title: Perchlorate in dust fall and indoor dust in Malta: An effect of fireworks.
abstract: We report on the presence of perchlorate in the settleable dust of Malta, a small central Mediterranean island. Both dust fall collected directly as it precipitated from atmosphere over a period of one month and deposited indoor dust from domestic residences were studied. Perchlorate was determined by ion chromatography of water extracts of the collected dusts. Dust fall was collected from 43 towns during 2011 to 2013 and indoor dust was sampled from homes in the same localities. Perchlorate was detected in 108 of 153 samples of dust fall (71%) and in 28 of 37 indoor dust samples (76%). Detectable perchlorate in dust fall ranged from 0.52μgg(-1) to 561μgg(-1) with a median value of 6.2μgg(-1); in indoor dust, levels were from 0.79μgg(-1) to 53μgg(-1) with a median value of 7.8μgg(-1), the highest recorded anywhere to date. Statistical analysis suggested that there was no significant difference in perchlorate content of indoor dust and dust fall. Perchlorate levels in dust fall escalate during the summer in response to numerous religious feasts celebrated with fireworks and perchlorate persists at low μgg(-1) concentrations for several months beyond the summer festive period. In Malta, perchlorate derives exclusively from KClO4, imported for fireworks manufacture. Its residue in dust presents an exposure risk to the population, especially via ingestion by hand to mouth transfer. Our results suggest that wherever intensive burning of fireworks takes place, the environmental impact may be much longer lived than realised, mainly due to re-suspension and deposition of contaminated settled dust in the urban environment.
authors.affiliation: Department of Chemistry, University of Malta, Malta. Electronic address: alfred.j.vella@um.edu.mt.
authors.forename: Alfred J
authors.initials: AJ
authors.lastname: Vella
authors.affiliation: Department of Chemistry, University of Malta, Malta.
authors.forename: Cynthia
authors.initials: C
authors.lastname: Chircop
authors.affiliation: Department of Chemistry, University of Malta, Malta.
authors.forename: Tamara
authors.initials: T
authors.lastname: Micallef
authors.affiliation: Department of Chemistry, University of Malta, Malta.
authors.forename: Colette
authors.initials: C
authors.lastname: Pace
mesh_terms: D000393:Air Pollutants / Q000032:analysis*; D016902:Air Pollution, Indoor / Q000032:analysis / Q000706:statistics & numerical data; D004391:Dust / Q000032:analysis*; D004784:Environmental Monitoring; D053834:Explosive Agents; D006798:Housing; D008319:Malta; D010472:Perchlorates / Q000032:analysis*; D012621:Seasons
chemical_list: D000393:Air Pollutants; D004391:Dust; D053834:Explosive Agents; D010472:Perchlorates; C494474:perchlorate
keywords: Dust fall; Fireworks; Indoor; Malta; Perchlorate; Urban