title: An assessment of the fate, behaviour and environmental risk associated with sunscreen TiO₂ nanoparticles in UK field scenarios.
abstract: The fate of Ti was examined in an activated sludge plant serving over 200,000 people. These studies revealed a decrease of 30 to 3.2 μg/L of Ti < 0.45 μm from influent to effluent and a calculated Ti presence of 305 mg/kg DW in wasted sludge. Thus, using sludge as a fertiliser would result in a predicted deposition of up to 250 mg/m² of Ti to soil surfaces using a recommended maximal agricultural application rate. Given the major use of TiO₂ in many industrial and domestic applications where loss to the sewer is possible, this measured Ti was presumed to have been largely TiO₂, a proportion of which will be nanoparticle sized. To assess the behaviour of engineered nanoparticle (ENP) TiO₂ in sewage and toxicology studies, Optisol (Oxonica Materials Ltd) and P25 (Evonik Industries AG), which are representative of forms used in sunscreen and cosmetic products, were used. These revealed a close association of TiO₂ ENPs with activated sludge. Using commercial information on consumption, and removal rates for sewage treatment, predictions were made for river water concentrations for sunscreen TiO₂ ENPs for the Anglian and Thames regions in Southern England. The highest predicted value from these exercises was 8.8 μg/L for the Thames region in which it was assumed that one in four people used the recommended application of sunscreen during a low flow (Q95) period. Ecotoxicological studies using potentially vulnerable species indicated that 1000 μg/L TiO₂ ENP did not affect the viability of a mixed community of river bacteria in the presence of UV light. Direct exposure to TiO₂ ENPs did not impair the immuno-effectiveness of earthworm coelomocyte cells at concentrations greatly above those predicted for sewage sludge.
authors.affiliation: Centre for Ecology and Hydrology, Wallingford OX108BB, United Kingdom. ajo@ceh.ac.uk
authors.forename: Andrew C
authors.initials: AC
authors.lastname: Johnson
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Bowes
authors.forename: Alison
authors.initials: A
authors.lastname: Crossley
authors.forename: Helen P
authors.initials: HP
authors.lastname: Jarvie
authors.forename: Kerstin
authors.initials: K
authors.lastname: Jurkschat
authors.forename: Monika D
authors.initials: MD
authors.lastname: Jürgens
authors.forename: Alan J
authors.initials: AJ
authors.lastname: Lawlor
authors.forename: Barry
authors.initials: B
authors.lastname: Park
authors.forename: Phillip
authors.initials: P
authors.lastname: Rowland
authors.forename: David
authors.initials: D
authors.lastname: Spurgeon
authors.forename: Claus
authors.initials: C
authors.lastname: Svendsen
authors.forename: Ian P
authors.initials: IP
authors.lastname: Thompson
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Barnes
authors.forename: Richard J
authors.initials: RJ
authors.lastname: Williams
authors.forename: Nan
authors.initials: N
authors.lastname: Xu
mesh_terms: D000818:Animals; D001419:Bacteria / Q000187:drug effects; D004784:Environmental Monitoring; D004785:Environmental Pollutants / Q000032:analysis / Q000633:toxicity*; D053768:Metal Nanoparticles / Q000032:analysis / Q000633:toxicity*; D009835:Oligochaeta / Q000187:drug effects; D018570:Risk Assessment; D045483:Rivers / Q000737:chemistry / Q000382:microbiology; D012722:Sewage / Q000737:chemistry; D013473:Sunscreening Agents / Q000032:analysis / Q000633:toxicity*; D014025:Titanium / Q000032:analysis / Q000633:toxicity*; D006113:United Kingdom; D014865:Waste Disposal, Fluid; D014871:Water Microbiology
chemical_list: D004785:Environmental Pollutants; D012722:Sewage; D013473:Sunscreening Agents; C009495:titanium dioxide; D014025:Titanium