Trisodium hexafluoroaluminate

Toxicity to terrestrial plants

Description of key information

The lowest NOEC-value at 7 months exposure to HF of highly sensitive plants species of 0.2 µg/m3 will be taken into consideration for the assessment of the atmospheric compartment.

Additional information

In some high-temperature processes werealuminium potassium fluoride is used,HF may be formed, therefore a plant PNEC is developed based on HF. ThePNECplant-air for HF is taken from the risk assessment of HF (EU, 2001). This value is based on many experiments that are available in which a variety of plants (bean, barley, corn, garden flowers, strawberries, pine, shrubs, grass, rice, etc.) are exposed to HF in fumigation experiments. Gaseous fluoride enters the leaves through the stomatal pores and causes foliar injury (chlorosis, necrosis), decreased sugar and chlorophyll content, respiration rate and ATPase activity. Reduced yield and smaller fruits are also observed. Sensitive plants are tulip, gladiolus, fruit crops, conifers and grasses, which are affected at concentrations ranging from 0.4 to 1.0 µg/m3 after exposure for several days.

On the basis of a larger number of fumigation experiments with plants (ornamental crops, fruit crops and conifers) exposed to HF, a relationship was derived between the NOEC and exposure time (Slooff et al., 1989). In this report NOEC-values were calculated with this formula for several exposure durations.

In(VDI, 1989) NOEC-values have been calculated for highly sensitive, sensitive and slightly sensitive plants. The Dutch Health Council (Gezondheidsraad, 1990) also gave NOEC-vales for all plant species and different exposure periods (EU, 2001).

A compilation of these NOEC-values is given in the Table below.

Table. NOEC-values for HF (inµg/m³) for plants

 

Plants species	Exposure duration			Reference
	1 day	1 month	7 months
All	0.76	0.34	0.27 (3 month exp.)	Slooff et al. (1988)
Highly sensitive	1.0	0.3	0.2	VDI (1989)
Sensitive	2.0	0.6	0.4	VDI (1989)
Slightly sensitive	7.5	2.5	1.2	VDI (1989)
All	2.8	0.8	0.4	Gezondheidsraad (1990)

The lowest NOEC-value at 7 months exposure of highly sensitive plants species will be taken into consideration for the derivation of the PNEC for the atmospheric compartment.

The following information is taken into account for toxicity on terrestrial plants for the derivation of PNEC:

The lowest NOEC-value at 7 months exposure to HF of highly sensitive plants species of 0.2 µg/m3 will be taken into consideration for the assessment of the atmospheric compartment.

Table. PNEC atmospheric

 

PNEC	Assessment factor	Remarks/Justification
PNEC plant-air: 0.2 µg/m^3		Because of the size and the diversity of the dataset and the character of the experimental setup the application of an assessment factor is considered not to be necessary.

 

Because of the size and the diversity of the dataset and the character of the experimental setup the application of an assessment factor is considered not to be necessary.