Reduction of synthetic fertilizer application and heavy metal absorption on oil palm nursery related to the application of humic substances

Humic acid with amorphous and colloidal characteristics can improve soil chemical properties, especially tropical soil with lower fertility. To contribute to an environmentally friendly farming system, the capacity of humic acid to reduce the consumption of synthetic fertilizer on nursery oil palm was tested in this experiment. The experiment’s purpose was to confirm the minimizing fertilizer application and reduce the heavy metal absorption in oil palm nurseries without any deterioration effects on the growth performance. Varied composition types of humic substance products were applied, i.e., in combination with fish meal, seaweed, and chicken manure.The concentration of heavy metals Ba, Cd, Ba and the absorption of macroelements N, P, K, Ca, and Mg in the growing plants was also observed. It showed that humic acid in the dosage of 40 g/plant in the main nursery was capable of reducing the application of mineral fertilizer by 25% base on recommended standard application and at the same time reducing heavy metal Ba and Cd absorption by the plant.

PEMANFAATAN TONGKOL JAGUNG SEBAGAI ADSORBEN LIMBAH LOGAM BERAT

Logam berat adalah istilah untuk logam-logam seperti Cd, Cr, Cu, Hg, Ni, Pb, dan Zn yang sering berhubungan dengan polusi dan toksisitas. Adsorpsi merupakan metode yang paling sering digunakan untuk menghilangkan ion logam. Tongkol jagung berpotensi menjadi adsorben karena kadar selulosanya yang tinggi. Penelitian ini bertujuan untuk mengkaji performa tongkol jagung sebagai adsorben ion Cr(VI) dan Cd(II). Penelitian dimulai dengan perlakuan awal adsorben dan dilanjutkan dengan proses adsorbsi. Kadar logam berat dihitung dengan metode spektrofotometri. Nilai efisiensi penyerapan Cd(II) meningkat dengan adanya perlakuan awal menggunakan suhu tinggi. Jumlah logam yang terserap semakin banyak seiring dengan lamanya waktu adsorpsi dengan efisiensi penyerapan sebesar 94,76% untuk Cr(VI) dan 83,96% untuk Cd(II). Penambahan jumlah adsorben tongkol jagung juga meningkatkan efisiensi penyerapan logam kromium hingga 82,33% dan kadmium sebesar 83,98%. Sedangkan jumlah ion Cr(VI) yang terserap tidak linear dengan penambahan kecepatan pengadukan. Berdasarkan hasil penelitian, dapat disimpulkan bahwa tongkol jagung berpotensi digunakan sebagai adsorben ion logam berat dengan efisiensi di atas 80%. Kata kunci: adsorpsi, kadmium, kromium, tongkol jagung AbstractHeavy metal is a term for metals such as Cd, Cr, Cu, Hg, Ni, Pb, and Zn, often associated with pollution and toxicity. Adsorption is the most commonly used method to remove metal ions. Corncob have the potential to be an adsorbent because of their high cellulose content. This study aimed to examine the performance of corncob as an adsorbent of Cr(VI) and Cd(II) ions. The study began with the pretreatment of the adsorbent and continued with the adsorption process. Heavy metal concentration was calculated by the spectrophotometric method. The value of the absorption efficiency of Cd(II) increased with the pretreatment using high temperature. The amount of metal adsorbed increased with the length of adsorption time with the absorption efficiency of 94.76% for Cr(VI) and 83.96% for Cd(II). The addition of corncob adsorbent also increased the efficiency of chromium metal absorption up to 82.33% and cadmium by 83.98%. Meanwhile, the amount of Cr(VI) ion adsorbed was not linear with increasing stirring speed. Based on the results, it can be concluded that corncob could be used as heavy metal ion adsorbents with an efficiency above 80%. Keywords: adsorption, cadmium, chromium, corn cob

Metal Nanoparticles in Laser Bioprinting

Laser bioprinting is a promising method for applications in biotechnology, tissue engineering, and regenerative medicine. It is based on a microdroplet transfer from a donor slide induced by laser pulse heating of a thin metal absorption film covered with a layer of hydrogel containing living cells (bioink). Due to the presence of the metal absorption layer, some debris in the form of metal nanoparticles is printed together with bioink microdroplets. In this article, experimental investigations of the amount of metal nanoparticles formed during the laser bioprinting process and transported in bioink microdroplets are performed. As metal absorption layers, Ti films with the thickness in the range of 25–400 nm, produced by magnetron spattering, were applied. Dependences of the volume of bioink microdroplets and the amount of Ti nanoparticles within them on the laser pulse fluence were obtained. It has been experimentally found that practically all nanoparticles remain in the hydrogel layer on the donor slide during bioprinting, with only a small fraction of them transferred within the microdroplet (0.5% to 2.5%). These results are very important for applications of laser bioprinting since the transferred metal nanoparticles can potentially affect living systems. The good news is that the amount of such nanoparticles is very low to produce any negative effect on the printed cells.

Recent Advances of Phytoremediation in Environmental Detoxification

Phytoremediation is a process of environmental clean-up that uses plants and associated microbes to clean up pollutants from the air, water, and soil by producing substances beneficial for plant growth and through controlling plant pathogens. There is an adverse effect of heavy metals on both aquatic life forms as well as terrestrial living beings including humans. Being recalcitrant, heavy metals accumulate in the environment and are eventually biomagnified via the food chain. There are advanced molecular tools for a better understanding of the mechanism of metal absorption, translocation, sequestration, and tolerance in plants and microbes. This review article describes the accumulation of heavy metals in the environment, its effect on the environment, and the current role of phytoremediation in the extinction of heavy metals.

Genome-Wide Identification, Structure Characterization, Expression Pattern Profiling, and Substrate Specificity of the Metal Tolerance Protein Family in Canavalia rosea (Sw.) DC

Plant metal tolerance proteins (MTPs) play key roles in heavy metal absorption and homeostasis in plants. By using genome-wide and phylogenetic approaches, the origin and diversification of MTPs from Canavalia rosea (Sw.) DC. was explored. Canavalia rosea (bay bean) is an extremophile halophyte with strong adaptability to seawater and drought and thereby shows specific metal tolerance with a potential phytoremediation ability. However, MTP genes in leguminous plants remain poorly understood. In our study, a total of 12 MTP genes were identified in C. rosea. Multiple sequence alignments showed that all CrMTP proteins possessed the conserved transmembrane domains (TM1 to TM6) and could be classified into three subfamilies: Zn-CDFs (five members), Fe/Zn-CDFs (five members), and Mn-CDFs (two members). Promoter cis-acting element analyses revealed that a distinct number and composition of heavy metal regulated elements and other stress-responsive elements existed in different promoter regions of CrMTPs. Analysis of transcriptome data revealed organ-specific expression of CrMTP genes and the involvement of this family in heavy metal stress responses and adaptation of C. rosea to extreme coral reef environments. Furthermore, the metal-specific activity of several functionally unknown CrMTPs was investigated in yeast. These results will contribute to uncovering the potential functions and molecular mechanisms of heavy metal absorption, translocation, and accumulation in C. rosea plants.

Recent Advances in Covalent Organic Frameworks for Heavy Metal Removal Applications

Covalent organic frameworks comprise a unique class of functional materials that has recently emerged as a versatile tool for energy-related, photocatalytic, environmental, and electrochromic device applications. A plethora of structures can be designed and implemented through a careful selection of ligands and functional units. On the other hand, porous materials for heavy metal absorption are constantly on the forefront of materials science due to the significant health issues that arise from the release of the latter to aquatic environments. In this critical review, we provide insights on the correlation between the structure of functional covalent organic frameworks and their heavy metal absorption. The elements we selected were Pb, Hg, Cr, Cd, and As metal ions, as well as radioactive elements, and we focused on their removal with functional networks. Finally, we outline their advantages and disadvantages compared to other competitive systems such as zeolites and metal organic frameworks (MOFs), we analyze the potential drawbacks for industrial scale applications, and we provide our outlook on the future of this emerging field.

A Review Over the effect of Heavy Metal in Metabolism of Brassica juncea (L.) and Myristica fragrans

Brassica juncea (L.) and Myristica fragrans are common plants found in India where the concentration of heavy metals in water and soil is observed more frequently and in sufficient amounts to cause bad effects to the living entity. In plants various kinds of bad effects such as dwarfness, yellowish leaves, dead leaves, brownish and dead stem. These are kinds of symptoms that one can observe in plants suffering from the bad effects of heavy metal absorption. At a specific time, they should be identified and treated for the same otherwise this may cause an increase in dead material in the plant, day by day. This review summarizes the bad effects of heavy metals in plants like these two.