Boric acid as reference substance: pros, cons and standardization
- 303 Downloads
- 11 Citations
Abstract
Boric acid (BA) has been successfully used as reference substance in some standard test guidelines. Due to the fact that previously selected reference substances present a significant risk to human health and/or are banned for environmental reasons, BA is being discussed for broader adoption in OECD or ISO guidelines. To provide input on BA data and contribute to the discussion on its suitability as a reference substance, in the present study BA was tested with two standard soil organisms, Enchytraeus albidus and Folsomia candida, in terms of survival, reproduction and avoidance. Additionally, published data on other organisms was analysed to derive the most sensitive soil dwelling invertebrate (hazard concentration–HC5). Results showed that BA affected the tested organisms, being two times more toxic for collembolans (LC50 = 96; EC50 = 54 mg/kg) than for enchytraeids (LC50 = 325; EC50 = 104 mg/kg). No avoidance behaviour occurred despite the fact that BA affects earthworms. Actually, it is the recommended reference substance for the earthworm avoidance test. Clearly, the suitable performance of BA in one species should not be generalized to other species. Absolute toxicity is not an important criterion for the selection of a reference substance, but it has been proposed that effects should occur within a reasonable range, i.e. <1,000 mg/kg. We could confirm, compiling previous data that for most soil invertebrates, the EC50 is expected to be below 1,000 mg/kg. From these data it could be derived that the most sensitive soil dwelling invertebrate (HC5, 50%) is likely to be affected (EC10) at 28 (8–53) mg H3BO3/Kg, equivalent to 4.6 (1.4–8.7) mg boron/kg.
Keywords
Enchytraeids Collembolans Reproduction Reference substance HC5Notes
Acknowledgment
This work was supported by funding FEDER through COMPETE-Programa Operacional Factores de Competitividade and by National funding through FCT-Fundação para a Ciência e Tecnologia, within the research project FUBIA FCOMP-01-0124-FEDER-008651 (Refª. PTDC/AAC-CLI/103719/2008).
References
- Amorim MJB, Novais S, Römbke J, Soares AMVM (2008) Enchytraeus albidus (Enchytraeidae): a test organism in a standardised avoidance test? Effects of different chemical substances. Environ Int 34(3):363–371CrossRefGoogle Scholar
- Becker L, Scheffczyk A, Förster B, Oehlmann J, Princz J, Römbke J, Moser T (2011) Effects of boric acid on various microbes, plants, and soil invertebrates. J Soils Sediment 11:238–248CrossRefGoogle Scholar
- Frampton GK, Scott-Fordsmand JJ, Römbke J, Van den Brink NW (2006) Effects of pesticides on soil invertebrates in laboratory studies: a review and analysis using species sensitivity distributions. Environ Toxicol Chem 25(9):2480–2489CrossRefGoogle Scholar
- Goldberg S (1997) Reactions of boron with soils. Plant Soil 193:35–48CrossRefGoogle Scholar
- ISO (1999) Soil quality—inhibition of reproduction of Collembola (Folsomia candida) by soil pollutants. Guideline No. 11267. ISO—The International Organization for Standardization. Genève, Switzerland Google Scholar
- ISO (2005) Soil quality—effects of pollutants on Enchytraeidae (Enchytraeus sp.)—determination of effects on reproduction and survival. Guideline No. 16387. ISO—The International Organization for Standardization, Genève, SwitzerlandGoogle Scholar
- ISO (2007a) Soil quality—avoidance test for testing the quality of soils and effects of chemicals—part 1: test with earthworms (Eisenia fetida and Eisenia andrei) ISO Guideline 17512-1, Geneve, SwitzerlandGoogle Scholar
- ISO (2007b) Soil Quality—avoidance test for testing the quality of soils and effects of chemicals—part 2: test with collembolans (Folsomia candida) Guideline 17512-2, International Standardization for Organization, Geneve, SwitzerlandGoogle Scholar
- Krogh PH (2008) Toxicity testing with the collembolans Folsomia fimetaria and Folsomia candida and the results of a ringtest (trans: DMU/AU DoTE). Miljoministeriet, DenmarkGoogle Scholar
- Natal-da-Luz T, Ribeiro R, Sousa JP (2004) Avoidance tests with collembola and earthworms as early screening tools for site-specific assessment of polluted soil. Environ Toxicol Chem 23:2188–2193CrossRefGoogle Scholar
- Natal-da-Luz T, Serena T, Jesus B, Morais PV, Sousa JP (2009a) The use of sludge as soil amendment. The need for an ecotoxicological evaluation. J Soils Sediment 9:246–260CrossRefGoogle Scholar
- Natal-da-Luz T, Tidona S, Van Gestel CAM, Morais PV, Sousa JP (2009b) The use of collembola avoidance tests to characterize sewage sludges as soil amendments. Chemosphere 77:1526–1533CrossRefGoogle Scholar
- Novais SC, Soares AMVM, Amorim MJB (2010) Can avoidance in Enchytraeus albidus be used as a screening parameter for pesticides testing? Chemosphere 79:233–237CrossRefGoogle Scholar
- OECD (1984) Guideline for testing of chemicals No. 207. Earthworm, acute toxicity tests. Organization for Economic Cooperation and Development, ParisGoogle Scholar
- OECD (2004) Guidelines for the testing of chemicals No. 220. Enchytraeid reproduction test. Organization for Economic Cooperation and Development. ParisGoogle Scholar
- OECD (2008) OECD Guideline for the testing of chemicals No 226. Predatory mite (Hypoaspis (Geolaelaps) aculeifer) reproduction test in soil. Organization for Economic Cooperation and Development. ParisGoogle Scholar
- Römbke J, Athtiainen J (2007) The search for the “ideal” soil toxicity test reference substance. Integr Environ Assess Manag 3:464–466CrossRefGoogle Scholar
- Scott-Fordsmand JJ, Jensen J (2002) The use of species sensitivity distributions (SSD). In: Posthuma L, Suter GW, Traas TP (eds) Species sensitivity distribution in ecotoxicology. Lewis Publishers, Boca RatonGoogle Scholar
- Smit CE, Bakker F, Heimbach F, Krog PH, Kula C, Römbke J, Ruf A, Schmitz S et al. (2007) Development of an OECD test guideline for the soil mite Hypoaspis (Geolaelaps) aculeifer. In: SETAC Europe, Porto, Portugal, 20–24Google Scholar
- Stegger P, Ebke KP, Römbke J (2011) Boric acid as alternative reference substance for earthworm field tests. J Soils Sediment 11:330–335CrossRefGoogle Scholar
- ToxRat® (2003) Software for the statistical analysis of biotests. Copyright: ToxRat Solutions GmbH, Alsdorf, GermanyGoogle Scholar
- Van Vlaardingen P, Traas TP, Aldenberg T (2003) ETX-2.0. Normal distribution based hazardous concentration and potentially affected fraction. Rijksinstituut voor Volksgezondheid en Milieu, BilthovenGoogle Scholar