Clonal variation in heavy metal accumulation and biomass production in a poplar coppice culture. II. Vertical distribution and phytoextraction potential

Short rotation coppice cultures (SRC) are intensively managed, high-density plantations of multi-shoot trees. In April 1996, an SRC field trial with 17 different poplar clones was established in Boom (Belgium) on a former waste disposal site. In December 1996 and January 2001, all shoots were cut back to a height of 5 cm to create a coppice culture. For six clones, wood and bark were sampled at the bottom, middle and top of a shoot in August and November 2002. No significant height effect of metal concentration was found, but for wood, metal concentrations generally increased toward the top of the shoot in August, and decreased toward the top of the shoot in November. Phytoextraction potential of a clone was primarily determined by metal concentration and by biomass production. Shoot size and number of shoots per stool were less important, as a high biomass production could be achieved by producing a few large shoots or many smaller shoots. Clone Fritzi Pauley accumulated 1.4 kg ha(-1) of Al over two years; Wolterson and Balsam Spire showed a relatively high accumulation of Cd and Zn, i.e. averaging, respectively 47 and 57 g ha(-1) for Cd and 2.4 and 2.0 kg ha(-1) for Zn over two years.     

An observational pressure vessel for studying the behaviour of planktonic animals

A design for a pressure vessel, suitable for continuous observation of small planktonic animals at moderate hydrostatic pressures is presented. The long side windows are 3/4 inch (ca. 19 mm) armourplate glass, and smaller windows are provided at each end. The dimensions of the inner working chamber are approximately 16 × 2 × 1 3/4 inches (ca. 0.41×0.05×0.045 m). Internal pressures up to 800 psi (55 bar) have been used successfully during testing. The entire apparatus is placed in a water jacket to provide precise temperature regulation.     

Bioavailability to rats and toxicological potential in mice of bound residues of malathion in beans.

Under conditions of local practice, the application of 2,3-succinate-14C-malathion on beans led to the formation of 17-18% of bound 14C-residues after 30 weeks. When fed to rats, 75% of these residues became bioavailable after 2 days with the major part, excreted via expired air (8%) and urine (60%). The main radioactive metabolites detected in urine were malathion monocarboxylic acid and malathion dicarboxylic acid. Feeding of bound residues to mice (1.8 ppm in feed) for 90 days resulted in a reduction in body weight gain after 60 days and inhibition of erythrocyte cholinesterase activity after 90 days. Increased levels of serum glutamic oxaloacetic transaminase and alkaline phosphatase were also observed. The results strongly suggest that bean-bound malathion residues can cause adverse biological effects in mice.     

Some toxicological aspects of methamidophos exposure in mice

Cholinesterase activity in the brain, RBC and plasma of Swiss mice was determined following different routes of administration of methamidophos. Continuous feeding with the insecticide caused a progressive inhibition of both plasma- and erythrocyte enzymes. The effect of methamidophos was more pronounced when applied in diet than when administered dermally or intraperitoneally. Following a single injection (i.p.) of methamidophos, the brain enzyme showed maximum inhibition 24 hr following treatment. At the appearance of tremors, the plasma and RBC-enzymes showed considerable inhibition, the former being more inhibited. The plasma enzyme appears to be the most sensitive enzyme and may be taken as a suitable index for exposure to methamidophos.