Environmental and Health Assesment of Alternatives to Phthalates and to
flexible PVC

8. Conclusion 

Physical chemical parameters
Key parameters with respect to release of plasticisers under polymer pro-duction and consumer use are their potential for evaporation and migration out of the PVC polymer. Some data exists for volatility, but only few data has been identified on migration potential for the substitutes.

Hazardous properties
Available toxicity data for acute and local effect suggests classification for some of the substances. This is the case for di(2-ethylhexyl) phosphat which should be 'Corrosive' (R34) and 'Harmful' (R21), tri(2-ethylhexyl)phosphate which should be 'Irritant' (R36/38), tri-2-ethylhexyl trimellitate which should be 'Harmful' (R20) and dioctyl sebacate which should be 'Harmful' (R22). The classification for the phosphates is suggested by Bayer AG and supported by the literature. For other effects it is either not possible to suggest a classification based on the reviewed literature or the substances do not display these effects.

The substances for which data are available for some of the critical properties toward humans, such as CMR, sensitisation etc., do not display such effects based on the available data. This concerns diethylhexyl adipate, o-acetyl tributyl citrate, tri-2-ethylhexyl trimellitate, epoxidised soybean oil and the dioctyl sebacate. For some substances the available data suggest that reproductive and developmental toxicitity is investigated further in order to conlude about a possible effect. This is the situation for diethylhexyl adipate, o-acetyl tributyl citrate, tri(2-ethylhexyl)phosphate, o-toluene sulfonamide and epoxidised soybean oil.

The compounds for which ecotoxicity data are available (only data for the aquatic environment available) show relatively high acute ecotoxicity that in all cases would lead to an environmental hazard classification. The adipate would be 'Very toxic' (R50/53) and epoxidised soybean oil is classifiable as 'Toxic' (R51/53). O-acetyl tributyl citrate, di(2-ethylhexyl) phosphate and tri(2-ethylhexyl) phosphate would be classified as 'Harmful' (R52/53). For the trimellitate and the sebacate, the low aqueous solubility in combination with persistence and bioaccumulation potential would lead to a classification as 'May cause long term effects in the aquatic environment' (R53).

It is emphasised that for o-toluene sulfonamide, diisobutyrate (TXIB), epoxidised soybean oil, dipropylene glycol dibenzoate and dioctyl sebacate the lack of data regarding ecotoxicity is limiting the assessment. The tentative classification of the citrate and trimellitate is based on only one and two studies, respectively (the citrate study is almost 30 years old).

Degradability
Several substances show limited degradability in the environment (the trimellitate and possibly both phosphates). Some have a high estimated bio-accumulation potential (citrate, trimellitate, dibenzoate and sebacate). The trimellitate possibly combines both of the environmentally undesired properties. It must be emphasised that this is based on estimated values for bio-accumulation based on estimated octanol-water partition coefficients. It is possible that these compounds to some extent degrades through hydrolysis in the environment and the bioaccumulation is then expected to be considerably less. Although no data on the dibenzoate and sebacate are available similar processes may apply to these structurally related compounds. Meas-ured bioaccumulation for the adipate and the two phosphates are below the criteria for bioaccumulation.

Risk for humans from environment
A possible risk to humans has only been suggested by the selected scenarios for a few of the substances and primarily in relation to the workplace sce-narios. The workplace scenario considers aerosol generation in connection with production of floor and wall coverings using a process temperature of 200°C and eight exposure events per day, which is most likely a very con-servative scenario. For the adipate the selected scenario results in concen-trations in workplace air 104 times the concentration resulting in more pro-nounced reactions in workers with an allergy or asthma case history. For the two phosphates the estimated concentrations were lower than observed ef-fect levels in animal studies, but within commonly used safety margins.

The estimated exposure of consumers and the public to the phthalate alternatives were generally much lower than the established ADI value even in the worst case scenarios. Only the worst case scenario for dioctyl sebacate displayed doses exceeding the ADI (conservatively) based on peroxisome proliferation data for di-ethylhexyl phthalate. The human exposure comes almost exclusively from the contribution by root crops due to high estimated octanol-water partitioning values and the low biodegradation potential. Only limited toxicological and ecotoxicological data are available and conservative default values are used. More data may very well change the risk perception.

The citrate does reach 37% of a preliminary ADI of 1 mg/kg bw/day in a teething ring scenario. The preliminary ADI is not officially recognised and a closer investigation of the citrate exposure conditions and human toxicity may be warranted.

Risk for the environment
The risk quotient does not exceed one (the critical value) in the water phase for any of the five compounds for which it could be calculated (diethylhexyl adipate, o-acetyl tributyl citrate, di(2-ethylhexyl) phosphate, tri(2-ethylhexyl) phosphate, and tri-2-ethylhexyl trimellitate). The adipate exceeded the risk quotient of one for the sediment compartment due to the lipophilicity. PEC/PNECs could not be calculated for o-toluene sulfona-mide, the diisobutyrate (TXIB), epoxidised soybean oil, dipropylene glycol dibenzoate and dioctyl sebacate.

Terrestrial and microbial toxicity
It must be stressed that a number of the assessed substances are lipophilic and may have a high affinity for sludge particles similar to that of DEHP. No data on terrestrial toxicity has been identified and virtually no information on effects on microorganisms in the sewage treatment plant was found.

Assessment of polymer materials
Due to the assessment principles of the EU TGD the materials and the poly-adipate plasticiser are assessed by expert judgement. The polymer materials and the polyadipate are estimated as unlikely to give rise to effects in the aquatic environment. In general, no effects are expected in the consumer use situation of these.

Data availability
The data availability varies among the suggested alternatives for phthalate plasticisers and materials. For di(2-ethylhexyl) adipate, o-acetyl tributyl cit-rate, tri(2-ethylhexyl) phosphate and tri-2-ethylhexyl trimellitate information is available covering a range of results from tests on toxicological proper-ties. However, only di(2-ethylhexyl) adipate can be considered adequately covered, although some areas need further investigation. Di(2-ethylhexyl) phosphate, o-toluene sulfonamide, 2,2,4-trimethyl 1,3-pentandiol diisobuty-rate, epoxidised soybean oil, dipropylene glycol dibenzoate and dioctyl se-bacate are covered in less detail, either because of lack of information or because of inferiour quality of the tests.

For di(2-ethylhexyl)adipate a large number of studies are covering acute toxicity, local effects, sensitisation, repeated dose/chronic toxicity, genetic toxicity, reproductive toxicity and carcinogenicity. Reviews discussing the toxicological profile of the substance are also available. In a substitution context it is however important to consider all areas which may give rise to concern, to make sure that only less hazardous substituents are introduced. Based on comparisons with the structural analogue, di(2-ethylhexyl) phthalate, for which the most critical effect is considered to be testicular toxicity, a need to address this issue for the adipate as well has been identified.

For o-acetyl tributyl citrate the available data are not sufficient for a pro-found assessment. Data on acute toxicity are sparse and other effects like carcinogenicity are not sufficiently covered for a qualified assessment.

For the two phosphates, di(2-ethylhexyl)phosphate and tri(2-ethylhexyl)phosphat, a number of studies are available, sufficient to suggest a classification of the substances for acute and local effects. Studies on re-peated dose and chronic toxicity like reproductive toxicity and carcinogenicity are either not available or not sufficient for an assessment.

For tri-2-ethylhexyl trimellitate a number of studies are available covering acute and local effects. More details are however needed in order to classify the substance with regard to irritant effects. More data are also needed on repeated dose and chronic toxicity studies. Reproductive toxicity is not cov-ered at all in the reviewed literature.

O-toluene sulfonamide is sparsely covered in the literature and no data are found available on acute toxicity. Few studies are available on other effects, but not sufficient for a qualified assessment or classification. Human data are only available for related substances or combined products.

Few data are available for 2,2,4-trimethyl 1,3-pentandiol diisobutyrate. In order to make a proper evaluation of acute toxicity more detailed information is necessary. Repeated dose and chronic toxicity are not covered in the reviewed information.

A limited number of studies are available for epoxidised soybean oil. Studies on acute toxicity suggest low toxicity, but more detailed information is needed for a proper evaluation. Data on repeated dose toxicity and chronic effects are also insufficient for a qualified assessment.

No toxicological data have been found for dipropylene glycol benzoate.

Also dioctyl sebacate is sparsely covered in the available literature. Few data are available describing acute toxicity and only oral toxicity has been evaulated. Data on other effects are not sufficient for an evaluation.

No toxicological data have been found for polyester (polyadipate).

Regarding environmental properties only di(2-ethylhexyl) adipate, o-acetyl tributyl citrate, and tri(2-ethylhexyl) phosphate have a data set comprising algae, crustaceans and fish, and data on biodegradation. The remaining substances have very few or no ecotoxicological data. There are very few data on chronic endpoints, very limited data on effects on microorganisms and no data on terrestrial ecotoxicity.