| Popis: |
Cress(Lepidium sativum L.) seed germination test is an internationally recognized method for evaluating the maturity of biosolids.However the cress seed is not available in China and needs import from foreign countries.In order to screen out vegetable seeds native in China and sensitive to the phyto-toxicity of treated municipal sewage sludge,17 species of vegetable seeds from 5 families were used to test the germination index of composted or phyto-treated sewage sludge in comparison with the cress seed.The preliminary tests with non-matured sludge composts,which were co-composted with wood chips for 12,26 and 40 days,showed that there were significant difference between the seeds of 6 species and the cress seed towards to the sludge composts according to the paired T-test,while the seeds of Brassica parachinensis Bailey(Cultivar: Youqing Sijiu),Brassica campestris Pekinensis and Brassica oleracea L.(Cultivar: Jingfeng-1) were rather sensitive to the phyto-toxicity,rather similar to the cress seed and classified in a same group according to the cluster analysis of the germination indexes.Further tests with phyto-treated sludges including matured and non-matured samples showed that B.campestris and B.oleracea were significantly different to the cress,only B.parachinensis did not exhibit significant difference to the cress seed.The germination indexes of B.parachinensis were significantly correlated(R2=0.7465) with those of the cress.When the cress seed germination index is 0.50,which signifies fairly matured of the compost sample,the corresponding value of B.parachinensis was 0.53,the two values were rather similar.Therefore,this native vegetable seed can replace the cress seed for evaluating the maturity of the biosolids. |
