GLOBAL OVERVIEW OF HYDROPONICS: NUTRIENT FILM TECHNIQUE

Hydroponics is a cultivation technique without soil. There are several modalities for the system and among them is the Nutrient Film Technique (NFT), which consists of using channels to circulate a nutrient solution intermittently. Due to the existence of risks of soil and water contamination in metropolitan areas, hydroponics is a potential alternative to conventional production. Therefore, the present work sought to verify the current study of knowledge of the NFT hydroponic system in the international literature and the performance of the countries on it. For this, a bibliographic survey was carried out from 2010 to 2019 on the international research bases Science Direct, Portal de Periódicos da Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) and Scielo using the search terms “Hydroponics” and “Nutrient Film Technique Hydroponics”. An increase in the number of studies was observed in the last four years of the analyzed period, that is, from 2016 to 2019, thus representing an increase in interest in hydroponics, especially the NFT type. This increase may be related to the efficiency and ease of handling this model, gains in productivity and the potential that this technique has for reducing the carbon footprint. Thus, Nutrient Film Technique is of great value in urban agriculture, especially in Brazil – its greatest representative –, with the potential to grow a lot in the future, due to its numerous benefits.

The Use of Polymer Membranes to Counteract the Risk of Environmental of Soil and Water Contamination

Chemical, biological, radiological, or nuclear (CBRN) contamination of the environment is a significant threat to human health and life as well as environmental safety. It is then necessary to take actions aimed at minimizing and eliminating the threat. Depending on the type of contamination, various methods are used, including sorption, biodegradation, separation, or ion exchange processes in which membranes play an important role. The type of membrane is selected in respect of both the environment and the type of neutralized pollutants. Therefore, the production and modification of membranes are being adapted to the type of contamination and the purpose of the work. This article presents examples of membranes and their possible applications depending on the part of the environment subject to reclamation and the type of contamination.

Water-Rock Interaction and Potential Contamination Risk in a U-Enriched Area

The Picoto mining area is in the village of Vilar Seco (Viseu), central Portugal. Mineralization occurs mainly in quartz veins with meta-torbernite and uranophane and some U-bearing minerals, cutting a Variscan granite. Exploitation took place in two phases, between 1917 and 1953, and since the closure, the area has never been remediated. Water–rock interaction processes, including the mobility of potentially toxic elements through soil and water (surface and groundwater), were identified with the determination in situ of physicochemical parameters and selected anions and cations, by ICP-OES. The soils are contaminated with As (>44 mg/kg), Cu (>23 mg/kg), and U (>40 mg/kg) and cannot be used for agricultural or domestic purposes. The waters are generally weakly mineralized and have pH values ranging from acidic to neutral. However, some of them are contaminated with NO2 (up to 2.3 mg/L), Fe (up to 1849 mg/L), Mn (up to 777 mg/L), Cu (up to 5.4 µg/L), As (up to 14.7 µg/L), and U (up to 66.2 µg/L) and cannot be used for human consumption or agricultural activities. The soil and water contamination are mainly related to the old mine activities and the subsequent human activities that have developed in the area.

Hazardous Solid Waste Confined in Closed Dump Sites: An Urgent Environmental Liability to Attend

The soil and water contamination by metals from hazardous waste confined with urban solid wastes, highlights the importance of enhance the monitoring of disposal sites once closed. It is common to fail to comply with the regulations on their location, operation and post-closure, and located in areas that affect the environment and the health of the population. In the closed dump of Morelia, contamination of the soil and groundwater by leachates with heavy metals in the water from supply wells has been reported. The objective of this study was to determine the presence of heavy metals and arsenic in the confined wastes of the Morelia closed dump, in order to diagnose the affectation from the contaminants. Composition, degradation status and the presence of heavy metals were analyzed in samples of confined solid wastes from eight wells with different age of confinement. The results of this study ratify the contamination of the leachates of the site and are associated with the contamination of the water for human consumption in the area. The actual regulation does not apply in the case of urban solid waste, so it is crucial to regulate monitoring and management for correct decision-making during post-closure management.

Hazardous Solid Waste Confined in Closed Dump Sites: An Urgent Environmental Liability to Attend

The soil and water contamination by metals from hazardous waste confined with urban solid wastes, highlights the importance of enhance the monitoring of disposal sites once closed. It is common to fail to comply with the regulations on their location, operation and post-closure, and located in areas that affect the environment and the health of the population. In the closed dump of Morelia, contamination of the soil and groundwater by leachates with heavy metals in the water from supply wells has been reported. The objective of this study was to determine the presence of heavy metals and arsenic in the confined wastes of the Morelia closed dump, in order to diagnose the affectation from the contaminants. Composition, degradation status and the presence of heavy metals were analyzed in samples of confined solid wastes from eight wells with different age of confinement. The results of this study ratify the contamination of the leachates of the site and are associated with the contamination of the water for human consumption in the area. The actual regulation does not apply in the case of urban solid waste, so it is crucial to regulate monitoring and management for correct decision-making during post-closure management.

Degradation of Pyrethroid Insecticide- cypermethrin (25% EC) using Soil Microorganisms and Detection of Degradation Products

Background: Cypermethrin is used extensively to kill the pests that decreases the crop yield. Excessive use of cypermethrin results in soil and water contamination, thus affecting soil microflora and the aquatic life. Thus, removal of cypermethrin is particularly important. Different physical and chemical methods are available for the cypermethrin removal but are time consuming and costly. So, microbial degradation of cypermethrin is important. The present study aimed to isolate and identify cypermethrin degrading organisms, detection of the cypermethrin degradation product by GC- MS analysis and detection of residual amount of cypermethrin from the medium.Methods: In this laboratory investigation, soil samples were collected from different farms and isolation and identification of microorganisms capable of cypermethrin degradation was performed. Further, detection of residual cypermethrin concentration, cod value and cypermethrin degradation products using GC- MS analysis was performed.Result: Cypermethrin degrading microorganisms were isolated and identified as P. aeruginosa and K. pneumoniae. These microorganisms degraded 200mg\lit cypermethrin and the cypermethrin degradation products were detected and identified by comparing with the standard database. Residual amount of cypermethrin was detected from the medium by colorimetric method. Residual cypermethrin concentration was decreased with time in the test indicating cypermethrin degradation ability of the P. aeruginosa and K. pneumoniae. Further, COD value was determined and COD value was found to be decreased in the medium in presence of P. aeruginosa and K. pneumoniae indicating cypermethrin removal.

Effect of Citric Acid on Growth, Ecophysiology, Chloroplast Ultrastructure, and Phytoremediation Potential of Jute (Corchorus capsularis L.) Seedlings Exposed to Copper Stress

Soil and water contamination from heavy metals and metalloids is one of the most discussed and caused adverse effects on food safety and marketability, crop growth due to phytotoxicity, and environmental health of soil organisms. A hydroponic investigation was executed to evaluate the influence of citric acid (CA) on copper (Cu) phytoextraction potential of jute (Corchorus capsularis L.). Three-weeks-old seedlings of C. capsularis were exposed to different Cu concentrations (0, 50, and 100 μM) with or without the application of CA (2 mM) in a nutrient growth medium. The results revealed that exposure of various levels of Cu by 50 and 100 μM significantly (p < 0.05) reduced plant growth, biomass, chlorophyll contents, gaseous exchange attributes, and damaged ultra-structure of chloroplast in C. capsularis seedlings. Furthermore, Cu toxicity also enhanced the production of malondialdehyde (MDA) which indicated the Cu-induced oxidative damage in the leaves of C. capsularis seedlings. Increasing the level of Cu in the nutrient solution significantly increased Cu uptake by the roots and shoots of C. capsularis seedlings. The application of CA into the nutrient medium significantly alleviated Cu phytotoxicity effects on C. capsularis seedlings as seen by plant growth and biomass, chlorophyll contents, gaseous exchange attributes, and ultra-structure of chloroplast. Moreover, CA supplementation also alleviated Cu-induced oxidative stress by reducing the contents of MDA. In addition, application of CA is helpful in increasing phytoremediation potential of the plant by increasing Cu concentration in the roots and shoots of the plants which is manifested by increasing the values of bioaccumulation (BAF) and translocation factors (TF) also. These observations depicted that application of CA could be a useful approach to assist Cu phytoextraction and stress tolerance against Cu in C. capsularis seedlings grown in Cu contaminated sites.

Lime and phosphate effects on atrazine sorption, leaching and runoff in soil

ABSTRACT Atrazine still is a widely used herbicide in tropical soils to control annual broad-leaved weeds and annual grasses mainly in maize and sorghum plantations. Sorption and desorption in such soils are important processes that affect transport, ending with soil and water contamination, not only in these soils, but in other soils around the world. Lime and phosphate are important amendments in tropical soils to mitigate low fertility. These treatments can affect interaction among soil particles and between soil and atrazine. The objectives here were to evaluate the effect of lime, phosphate, and lime + phosphate treatments on sorption and transport of atrazine in a Typic Hapludult, using soil-erosion-plots at field conditions in a 3%-slope landscape 20 m away from the floodplain. Water- and sediment-sampler devices were used to measure runoff during an entire rainy season. Soil, water and sediments were sampled and analyzed for atrazine. By increasing pH and changing soil organic matter interaction with mineral particles, lime and lime + phosphate decreased sorption in the upper 20-cm layer. This affected leaching and runoff of atrazine, showing that when lime and lime + phosphate were applied to soil, this herbicide had more potential to go deeper in the soil profile, towards the groundwater, or to runoff towards the lower part of the landscape. However, even with increasing leaching, the amount of rainfall, and water infiltration, were enough to dilute atrazine into levels below the maximum contaminant level (MCL) of atrazine in drinking water.