重金属污染矿区复垦土壤微生物生物量及酶活性的研究

对铜矿废弃地复垦土壤微生物生物量及酶活性研究结果表明 ,与对照土壤相比 ,矿区复垦土壤微生物生物量C、N和P均有所降低 ,微生物商Cmic Corg可作为矿区重金属污染土壤微生物学敏感指标之一 ;酶活性变化与此相似 ,脲酶、脱氢酶和酸性磷酸酶与对照差异显著 ,其他则与对照差异明显 ,一定程度削弱了矿区土壤中C、N营养元素周转速率和能量循环     

超积累植物东南景天根际土壤酶活性研究

通过野外调查和盆栽试验研究了超积累植物东南景天根际土壤酶活性变化及其与重金属有效态的关系。研究结果表明,在矿山土壤、重度污染土壤和轻度污染土壤上,种植超积累生态型东南景天后,根际土壤有效态Zn分别比非根际减少了14.3%,7.9%和47.4%,有效态Cd分别比非根际减少25.1%,21.9%和20%。在铅锌矿区,东南景天生长地段土壤蔗糖酶、酸性磷酸酶、脱氢酶活性高于其它植物生长地段。在矿山土壤和重度污染土壤中,超积累生态型东南景天根际土壤酶活性明显高于非根际土壤,同时也高于非超积累生态型根际土壤。Pb、Zn、Cd、Cu4种重金属对东南景天根际土壤脲酶、蔗糖酶、脱氢酶活性均有抑制作用,而Pb对磷酸酶有一定的刺激作用。东南景天根际土壤脱氢酶、酸性磷酸酶活性与重金属有效态含量呈极显著相关。     

Cd Pb污染土壤中蛋白酶酸性磷酸酶脱氢酶活性的变化

通过现场采样及室内分析方法,研究了Cd、Pb严重污染的土壤中蛋白酶、酸性磷酸酶和脱氢酶活性的变化及其与土壤Cd、Cu、Pb、Zn含量和土壤基本性质之间的关系。通径分析表明,影响蛋白酶活性主要直接因素为土壤有效Cd、土壤有效Zn、砂粒和黏粒,其中土壤有效Zn刺激了酶活性而土壤有效Cd抑制了酶活性;影响酸性磷酸酶活性主要直接因素为碱解氮、速效磷、pH值,土壤有效Cu、土壤有效Cd、土壤有效Pb、土壤有效Zn对酸性磷酸酶的直接影响较小;影响脱氢酶活性主要直接因素为土壤有效Cd、土壤有效Zn、土壤速效钾,其中土壤有效Cd抑制了酶活性而土壤有效Zn刺激了酶活性。总体而言,4种重金属有效态对酶活性毒性大小依次为：Cd〉Cu〉Pb〉Zn。综合简单相关分析结果可知,总体上Cu、Cd、Pb、Zn复合污染刺激了蛋白酶活性,抑制了脱氢酶活性,对酸性磷酸酶活性影响不大,脱氢酶可作为上述土壤重金属复合污染的指标。3种土壤酶活性变化是重金属与土壤理化性质综合作用的结果。     

大气CO2和O3升高对菜地土壤酶活性和微生物量的影响

利用OTC平台和青菜盆栽实验,探索[CO2]、[O3]或[CO2+O3]升高条件下,土壤理化性质、微生物量和土壤酶活性的变化,以期获得未来大气CO2或/和O3升高对土壤微生态系统的风险性。结果表明,[CO2]升高不同程度地提高了土壤的可溶性有机碳（DOC）、可溶性有机氮（DON）、总磷（TP）、总碳（TC）、铵态氮（AN）、硝态氮（NN）含量和含水量（SWC）,进而不同程度地提高了土壤微生物量碳（MBC）、微生物量氮（MBN）含量以及土壤蛋白酶（PRA）、蔗糖酶（SA）、脲酶（UA）、多酚氧化酶（POA）、酸性磷酸酶（APA）和中性磷酸酶（NPA）活性。相反,[O3]升高不同程度降低了土壤DOC、TP、TK、TC、TN、AN、NN、SWC、MBC和MBN含量,提高了MBC/MBN比值,在不同程度上降低了土壤PRA、SA、UA、POA、APA和NPA酶活性。而[CO2+O3]在一定程度上消减了[O3]对土壤微生物量和酶活性的抑制作用,也降低了[CO2]升高对土壤微生物量和酶活性的刺激效应。因此,土壤微生物量和土壤酶活性的变化可用于评价未来大气CO2或/和O3升高对菜地土壤微生态环境的影响。     

铅镉、石油污染和黑麦草种植对土壤微生物活性的影响差异

矿产和石油的生产与使用导致不同程度的土壤重金属和石油污染,已影响到人类健康与安全,土壤污染修复迫在眉睫。本研究采用室内盆栽试验的方法,在铅镉污染、石油污染土壤中种植黑麦草(Lolium perenne),探究土壤基础呼吸(SBR)、微生物生物量碳(MBC)及相关土壤酶活性的变化,揭示铅镉、石油污染对土壤微生物的影响,进而为重金属及石油污染土壤修复及其环境评价提供理论依据。共设置6个处理:未污染土壤(S),未污染土壤+黑麦草(SG),铅镉污染土壤(SH),铅镉污染土壤+黑麦草(SHG),石油污染土壤(SP),石油污染土壤+黑麦草(SPG)。研究发现:与处理S相比,在本研究铅镉及石油污染水平下,处理SH的SBR、MBC、过氧化氢酶活性和脲酶活性分别显著降低22.42%、44.90%、6.35%和44.88%(P 0.05);处理SP的SBR、MBC、脲酶活性和脱氢酶活性分别增加23.06%、52.04%、42.26%和65.37%(P 0.05);处理SG的MBC和过氧化氢酶活性分别降低60.54%和4.55%(P 0.05),SBR和脱氢酶活性分别增加31.51%和94.86%(P 0.05)。土壤受污染后,种植黑麦草处理的SBR和MBC、过氧化氢酶活性、脲酶活性高于对应未种植黑麦草的处理。这一结果表明,在一定含量范围内重金属污染抑制土壤微生物活性,而石油污染初期抑制、后期可以提升微生物活性,种植黑麦草在后期可显著增强污染土壤的微生物活性、提高土壤微生物生物量。     

铅锌矿区污染土壤微生物活性研究

通过野外调查和采样分析，研究了浙江衢州铅锌矿区土壤的微生物、土壤酶活性及植物重金属积累特性。结果表明：矿区污染区土壤Ph、Zn、Cd、Cu全量的平均值分别是对照土壤的267．8倍、132．6倍、41．8倍、17．0倍。矿区植物体内重金属含量与土壤重金属全量和有效态含量呈显著正相关。矿区土壤随着重金属含量的增加，土壤微生物生物量碳逐渐降低，而土壤基础呼吸、微生物代谢商则升高，矿区中心污染土壤微生物生物量碳只有对照土壤的72％，而基础呼吸和微生物代谢商分别是对照土壤的1．6倍和2．3倍。铅锌矿口附近污染区土壤酶活性较低，对照土壤的各种酶活性最高。其中土壤脱氧酶的活性变化最大，作为矿区重金属污染的指标更灵敏。     

镉胁迫对洞庭湖湿地土壤微生物数量与活性的影响

为探讨Cd污染胁迫与洞庭湖湿地土壤微生物学特性之间的内在关系,通过野外土样采集和室内模拟胁迫相结合的方法,研究Cd污染胁迫对洞庭湖湿地土壤微生物数量和微生物活性的影响。结果表明,当Cd胁迫浓度为3 mg kg~(-1)时对洞庭湖湿地土壤细菌、微生物总数及土壤微生物生物量碳(SMBC)刺激作用显著,当Cd胁迫浓度为6 mg kg~(-1)时对真菌有显著的刺激作用,而对细菌、放线菌、微生物总数及微生物生物量氮(SMBN)均表现出抑制作用,且随Cd胁迫浓度的进一步增加对细菌、真菌、放线菌、微生物总数及SMBC、SMBN的抑制作用增强;土壤脲酶、蔗糖酶、过氧化氢酶、磷酸酶和脱氢酶活性随Cd胁迫浓度的增加而降低;土壤基础呼吸(SBR)与代谢墒(qCO_2)随Cd胁迫浓度的增加呈上升趋势。放线菌、SMBC、SMBN、土壤脲酶活性、蔗糖酶活性、过氧化氢酶活性、磷酸酶活性、脱氢酶活性、SBR及qCO_2与Cd胁迫浓度相关显著或极显著;Cd胁迫条件下脱氢酶活性的变异系数最大为50.0%,表明脱氢酶活性的变化对Cd胁迫反映最为敏感,可作为洞庭湖湿地Cd污染土壤质量评价的灵敏指标。     

秸秆还田与氮肥运筹对农田棕壤微生物生物量碳氮及酶活性的调控效应

如何有效运筹秸秆还田与氮肥施用，研发高效节氮秸秆还田技术，是目前东北地区农业生产中亟待解决的问题。基于田间定位试验，研究不同秸秆还田方式（秸秆不还田、秸秆粉碎翻压还田、秸秆堆腐旋耕还田）与施氮水平（180、210、240 kg N/hm2）运筹对土壤微生物量碳氮和氮代谢关键酶活性的影响。结果表明，与秸秆不还田相比，秸秆还田处理土壤MBC、MBN、MBC/MBN和脲酶活性均显著增加，硝酸还原酶活性无规律性变化。随着生育时期推进，秸秆还田处理土壤MBC和MBN分别呈现单峰和双峰曲线变化，脲酶和硝酸还原酶活性均呈波动式变化，高峰期均出现在春玉米旺盛生长期（拔节期 ~ 灌浆期）。随着施氮水平增加，秸秆还田处理土壤MBC、MBN均增加，MBC/MBN降低，而脲酶和硝酸还原酶活性变化行为因秸秆还田方式而异。在保证氮肥总量不变前提下，秸秆粉碎翻压还田配以15％氮肥后移能够增加土壤MBC和MBN，降低MBC/MBN。综上，在东北农业产区，秸秆粉碎翻压还田 + 210 kg N/hm2 + 15％氮肥后移的秸秆还田技术模式具有优化氮素管理、提高土壤肥力的潜力。     

外源氮输入对小叶章湿地土壤微生物活性的影响

选择三江平原沼泽湿地典型草甸植被小叶章(Deyeuxia angustifolia),在水分、温度等环境因素均一的前提下,分别以NH4NO3水溶液的形式均匀撒入0,6,12,24g/(m2.a)(以N元素量计),进行了室外盆栽实验。结果表明,氮输入后,土壤MBC、MBN、BR、qCO2、SIR季节变化明显;在植物不同生长阶段,土壤基础呼吸总体趋势均是随时间的推移而逐渐减弱,且与氮输入量间的关系不同,说明土壤基础呼吸与植物的生长阶段密切相关;不同施氮水平的土壤MBC浓度随氮输入量增加呈波动变化,氮输入量与土壤MBN、BR、qCO2、SIR之间均存在线性正相关关系,即他们随氮输入量增加而逐渐增大,说明氮输入促进了土壤MBN、BR、qCO2、SIR的增大。     

土霉素及镉污染对土壤呼吸及酶活性的影响

随着饲料工业以及畜禽养殖业的规模化发展,抗生素和重金属在土壤环境中同时存在的几率不断增大。为了分析抗生素和重金属对土壤微生物生态系统的影响,以土霉素(OTC)与镉(Cd)为污染物,采用室内培养法,研究了土霉素(OTC)与镉(Cd)单一处理及复合污染对土壤呼吸和酶活性的影响。结果表明,10mg/kg重金属镉单独污染对土壤微生物呼吸表现为先抑制后激活作用,且显著抑制了土壤蔗糖酶、脲酶、磷酸酶活性,对3种酶活性平均抑制率从大到小依次为:蔗糖酶磷酸酶脲酶;1mg/kg土霉素显著激活土壤微生物呼吸,50和200mg/kg土霉素对土壤微生物呼吸的影响呈现出先抑制后激活的规律。各处理浓度下的土霉素对蔗糖酶和脲酶活性均主要表现为抑制作用,对磷酸酶活性的影响呈现出一定的波动性;当土霉素的浓度为1和200mg/kg时,其与10mg/kg镉的复合污染对土壤微生物呼吸及3种酶活性的影响主要为拮抗作用,但当土霉素的浓度为50mg/kg时,与10mg/kg镉的复合污染对土壤微生物呼吸及3种酶活性的影响则主要为协同作用。微生物呼吸对土霉素与镉胁迫更为敏感,最高抑制率和激活率分别可达98.98%和300.82%,土壤酶活性受土霉素和镉污染的影响要弱于它们对土壤微生物呼吸的影响。     

长期重金属胁迫下的土壤微生物特征: 沈阳张士污灌区的案例研究

Soil samples were collected from Zhangshi Wastewater Irrigation Area in the suburb of Shenyang City, China, an area with a 30-year irrigation history with heavy metal-containing wastewater. The chemical properties and microbial characteristics of the soils were examined to evaluate the present situation of heavy metal pollution and to assess the soil microbial characteristics under long-term heavy metal stress. In light of the National Environmental Quality Standards of China, the soil in the test area was heavily polluted by Cd and to a lesser degree by Zn and Cu, even though wastewater irrigation ceased in 1993. Soil metabolic quotient （qCO2） had a significant positive correlation, while soil microbial quotient （qM） had a negative correlation with content of soil heavy metals. Soil microbial biomass carbon （MBC） had significantly negative correlation with Cd, but soil substrate~induced respiration （SIR）, dehydrogenase activity （DHA）, cellulase activity, and culturable microbial populations had no persistent correlations with soil heavy metal content. Soil nutrients, except for phosphorous, showed positive effects on soil microbial characteristics, which to a certain degree obscured the adverse effects of soil heavy metals. Soil Cd contributed more to the soil microbial characteristics, but qM and qCO2 were more sensitive and showed persistent responses to heavy metals stress. It could be concluded that qM and qCO2 can be used as bioindicators of heavy metal pollution in soils.     

Response of microbial characteristics to heavy metal pollution of mining soils in central Tibet,China

Soil microbial activity plays a crucial role in soil microbiological processes, which can be used as a useful indicator to determine the ecological effects of heavy metal pollution on soils. The objective was to determine the effects of heavy metal pollution on mining soils at the Lawu mine of central Tibet, China on soil enzyme activities (sucrase, urease and acid phosphatase), microbial biomass C, N and P (MBC, MBN, and MBP), basal respiration, metabolic quotients, and N mineralization. Sixteen soil samples around the mine were sampled, and one soil sample, 2 km from the mine center, was taken as the control. Compared to the control, mining soils were polluted by heavy metals, Cu, Zn, Pb and Cd, resulting in decreases of sucrase activities, urease activities, acid phosphatase activities, MBC, MBN, MBP, and N mineralization, and increases of basal respiration and qCO₂. Multivariate analysis (cluster analysis [CA], principle component analysis [PCA] and canonical correlation analysis [CCA]) indicated nine microbial variables were only reduced to one principal component explaining 72% of the original variances, and MBC (R² = 0.93) had the highest positive loadings on the principal component. Mining soils polluted by heavy metals were perfectly clustered into four groups, which were highly distinguished by MBC. There were significant canonical correlations between soil heavy metals and microbial indexes on two canonical variates (R1 = 0.99, p < 0.001; R2 = 0.97, p < 0.01), which further demonstrated significant correlations between soil heavy metal contents and microbial characteristics. Hence, our results suggested that MBC may be used a sensitive indicator for assessing changes in soil environmental quality in metal mine of central Tibet.     

南方几种水稻土重金属污染下的土壤呼吸及微生物学效应

采集南方几种重金属污染下的水稻土,通过室内培养的方法研究土壤CO2排放的动态变化以及微生物学指标的差异。结果表明,在60d的培养期内,前7d土壤呼吸速率较高,占了整个排放量的30．89％～64．37％,并且这一阶段重金属对土壤呼吸速率的影响最大。重金属对土壤微生物生物量的影响表现出增加、抑制与无显著性差异的结果,而重金属对微生物熵及微生物代谢熵（qCO2）的影响却是极显著的,同时表现出增加与降低的不同结果。这说明土壤呼吸以及不同的微生物学指标,在长期的复合重金属污染条件下,其表现并不一致,微生物熵与代谢熵用于基本性质差异较大的土壤时,对重金属的响应更为灵敏。此外,土壤重金属的累积还能提高土壤中有机碳的含量。     

粤北铅锌矿区土壤生态系统微生物特征及其重金属含量

粤北大宝山金属矿产资源的开发给生态环境带来了严重危害。对该铅锌矿区土壤的微生物特征进行研究。结果表明:五节芒植物中的元素含量表现为Zn>Pb>Cu>Cd,Zn与土壤元素的相关性最为显著,其次为Pb。与对照土壤相比,矿区土壤的微生物基础呼吸作用增强,但微生物生物量却显著降低,微生物生理生态参数Cmic/Corg、qCO2值明显升高。随着矿区土壤的重金属含量增加,矿区(1#、2#)土壤的生化作用强度明显下降,生化作用表现为与土壤重金属含量呈显著负相关。与非矿区(6#)土壤相比,其中土壤氨化作用、硝化作用、固N作用和纤维素分解作用强度分别下降43.19%～70.01%,70.71%～92.02%,58.54%～87.76%和55.00%～79.60%。生化作用表现为与土壤中重金属含量呈显著负相关。土壤微生物活性下降是矿区土壤生态系统遭受破坏的重要标志之一,也是矿区土壤微生物生态演变的重要因素之一。土壤微生物活性降低削弱了矿区土壤中C、N营养元素的循环速率和能量流动。     

铅锌银尾矿区土壤微生物活性及其群落功能多样性研究

通过对浙江省天台铅锌银尾矿区土壤微生物活性指标以及微生物群落功能多样性研究 ,结果表明 ,尾矿污染区土壤几种重金属含量比非矿区土壤有明显的增加。尾矿区土壤微生物特征发生了显著的变化 ,微生物生物量和可培养细菌数量显著降低 ,但土壤基础呼吸和微生物代谢商 (qCO2 )值却明显升高。Bi olog测试结果显示 ,随着重金属污染程度的加剧其土壤微生物群落结构发生了相应变化 ,尾矿区土壤微生物群落代谢剖面 (AWCD)及群落丰富度、多样性指数均显著低于非矿区土壤 ,且供试土壤间均达极显著水平差异 (p <0 .0 1) ,表明尾矿区重金属污染引起了土壤微生物群落功能多样性的下降 ,减少了能利用有关碳源底物的微生物数量、降低了微生物对单一碳源底物的利用能力     

Effect of Clay Minerals on Immobilization of Heavy Metals and Microbial Activity in a Sewage Sludge-Contaminated Soil (8 pp)

Background   Aims, and Scope. Reducing heavy metal solubility and bioavailability in contaminated area without removing them from the soil is one of the common practices in decreasing the negative impacts on the environment and improving the soil quality. Therefore, our aim was to study the effect of clay minerals: Na-bentonite, Ca-bentonite, and zeolite applied to a contaminated soil on immobilization of heavy metals, as well as on some soil parameters related with microbial activity. Methods   A soil derived from sewage sludge was incubated with clay minerals of either Na-bentonite, Ca-bentonite, or zeolite for 111 days (d). During the incubation experiment, concentrations of water soluble Zn, Cd, Cu, and Ni were measured after extraction of 2 g air-dry soil with 50 ml of H2O for 2 h. After the water extraction, the soil sediment was extracted with 50 ml of 1 M NH4NO3 for 2 h to estimate the exchangeable amounts of heavy metals. Furthermore, soil microbial respiration, microbial biomass C, Corg mineralization, metabolic quotient (qCO2), and inorganic N were also investigated. Results and Discussion   Water extractable and exchangeable forms of heavy metals were changed by incubation and addition of clay minerals. Incubation of soil without addition of clay minerals (control) increased water extractable Cu by 12, 24 and 3.8% of initial content after 21, 62, and 111 d of incubation, respectively. The water extractable Zn decreased by 9% during 62 d of incubation and it tended to increase by 14% at the end of the incubation, as compared with the initial soil. Water extractable Cd decreased by 71, 66 and 33% of initial content, and Ni decreased by 54, 70, and 58%, after 21, 62, and 111 d of incubation, respectively. During the incubation experiment, the exchangeable form of all tested metals was decreased by incubation. The addition of clay minerals led to a significant decrease in water soluble and exchangeable forms of heavy metals during the incubation experiment, resulting in low metal extractability. The reduction in metal extractability was greater due to the addition of Na-bentonite or Ca-bentonite than that due to the addition of zeolite. During the first 3 weeks after addition of clay minerals, the studied biological parameters were not affected. However, as incubation progressed, the addition of Na- or Ca- bentonite led to a significant increase in soil respiration, microbial biomass C, Corg mineralization, and inorganic N; and a significant decrease in qCO2. This result is explained by sorption of heavy metals on Na-bentonite and Ca-bentonite and strong reduction of their toxicity. Conclusions   Our results clearly show that the addition of clay minerals, especially of Na-bentonite and Ca-bentonite, decreased the extractability of four metals during incubation. The decreased metal extractability was accompanied by an increase of soil respiration, Corg mineralization, microbial biomass C, and inorganic N and a decrease of metabolic quotient (qCO2), showing positive effect of clay mineral addition on soil biological parameters. Recommendations and Outlook   The use of Na-bentonite and Ca-bentonite is promising tool for reduction the extractability and possible toxicity of heavy metals in sewage sludge-contaminated soil. Therefore, the soils polluted with heavy metals may be ameliorated by addition of clay minerals, especially Na-bentonite and Ca-bentonite.     

喀斯特峡谷区不同恢复阶段土壤微生物量及呼吸商

土壤微生物生物量、土壤微生物呼吸及微生物商值（微生物商qMB、微生物呼吸商qCO2）是土壤质量的敏感性指标。对喀斯特峡谷区不同植被恢复阶段土壤微生物生物量、土壤微生物呼吸及其qMB、qCO2进行研究,结果表明：在植被恢复过程中,土壤微生物生物量、土壤微生物呼吸及qMB均表现为从退耕地到草本群落下降,从草本到灌木群落上升,从灌木到乔木群落略微上升或者趋于稳定;qCO2的变化规律与它们相反。在同一恢复阶段,土壤微生物生物量,土壤微生物呼吸,qMB值均随土层加深而减小。土壤微生物生物量、微生物呼吸及其qMB、qCO2与土壤总有机碳、全氮、全磷具有显著的线性相关关系（p〈0.05）,可用来评价土壤质量。     

污泥生物炭对杨树人工林土壤环境质量的影响

通过田间实验,研究污泥生物炭(SSBC)施用对杨树人工林土壤理化性质、重金属含量、土壤微生物生物量碳氮以及土壤酶活性的影响。试验设置4个处理:对照 (CK: 0 t·hm-2)、低量(LS: 15 t·hm-2)、中量(MS: 30 t·hm-2)及高量(HS: 60 t·hm-2)。结果表明:SSBC的施用可降低土壤pH,增加土壤EC值;随着SSBC用量的增加,土壤营养成分和重金属含量均呈现增加趋势,其中SOC增加18.4~47.9%、全N含量增加20.4~46.5%、全P含量增加27.9~74.9%、有效氮增加4.2~23.1%及有效磷增加16.3~ 28.3%,且重金属污染可控。SSBC提高微生物生物量碳氮含量,并使土壤 β-葡糖苷酶(BG)、N-乙酰-葡糖苷酶(NAG)和蛋白酶(LAP)活性显著增加,即BG、NAG和LAP分别增加17.1%~35.3%、18.1~36.8%及29.3~70.3%,其中MS处理的增幅最大。总体而言,SSBC的应用不仅显著增加土壤营养成分,而且改善部分微生物环境,致使土壤环境质量一定程度上有所改善。     

Influence of heavy metals on the functional diversity of soil microbial communities

Three soil types-Calcaric Phaeozem, Eutric Cambisol and Dystric Lithosol-in large container pots were experimentally contaminated with heavy metals at four different levels (light pollution: 300 ppm Zn, 100 ppm Cu, 50 ppm Ni, 50 ppm V and 3 ppm Cd; medium pollution: twofold concentrations; heavy pollution: threefold concentrations; uncontaminated control). We investigated the prognostic potential of 16 soil microbial properties (microbial biomass, respiration, N-mineralization, 13 soil enzymes involved in cycling of C, N, P and S) with regard to their ability to differentiate the four contamination levels. Microbial biomass and enzyme activities decreased with increasing heavy metal pollution, but the amount of decrease differed among the enzymes. Enzymes involved in the C-cycling were least affected, whereas vartous enzyme activities related to the cycling of N, P and S showed a considerable decrease in activity. In particular, arylsulfatase and phosphatase activities were dramatically affected. Their activity decreased to a level of a few percent of their activities in the corresponding unpolluted controls. The data suggest that aside from the loss of rare biochemical capabilities-such as the growth of organisms at the expense of aromatics (Reber 1992)-heavy metal contaminated soils lose very common biochemical propertities which are necessary for the functioning of the ecosystem. Cluster analysis as well as discriminant analysis underline the similarity of the enzyme activity pattern among the controls and among the polluted soils. The trend toward a significant functional diversity loss becomes obvious already at the lowest pollution level. This implies that concentrations of heavy metals in soils near the current EC limits will most probably lead to a considerable reduction in decomposition and nutrient cycling rates. We conclude that heavy metal pollution severely decreases the functional diversity of the soil microbial community and impairs specific pathways of nutrient cycling.Dedicated to Professor J. C. G. Ottow on the occasion of his 60th birthday