title: Sorption of pesticides by a mineral sand mining by-product, neutralised used acid (NUA).
abstract: This study investigated the sorption-desorption behaviour of four pesticides by a by-product from mineral sand mining, commonly referred to as neutralised used acid (NUA). In batch studies the average amount of pesticide removed after 6h was 69% for atrazine, 89% for diuron, 61% for 2,4-D and 83% for chlorpyrifos. The lower sorption of 2,4-D to NUA compared with the other pesticides studied is most likely to be due to the high pH of the solutions (7.8 to 8.8) which would have resulted in 2,4-D being predominantly in an anionic form. The presence of other pesticides only significantly decreased the amount of 2,4-D sorbed from 59% to 34% when present in a mixture. Little (2 to 17%) diuron, chlorpyrifos, atrazine or 2,4-D were found to desorb from the NUA. The presence of nitrate or phosphate had minimal effect on the amount of diuron or atrazine sorbed to the NUA. However, all phosphate and nitrate treatments significantly (P<0.05) decreased the amount of 2,4-D sorbed (<50%) compared with when 2,4-D was present alone (65%). This study has shown that NUA has potential to be used as a sorbent for pesticides.
authors.affiliation: CSIRO Land and Water, Water for a Healthy Country National Research Flagship, PMB 2 Glen Osmond, South Australia 5064, Australia. danni.oliver@csiro.au
authors.forename: Danielle P
authors.initials: DP
authors.lastname: Oliver
authors.forename: Yi Fong
authors.initials: YF
authors.lastname: Pan
authors.forename: Jenny S
authors.initials: JS
authors.lastname: Anderson
authors.forename: Tsair Fuh
authors.initials: TF
authors.lastname: Lin
authors.forename: Rai S
authors.initials: RS
authors.lastname: Kookana
authors.forename: Grant B
authors.initials: GB
authors.lastname: Douglas
authors.forename: Laura A
authors.initials: LA
authors.lastname: Wendling
mesh_terms: D000327:Adsorption; D017610:Calcium Compounds / Q000737:chemistry; D007700:Kinetics; D008903:Minerals / Q000737:chemistry*; D008906:Mining; D008962:Models, Theoretical; D015394:Molecular Structure; D010087:Oxides / Q000737:chemistry; D010575:Pesticides / Q000737:chemistry / Q000302:isolation & purification*; D011786:Quality Control; D013464:Sulfuric Acids / Q000737:chemistry; D014874:Water Pollutants, Chemical / Q000737:chemistry / Q000302:isolation & purification*; D018508:Water Purification / Q000379:methods* / Q000592:standards
chemical_list: D017610:Calcium Compounds; D008903:Minerals; D010087:Oxides; D010575:Pesticides; D013464:Sulfuric Acids; D014874:Water Pollutants, Chemical; C016538:lime; C033158:sulfuric acid