在种稻和未种稻2种条件下,研究了五氯酚(PCP,初始浓度85 mg/kg)在长期不同施肥处理红壤性水稻田中的消解特征.长期不同施肥方式为:不施肥(CK)、施无机肥尿素(N)、施有机肥(OM)和无机有机肥配施(N+OM).结果表明,到收割水稻时,在未种稻情况下,CK、N、OM和N+OM处理表层土壤中可提取PCP残留分别为28.3、34.2、19.3、18.7 mg/kg,在亚表层土壤中可提取PCP残留分别为6.3、9.1、5.1和4.1 mg/kg;在种稻情况下,表层土壤中可提取PCP残留分别为19.4、30.9、16.7和8.7mg/kg,在亚表层土壤中可提取PCP残留分别为3.7、6.1、2.6和2.8 mg/kg.长期单施有机肥或无机有机肥配施显著加速表层土壤中PCP的消解,减缓表层土壤中PCP向下迁移;长期施尿素抑制表层土壤中PCP的消解,加速表层土壤中PCP向下迁移.与未种稻相比,种稻对表层土壤中PCP的消解呈现不同程度的促进作用,除N处理外,在其它3种长期施肥处理(CK、OM、N+OM)中均达到显著的水平.同时,种稻显著减少表层土壤中PCP向下迁移.无论种稻与否,PCP在稻田系统中均能发生还原脱氯降解生成2,3,4,5-四氯酚(2,3,4,5-TeCP)和3,4,5-三氯酚(3,4,5-TCP);在未种稻情况下,2,3,4,5-TeCP是PCP脱氯降解的主要产物,而在种植水稻的情况下,3,4 5-TCP是PCP脱氯降解的主要产物.
Dissipation of pentachlorophenol (PCP) with initial concentration of 85 mg/kg in red paddy field with rice cultivation and non-rice cultivation were investigated under the conditions of four long-term fertilization treatments, including the ones without fertilizer (CK), application of urea (N), application of organic fertilizer (OM), and N + OM. The results showed that the extractable PCP residues in surface soil in the treatments CK, N, OM and N + OM under non-flee cultivation condition were 28.3, 34.2, 19.3, 18.7 mg/kg after harvesting flee plant, and the extractable PCP residues in subsurface soil were 6.3, 9.1, 5.1, 4.1 mg/kg, respectively. Under rice cultivation condition, the extractable PCP residues in surface soil were 19.4, 30.9, 16.7, 8.7 mg/kg, and the extractable PCP residues in subsurface soil were 3.7, 6.1, 2.6, 2.8 mg/kg, respectively. The results indicated that the long-term application of organic fertilizer or inorganic plus organic fertilizer significantly accelerated the dissipation of PCP in surface soil, and decreased the transportation of PCP down the soil profile. However,long-term application of urea inhibited the dissipation of PCP in surface soil, and increased the transportation of PCP down the soil profile. When compared with non- flee cultivation, rice cultivation significantly accelerated the dissipation of PCP in surface soil other than the treatment N. In addition, the rice cultivation significantly decreased the transportation of PCP down the soil profile. No matter flee was cultivated or not, the dechlorinated metabolites of PCP detected in paddy soil were 2,3,4,5-TeCP and 3,4,5-TCP. 2,3,4,5-TeCP was the major dechlorinated metabolite of PCP under non-flee cultivation condition, whereas 3,4,5-TCP was the major deehloflnated metabolite of PCP under rice cultivation condition.