112 J. Math. Fund. Sc i., Vo l. 51, No . 2, 2019, 112-126 Received November 7 th , 2017, Revision September 18 th , 2018, Accepted for publication November 15 th , 2018. Copyright © 2019 Published by ITB Journal Publisher, ISSN: 2337-5760, DOI: 10.5614/j.math.fund.sci.2019.51.2.2 Evaluation of Batch Culture Phytoremediation Process using Local Hydromacrophytes to Reduce Synthetic Pesticide Residue in Contaminated Irrigation Water Catur Retnaningdyah & Endang Arisoesilaningsih Department of Biology, Faculty of Mathematics and Natural Sciences, Universitas Brawijaya, Jalan Veteran, Malang 65145, Indonesia E-mail: caturretnaningdyah@gmail.com Abstract. The aim of this study was to evaluate the effectivity of batch culture phytoremediation to remediate irrigation water that was contaminated with 6.4 µL/L synthetic pesticide Prevathon. This was a true experimental research study using a completely randomized design, conducted in a 30 L bucket with sand and gravel as the substrate. The treatment comprised five types of hydromacrophytes (emergent, floating leaf, submerged, polyculture and control without plants), repeated three times at the same time. The effectiveness of the phytoremediation model was determined by water physicochemical parameters, periphyton diversity, percentage of pollution tolerant values (%PTV) and trophic diatom index (TDI) on day 6, 13, 29 and 37 after incubation. The research results showed significantly decreased values of biochemical oxygen demand, turbidity, bicarbonate, nitrate, orthophosphate, total phosphate and free chlorine after incubation for 6 days; decreased concentration of chemical oxygen demand after incubation for 13 days. The water quality improved from slightly and moderately polluted (diversity index 1.6-2.8) to clean and slightly polluted (diversity index 2.8-4.2), from moderately and heavily organically polluted (PTV 40.0-93.7%) to slightly organically polluted and free of organic pollution (PTV 2.4-34.1%), and from meso-eutrophic and eutrophic (TDI 37.4-70.4) to oligo and meso-eutrophic (TDI 13.7-26.4). Keywords: diatom biotic indices; evaluation; irrigation water; phytoremediation; Prevathon. 1 Introduction Indonesia is predicted to have a rice deficit of 8,857,000 tons in 2020 [1]. Because of this, agricultural intensification is needed through regulating the use of irrigation water and the use of synthetic fertilizers and pesticides. Results of previous researches indicate that irrigation water is generally contaminated with organic matter and has etrophication due to human activity around it [2-5]. The issue of irrigation water pollution is complex due to the use of synthetic pesticides to control pests. Prevathon is a new chemical pesticide manufactured by DuPont and is one of the synthetic pesticides most commonly used by