Evaluation of Daphniamagna for the Ecotoxicity Assessment of Alkali Leachate from Concrete

Abstract

The cladoceran Daphniamagna has been used as an aquatic test species in aquatic toxicology. To evaluate the aquatic toxicity of leachate from concrete, the immobilization of D. magna was observed after treatment of various concentrations of leachate specimens. Reliabilities of the culture condition and the experimental protocol for acute toxicity test were successfully achieved from the standard toxicity test. The leachates were prepared from the mixture of Ordinary Portland Cement (OPC) and pozzolanic admixtures, Pulverised fuel ash (PFA), Ground granulated blast furnace slag (GGBS) and GGBS containing loess. Acute toxicity test showed 100% immobilization of D. magna for OPC or PFA. The leachates from OPC or PFA had high pH 10 to 12. However, GGBS and GGBS containing loess showed less toxicity according to the concentrations. Especially, immobilization was not observed at the concentrations below 12.5% of GGBS containing loess. Also the range of pH for these specimens was 8 to 9. This suggested that the use of loess as the admixture in concrete may be useful to reduce eco-toxicity of leachates from concrete. This our study provided the harmfulness of the alkali leaching from concrete in aquatic environment and the usefulness of D. magna to evaluate the toxicity of leachates from concrete. IntroductionThe detection and presence of toxic materials in environment is one of the most popular interests because of their harmful effects on ecosystem including human. Especially, the presence of toxic materials in aquatic environment is more considerable to evaluate the harmfulness. The evaluation of contamination in aquatic environment has been for a long time performed only by specific chemical analyses, but many experiences and studies have shown the inadequacy of such approach. To complement this chemical analysis, the biological methods using fish or algae have been used to evaluate and monitor the water quality for many years (Sandbacka et al., 2000;Versteeg et al., 1997 component, but its assessment for environment has not been studied yet. The alkali leaching is not only problem to architectural structures but also more serious to the construction of bridges, dams and other offshore structures (Van Gerven et al., 2007;Mohamed and El Gamal, 2011). The purpose of this study, therefore, was to evaluate the usage of eco-toxicity assays with D. magna in water contaminated with alkali leaching of concrete. To reduce toxicity, in additionally, the effect of loess as the eco-friend admixture was evaluated. Materials and Methods Culturing of D. magnaDaphniamagna was obtained from Korea Envicladoceran Daphniamagna Straus has been used as a "standard" aquatic test species among cladoceran and most frequently used for chronic and acute tests in aquatic toxicology (ASTM, 1987; EEC, 1992;OECD, 1992). Many countries are using aquatic toxicity tests as part of their water quality monitoring program (Slabbert and Venter, 1999). In Korea also, the D. magna has been used for the assessment of toxicity in aquatic environment from 2...

Evaluation of the Ecotoxicological Potential of Fly Ash and Recycled Concrete Aggregates Use in Concrete

“…This is because eluates from RA (A1) with a pH value of 12.5 were found much less toxic to the crustacean than the A2 and A3 eluates with pH values equal to 12.4 and 12.1, respectively (Table 8). Therefore, other factors, for instance the release of chemical compounds, including metals, from these materials into water due to leaching, may be influencing the biological response of the test-organism to the eluates' samples, as reported by others [13,19].…”

“…Choi et al [13] proved Daphnia magna could be suitable to evaluate the ecotoxicity of leachate from concrete. The leachates of cement samples in acute toxicity test showed 100% Daphnia magna immobilization upon 24 h exposure.…”

“…The leachates of cement samples in acute toxicity test showed 100% Daphnia magna immobilization upon 24 h exposure. The authors pointed out the potential negative impact of alkali leaching from concrete into the aquatic environment [13].…”

Ecotoxicity and Essential Properties of Fine-Recycled Aggregate

“…According to [ 38 ] these leachates were classified as inhibitory—mild toxic ( Table 5 ). The ecotoxicity of concrete leachates can result both from toxic compounds presence and alkalinity [ 12 , 39 , 40 ]. Besides the high conductivity in RA 2 and particularly RA 3 ( Table 4 ) the pH values remained highly alkaline even after dilution of the original leachates unlike in the case of NA, RA 1, and RA 4 samples.…”

“…The most sensitive bioindicator of ecotoxicity was daphnia which was already recommended for ecotoxicological assessment of concrete leachates [ 39 , 42 ]. Our study also confirmed duckweed as a suitable plant test organism because of its sensitivity where toxic effect can be detected on both morphological and biochemical level and various symptoms such as necrosis can be observed.…”