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Changes in toxicity and bioavailability of lead in contaminated soils to the earthworm Eisenia fetida (savigny 1826) after bone meal amendments to the soil
Author(s) -
Davies Nicola A.,
Hodson Mark E.,
Black Stuart
Publication year - 2002
Publication title -
environmental toxicology and chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.1
H-Index - 171
eISSN - 1552-8618
pISSN - 0730-7268
DOI - 10.1002/etc.5620211222
Subject(s) - eisenia fetida , meat and bone meal , bioavailability , earthworm , bone meal , meal , chemistry , zoology , environmental chemistry , agronomy , food science , biology , pharmacology , fish meal , raw material , organic chemistry , fishery , fish <actinopterygii> , bran
The effect of bone meal (Ca 5 (PO 4 ) 3 OH) amendments on lead (Pb) bioavailability to Eisenia fetida (Savigny 1826) was investigated. A standard uncontaminated soil was amended with Pb(NO 3 ) 2 solution to give Pb concentrations of 7,000 μg/g of soil. After one week, bone meal was added to one half of the soil in the ratio 1:20 bone meal:soil. Immediately after addition of the bone meal, survival times of E. fetida were 23 and 41 h in the bone meal‐free and bone meal‐amended soil, respectively. Twentyeight days after addition of the bone meal, survival times of Eisenia fetida were 67 h in the bone meal‐free soil and more than 168 h in the bone meal‐amended soil. In a second experiment, a standard Organisation for Economic Co‐operation and Development reproduction toxicity test was carried out, but in addition to Pb(NO 3 ) 2 solution, bone meal was added to the soil in the ratio 1:20 bone meal:soil. The bone meal‐free soil was left for five weeks before addition of E. fetida. In the bone meal‐amended soil, bon emeal was added to the soil one week after addition of the Pb. The soil was left for a further four weeks before addition of Eisenia fetida. Calculated toxicities were significantly lower for the bone meal‐amended soil than those calculated for the bone meal‐free soil. Twenty‐eight‐day median lethal concentrations (LC50s; concentration that is statistically likely to kill 50% of the exposed test organism within a given time period ± 95% confidence intervals) of Pb were 4,379 ± 356 μg/g of soil for bone meal‐free soil and 5,203 ± 401 μg/g of soil for bone meal‐amended soil. Twenty‐eight‐day median effect concentrations (EC50s; concentration causing a reduction by 50% of a stated parameter) of Pb for weight change were 1,408 ± 198 μg/g of soil for bone meal‐free soil and 3,334 ± 731 μg/g of soil for bone meal‐amended soil and EC50s for cocoon production were 971 ± 633 μg/g of soil for bone meal‐free soil and 1,814 ± 613 μg/g of soil for bone meal‐amended soil. Significant mortalities occurred at Pb concentrations of 2,000 μg/g of soil in the bone meal‐free soil and 5,000 μg/g of soil in the bone meal‐amended soil. Earthworm Pb body load was lower in the bone meal‐treated soil than in the bone meal‐free soil up to a Pb concentration of 5,000 μg/g of soil. Earthworm Pb body load was approximately 100 μg/g of worm in surviving earthworms in both experiments when significant mortality occurred. Water and diethylenetriamine pentaacetic acid‐extractable soil Pb showed good correlations with earthworm Pb body load. These extractions could be used as estimates for Pb bioavailability.