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Survey and health assessment of chemical substances in hobby products for children

5 Environmental assessment

• 5.1 Aniline
• 5.2 p-chloroaniline
• 5.3 Assessment of environmentally hazardous substances

In the assessment of substances a number of environmentally hazardous substances were identified. Totally 12 hazardous substances were detected with R-phrases R50, R51, or R52 and in combination with R53 as well.

An assessment has been made of the effect of two selected substances presented in this project with an assessment of the consequences of discharging the environmentally harmful substances to the water environment in Denmark.

5.1 Aniline

Aniline, CAS-no. 62-53-3 has environmental classification N;R50.

Table 5.1 shows ecotoxilogical data for aniline in fish, daphnia and algae.

Table 5.1 Ecotoxilogical data for aniline

Aniline has an octanol-water distribution coefficient of log K_ow = 0,9.

Henry’s law constant for aniline is 2.02 *10^-6 atm m³ /mol at 25 °C (Jayasinghe, 1992).

Bioaccumulation is determined to BCF=2.6 (EU risk assessment, 2004).

Biodegradability tests establish easy degradability of the substance under aerobic conditions. Thus a “closed bottle test” according to OECD 301 D shows a mineralization of 90 % after 30 days. According to OECD 301E the test shows a mineralization of 100 % after 5 days and a modified Sturm test according to OECD 301B shows a mineralization of 90 % after 30 days. The substance is not biodegradable under aerobic conditions.

A SIMPLETREAT calculation gives more than 87 % removal in a waste water plant. (EU risk assessment, 2004). The results can be seen from Appendix II, part 2 in (TGD, 2003).

Table 5.1 indicates that the substance is most toxic for daphnia with a toxicity factor of 10 over the requirements for marking with the R-phrase R50.

An EU risk assessment for aniline includes test data where NOEC has been determined for daphnia. The mean value of 3 tests with effect determination over 21 days was used for calculating NOEC =15µg/l.

The estimated zero effect concentration for aquatic organisms PNEC_vand  is calculated to 1.5 µg/l using an evaluation factor of 10 (EU risk assessment, 2004).

5.2 p-chloroaniline

p-chloroaniline, CAS-no.106-47-8 is classified with N;R50-53.

Table 5.2 shows the ecotoxilogical data for fish, daphnia and algae.

Table 5.2 Ecotoxilogical data for p-chloroaniline

p-chloroaniline has an octanol-water partition coefficient of log K_ow =1.83.

Henry’s law constant is 3.1 *10^-6 atm m³/mol at 25 °C (US EPA, 2004).

Bioaccumulation of fish has a factor in the area of 4-20, whereas the concentration in algae may be considerably higher. This may be due to the absorption to surfaces (CICAD, 2003). 

Data for biodegradability indicate that the substance is not easy degradable under aerobic conditions. 3 different aerobic biodegradability tests over 28 days of the ”closed bottle” type demonstrated a degradation from 0-7 %.

The substance indicates a low degree of biodegradability under anaerobic conditions.

Tests for inherent biodegradability show that the substance can be biodegraded by microorganisms which have sufficient time to adapt to the conditions. Most tests indicated over 60% degradation CICAD, 2003).

The TGDs SIMPLETREAT model under ”inherent biodegradability”, appendix II, part 2 of (TGD, 2003) states that approx. 41 % is expected to be removed in the sewage plant.

p-chloroaniline is degraded by light with wave lengths over 290 nm with a half-life period of 7 hours and is thus quickly degraded by photolysis in surface water. In the atmosphere the substance is degraded by hydroxyl radicals with an estimated half-life period in the troposphere of approx. 4 hours (CICAD, 2003).

The table indicates that the substance is most toxic for daphnia with a toxicity of up to a factor 3 over the requirements for R50 classification.

In (CICAD, 2003) data was found where NOEC in a 21-day test with daphnia is determined to NOEC=0.01 mg/l. This is approximately, the same as for aniline.

From the NOEC the zero effect concentration for aquatic organisms PNEC_water be estimated to 1.0 µg/l by using an evaluation factor of 10.

5.3 Assessment of environmentally hazardous substances

The amount of hazardous substances discharged into the water environment through water from the analysed products is estimated below.

Of the substances quantified we found 5 which were harmful to the environment. Three of these were neither easy degradable nor bio-accumulative (R53).

Table 5.3 Environmentally harmful substances in the products

The amounts of substances with an R53 classification fed to the sewage plant are listed in Table 5.4.

It is expected that the substances are used by all Danish children of 3-13 years with the exposure scenarios described in the health assessment.

It is assumed that the substances are washed off the skin before absorption and that they are subsequently flushed with the waste water to the sewage plant.

According to Statistics Denmark the population of children at the age of 3-13 years numbered 734.000 persons in 2006.

Table 5.4 Estimate of environmentally harmful substances supplied to the Danish sewage plant from the products analysed

1 apart from amounts washed off the skin a certain amount will be flushed by washing clothes. This amounts has not been included in our assessment.

Totally a maximum of 412 gram of the substances are led to sewage plants in Denmark. The most dominant substance is p-chloroaniline with 348 g and it is also the most toxic of the substances. Therefore it is used as ”worst case” in order to evaluate the possible environmental impact.

Orientering no. 1, 2005 contains a calculation of the concentrations of the discharged waste water based on an annual volume of 611 millions m³ (Punktkilder, 2005).

From data on biodegradability it is assumed that p-chloroaniline is not degraded significantly in the sewage plant.

Based on the SIMPLETREAT method a limited degradation in sewage treatment plants of 41 % has been estimated for p-chloroaniline.

Table 5.5 calculates the ratio between the maximum discharged concentration in the water environment PEC_local,water and the zero-effect value PNEC.

The following calculation formula has been used:

The concentration in the discharged waste water C_eff::

C_eff = C_ind *(1-f), where f is the degradation degree in sewage plants and C_ind is concentration in the supplied waste water.

C_{local, water} = C_eff /Dilution factor. The dilution factor has been set at 10 as specified in TGD (Technical Guidance document, 2003). Any absorption of p-chloroaniline in dissolved form in water has not been taken into account.

The concentration of p-chloroaniline from other sources PEC _reg,vand has been fixed to 0 thus

PEC_lokal,vand = PEC_reg,vand + C_lokal,vand = C_lokal,vand

Table 5.5 Calculated effect on water environment

As can be seen the concentration of PEC_local,water/PNEC << 1 and therefore p-chloroaniline is not expected to have any impact on the water environment. In this connection it shall be noted that p-chloroaniline is found only in a small number of the acrylic paint products, so the average effect is expected to be even lower.

As p-chloroaniline is a representative for the analysed products regarding concentration of substance and toxicity, it is assessed that the amount of environmental harmful substances in the analysed products being flushed into the waters will have no influence on the environment.

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Version 1.0 May 2008, © Danish Environmental Protection Agency