Document ID: chunk:federal_register_of_legislation:F2013C00288:reg:5:p1
Version: federal_register_of_legislation:F2013C00288
Segment Type: reg
Provision Reference: reg 5 (pt 1/4)
Character Range: 2514040–2516989

5                   Endrin (total)

5.1              General
Several comprehensive reviews of endrin in the environment and its toxicity to humans are available and should be consulted for more detailed information (ATSDR 1996; WHO 1992; DEH 2006). The following provides a summary of the key aspects of endrin that are relevant to the derivation of a soil HIL.

The organochlorine pesticide endrin is a white to light tan, crystalline solid with a mild chemical odour. It is relatively insoluble in water and has a low vapour pressure. Endrin is the common name for 1,2,3,4,10,10-hexachloro-6,7-epoxy-1,4, 4a,5,6,7,8,8a-octahydro-1,4-endo,endo-5,8- dimethanonaphthalene but the term is also used to describe the commercial grade insecticide which typically contains 96% endrin. Endrin is the endo,endo stereoisomer of dieldrin (WHO 1992; WHO 2011).

Endrin was manufactured as a broad-spectrum insecticide and rodenticide, which was active against a wide range of agricultural pests. It was mainly used in the cotton industry and to a lesser extent on rice, sugar cane and maize (WHO 2011). Endrin has been widely used in agriculture since the 1950s but its manufacture and use was banned under the Stockholm Convention.

Endrin use was phased out in Australia in 1987 (DEH 2006).

5.2              Previous HIL
No previous HIL is available for endrin (NEPC 1999).

5.3              Significance of Exposure Pathways

5.3.1         Oral Bioavailability
Insufficient data is available to adequately define the bioavailability of endrin hence a default approach of assuming 100% oral bioavailability has been adopted in the derivation of an HIL. It is noted that a site-specific assessment of bioavailability can be undertaken where required.

5.3.2         Dermal absorption
Insufficient data is available on the dermal absorption of endrin from soil. Hence the default values of 0.1 (10%) suggested by US EPA (1995) for pesticides has been adopted in the derivation of HILs.

5.3.3         Inhalation of Dust
Endrin is not considered sufficiently volatile to be of significance and inhalation exposures associated with particulates outdoors and indoors are expected to be of less significance than ingestion of soil. While likely to be negligible, potential inhalation exposures associated with dust have been considered in the HIL derived.

5.3.4         Plant Uptake
The few studies that are available with respect to the potential for plant uptake of endrin relate to the application of the product in solution, rather than uptake from soil. Endrin has a high Koc value (log Koc = 4.53) and low solubility in water (ATSDR 1996), suggesting that the compound is largely bound to soil particulates and is immobile in soil. For plant uptake to be significant, the chemicals must be able to partition to soil water. With respect to endrin bound to the soil, the potential for partitioning to soil water is considered to be low and hence plant uptake