An in vitro microcalorimetric method for studying the toxic effect of cadmium on microbial activity of an agricultural soil.
Using TAM III multi-channel thermocalorimetry combined with direct microorganism counting (bacteria, actinomycetes and fungi) under laboratory conditions, we determined the microbial population count, resistance and activity toward cadmium (Cd) toxicity in soil. The thermokinetic parameters, which can represent soil microbial activity, were calculated from power-time curves of soil microbial activity obtained by microcalorimetric measurement. Simultaneous application of the two methods showed that growth rate constant (k), peak-heat output power (P (max)) and the number of living microorganisms decreased with increasing concentration of Cd. Anncrease in Cd concentration resulted in the decrease of the peak-heat output power and increase in the time of the peak of power. However, the relationships between the thermokinetic parameters (k and P (max)) and the number of microorganism were not linear, but the trend was similar. Our research also suggests that microcalorimetry is a very sensitive, simple and useful technique for in vitro investigation of the effects of toxic heavy metals on soil microbial activity.
Yao
Jun
J
School of Environmental Studies & MOE Biogeology and Environmental Geology Laboratory, China University of Geosciences, Wuhan 430074, P.R. China. junyao@cug.edu.cn
Xu
Chaoqian
C
Wang
Fei
F
Tian
Lin
L
Wang
Yanxin
Y
Chen
Huilun
H
Yong
Zhou
Z
Choi
Martin M F
MM
Bramanti
Emilia
E
Maskow
Thomas
T
D001419:Bacteria / Q000187:drug effects / Q000254:growth & development; D002104:Cadmium / Q000633:toxicity*; D002151:Calorimetry / Q000379:methods*; D002681:China; D015169:Colony Count, Microbial; D004784:Environmental Monitoring / Q000379:methods*; D005658:Fungi / Q000187:drug effects / Q000254:growth & development; D012988:Soil Microbiology; D012989:Soil Pollutants / Q000633:toxicity*; D013816:Thermodynamics
D012989:Soil Pollutants; D002104:Cadmium