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Safety aspects of the nano TiO 2 production and application

ČTP SusChem. Safety aspects of the nano TiO 2 production and application. Presentation at the Nano Safety Conference Ljubljana 22nd- 24th of April 2009 Antonín Mlčoch . Content. Preface Risk assessment framework of nano TiO 2 Common activities of TDMA Ongoing iniciatives

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Safety aspects of the nano TiO 2 production and application

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  1. ČTP SusChem Safety aspects of the nano TiO2production and application Presentation at the Nano Safety Conference Ljubljana 22nd- 24th of April 2009 Antonín Mlčoch

  2. Content • Preface • Risk assessment framework of nano TiO2 • Common activities of TDMA • Ongoing iniciatives • Relative risk assessment for the several industrial fabrications of nano TiO2 • Conclusions

  3.  World consumption of TiO2 : ~ 5 mil t/year  World consumption of UF and nano TiO2 : 40 kt/ year (including 25 kt /year DeNOx catalysts) ►UF TiO2 has a long history of safe use in cosmetics products spanning many decades (UV Attenuator ) ►Nano TiO2 are also used in catalysts,coatings for self-cleaning windows,electronics,fotovoltaics and medicine  Czech Republic – Prechezaproducer of the pigmentary TiO2 and development of production and application of the precursors for catalysts , photocatalysts and UV absorbers

  4. 3 MARKETS REPRESENT 80% OF MARKET SHARE 40 000 Mt / Year estimated 2006 Spring 2008

  5. The industry is responsible for the evaluation of any such risks in production and application • ► Attention focuses upon the questions of risk assessment and risk management within the first phase of application research • ► Definition and structure of nanomaterials, toxicological and ecotoxicological behaviour of nanomaterials , exposure and need for specific ”nanoregulation • I Is thewhole life cycle (workers – consumers – disposal to the environment) under the control by the industry ? •  Is there information enough and has the relevant information • distributed adequately?

  6. Potential for exposure to nano TiO2 Risk = Hazard x Exposure Adapted from Tsuji J.S. § all : Toxicological Sciences;2006 89, No.1 ,42-50

  7. Routes of exposure, distribution and degradation of NSP Adapted from Oberdörster G.: Inhalation Toxicology 2004

  8. Adapted from Oberdörster G.: Inhalation Toxicology 16,2004,23-45

  9. Common activities of TDMATDMA Ultrafine TiO2 Working Group : TDMA members + Ishihara,Tayca, Merck • Assessment of substance risk is time consuming and costly procedure,multidisciplinary approach.  Developing of an extensive dossier of safety data and other evidence which examine the various aspects of the consumer safety of UF TiO2 → EC Directive : TiO2 is safe for use in cosmetic products at maximum concentration of 25 % in order to protect the skin • Standartization of respirable dust measurement • Review of Toxicology and Epidemiology of TiO2 literature TDMA = Titanium Dioxide Manufacturers Association A Sector Group of Cefic

  10. Several basic studies sponsored by TDMA • Historical Cohort Study of Workers Employed in the Titanium Dioxide Production Industry in Europe, Results of Mortality Followup; Boffetta, et al; Department of Medical Epidemiology; Karolinska Institute, Stockholm, Sweden, January 2003  Subchronic Inhalation Toxicity Study on Pigmentary TitaniumDioxide in Mice,Rats ,and Golden Hamsters, Chemical Industry Institute of Toxicology (CIIT),2002  Subchronic Inhalation Toxicity Study of Ultrafine Titanium Dioxide with Mice,Rats,and Golden Hamsters ,CIIT USA 2003

  11. Inhalation Toxicology and Epidemiology Subchronic, inhalation study CIIT Centres for Health Research USA Rats, mice and hamsters Photocatalytic TiO2 (Degussa P 25), Aerosol concentrations of 0,5 , 2 or 10 mg/m3;6 hours/day,13 weeks Main findings of inhalation study: There is no evidence that titanium dioxide itself has toxic properties,that would lead to cancer. This recent study leads us to believe that titanium dioxide does not present a carcinogenic risk to man at exposures experienced in the workplace.

  12. ►The results of our two mortality studies are most powerful evidence that UF TiO2 does not have a significant carnigonic effect on the human lung. ►The studies do not suggest an association between occupational exposure to TiO2 and risk for cancer. ►Studies on application of sunsreens containing UF TiO2 to healthy skin revealed that TiO2 particles only penetrate into the outermost layers of the stratum cornum,suggesting that healthy skin is an effective barrier to TiO2 ►Oral,subcutaneous and intraperitoneal administration did not produce a significant increase in frequency of any type of tumor in mice and rats.

  13. Occupational Exposure Limits NIOSH,USArecommend new exposure limits of 1.5 mg/m3 for fineand 0.1 mg/m3 ultrafine TiO2 as time weighted averageconcentrations for up to 10 hr/day during a 40-hours work week. These levels will serve to minimize any risks that might be associated with the development of pulmonary inflammation and cancer. TDMA opinion : the lower limit for the critical dose of UF TiO2 may be as high as 2 mg/m3.Hence ,REL of 1,5 mg/m3 would be protective for ultrafine exposures.

  14. Ongoing iniciatives • In April, 2008 the European Commission requested additional information for nanoscaled material in cosmetics especially for TiO2.The final dossier was submitted to EC 23.2.2009 . • At the moment WG 4 of ISO Committee is preparing ISO/AWI 11937 Nanotechnologies - Nano-titanium dioxide as a technical specification, consisting of two parts: characterization and determination and material specifications of certain applications (e.g. coatings, cosmetics, plastics, ceramics). Under WPMN there have been selected 14 nanomaterials for which data should be gathered. If no data exists, it should be conducted by testing. Titanium dioxide is one of those substances selected. TDMA participation and data gathering WPMN= OECD Working Party on manufactured nanomaterials

  15. UF TiO2 Manufacture and Processing • The main difference between ultrafine and pigmentary titanium dioxide is primary particle size.Primary particles form aggregates and agglomerates.The primary particle is not normally present as discrete particles • The processes for manufacturing UF TiO2 are usually similar to that of pigmentary titanium dioxide ,having adopted many of the standard unit operations and process equipment from pigment technology . • The UF and nano product can be sourced from the sulphate ,the • chloride,hydrothermal process ,flame pyrolization or sol-gel method

  16. Process Flow Diagram of manufacture UF TiO2

  17. Relative risk assessment for the several industrial fabrications of nano TiO2 • representative synthesis method was selected based on its potential for scale up and near-term potential for large-scale production and commercialization . • A list of input and output materials,and waste streams for each step of fabrication was developed and entered into a database that included key process characteristics such as temperarature and pressure.The physical/chemical properties and quantities of the inventoried materials were used to assess relative risk based on factors such as volatibility,carcinogenity,flammability,toxicity,and persistence • The protocol ranks three categories of risk relative to a 100 point scale • (where 100 represents maximum risk) : • incident risk,normal operation risk and latent contamination risk

  18. Conclusions from risk assessment • The manufacture of nano TiO2 may present lower risks than of those of current activities such as petroleum refining,polyolefin production,and synthetic pharmaceutical production • Almost as much as constituent substances in a process,differences in handling operations could have a marked effect on the final risk scores • Recycling and successful recapture of materials play a key role in lowering normal operations risk score.

  19. Risk Assessment of exposure to TiO2 nanoparticles

  20. Results for safe procedures for handling nano TiO2 ► The main hazards of the production and application of nano TiO2 are physiological hazards, i.e. by inhalation ► Potential dust exposure occurs only in specific areas of the plant ► Safe procedure for manufactiring and handling nano TiO2 have defined for each phases of activity ► Wastes of nano TiO2 are not considered hazardous for disposal into sanitary landfill or industrial waste disposal landfill.

  21. Conclusions ► The safety of nano TiO2 has been the subject of numerous experimental and clinical studies and has been fully demostrated. These studies show no adverse systemic effects with nanoscale titanium dioxide; no skin penetration detected, no skin irritant or sensitising potential, no genotoxic potential, no toxic potential by the oral route, no ecotoxicological potential. ► Low potential to produce tissue inflammation by inhalation. ► Limited human data are limited, quantitative data are available from rodent studies.To use these data in risk assessment ,a reasonable approach for extrapolating the rodent data to humans is required. ► Use the best information available to make interim recommendations on occupational safety and health practises in the production and use of nano TiO2

  22. ► These interim recommendations will be updated as appropriate to reflect new information ► They will address key components of occupational safety and health, including monitoring, engineering controls, personal protective equipment, occupational exposure limits, and administrative controls . ► Additional are required to make a better assessment (for example NIOSH plans to study airborne exposures to fine and ultra-fine TiO2 along with workplace procedures and end useres in comparison with unexposed workers ;last year European Commission requested of additional information for nano TiO2 in cosmetics.) ► TDMA members take all possible precautions against all potential work place exposures and support the continuous improvement of procedures and processes to minimalize any potential exposure NIOSH= National Institute for Occupational Safety and Health,USA

  23. Thank you for your attention antonin.mlcoch@precheza.cz Author acknowledge partial support for this work from Ministry of Industry of the Czech republic within the framework of state programme TANDEM

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