Data/hora: 16/06/2024 04:42:59

Biblioteca(s): | Embrapa Florestas.
Data corrente: | 23/09/2008
Data da última atualização: | 23/09/2008
Autoria: | KUPERMAN, R. G.; SIMINI, M.; PHILLIPS, C. T.; CHECKAI, R. T.
Título: | Baseline toxicity determination for the use of boric acid as reference toxicant in soil invertebrate toxicity testing with light-textured soils.
Ano de publicação: | 2008
Fonte/Imprenta: | In: INTERNATIONAL COLLOQUIUM ON SOIL ZOOLOGY, 15; INTERNATIONAL COLLOQUIUM ON APTERYGOTA, 12., 2008, Curitiba. Biodiversity, conservation and sustainabele management of soil animal: abstracts. Colombo: Embrapa Florestas. Editors: George Gardner Brown; Klaus Dieter Sautter; Renato Marques; Amarildo Pasini. 1 CD-ROM.
Idioma: | Inglês

Conteúdo:

A positive chemical control is required in toxicity testing with soil invertebrates to validate the
condition of the test species, and reliability and precision of results. Agricultural pesticides are
recommended by International Standardization Organization (ISO) as positive controls in definitive
toxicity tests with soil invertebrates in standard artificial soils. These reference toxicants include
Carbendazim for earthworms (ISO/11268-2:1998) and enchytraeids (ISO/16387:2005), and
Phenmedipham or Parathion for collembola (ISO/11267:1998). Reference toxicity benchmarks
for these pesticides, established by international ring tests conducted with OECD artificial soil,
cannot be used for validating test results in natural soils or with alternative test species, due to
contrasting chemical toxicities in natural soils, and differences in species-specific sensitivities.
Limited worldwide availability, potential variability in product formulations, and by-product and
contaminant concentrations,, further complicate the use of pesticides as positive controls. We
conducted four individual tests per species with Eisenia fetida and Enchytraeus crypticus,
respectively, plus five tests with Folsomia candida, using boric acid (H3B03) as an alternative
reference toxicant for soil invertebrates. The respective ISO protocols were appropriately adapted
for toxicity testing in natural soil, utilizing Sassafras sandy loam soil [Fine-loamy, siliceous, mesic
Typic Hapludult] having physico-chemical properties (including low pH (4.9), clay (17%), and
organic matter (2.3%), and relatively high sand content (55%)) that supports relatively high
bioavailability of many organic and inorganic chemicals. We analyzed the data for adult survival
in the earthworm test, and production of juveniles in all three tests, using appropriate regression
models to determine the LC50 and EC50 benchmark values (lethal and effective median
concentrations) and the 95% Confidence Limits (CL) associated with the respective point
estimates. These benchmark values were also used to determine minimum?maximum factors,
the geometric and arithmetic means, standard deviations, coefficients of variance, and the upper
and lower warning limits (mean LC50 or EC50 ± 2xSD) for the respective point estimates, and
to prepare Warning Charts for the final assessment of the results of these tests according to
Environment Canada Guideline (EC 2005). Preliminary results indicate that boric acid is an
effective reference toxicant for soil invertebrates in light-textured natural soils.

Categoria do assunto: | --
Registro original: | Embrapa Florestas (CNPF)
Exemplares: | CNPF - (43690-1) - UPE - PL - -- - CD0305 -  -  - DIS