Dimethyl disulphide

Toxicity to terrestrial plants

Description of key information

Key parameters are converted from lbs/acre to kg/ha.

In 2008, toxicity studies of DMDS were carried out by Porch to determine the effects of the test substance on vegetative vigor and of seedling emergence of ten species of plants, according to EPA Guidelines and GLP requirements. A toxicity test to determine the toxicity of DMDS on vegetative vigour of ten species of plants was performed according to EPA OPPTS 850.4150. Exposure to vapours resulting from application of DMDS at the rate of 672 kg/hectare, 67.2 g/m² resulted in adverse effects (mean survival, height, and dry weight) of 25% or more for nine of ten species (all exceptLolium perenne). 

A toxicity test to determine the tier II toxicity of DMDS on vegetative vigour of ten species of plants was investigated according to EPA OPPTS 850.4250 (Terrestrial Plant Toxicity Tier I (vegetative vigor tier II)) (Porch JR Krueger HO 2008). 10 species were exposed to nominal test levels in the range of 21.1 kg/hectare, 2.1 g/m² to 336 kg/ha, 33.6 g/m². At test termination there were no observed effects on three of the ten species tested. Reductions of 25% or greater in one or more of mean survival, height, and dry weight were observed on five of the ten test species at the rate of 336 kg/ha, 33.6 g/m². The most sensitive species wasLycopersicon esculentum(tomato) for which the most sensitive endpoint was height with an EC₂₅of 60.5 kg/ha or 6.05 g/m².

A toxicity test to determine the toxicity of DMDS on seedling emergence of ten species of plants was investigated according to EPA OPPTS 850.4225 (Seedling Emergence Tier II) (Porch JR Krueger HO 2007). Ten species exposed to nominal test levels in the range of 42.0 kg/ha, 4.2 g/m² to 672 kg/ha or 67.2 g/m². The EC₂₅s ranged from > 672 kg/ha or 67.2 g/m² with no adverse effects forAvena sativa(oat) to 102 kg/ha, 10.2 g/m² for dry weight in Cucumis sativa(cucumber).

Based on these data the EC₂₅for toxicity to plants is nominally 60.5 kg/ha, 6.05 g/m². From this value, a conversion factor of 0.0133 has to be applied in order to convert from kg/ha ww to mg/kg soil dw (making use of conversion from ww to dw: 1.13, taking account of DEPTHsoil = 0.2 m and RHOsoil = 1700 kg.m-3). A NOEC has been calculated as being 41.5 mg/kg soil dw.

Key value for chemical safety assessment

Short-term EC50 or LC50 for terrestrial plants:

59.8 mg/kg soil dw

Long-term EC10, LC10 or NOEC for terrestrial plants:

41.5 mg/kg soil dw

Additional information

In 2008, toxicity studies of DMDS were carried out by Porch to determine the effects of the test substance on vegetative vigor and of seedling emergence of ten species of plants, according to EPA Guidelines and GLP requirements.

A toxicity test to determine the toxicity of DMDS on vegetative vigour of ten species of plants was performed according to EPA OPPTS 850.4150 (Terrestrial Plant Toxicity Tier I (vegetative vigor)) (Porch JR Krueger HO 2008).Allium cepa(onion),Avena sativa(oat),Lolium perenne(ryegrass),Zea mays(corn),Beta vulgaris(sugarbeet),Brassica oleracea(cabbage),Cucumis sativus(cucumber),Glycine max(soybean),Lactuca sativa(lettuce) andLycopersicon esculentum(tomato) were the species exposed to a nominal test level of 600 lb/A(672 kg/hectare, 67.2 g/m²). Exposure to vapours resulting from application of DMDS at the rate of 600 lb/A(672 kg/hectare, 67.2 g/m²)resulted in adverse effects (mean survival, height, and dry weight) of 25% or more for nine of ten species (all exceptLolium perenne).

 

A toxicity test to determine the tier II toxicity of DMDS on vegetative vigour of ten species of plants was investigated according to EPA OPPTS 850.4250 (Terrestrial Plant Toxicity Tier I (vegetative vigor tier II)) (Porch JR Krueger HO 2008)Allium cepa(onion),Avena sativa(oat),Lolium perenne(ryegrass),Zea mays(corn),Beta vulgaris(sugarbeet),Brassica oleracea(cabbage),Glycine max(soybean),Lactuca sativa(lettuce),Lycopersicon esculentum(tomato) andRaphanus sativus(radish) were the species exposed to nominal test levels in the range of 18.8 lb/A (21.1 kg/hectare, 2.1 g/m²) to 300 lb/A (336 kg/ha, 33.6 g/m²). At test termination there were no observed effects on three of the ten species tested. Reductions of 25% or greater in one or more of mean survival, height, and dry weight were observed on five of the ten test species at the rate of 300 lb/A A (336 kg/ha, 33.6 g/m²). The most sensitive species wasLycopersicon esculentum(tomato) for which the most sensitive endpoint was height with an EC₂₅of 54 lb/Ac (60.5 kg/ha or 6.05 g/m²).

 

A toxicity test to determine the toxicity of DMDS on seedling emergence of ten species of plants was investigated according to EPA OPPTS 850.4225 (Seedling Emergence Tier II) (Porch JR Krueger HO 2007).Avena sativa(oat),Glycine max(soybean),Brassica oleracea(cabbage),Zea mays(corn),Lycopersicon esculentum(tomato),Allium cepa(onion),Lolium perenne(ryegrass),Lactuca sativa(lettuce),Beta vulgaris(sugarbeet) andCucumis sativa(cucumber)were the species exposed to nominal test levels in the range of 37.5 lb/A (42.0 kg/ha, 4.2 g/m²) to 600 lb/Ac (672 kg/ha or 67.2 g/m²). The EC₂₅s ranged from > 600 lb/Ac (672 kg/ha or 67.2 g/m²) with no adverse effects forAvena sativa(oat) to 91.2 lb/Ac (102 kg/ha, 10.2 g/m²) for dry weight inCucumis sativa(cucumber).

 

Based on these data the EC₂₅for toxicity to plants is nominally54 lb/Ac (60.5 kg/ha, 6.05 g/m²).