title: Influence of phenanthrene on cadmium toxicity to soil enzymes and microbial growth.
abstract: BACKGROUND
  Many contaminated sites contain a variety of toxicants. Risk assessment and the development of soil quality criteria therefore require information on the interaction among toxicants. Interactions between heavy metals are relatively well studied, but little is known about those between heavy metals and polycyclic aromatic hydrocarbons (PAHs).
  
  
  METHODS
  0.1 mg/kg dry soil phenanthrene alone or phenanthrene plus 10 mg/kg cadmium (Cd) were added to soil to determine the influence of phenanthrene on Cd toxicity to soil enzymes (invertase, urease, dehydrogenase and phosphatase) and microorganisms (fungi, bacteria and actinomycete) in paddy soil.
  
  
  CONCLUSIONS
  0.1 mg/kg phenanthrene did not reduce the number of microorganisms. However, the addition of phenanthrene to soil with Cd enhanced the Cd toxicity to soil enzymes and microorganisms. This deleterious effect was seen to mainly affect the growth of fungi and the activity of invertase, urease and dehydrogenase. The order of combined inhibition of Cd and phenanthrene was fungi>bacteria>actinomycete.
  
  
  CONCLUSIONS
  The presence of phenanthrene might enhance the toxicity of Cd to soil microorganisms. Phenanthrene can easily be used by the soil actinomycetes as a source of carbon and energy and the finding may be supportive to the development of bioremediation techniques.
authors.affiliation: Department of Environment and Resource, College of Agriculture and Biology, Shanghai Jiaotong University, Shanghai 201101, PR China.
authors.forename: Guoqing
authors.initials: G
authors.lastname: Shen
authors.forename: Linkui
authors.initials: L
authors.lastname: Cao
authors.forename: Yitong
authors.initials: Y
authors.lastname: Lu
authors.forename: Jingbo
authors.initials: J
authors.lastname: Hong
mesh_terms: D001419:Bacteria / Q000254:growth & development; D002104:Cadmium / Q000633:toxicity*; D004798:Enzymes / Q000378:metabolism; D005658:Fungi / Q000254:growth & development; D010616:Phenanthrenes / Q000737:chemistry*; D011157:Population Dynamics; D018570:Risk Assessment; D012988:Soil Microbiology; D012989:Soil Pollutants / Q000633:toxicity*
chemical_list: D004798:Enzymes; D010616:Phenanthrenes; D012989:Soil Pollutants; D002104:Cadmium; C031181:phenanthrene