1,2-dichlorobenzene

Toxicity to terrestrial plants

Administrative data

Endpoint:

toxicity to terrestrial plants, other

Remarks:

Several studies on the toxicity of 1,2 -dichlorobenze to terrestrial plants were summarized in the assessment of the BUA report 53 (1990).

Type of information:

other: BUA report

Adequacy of study:

other information

Reliability:

other: BUA report

Rationale for reliability incl. deficiencies:

other: BUA report

Data source

Reference

Reference 1

Reference Type:

other: BUA report

Title:

Unnamed

Year:

1990

Reference 2

Reference Type:

publication

Title:

Effect of organophosphorus insecticides on Hill reaction

Author:

Yukimoto M

Year:

1983

Bibliographic source:

J Pesticide Sci, 8: 63-68

Reference 3

Reference Type:

publication

Title:

The fever fly, Dilophus febrilis L., and methods for control of its larvae in cultivated lawns

Author:

Edwards EE

Year:

1941

Bibliographic source:

Ann Appl Biol, 28: 34-38

Reference 4

Reference Type:

publication

Title:

The effect of a chemical soil sterilizing agent on the subsequent development of tomato plants

Author:

Western JH, Stewart R

Year:

1943

Bibliographic source:

Ann Appl Biol, 30: 370-372

Reference 5

Reference Type:

publication

Title:

Phytotoxizität und Fungizidität chlorsubstituierter Derivate des Benzols in Bezug zu deren Konstitution

Author:

St'ota Z, Toman M

Year:

1957

Bibliographic source:

Biológia, 12: 683-692

Reference 6

Reference Type:

publication

Title:

Effects of DCB, DCB-xylene mixtures, amitrol, and sodium salt of dalapon in irrigation water on corn and rutabagas

Author:

Bruns VF, Dawson JH

Year:

1959

Bibliographic source:

Weeds, 7: 333-340

Reference 7

Reference Type:

publication

Title:

Report by entomologist in charge at Meringa (1929-30)

Author:

Jarvis E

Year:

1931

Bibliographic source:

30th Ann Rep Bur Sugar Expt Stas Queensland, Brisbane, 1930. Rev Appl Entomol, A19: 256

Reference 8

Reference Type:

publication

Title:

Investigation on injury to plants from air polllution in the Los Angeles area

Author:

Haagen-Smit AJ, Darley EF, Zaitlin M, Hull H, Noble W

Year:

1952

Bibliographic source:

Plant Physiol, 27: 18-34

Materials and methods

Principles of method if other than guideline:

BUA report

GLP compliance:

not specified

Test material

Test material information

Constituent 1

Reference substance name:

1,2-dichlorobenzene

EC Number:

202-425-9

EC Name:

1,2-dichlorobenzene

Cas Number:

95-50-1

Molecular formula:

C6H4Cl2

IUPAC Name:

1,2-dichlorobenzene

Results and discussion

Any other information on results incl. tables

BUA report:

Several studies on the toxicity of 1,2 -dichlorobenze to terrestrial plants were summarized in the assessment of the BUA report 53 (1990). Due to their age, the cited studies were not reliable studies as they were not conducted according to current guidelines.

The phytotoxic action of chlorinated benzenes on spinach leaves was studied via inhibition of the Hill reaction. The extent of inhibition increases along the series monochlorobenzene to dichlorobenzenes to trichlorobenzenes in line with increase in hydrophobic character and decrease in solubility in water. Inhibition concentrations (IC) were found to be 10.3 mg/L (IC7), 58.8 mg/L (IC46) and 102.9 mg/L (IC85). 1,2 -Dichlorobenzene apparently has a certain affinity for chloroplasts rich in lipids with the result that the primary reactions of photosynthesis are inhibited.

A phytotoxic effect on herbage was not observed when lawn is treated with a 1 -% emulsion at a rate of 54.4 g 1,2 -dichlorobenzene/m2.

However, a phytotoxic effect was noted in the tomato plant. Although germination of tomato seed in soil compost treated with a 0.5 -%emulsion of 1,2 -dichlorobenzene was not impaired, development of the young plant was affected. The part of the plant above the 5th and 6th leaves was stunted and consequently there was a sgnificant reduction in yield of 35%.

The phytotoxic action on wheat seedlings in a greenhouse was also tested. Treatment of the seedlings with 5620 mg/kg or more of 1,2 -dichlorobenzene caused significant (> 40%) inhibition of growth.

Furthermore, phytotoxic effects on Indian corn (Zea mays L.) and the plant of the rutabagas (Brassica napobrassica) were studied. Two days watering of the corn plant at the 5 -7 leaf stage with irrigation water containing 740 mg/L of emulsified 1,2 -dichlorobenzene (equivalent to 56.4 g/m2 soil) resulted one week later in pronounced growth inhibition and ultimately reduced the harvest to 25%. Impaired growth was also observed in the similarly treated rutabagas at the 6 -7 leaf stage. At harvest time, the number of rutabagas of diameter in excess of 5 cm was reduced by 87%.

Treatment of the sugar-cane stool in a radius of 7 -8 cm with 9.1 g of 1,2 -dichlorobenzene in order to control harmful grubs caused the plant to wilt and ultimately to die.

A period of 5 hours exposure of 10 -day-old oat seedlings and 30 -day-old lucerne, endives, sugarbeet and spinach plants to 152 mg/m3 of 1,2 -dichlorobenzene in gaseous form did not result in any damage to the leaves of the plants.

Applicant's summary and conclusion

Executive summary:

Several studies on the toxicity of 1,2 -dichlorobenze to terrestrial plants were summarized in the assessment of the BUA report 53 (1990). Due to their age, the cited studies were not reliable studies as they were not conducted according to current guidelines.

The phytotoxic action of chlorinated benzenes on spinach leaves was studied via inhibition of the Hill reaction. The extent of inhibition increases along the series monochlorobenzene to dichlorobenzenes to trichlorobenzenes in line with increase in hydrophobic character and decrease in solubility in water. Inhibition concentrations (IC) were found to be 10.3 mg/L (IC7), 58.8 mg/L (IC46) and 102.9 mg/L (IC85). 1,2 -Dichlorobenzene apparently has a certain affinity for chloroplasts rich in lipids with the result that the primary reactions of photosynthesis are inhibited.

A phytotoxic effect on herbage was not observed when lawn is treated with a 1 -% emulsion at a rate of 54.4 g 1,2 -dichlorobenzene/m2.

However, a phytotoxic effect was noted in the tomato plant. Although germination of tomato seed in soil compost treated with a 0.5 -%emulsion of 1,2 -dichlorobenzene was not impaired, development of the young plant was affected. The part of the plant above the 5th and 6th leaves was stunted and consequently there was a sgnificant reduction in yield of 35%.

The phytotoxic action on wheat seedlings in a greenhouse was also tested. Treatment of the seedlings with 5620 mg/kg or more of 1,2 -dichlorobenzene caused significant (> 40%) inhibition of growth.

Furthermore, phytotoxic effects on Indian corn (Zea maysL.) and the plant of the rutabagas (Brassica napobrassica) were studied. Two days watering of the corn plant at the 5 -7 leaf stage with irrigation water containing 740 mg/L of emulsified 1,2 -dichlorobenzene (equivalent to 56.4 g/m2 soil) resulted one week later in pronounced growth inhibition and ultimately reduced the harvest to 25%. Impaired growth was also observed in the similarly treated rutabagas at the 6 -7 leaf stage. At harvest time, the number of rutabagas of diameter in excess of 5 cm was reduced by 87%.

Treatment of the sugar-cane stool in a radius of 7 -8 cm with 9.1 g of 1,2 -dichlorobenzene in order to control harmful grubs caused the plant to wilt and ultimately to die.

A period of 5 hours exposure of 10 -day-old oat seedlings and 30 -day-old lucerne, endives, sugarbeet and spinach plants to 152 mg/m3 of 1,2 -dichlorobenzene in gaseous form did not result in any damage to the leaves of the plants.