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Ecotoxicological information

Toxicity to soil microorganisms

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Description of key information

Key value for chemical safety assessment

Long-term EC10 or NOEC for soil microorganisms:
52.7 mg/kg soil dw

Additional information

Tests on microbial processes are multi-species tests, in which the native soil microbial community is exposed. The selected NOEC or EC10 values comprise functional parameters (n=39), and microbial species (n=13). The functional parameters are based on the carbon cycle (n=27), nitrogen cycle (n=12), including denitrification and mineralization of specific substrates. Enzymatic parameters are also further considered in the effects assessment. Six different enzymatic processes were compiled in the database. In the total risk approach, NOEC or EC10 values range from 28 mg/kg (nitrification mineralisation; Smolders, 2000) to 2.491 mg/kg (respiration; Doelman & Haanstra, 1984). Additional data are available for enzyme activity measured in soil, with NOEC/EC10 values ranging from 7.9 mg Ni/kg for dehydrogenase to 7.084 mg Ni/kg for arylsulfatase activity. Finally, NOEC values for a range of Eubacteria, actinomycetes, yeasts, and filamentous fungi are also reported, and these values range from 32 mg Ni/kg for Aspergillus (Babich and Stotzky 1982) to 550 mg Ni/kg for Trichoderma viride (Babich and Stotzky 1982).

 

Below are the accepted high quality studies for soil microorganisms used for derivation of the HC5 and terrestrial PNEC.

Key Study

(Soil micro-organisms)

Selected values for the most sensitive endpoints used for derivation of the terrestrial HC5

Measurement

Added NOEC or EC10 (mg/kg dw)

Total NOEC or EC10 (mg/kg dw)

University of Leuven, 2005

Glucose respiration

45-376

56-415

Maize respiration

42-446

43-479

Babich & Stotzky, 1982b

Aspergillus flavipes (hyphal growth)

347

367

Aspergillus flavus (hyphal growth)

393

413

Aspergillus clavatus (hyphal growth)

13

32

Aspergillus(hyphal growth)

400

420

Penicillium vermiculatum (hyphal growth)

102

121

Rhizopus stolonifer (hyphal growth)

288

308

Trichoderma viride (hyphal growth)

530

550

Gliocladium sp. (hyphal growth)

200

220

Serratia marcescens (colony count)

155

174

Proteus vulgaris (colony count)

15

35

Bacillus cereus (colony count)

285

305

Nocardia rhodochrous (colony count)

177

197

Rhodotorula rubra (colony count)

247

266

Doelman & Haanstra, 1984

Respiration (CO2 release)

291-2542

295-2491

Saviozzi et al., 1997

Respiration (CO2 release)

27

41

Wilke 1988

ATP content

77

86

Haanstra $ Doelman, 1984

Glutamate respiration (C02)

55

63-94

Doelman & Haanstra, 1986

Urease

90-2300

128-2302

Doelman & Haanstra, 1989

Phosphatase

251-7021

276-7023

Doelman & Haanstra, 1991

Arylsulfatase

272-7080

311-7084

Welp, 1999

Dehydrogenase

7.9

27.3

Wilke, 1988

Saccharase

77

86

Protease

77

86

Smolders, 2000

N-mineralisation

20-257

28-265

There is some activity derived also from the presence of fluoride. However, the report issued by the Commission (SCHER 2010, Critical review of any new evidence on the hazard profile, health effects, and human exposure to fluoride and the fluoridating agents of drinking water) about the addition of fluoride in drinking water clearly states that "Exposure of environmental organisms to levels of fluoride as used in fluoridation of drinking waters are not expected to lead to unacceptable risks to the environment."

CONCLUSION NOEC 32 mg/Kg dw Ni2+ = 52.7 mg/Kg dw NiF2 = 91.9 mg/Kg dw NiF2 * 4H2O