Evaluation of bioaccumulation potential of 3,4,5-trichloroguaiacol in a zooplankton ( Daphnia magna) by pyrolysis-GC/MS in the presence of tetramethylammonium hydroxide (TMAH)

Abstract

The bioaccumulation potential of 3,4,5-trichloroguaiacol (345-TCG), a representative chlorophenol present in bleached kraft mill effluents of Japanese pulp and paper industry, in zooplankton ( Daphnia magna) was evaluated by using pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS) in the presence of tetramethylammonium hydroxide (TMAH). This TMAH/Py-GC/MS was used to determine the amount of 345-TCG accumulated in individual zooplankton that were exposed to a 345-TCG aqueous solution for 3 weeks. TMAH/Py-GC/MS could detect ∼0.5 ppm of 345-TCG, an amount that is below the detection level of conventional GC or LC methods, which require pre-extraction of organisms. The repeatability was also good among three TMAH/Py-GC/MS runs (RSD: ∼1.96–2.61%). Static exposure experiments with 345-TCG (0.3 ppm: mg/l) showed a rapid uptake in D. magna reaching a level of 3.95 ppm (μg/g) after 3 weeks, which was ten times higher than the acute toxicity (48 h LC50) of D. magna. Compared with the concentration in the original incubation solution, the concentration in individual D. magna after a 3-week exposure increased about ∼13-fold. The TMAH/Py-GC/MS approach for assessing the bioaccumulation of chlorophenols in individual zooplankton is simple, requires only a small sample (0.2–0.25 mg/trace), and is rapid, with a total analysis time of less than 1 h/sample. TMAH/Py-GC/MS is therefore useful for assessing the bioaccumulation of toxic components in industrial mill effluents.