The Use of the Direct Test on Substrate in the Assessment of Phytotoxicity of Foundry Waste

The article presents the results of phytotoxicity tests on foundry dust and landfilled waste. Currently, all of this waste is being reused. The results supplement the previous study on the phytotoxicity of waste leachate. The research has focused on phytotoxicity tests performed directly on the waste. Watercress (Lepidium sativum L.) was used as the test plant. The germination test (GI) and the accumulation test were used to assess phytotoxicity. The results show that the dust from electric furnaces, classified as hazardous waste, was the most phytotoxic. Most of the dust samples inhibited germination and root growth. A possible cause of this phytotoxicity was the high content of heavy metals and low pH. The phytotoxicity were different from previous studies on waste leachate. A lower phytotoxicity effect was found for those waste leachates. The differences could have been caused by the higher concentration of toxic substances available to plants in the direct test. Moreover, the direct contact of sprouts and roots of L. sativum could have contributed to the higher phytotoxicity of the wastes than the leachate. Therefore, it seems appropriate to use both tests simultaneously to assess the phytotoxicity of waste.

S-Carvone Formulation Based on Granules of Organoclay to Modulate Its Losses and Phytotoxicity in Soil

Based on the effects that allelochemicals can exert over organisms, their use as alternatives to synthetic pesticides has been proposed. To this aim, it is important to understand their behavior in soils as allelochemicals can readily dissipate by different routes. In this work, novel granules based on the commercial organoclay Cloisite® 10A were prepared as a new strategy for the possible application of S-carvone as a bioherbicide, overcoming its rapid dissipation in the environment. Batch release, degradation, mobility, and phytotoxicity tests in soil were performed. Until now, the phytotoxicity of organoclay-based formulations of S-carvone in soil has not been studied. The release of S-carvone in water from the granules occurred slowly. There were no differences in the persistence of the allelochemical after its application to soil as a free compound (readily available form) or supported on granules. However, the granulated formulation reduced and delayed the leaching of S-carvone, thus controlling its downward movement in soil columns, as compared to the free S-carvone. Bioassays revealed that S-carvone supported on granules reduced the germination and aerial biomass of Lactuca sativa L. to a greater extent than the free compound. Our results demonstrated that the prepared formulation of S-carvone, based on granules of the commercial organoclay Cloisite® 10A, could be used to control transport losses, such as leaching or volatilization, increasing the bioefficacy of the allelochemical. These findings could inspire further investigations for the preparation of novel formulations of monoterpenes as potential bioherbicides.

Valorization of the use of Waste Agricultural Materials for the Anodic Oxidation of Amaranth Red (E123) using SS/PbO2 Anodes Elaborated by Pulsed Mode Current

The present paper aims to valorize the use of cheap agricultural waste materials for polluted water decontamination. An evaluation of the efficiency of coupling anodic oxidation (AO) using SS/PbO 2 electrodes with biosorption by Luffa cylindrica (L.C) for the removal of Amaranth Red (E123) from aqueous solution was investigated. The effects of pH, contact time, and initial concentration were studied. The regeneration of L.C was estimated based on biosorption /desorption tests. The performance of the coupling process was evaluated based on the color, chemical organic carbon (COD), Total organic carbon (TOC) removals, the energy consumed, and the time required for the degradation of Amaranth. A comparison between the efficiency of the AO and the coupling process for the increase of the lifetimes of the anodes used was done. 54.1, 97.8, and 99.9% of 50 mg.L -1 of Amaranth were removed respectively after 85, 65, and 50 min by biosorption, AO, and coupling AO with biosorption. An increase in the percentages of COD, TOC, germination indexes (GI), and Amaranth removals were observed when adopting the coupling process. Furthermore, a decrease in the release of Pb 2+ ions was observed confirming the good stability of the elaborated anodes during the coupling process. Atomic absorption analysis showed that the Pb 2+ ions reached about 0.020 mg.L -1 , after the total removal of Amaranth dye (60 min) and 0.051 after (80 min) respectively, for coupling AO with biosorption and the AO process. These values are inferior to those allowed by the Standards. Phytotoxicity tests confirmed the possibility of the reuse of the treated solutions.

Evaluation of the Phytotoxicity of Leachate from a Municipal Solid Waste Landfill: The Case Study of Bukov Landfill

Municipal solid waste landfilling, landfilling process and landfill reclamation result in leachate, which may be dangerous to the environment. Municipal solid waste leachate phytotoxicity tests were performed using the toxicity test and a subchronic toxicity pot experiment by direct application of leachate to reference soil in 5, 25, and 50% concentration for a period of 28 days. White mustard (Sinapis alba L.) seeds were exposed to different leachate dilution. Leachate were collected monthly in 2018 in the period from April to September. Furthermore, pH, conductivity, and dissolved oxygen were measured. The inhibition results on Sinapis alba L. seeds in the tested leachate samples ranged from −18.02 to 39.03%. Lower concentration of leachate showed a stimulating effect (only for Sample 1 and Sample 2 at 5% concentration). It was found out that leachate taken at the landfill is phytotoxic. The results of measurements are based on rainfall which affects the quantity and quality of the leachate. The values of germinated seeds/growing plants from the subchronic toxicity pot experiment ranged from 80 to 104%; therefore, the leachate is considered phytotoxic. However, it was confirmed that leachate may be used for landfill irrigation.

Leachate and contact test with Lepidium sativum L. to assess the phytotoxicity of waste

The study evaluated the use of Lepidium sativum L. to assess the phytotoxicity of three types of waste such as hazardous waste (slags from zinc to copper smelters) and nonhazardous waste (mineral–organic composite). Previous studies evaluated heavy metal leaching and the environmental impact of the tested waste. The purpose of phytotoxicity studies was to increase knowledge about this waste. Two types of tests were used to assess the phytotoxicity of wastes: germination index and accumulation test. Both tests were carried out for leachate (leachate test) and waste (contact test). The results of both tests were compared to assess the phytotoxic effects of tested waste. Phytotoxicity tests have shown that the mineral–organic composite leachate was stimulated plant growth, copper smelter slag leachate was characterized by no phytotoxicity and zinc slag leachate inhibited the growth of plants. In contrast, contact test showed inhibitory effects from all tested waste. Wherefore, the contact test was indicated as more sensitive in the assessment of phytotoxicity. However, this is not a clear assessment, because the germination index values for both tests were a result of differences of root length for both control samples (deionized water and sand). The study confirmed the usefulness of L. sativum for the assessment of phytotoxicity of various types of waste. Additionally, it was found that L. sativum was resistant to high concentrations of heavy metals in the leachate, without causing any negative physiological effects.

Enviromental Impact of Municipal Solid Waste Landfill in North of Iraq

solid wastage yielding in a landfill badly influenced the encompassing condition and people habitat nearer to landfill destinations. Landfill is the most established and the most widely recognized type of evacuation and transfer of waste, comprising the last discarding technique for solid waste in the city. It is outstanding that the effect of MSW landfills leads to contamination of every single natural segment. The negative natural effect of landfills diminished by employing preservation advancements and proper sold waste administration techniques. The nowadays investigation attempted observing of the city wastage landfill effect on the circumference. The spatial attributes of the region affected by the waste dumping and the conceivable effect of leachate utilizing phytotoxicity tests were done. The landfill is built, with base liner and leachate and landfill gas gathering and remedy and curing framework. The transition of leachate and gas from the corpus of landfill into the encompassing condition present a genuine natural concern, which mingle to groundwater squalor, air contamination with sway on atmosphere through methane outflow and potential wellbeing risks. This paper shows an influenced of solid waste land fill in environment. Populaces, particularly those living nearer to the landfill area contamination sources are in danger of both short and long haul impacts of natural, physical and chemical contaminants, including water and food borne sicknesses, substantial metals poisonings and other possibly dangerous components and mixes present noticeable all around, water, soil, particularly in north of Iraq. By and large, there is absence of vital strategies, guidelines and rules in all divisions and at all levels in connection to sheltered and ecological neighborly tasks in agribusiness, industry, vitality, and open administrations.

Phytotoxicity of graphene oxide on rice plants is concentration-dependent

Graphene significantly affects seeds germination and seedling growth of food plants. Phytotoxicity tests by seeds germination and seedling growth are important means to detect toxicity of graphene oxide. We in this study assessed the effect of graphene oxide on rice plants at low concentration. Graphene oxide significantly inhibited water absorption during 3–6 h soaking, postponed seeds germination, but significantly decreased seeds germination rate under 10 μg/mL treatment. Graphene oxide showed most destructive effect on root than upper ground part, and severely restrained root development and increased chlorophyll content. Moreover, graphene oxide enhanced superoxide dismutase, catalase and peroxidase activities, and the change could alleviate oxygen damage. All these results indicate graphene oxide has some concentration-dependent phytotoxicity on seeds germination and seedling development, but also decreases damage by improving activities of antioxidant enzymes.

Évaluation de l’activité antifongique et de la phytotoxicité de Isoberlinia doka craib & staff

This study has been designed to contribute to search alternative solutions based on plant extracts against phytopatogenic fungi. It aims to test the efficacy of ethanolic extract (70%) of Isoberlinia doka trunk bark on the mycelial growth of eight phytopagenic fungi species and on maize and cowpea seedlings germination and growth. The results showed that the ethanolic extract inhibits mycelial growth. This extract has showed an interesting efficiency on three fungi such as Colletotrichum dematium, Curvularia lunata and Fusarium verticilloides. Among these fungi, Curvularia lunata was the most sensitive with a rate of inhibition of mycelial growth of 52.35% after four days incubation at 10 mg / ml. After seven days incubation, the extract was more effective in reducing Fusarium verticilloides mycelial growth with 50,70% inhibition rate at the same concentration. After the phytotoxicity tests, it was found that this extract had no phytotoxic effect on the germination and growth of maize seedlings while it reduced significantly seed germination and cowpea seedling growth. The ethanolic extract of I. doka bark has antifungal properties and did not inhibited maize growth parameters. It could be used in maize seed treatment. Investigations could also be made into the herbicidal properties of some invasive legumes close to cowpea.