Opinion on the non-food aspects of assessment of the risks to health and the environment posed by the use of organostannic compounds

Overview

The European Commission’s Scientific Committee on Toxicity, Ecotoxicity and the Environment reviewed non-food consumer and environmental exposures to organostannic compounds, while explicitly noting that foods and food-contact materials contribute to total exposure. This is an A-tier regulatory opinion and exposure-context source, not a primary occurrence survey. The opinion keeps organotin species such as MBT, DBT, TBT, MOT, DOT, and TPT distinct from total elemental tin.

Key numbers

• Document identity: CSTEE opinion adopted at the 38th plenary meeting on 12 June 2003; the reviewed report version was Final Report 19 July 2002; extracted PDF has 14 pages.
• Species groups reviewed in the report: monomethyltins (MMT), dimethyltins (DMT), monobutyltins (MBT), dibutyltins (DBT), tributyltins (TBT), monooctyltins (MOT), and dioctyltins (DOT). The CSTEE flagged triphenyltins (TPT) and other alkyltins as important omissions.
• Environmental exposure context: site-specific local predicted environmental concentrations for production were 0.2 - 0.4 µg/L for MBTC, DBTC, MOTC, and DOTC, and up to 0.015 for TBTC.
• PVC-processing context: applying the selected low-volatility emission factors predicted local environmental concentrations up to 3 µg/L for mono- and dialkyl compounds; wood treatment gave TBTC values of about 0.16 µg/L.
• Measured-water comparators cited by CSTEE: older regional data indicated up to 2 and 16 µg/L of MBT and DBT in fresh water; a more recent investigation found 0.076, 0.81, and 3.6 µg/L of MBT, DBT, and TBT, respectively.
• TBT ecotoxicity context: the reviewed report used a chronic NOEC of 60 ng Sn/litre for Daphnia magna. CSTEE noted imposex observations at lower concentrations, including 1 ng TBT /litre in dog-whelk and a 0.1 ng TBT-Sn/litre threshold in Ocinebrina aciculata. It also cited flounder effects after exposure to 0.1 mg TBTO/kg diet.
• Food-contact context: the opinion states that food wrapped in organotin-stabilised PVC may add to total exposure and that butyltins from cookies prepared using silicone-coated baking paper may be problematic.
• Baking-paper risk statement: CSTEE cites the Scientific Committee on Food conclusion that the estimated migration level exceeded the specific migration limit for dioctyltin compounds by a factor of 10, while the SCF judged occasional consumption unlikely to pose a risk in the phase-out context.
• Child-cookie correction: CSTEE says the highest cookie value of 15.9 µg/kg bw/day was a miscalculation and should be 2 µg/kg bw/day, from 50 g x 318 µg Sn/kg = 15.9 µg Sn for an 8 kg child.
• Cycling-shorts correction: CSTEE recalculated TBT in the exposed area as 0.1 m2 x 1.2 kg/m2 x 45 mg Sn/kg = 5.4 mg Sn, with uptake estimated at 0.09 µg/kg bw/day.
• Paddling-pool scenario: daily exposure over the 20 days of use was 0.21 µg/kg bw for an 8 kg child, calculated from 5.1 µg Sn/L x 0.33 L / 8 kg bw.
• PVC-toy oral-exposure proxy: using a doll DINP oral intake of about 20 µg/kg bw/day, the opinion estimated DBT oral intake at about 0.2 µg/kg bw/day if DBT concentration was 1 % of DINP and the same release factor applied.

Dust organotin concentrations

The opinion cites a study of parliament-building dust samples:

Toxicological reference and indoor-air scenario values

• TBT reference value used in the reviewed report: 0.27 µg/kg per day TBT as chloride, based on WHO 1999.
• U.S. EPA benchmark cited by CSTEE: benchmark dose 0.68 ppm, corresponding to 0.03 mg/kg BW/day.
• CSTEE proposed adopting the low TDI value of TBT for DBT, DOT, and TPT for shared immunotoxicity, and treating effects as additive in the absence of contradictory data.

Annex 1 estimates DBT indoor-air exposure under four scenarios:

Methods (brief)

CSTEE reviewed a July 2002 risk-assessment report on non-biocidal organostannic uses, including polymer stabilisers, catalysts, wood preservatives, and selected consumer products. The opinion evaluates the report’s scenario assumptions, emission factors, environmental predicted concentrations, consumer-exposure calculations, toxicological reference values, and data gaps. It is not a laboratory study; the numbers are regulatory-review calculations, cited measurements, and CSTEE corrections to the reviewed report.

Related evidence

• Flexible pouches/films
• Bakeware
• Toy substrate materials (accessible plastics/metals/woods/rubbers)
• Tin
• Organotins

Update history

The five most recent substantive edits to this page, classified major (evidence or structure moved), correction (a published value or statement was wrong and has been fixed), or minor (narrative rewritten without changing the underlying evidence). Each description is derived from what the edit did to this page; the linked commit is the authoritative record, routine regeneration passes are excluded, and the full version history lives in git.