Editorial notes , by Norhashimah Morad and Norli Ismail

1. Application of Nitrate Stable Isotopes, δ15N-NO₃^– and δ18O-NO₃^–, in Bukit Merah Reservoir, Malaysia, by Nur Syahirah Yaccob, M. I. Syakir, Syahidah Akmal Muhammad, Zarul Hazrin Hashim, Azimah Rahman, Fu-Jun Yue, Si-Liang Li and Widad Fadhullah
2. Heavy Metals in Soil of the Tropical Climate Bauxite Mining Area in Malaysia, by Sharifah Norkhadijah Syed Ismail, Emilia Zainal Abidin, Sarva Mangala Praveena, Irniza Rasdi, Syukriah Mohamad and Wan Muhamad Isharman Wan Ismail
3. Base Metal Ion Extraction and Stripping from WEEE Leachate by Liquid-liquid Extraction, by Amir Talebi, Alessandra Cesaro, Alessandra Marra, Vincenzo Belgiorno and Norli Ismail
4. The Efficiency of Carbon Dioxide and Hydrogen Sulphide Adsorption using Impregnated Granular Activated Carbon and Zeolite, by Rewadee Anuwattana, Pattamaphorn Phungngamphan and Petchporn Chawakitchareon
5. Analysis of Air Quality Index Distribution of PM₁₀ and O₃ Concentrations in Ambient Air of Medan City, Indonesia, by Isra’ Suryati, Hafizhul Khair and Deni Gusrianti
6. Hydrometallurgical Extraction of Zinc and Iron from Electric Arc Furnace Dust (EAFD) using Hydrochloric Acid, by Yao Yi Teo, Hwang Sheng Lee, Yong Chen Low, Seng Wei Choong and Kin Onn Low
7. Ultrafiltration Behaviour of Trihalomethanes (THMs) from Petrochemical Wastewater, by Indok Nurul Hasyimah Mohd. Amin and Nur Fatihah Hakema Ishak
8. Determination of Selected Heavy Metal Concentrations in an Oil Palm Plantation Soil, by Wan Noni Afida Ab Manan, Fazrul Razman Sulaiman, Rubaiyah Alias and Rusdin Laiman
9. The Effects of PO₄^3- Removal from Aqueous Solution with Varied Concentrations of Metal Oxides in Steel Slag Filter System, by Rafidah Hamdan, Nur Ain Nazirah Mohd Arshad and Siti Zu Nurain Ahmad
10. Heavy Metal Concentrations in Tin Mine Effluents in Kepayang River, Perak, Malaysia, by Farhana Ahmad Affandi and Mohd Yusoff Ishak
11. Validation of HPLC Method for the Determination of 17α-Ethynylestradiol (EE2) in Aqueous Phase, by Lim Yee Ling, Norhashimah Morad, Abbas F. M. Alkarkhi and Norli Ismail