage facilities. None of the food vendors had had any formal training on food safety. Despite progress recently made in solid and liquid waste management during the “Transform Freetown” agenda much more improvement in infrastructure and behaviour change is required. Similarly, despite improvements in formal market facilities the pattern of informal street trading remains the most prevalent especially for the poor. The link between “safe food” and good health was only partially understood, whilst the widespread application of recommended practices to reduce risks was lacking due in part to inadequate infrastructure. As the importance of food safety becomes better understood by administrators and the public the investments required in infrastructure and social and behavioural change will contribute towards a healthier environment and outcomes.

Burden and factors associated with schistosomiasis and soil-transmitted helminth infections among school-age children in Huambo,Uige and Zaire provinces,Angola

Background:Schistosomiasis and soil-transmitted helminths(STHs)contribute high disease burdens amongst the neglected tropical diseases(NTDs)and are public health problems in Angola.This study reports the prevalence,intensity and risk factors for schistosomiasis and STH infection in Huambo,Uige and Zaire provinces,Angola,to inform a school-based preventive chemotherapy program.Methods:A two-stage cluster design was used to select schools and schoolchildren to participate in parasitological and water,sanitation and hygiene(WASH)surveys across Huambo,Uige,and Zaire provinces.Point-of-care circulating cathodic antigen and urinalysis rapid diagnostic tests(RDTs)were used to determine the prevalence of Schistosoma mansoni and S.haematobium,respectively.Kato-Katz was used to identify and quantify STH species and quantify and compare with RDTs for S.mansoni.Urine filtration was used to quantify and compare with RDTs for S.haematobium.Descriptive statistics were used for prevalence and infection intensity of schistosomiasis and STH infection.Performance of RDTs was assessed through specificity and Cohen’s Kappa agreement with microscopy.A multivariate regression analysis was used to determine demographic and WASH factors associated with schistosomiasis and STH infection.Results:A total 575 schools and 17,093 schoolchildren participated in the schistosomiasis survey,of which 121 schools and 3649 schoolchildren participated in the STH survey.Overall prevalence of S.mansoni was 21.2%(municipality range 0.9–74.8%)and S.haematobium 13.6%(range 0–31.2%),with an overall prevalence of schistosomiasis of 31.4%(range 5.9–77.3%).Overall prevalence of Ascaris lumbricoides was 25.1%(range 0–89.7%),hookworm 5.2%(range 0–42.6%),and Trichuris trichiura 3.6%(range 0–24.2%),with an overall prevalence of STH infection of 29.5%(range 0.8–89.7%).Ecological zone and ethnicity were factors associated with schistosomiasis and STH infection,with older age and female sex additional risk factors for S.haematobium.Conclusions:Most municipalities met World Health Organization defined prevalence thresholds for a schistosomiasis preventive chemotherapy program.A STH preventive chemotherapy program is indicated for nearly all municipalities in Uige and select municipalities in Huambo and Zaire.The association between ecological zone and ethnicity with schistosomiasis and STH infection necessitates further evaluation of home and school environmental,sociodemographic and behavioural factors to inform targeted control strategies to complement preventive chemotherapy programs.