Impact of Mg rich synthetic gypsum application on the environment and palm oil quality A.R. Sahibin a , J. Shamshuddin b , C.I. Fauziah b, ⁎, O. Radziah b , I. Wan Mohd Razi c , M.S.K. Enio d a Environmental Science Program, Faculty of Science and Natural Resources, Universiti Malaysia Sabah, 88400 Kota Kinabalu, Sabah, Malaysia b Department of Land Management, Faculty of Agriculture, Universiti Putra Malaysia, 43400 Serdang, Selangor, Malaysia c School of Environmental and Natural Resources Sciences, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor, Malaysia d Department of Science and Technical Education, Faculty of Educational Studies, Universiti Putra Malaysia, 43400 Serdang, Selangor, Malaysia HIGHLIGHTS • MRSG supplies Mg and Ca for oil palm growth. • Metal content in soil, plant tissue and oil are below the permitted concentration. • Oil palm treated with MRSG produces non-cytotoxic oil, hence is safe for con- sumption. • MRSG application does not affect the soil, plant tissue, water and palm oil quality. • MRSG is practical and sustainable as a soil amendment in oil palm plantation. GRAPHICAL ABSTRACT abstract article info Article history: Received 19 July 2018 Received in revised form 10 October 2018 Accepted 16 October 2018 Available online 17 October 2018 Editor: Filip M.G. Tack A study was conducted in an oil palm plantation in Peninsular Malaysia to elucidate the effects of applying Mag- nesium Rich Synthetic Gypsum (MRSG), a by-product of chemical plant, on the chemical properties of soil, the uptake of heavy metals by the palm trees, the oil quality and its impact on the surrounding environment. The re- sults showed that MRSG application onto soil cropped to oil palm could bring positive impact in terms of soil chemical properties and oil palm production. The quality of the oil was not significantly affected by the continu- ous MRSG application as shown by the low heavy metals and trace elements of concern content (Cu: 0.062 mg/kg; Fe: 2.10 mg/kg; Mn: 1.93 mg/kg; Pb: 0.006 mg/kg; Zn: 0.103 mg/kg; Cr: 0.354 mg/kg; Ni: 0.037 mg/kg). From the I-geochem index, the soil was found to have values ranging from -3.81 to -1.03 which is considered as uncontaminated. Further, its application did not result in negative impact on the sur- rounding environment; hence, the quality of the soil and surface water in the plantation and/or the surrounding area remained intact. Phytotoxic elements in the oil palm tissue (As: 0.12 mg/kg; Se: 0.05 mg/kg; Zn: 1.48 mg/kg; Ce: 0.47 mg/kg; La: 0.26 mg/kg; Sr: 3.03 mg/kg) and cytotoxic elements in the oil were below the acceptable limit. Based on the results of the Environmental Monitoring out during the period of the study, it was concluded that application of the by-product of the chemical plant as a source of Mg to enhance soil fertility in the oil palm plantation was considered safe and sustainable. The effects of applying MRSG and Chinese kieserite was almost similar. So, MRSG can be used as a possible source of Mg to replace Chinese kieserite for oil palm production on the Ultisols in Peninsular Malaysia. © 2018 Elsevier B.V. All rights reserved. Keywords: Cytotoxic Heavy metals Kieserite Magnesium Rare earth element Science of the Total Environment 652 (2019) 573–582 ⁎ Corresponding author. E-mail address: cfauziah@upm.edu.my (C.I. Fauziah). https://doi.org/10.1016/j.scitotenv.2018.10.232 0048-9697/© 2018 Elsevier B.V. All rights reserved. Contents lists available at ScienceDirect Science of the Total Environment journal homepage: www.elsevier.com/locate/scitotenv