0000000000528307
AUTHOR
Helena Palm
Bioaccumulation of organochlorine compounds in earthworms
Abstract Bioaccumulation of chlorophenolic wood preservatives 2,3,4,6-tetrachlorophenol (2346-TeCP) and pentachlorophenol (PeCP) and their metabolites in earthworms were studied in the laboratory, and by taking worm samples from the contaminated soil of a sawmill which was abandoned 28 yr ago. In two laboratory experiments 2346-TeCP (containing PeCP as impurity) was added into the soil, and samples were taken at certain intervals both from the soil and the earthworms ( Lumbricus rubellus in experiment 1 and Aporrectodea caliginosa tuberculata in experiment 2). Considerable amounts of chlorophenols were found in field samples. Soil concentrations ranged from 157 to 338 μg 2346-TeCP g −1 dry …
Polychlorinated phenols and their metabolites in soil and earthworms of sawmill environment
Abstract Topsoil and earthworm samples collected from three Finnish sawmill environments were analysed for polychlorinated phenols, 2,3,4,6-tetrachloro- and pentachlorophenol, and their metabolites. Analyses were carried out by gas chromatography/mass spectrometry using a selected ion monitoring technique and by dual-channel gas chromatography using quartz capillary columns and two electron capture detectors. The total chlorophenol concentrations ranged from ca. 260 to 480 μg/g (dry weight) in soil and from ca. 140 to 3500 μg/g fat in earthworms. The most important metabolites in soil were chlorinated dihydroxy-benzenes (also at ppm level); only traces of chlorinated anisoles were detected …
Chloroanisoles in soils and earthworms
One important group of metabolites of chlorophenols in Finnish soils is their methylation products, i.e. chloroanisoles. Bioaccumulation of chloroanisoles into the biomass of earthworms was studied both in laboratory and by taking earthworm samples from contaminated soils. Concentrations of these compounds in the soils were also analysed. In the laboratory experiment, concentrations of 2,3,4,6-tetrachloroanisole (2346-TeCA) and pentachloroanisole (PeCA) were high in earthworms 1 week after introduction (approx. 50 μ/g fat). Later on, the concentrations decreased to a low level at a considerable rate, bcth in soil and in earthworms. The higher the concentration of chloroanisoles in the soil …
STUDENT TEACHERS PROBLEMS IN TEACHING ELECTROLYSIS WITH A KEY DEMONSTRATION
This study is concerned with student teachers conceptions about teaching the topic of electrolysis and difficulties they encounter. The aim of the study was also to find out how the student teachers understand the meaning of a key demonstration that would show the main features of the phenomenon. During this study eight chemistry student teachers were invited to write a lesson plan on the topic of electrolysis for lower secondary level, grade 8 pupils (age 14 to 15). The written lesson plans and the semi-structured interviews were collected and analysed by using a set of analytical categories. Only two of the eight student teachers had a clear view that electrolysis is a process where an e…
Methylation products of chlorophenols, catechols and hydroquinones in soil and earthworms of sawmill environments
Abstract Soil samples and earthworms collected from one noncleaned and two cleaned sawmill environments were analysed for their content of chlorinated anisoles (methoxybenzenes), veratroles (1,2-dimethoxybenzenes) and 1,4-dimethoxybenzenes. 2,3,4,6-tetrachloroanisole and pentachloroanisole were observed in all soil samples studied, in maximum combined amount about 1.5 μg/g dry soil. Small amounts (ca. 1–110 ng/g dry mass) of 3,4,5-trichloroveratrole, tetrachloroveratrole and tetrachloro-1,4-dimethoxybenzene were found in the most polluted soil samples. Only 2,3,4,6-tetrachloroanisole and pentachloroanisole were found in earthworms, where concentrations of each were ca. 0.1–20 μg/g fat. In g…
Free and bound chlorophenols in kraft pulp bleaching effluents
Abstract Free (F; hexane extractable) and chemically bound (B; alkali extractable) chlorophenols, catechols and guaiacols were measured from effluents of the C and E stages of chlorobleaching of kraft softwood pulp. Ratio B/F was in moste cases nearly one, but for tetrachloroguaiacol B/F was 20 in C and 2.70 in E stage. Organically bound chlorine (OCl) in chlorophenols was less than one percent of the total AOX (Adsorbable Organic Halogen) emitted.