Suchergebnisse

AbstractThe impact of pharmaceutical and personal care products (PPCPs) on the performance of biological wastewater treatment plants (WWTPs) has been widely studied using whole-community approaches. These contaminants affect the capacity of microbial communities to transform nutrients; however, most have neither honed their examination on the nitrifying communities directly nor considered the impact on individual populations. In this study, six PPCPs commonly found in WWTPs, including a stimulant (caffeine), an antimicrobial agent (triclosan), an insect repellent ingredient (N,N-diethyl-m-toluamide (DEET)) and antibiotics (ampicillin, colistin and ofloxacin), were selected to assess their short-term toxic effect on enriched nitrifying cultures: Nitrosomonas sp. and Nitrobacter sp. The results showed that triclosan exhibited the greatest inhibition on nitrification with EC50 of 89.1 μg L−1. From the selected antibiotics, colistin significantly affected the overall nitrification with the lowest EC50 of 1 mg L−1, and a more pronounced inhibitory effect on ammonia-oxidizing bacteria (AOB) compared to nitrite-oxidizing bacteria (NOB). The EC50 of ampicillin and ofloxacin was 23.7 and 12.7 mg L−1, respectively. Additionally, experimental data suggested that nitrifying bacteria were insensitive to the presence of caffeine. In the case of DEET, moderate inhibition of nitrification (<40%) was observed at 10 mg L−1. These findings contribute to the understanding of the response of nitrifying communities in presence of PPCPs, which play an essential role in biological nitrification in WWTPs. Knowing specific community responses helps develop mitigation measures to improve system resilience.

Introduction -- Adsorption of anionic antibiotics by CTAB modified natural clay minerals -- Study on the adsorption of anionic antibiotics on natural clay minerals modified by ionic liquids -- Molecular Dynamics Simulation of Adsorption of Anionic Antibiotics on Organic Modified Natural Clay Minerals -- Dynamic adsorption experiment of modified zeolite and montmorillonite -- Conclusion.

Producción Científica ; Several analytical approaches have been developed for the determination of emerging pollutants (EPs), including pharmaceuticals and personal care products (PPCPs) in environmental matrices. This paper reviews the sample preparation and instrumental methods proposed in the last few years (2012e2018) to assess PPCPs in sewage sludge. Three main steps are examined: extraction, clean-up and analysis. Sample preparation is critical as target compounds are normally found at low concentrations in complex matrices. Most procedures include sewage sludge pretreatment mostly through ultrasound-assisted extraction (UAE) although other novel techniques such as QuEChERS (Quick, Easy, Cheap, Effective, Rugged and Safe) or MSPD (matrix solid-phase dispersion) have been also employed. In one report, no differences in extraction efficiency were detected among the most commonly used extraction techniques such as ultrasound, microwave and pressurized liquid. Clean-up usually involves a conventional method such as solid phase extraction (SPE). This step is needed to appreciably reduce matrix suppression, and is followed by an instrumental analysis using techniques of preference such as gas chromatography (GC) or liquid chromatography (LC), mostly coupled to mass spectrometry (MS). A fully automated on-line system that includes extraction, chromatographic separation, and mass spectrometry in one-stage is here presented as a novel way of determining PPCPs in sewage sludge. This review also discusses the advantages and limitations of the different techniques used. Miniaturizing analytical techniques use of novel solid and liquid phase materials are emerging as efficient options that fulfill the principles of so-called "green chemistry". ; This study was supported by the Spanish Government (MINECO-CTM2015-70722-R) as well as by the Regional Government of Castilla y Le on and European Union through the FEDER Funding Program (CLU 2017e09, UIC 071 and Red Novedar). Nereida P erez-Lemus and Rebeca L opez-Serna acknowledge the Spanish Ministry of Science, Innovation and Universities for research grants (predoctoral CTM2015-70722-R and Juan de la Cierva Incorporaci on JCI-2015-23304, respectively).

PurposeThis paper examines the relevance of Public-Private-Community Partnerships (PPCPs) as an alternative mechanism in enhancing food security during the COVID-19 pandemic and beyond in Zimbabwe. It also draws attention to the complexities of adopting PPCPs, and proposes possible options to improve their effectiveness.Design/methodology/approachThe study applied concurrent mixed research methods. The sample population comprised multiple stakeholders in the area of food security and agricultural financing in Zimbabwe. The research adopted purposive and snowball sampling techniques. Data were collected through questionnaire, in-depth interviews, focus group discussions (FGDs) and documentary analysis. Descriptive statistics were used to analyse quantitative data, while qualitative data analysis was conducted thematically.FindingsPrior to the outbreak of the COVID-19 pandemic, food insecurity was a consistent challenge in Zimbabwe. The pandemic has worsened the situation by further disruption of food systems and limiting people's access to food. PPCPs could be feasible alternative as they enhance value chain collaboration, improve access to inputs, reduce information asymmetry, ensure trust and facilitate risk sharing. PPCPs require proper design, control of transaction costs, clear definition of partners' roles, fair risk sharing, trust, and flexibility.Originality/valuePPCPs are yet to be adopted in the Zimbabwean agricultural sector. The research informs policymakers on the need to implement multi-stakeholder collaborations in food production.

Abstract
Background
Management of pharmaceuticals and personal care products (PPCPs) in the environment has become a social issue. In the present study, concentrations of 140 PPCPs at 20 sites in Baiyangdian Lake and Tai Lake from 2016 to 2017 were analyzed by ultra performance liquid chromatography mass spectrometer (UPLC–MS). Risk quotients (RQ) were calculated for each detected chemical at all sites and prioritization indices (PI), based on maximum RQ, were calculated. To assess the risk of chemicals that identified high priority (PI > 1), a more accurate method of joint probability curves (JPCs) was applied.

Results
A total of 42 PPCPs were identified and quantified detected in the two lakes, with maximum concentrations ranging from 0.04 to 889 ng/L. Among these, seven PPCPs were identified as high or moderate-risk pollutants for at least one site, 3 in Tai Lake and 5 in Baiyangdian Lake. Carbamazepine posed significant ecological risk at all 20 sites, such that more attention should be paid to that drug. Based on results of the JPCs, sulfamethoxazole, caffeine, diethyltoluamide, and carbamazepine were categorized as high or intermediate risks.

Conclusion
Occurrences and distributions of PPCPs were different in the two lakes. Multiple-level risk assessment from simple to more complex was appropriate in chemical risk management.