Efficiency of a low-cost pyramid-shaped solar still for pesticide removal from highly contaminated water

Potable water production through a low-cost single chamber solar still in north India

The main aim of this study is to evaluate the performance of a single slope solar still and to assess the effect of nanofluid on its performance. A single basin single slope solar still was designed and fabricated at the Department of Chemical Engineering, IET Lucknow. Its performance was assessed in terms of the yield of potable water. The effect of various climatic parameters was also studied. Al2O3 nanofluid was used to enhance the yield of the solar still. In the presence of nanofluid, the total yield of the solar still improved by 16.6%. Its economic feasibility was analyzed and reported. The portability of the small size of solar stills, its better economics, easy fabrication, and good performance make them very useful for industrial as well as household purposes.

Spatial-temporal occurrence of contaminants of emerging concern in urban rivers in southern Brazil

The widespread use and misuse of antibiotics and pesticides has been linked with several risks to the environment and human health. In the present report, the results of the monitoring of 64 pharmaceuticals and 134 pesticides occurrence in an urban river in Southern Brazil are presented and discussed. Sampling campaigns have covered the period 2016-2018. The identification and determination of the analytes were achieved by high-resolution mass spectrometry. The data were analyzed using chemometric tools to obtain spatial-temporal models. Toxicological evaluation was achieved using acute toxicity (zebrafish standardized protocol), and determination of risk quotient. Within the 198 analytes included in the targeted analysis method for surface water, 33 were identified in an urban river during 2 years of monitoring, being 20 pharmaceuticals and 13 pesticides. Using high-resolution mass spectrometry, a suspect screening approach was established in an un-target analysis. The evaluation was carried out using a data bank built from consumption data of drugs and pesticides, in the metropolitan region of Porto Alegre - RS and their respective metabolites. The suspect screening analysis done with a data bank with more than 1450 compounds results in 27 suspect findings. The target analysis results showed a continuous prevalence of non-steroidal anti-inflammatories, analgesics, antipyretics, beta-blockers, corticoids, and antibiotics. Regarding the pesticides, the main classes were fungicides, especially those from triazol and strobilurin classes.

Pesticides and herbicides

This paper highlights a review of scientific papers published in the year 2019 regarding pesticides and herbicides. The scientific review presented in this paper includes the presence and occurrence of pesticides and herbicides in the environment. The entire review divided into different sections, which are grouped into four main sections. Each of these sections provides studies conducted on toxicology, ecological risk assessment, strategies of treatment, policies, modeling, and guidelines regarding pesticides and herbicides management. PRACTITIONERS POINTS: This paper highlights the review of scientific literature published in the year 2019. The review includes the presence and occurrence of pesticides and herbicides in the environment. The review focuses on toxicology, ecological risk assessment, strategies of treatment, policies, modelling and guidelines regarding pesticides and herbicides management. The literature review covers selected papers relevant to the topic.

Sensitive Determination of Acetochlor, Alachlor, Metolachlor and Fenthion Utilizing Mechanical Shaking Assisted Dispersive Liquid-Liquid Microextraction Prior to Gas Chromatography-Mass Spectrometry

A green, sensitive and accurate dispersive liquid-liquid microextraction (DLLME) method was used to preconcentrate four selected pesticides in dam lake water samples for determination by gas chromatography-mass spectrometry (GC-MS). Conditions of the DLLME method were comprehensively investigated and optimized according to type/volume of extraction solvent, type/volume of dispersive solvent, and type/period of mixing. The developed method was validated according to the limits of detection and quantitation, accuracy, precision and linearity. Under the optimum conditions, limit of detection values calculated for alachlor, acetochlor, metolachlor and fenthion were 1.7, 1.7, 0.2 and 7.8 µg/kg (mass based), respectively. The method recorded 202, 104, 275 and 165 folds improvement in detection power values for acetochlor, alachlor, metolachlor and fenthion, respectively, when compared with direct GC-MS measurements. In order to evaluate the accuracy of the developed method, real sample application with spiking experiments was performed on dam lake water samples, and satisfactory percent recovery results in the range of 81%-120% were obtained.

Regulation of surface plasmon resonance and oxygen vacancy defects in chlorine doped Bi–BiO2−x for imidacloprid photocatalytic degradation

In this work, chlorine doped Bi–BiO_2−x (Cl–Bi–BiO_2−x) was prepared by a one-step solvothermal method using sodium bismuthate (NaBiO₃·2H₂O) as a Bi source without the addition of a surfactant.