The Utilization of Water Spinach (Ipomoea reptans Poir) as a Phytoremediation Agent for Heavy Metals in Growing Media

Waste is one of the most complex global issues faced by nearly every country in the world. The management of organic waste in Bali through the Reduce-Reuse-Recycle Waste Processing Facility (TPS3R) produces compost with potential use as a planting medium. However, compost derived from household waste is often contaminated with heavy metals such as arsenic (As), mercury (Hg), and manganese (Mn) that exceed the threshold limits set by SNI 19-7030-2004, thereby requiring bioremediation treatment before being agronomically utilized. This study aims to assess the effectiveness of a vermiremediation approach using earthworms combined with biochar in reducing heavy metal content in TPS3R compost and its impact on the growth and yield of water spinach (Ipomoea reptans Poir). The experiment was conducted using a factorial Completely Randomized Design (CRD) with two factors: compost sources from four TPS3R facilities (Kesiman, Jagapati, Belega, Darmasaba) and treatment combinations of earthworms (50 g, 100 g) with biochar (250 g). The results showed that the combination of earthworms and biochar significantly reduced heavy metal concentrations, such as arsenic from 836 ppm to 18.65 ppm, mercury from 22 ppm to 1.27 ppm, and manganese from 1289 ppm to 135.54 ppm. Additionally, this treatment improved plant growth and yield parameters, including plant height, number of leaves, fresh weight, and dry weight. Although the improvements were not statistically significant across treatments, they were evident in the media treated with bioremediation. These findings indicate that the combination of earthworms and biochar is a promising strategy to improve compost quality and support sustainable agriculture on drylands.

Water spinach (Ipomoea reptans Poir) had been identified as a nutritious vegetable with high demand in Indonesia. Besides, this plant also has been evidenced to play an important role in environmental cleaning as phytoremediator. The study about the effect of organic fertilizers on the growth and yield of water spinach (Ipomoea reptans Poir) has been conducted in the Green House of Biology Department, Faculty of Mathematics and Natural Sciences, Universitas Negeri Medan. The study aims to investigate the most effective type of fertilizers and the dose for water spinach’s (Ipomoea reptans Poir) growth and yield. A Completely Randomized Factorial Design was designed for the experiment with two factors and three repetitions. The first factor is the type of fertilizer (chicken manure, cow manure, and compost), and the second factor is the dose of the fertilizer (1:1, 2:1, and 3:1). The parameters such as plant height, number of shoots, number of leaves, fresh weight, dry weight, leaf’s total chlorophyll content, and water content were measured to evaluate plant growth and yield. The General Linear Model used SPSS 21 programs was applied to analyze the collected data. Study results revealed that cow manure increased plant growth and yield significantly with dose 2:1 as the finest treatment, followed by dose 3:1. Cow manure also increased total chlorophyll content (8.0574c mg. L-1), with the most suitable dose was 2:1 (8.2807 mg. L-1). The plant’s water content tended to be high in chicken manure (93%), and the lower water content was in cow manure with dose 3:1 (87.5%).

This study aimed to (1) Know the effect of a mixture of waste tea grounds, coffee grounds and pineapple peel on the growth of water spinach (Ipomoea reptans Poir) with simple hydroponic media, (2) Know what dose of a mixture of waste tea grounds, coffee grounds and pineapple peel that gives the best effect on the growth of water spinach (Ipomoea reptans Poir) with simple hydroponic media, (3) Know the results of the study can be used as biology teaching material in the form of student worksheet. The type of research used was quantitative using experimental methods and non-probability sampling techniques. This study used a Completely Randomized Design (CRD), applying 4 treatments and 3 replications with P0 (250 ml water), P1 (250 ml POC), P2 (200 ml POC+50 ml water), P3 (150 ml POC+ 100 ml water). Based on the results of the study, it can be concluded that there was an increase in height and number of leaf blades on water spinach (Ipomoea reptans Poir). With the research results, the best plant height was at P3= 20.33 cm and for the best leaf blade results it was at P3= 14 strands. The results of this study can be used as biology teaching material in the form of of student worksheet on growth and development material for SMA class XII. The results of the validation of learning resources by material experts, design experts and linguists concluded that of student worksheet was feasible to use as a learning resource with an average score of 100% material experts, 80% design experts and 90% linguists

Water spinach (Ipomoea reptans Poir) is a commonly cultivated vegetable in tropical regions like Indonesia. Water spinach faces challenges related to water availability, which can impact various cellular, biochemical, and physiological aspects. Drought can lead to reduced vegetative growth, and a lack of water can inhibit overall plant growth. Therefore, understanding the growth response of water spinach to water stress is crucial for achieving optimal results. This study used a Completely Randomized Design (CRD) with water concentration as the treatment. Water spinach seeds were selected before being sown and transferred to polybags. Irrigation was conducted with five levels of concentration: 100% (300 ml of water), 75% (225 ml of water), 50% (150 ml of water), 25% (75 ml of water), and 0% (0 ml of water). Observations were made at 14 days old with agronomic and anatomical parameters, and the data were analyzed using MANOVA followed by a Tukey post-hoc test at a 5% significance level with SPSS. The results showed that irrigation with 300 ml and 225 ml of water produced the highest number of stomata and the longest stomata size. For stomatal width, treatments of 300 ml, 225 ml, and 75 ml resulted in wider stomata. Meanwhile, for stomatal area, the 225 ml treatment showed the largest stomatal size. However, no significant differences were observed in plant height and leaf number among the treatments. Drought stress affects photosynthesis and plant growth, with increasingly severe impacts as drought intensity rises. Drought results in reduced stomatal number, smaller stomatal size, and inhibited plant growth.

This study aimed to determine the influence of Electrolyzed water on the growth of water spinach viewed from the dry weight, plant height, number of leaves, and stem circumferences factors. This research had been conducted using a hydroponic technique with iron-electrode electrolysis water as the treatment. The method used was regression analysis, both linear and quadratic. The optimizations of the treatments were seen using the surface response method. The results showed a significant effect on the length of electrolysis duration on dry weight, the number of leaves, plant height, and stem circumference. The most significant models were the model with the explanatory variables of electrolysis duration and the number of leaves. This result indicated the addition of Electrolyzed water with an iron diode increased the number of leaves’ stomata which affected the dry weight.

Valorisation of toxic paper mill waste through vermicomposting: An insight towards cleaner engineering through alleviation of wastes

Water spinach (Ipomoea reptans Poir.) is a short-lived plant that is highly nutritious, containing vitamins A, B, and C, protein, calcium, phosphorus, sitosterol, and minerals, especially iron, which are beneficial for body growth and health. The objectives of this study are to determine the significant interaction between organic (vermicompost) and inorganic (NPK) fertilizers on the growth and yield of water spinach and to identify the optimal dosages of vermi-compost and NPK fertilizers that have the best effect on its growth. The study was conducted in Tegalsari Village, Plered District, Cirebon Regency, West Java Province. The research was conducted using a Randomized Block Design (RBD) with a factorial pattern consisting of two factors: the dose of VermiCompost (K) and the dosage of NPK (N) Mutiara 16:16:16 (N). The results showed that a combination of rice straw compost at 14 tons/ha and 200 kg/ha of the NPK was found to be the best dose for achieving the highest values for plant height, number of leaves, leaf area, and fresh weight of the plants at 24 days after planting (DAP). The best results were achieved with the combination of K3 and N3 treatments, which provided the best results in terms of plant height and leaf area.

Water spinach (Ipomea reptans Poir) is a type of vegetable that is very popular among Indonesians because of its delicious taste. This plant originated in India but then spread to various countries in Asia and Africa (Plucknett and Beemer, 1981). NPK fertilizer in water spinach cultivation is the most widely used compound fertilizer containing the nutrients Nitrogen, Phosphorus and Potassium. Organic fertilizers are fertilizers composed of living matter, such as weathering of plant, animal and human remains. This research will be carried out in the experimental field of the Faculty of Agriculture, Indonesian Community Development University UPMI Medan, on Jl. Waqf, Pasar 12 Marindal II, Patumbak District, Deli Serdang Regency, North Sumatra Province. Altitude 40 m above sea level. Based on the results of field observations, it directly shows the normal growth of land kangkong plants (Ipomoea reptans Poir.). Parameters observed included plant height (cm), number of leaves (strands), sample wet weight (g), overall wet weight (g), root length (cm) and root volume (mm). Single effect NPK fertilizer application at N2 level (1.5 gram/plant (300 kg/ha) has an effect on increasing plant height growth at 3 WAP) based on the 5% DMRT test. The interaction effect of NPK fertilizer and liquid organic fertilizer had no effect on plant height, number of leaves, sample wet weight, overall wet weight, root length and root volume.

Chapter 4 - Electrochemical reduction of heavy metals from industrial effluents

The CSR program which is based on Government Regulation Number 47 of 2012 concerning Social and Environmental Responsibility of Limited Liability Companies has done a lot of research, one of which is testing compost fertilizer on the growth and yield of land spinach. Kangkung land (Ipomoea reptans Poir) is a type of vegetable that is already known by all levels of Indonesian society, water spinach is a short-lived plant, which contains quite high nutrients. The experimental design that will be used in this study is a 4 x 1 non-factorial randomized block design (RAK), with 3 replications, so there are 12 treatment combinations. The factors to be investigated are: The effect of compost fertilizer (K) consists of 4 levels, namely: Control K0 (without fertilizer) K1 3kg/block (1kg/polybag) K2 4kg/block (1.3kg/polybag) K3 5kg/block ( 1.6 kg/polybag). Parameters observed were plant height, number of leaves (strands), number of petioles, and stem length. the results showed that the best plant height was found in the K3 treatment. on the number of leaves, the highest value was found in the K3 treatment, namely compost 5kg/block (1.6kg/polybag) treatment (K3) which was significantly different from K0 and K1 treatments, but not significantly different from (K2). on the leaf length parameter the best value was found in the K3 treatment which was significantly different from K0 (control), but not significantly different from the K1, and K2 treatments. , (strands) and the highest leaf length were found in the K3 5kg/block (1.6kg/polybag) treatment which was significantly different from the other treatments.Keywords: compost, CSR program, land kale

A greenhouse experiment has been planned for this study to delineate the benefits of two types of rice husk biochars (namely B300 and B600 which are prepared at 300°C and 600°C, respectvely) and coal fly ash (CFA), as soil amendments, for decreasing the amount of some heavy metals (like Pb, Cd, Ni, Cr, and Cu) as well as mobility and phytoavailability in an artificially-calcareous multi-element-contaminated soil. The effect of soil amendment on heavy metals’ availability has been evaluated via sequential extraction experiment and phytoavailability of the plant. According to the results, among the studied amendments, B600 has had the highest positive effect on both dry matter yield in corn and heavy metals’ availability reduction in post-harvest soil samples (with the exception of Cr), compared to CFA and B300, due to the increasing specific surface area, CEC, and pH that promote heavy metals’ sorption in the soil through surface complexation and ion exchange mechanisms. Evaluation of heavy metals’ chemical forms in post-harvest soil samples indicates that addition of amendments has significantly decreased mobility factor of heavy metals (with the exception of Cr in CFA-amended soils). In general, application of three soil amendments to this polluted soil has considerable effect on the reduction of heavy metals’ availability and phytoavailability. However, among the studied amendments, B600 and CFA have had the maximum and minimum effect on heavy metals’ availability reduction, respectively.

Humic substances, which are stable complex compounds that come from the decomposition of organic matter, can be extracted from organic materials such as weathered coal, compost, and soils. They can improve the physical, chemical, and biological properties of soils and, more importantly, can function as plant growth stimulants. However, when applied in liquid form into the soil, these humic substances are readily leached, so that a binding agent that is used as their carrier is needed to make them stay longer in the soil, so that plants can absorb them. In this regard, zeolite, which is a porous mineral with a high cation exchange capacity (CEC), is a promising material to serve the said purpose. Thus, this study aimed to determine the effects of humic substances and zeolite (used as humic substance carrier) on the soil properties, nutrient uptake, and growth and yield of water spinach. Using a randomized block design with 10 treatments and 2 replications, the treatments consisted of (a) control (b) zeolite at 200 kg/ha (Z20), (c) four treatments with two humic substances (Type A and Type B) administered at dosages of 5 and 10 liters/ha (HA5, HA10, HB5, and HB10), and (d) four treatment combinations of humic substances and zeolite (HA5Z20, HA10Z20, HB5Z20, and HB10Z20). Water spinach (Ipomoea reptans Poir) was planted in Latosol soil on plots measuring 3 m × 0.7 m in treatment unit. The results showed that the application of humic substance with zeolite raised the soil CEC and exchangeable Ca and increased the uptake of N, P, K, Ca, Mg, Na, Cu, Mn, Fe, and Zn by the water spinach. The highest production of water spinach was achieved in Treatment HA10Z20 (humic substance at 10 liter/ha mixed with zeolite at 20 kg/liter humic substance), with a yield of almost 2.5 times that of control.

Magnetoelectric reduction of chromium(VI) to chromium(III)

Chapter 26 - Microbial Electrochemical Heavy Metal Removal: Fundamental to the Recent Development

Heavy metal contamination represents a critical environmental and public health challenge, necessitating effective remediation approaches. This study examines the bioremediation potential of three indigenous bacterial strains Aeromonas caviae KQ_21, Aeromonas hydrophila AUoR_24, and Shewanella putrefaciens SUoR_24 evaluated both individually and in consortia for their capacity to remove heavy metals. Tolerance assessments demonstrated that the coculture of these strains exhibited superior resistance to copper (Cu), zinc (Zn), and nickel (Ni), with optimal growth observed up to 6 mM for Cu, 9 mM for Zn, and 5 mM for Ni, outperforming the monocultures. The co-culture system also achieved higher metal reduction efficiencies, with reductions of 47.02% for Cu, 61.49% for Ni, and 61.93% for Zn, in contrast to lower reductions observed in individual strains. The study further explored the impact of environmental conditions on bioremediation efficiency. Optimal temperature for both monoculture and coculture setups was found to be 30°C. pH and salt concentration variations significantly affected bacterial growth and metal reduction, highlighting the necessity of tailored conditions for enhanced bioremediation. In terms of metal removal mechanisms, the results demonstrated that nickel (Ni) removal occurred primarily through bioaccumulation, while copper (Cu) removal involved both biosorption and bioaccumulation. Zinc (Zn) removal was facilitated through biosorption, bioaccumulation, and biotransformation. These findings underscore the effectiveness of bacterial consortia, particularly indigenous strains, in improving heavy metal tolerance and reduction through synergistic interactions and cooperative metabolic processes. This research offers valuable insights into optimizing bacterial consortia for environmental cleanup and advances the application of indigenous bacteria in bioremediation strategies. Future investigations should focus on exploring additional microbial species and further elucidating the molecular mechanisms that contribute to enhanced bioremediation efficacy.