Mass development of Stachybotrys chartarum on decomposable plant-pots made of recycling paper

After handling plants grown in decomposable pots made of recycling paper, three women working in a big horticulture developed very painful inflammated efflorescences at the finger-tips, followed by scaling off the skin. The pots appeared to be very mouldy. Black masses of conidia of Stachybotrys chartarum and perithecia of Chaetomium globosum were identified on almost every pot. Apart from various other fungal genera, Trichoderma und Acremonium were frequently detected. Considering the observed symptoms, special attention was payed to the mycotoxin producing species St. chartarum. To evaluate the inhalative spore load, air sampling was performed. The detection of St. chartarum in the air was only possible with the spore trap (sampling of particles) but not with the Andersen sampler (detection of colony forming units). Without moving the pots, measurements yielded values of 30-100 St. chartarum conidia per m(3) of air. The concentration of airborne conidia increased drastically by handling the pots, thus attaining up to 7 500 conidia per m(3) of air for St. chartarum only. The occurence of St. chartarum in such amounts is alarming because of possible toxin production. In addition, the allergenic stress by fungal spores has to be emphasized. The results are discussed with regard to general medical-mycological aspects related to the degradation of environmentally-friendly decomposable materials.