Degradation of sulfonamides during anaerobic composting of swine manure

Residual antibiotics in manure pose a potential threat to public and ecological health as a result of the application of manure from animals treated with antibiotics to land. The environmental fate of sulfonamides (SAs) in swine manure after composting and field application remains largely unknown. We studied the degradation of the antibiotics sulfadiazine (SD), sulfathiazole (ST), and sulfamethazine (SM2) during anaerobic composting. We tested the effects of temperature and antibiotic concentration on degradation rates. We also evaluated the changes in pH, moisture, and biological degradation material in manure spiked with SAs and in a control. Results showed that the 3 SAs decreased by between 52.31% and 90.30% in all 9 treatments following 14 days of anaerobic composting, and the highest removal efficiencies were observed at a temperature of 35°C and initial concentrations of 6.03, 6.48, and 6.32?µg/g of SD, ST, and SM2, respectively, which were degraded by 90.30%, 85.78%, and 75.18%. Removal efficiencies for all SAs correlated well with moisture and biological degradation material of the manure. These results indicate that composting may be a practical and effective way to reduce concentrations of these three SAs in swine manure prior to its land application.     

典型四环素类抗生素对土壤微生物及植物生长的影响

四环素类抗生素(TCs)在畜禽养殖中的大量使用甚至滥用,导致其在动物粪便中高浓度残留。随着畜禽粪便有机肥的农田施用,TCs持续进入土壤并且不断累积,由此带来的土壤生态危害和健康风险值得关注。以四环素(TC)、土霉素(OTC)为研究对象,采用室内培养试验法,考察2种典型TCs对土壤微生物、酶活性的影响及对植物生长的毒性作用。结果表明,低浓度TC和OTC作用下,土壤细菌和真菌数量即显著降低,土壤细菌较真菌对TCs的污染更为敏感。除TC对土壤酸性磷酸酶和OTC对土壤过氧化氢酶活性主要表现为激活作用外,总体上TC、OTC作用后土壤酶活性呈低浓度促进、高浓度抑制的变化趋势。80 mg·L~(-1)的TC、OTC暴露下,绿豆芽芽伸长被显著抑制,并且随着抗生素浓度的增大,绿豆芽伸长抑制率大幅升高。相同浓度、相同暴露时间条件下的TC对绿豆芽伸长的毒性大于OTC。     

Effects of different concentrations of tetracycline and oxytetracycline on the growth and ecotoxicity in lettuce北大核心CSCD

四环素类抗生素(TCs)是目前我国应用广泛、用量最大的一类抗生素,畜禽粪便和土壤中存在TCs残留,影响蔬菜作物的生长发育. TCs因水溶性较高更容易被植物转运和积累,植物对TCs耐受性机理研究仍不足.为更全面探究土壤TCs对蔬菜的毒性作用,研究不同浓度四环素(TC)和土霉素(OTC)分别对生菜的抗生素残留、生长特征及抗氧化酶系统的影响.结果显示,在0(对照)、2、10、50、250 mg/kg 5个施用水平下,生菜叶片抗生素含量逐渐增加,且土霉素含量始终大于四环素含量.与对照相比,抗生素浓度在50 mg/kg以上时对生菜生长具有显著抑制作用,其中,株高、根长、地上部和地下部鲜重与叶片TC残留量具显著负相关.生菜叶片的脯氨酸含量随浓度增加呈先增加后降低的趋势,在10 mg/kg时达到最大.并且低浓度(2 mg/kg)促进抗氧化酶基因SOD、POD21和CAT的表达,高浓度抗生素(50、250 mg/kg)对其产生抑制作用,10 mg/kg的抗生素处理对SOD、POD21和CAT基因表达的影响在抗生素种类上存在差异.本研究表明抗生素浓度超过50 mg/kg对生菜生长产生抑制作用,脯氨酸和抗氧化酶SOD、POD、CAT的转录水平及其酶活性能快速响应抗生素胁迫,可作为生菜对抗生素抗性的辅助评价指标.(图8表3参19)     

木薯渣堆肥及其对难溶性磷的活化试验研究

试验以干鸡粪、米糠、堆肥返料作调理剂,同时加入不同含量的磷矿粉,对木薯渣进行好氧堆肥,研究木薯渣堆肥过程中堆肥理化性质的变化及木薯渣堆肥对难溶性磷的活化作用。试验设置磷矿粉加入量10%(T1)、15%(T2)、20%(T3)和不加磷矿粉(CK)四个处理,干鸡粪、米糠、堆肥返料的添加量均为10%、15%和20%。在堆肥过程中,四个处理均在55℃以上高温持续了25d,超过了国家规定的标准。在堆肥结束时,各处理水分含量均降至30%左右,pH升高至弱碱性,淀粉降解率均在90%以上,水溶性碳(DOC)含量均降至10g·kg-1以下,达到了基本腐熟的标准。证明木薯渣通过堆肥能达到稳定无害化状态。在堆肥结束时,T1、T2、T3有效磷增加量分别为12.58、12.81、12.96g·kg-1,对磷矿粉的活化率分别为23.53%、17.07%、14.50%,T1活化效果最好。研究结果表明木薯渣堆肥对难溶性磷有一定的活化作用,可为解决堆肥资源化产品中植物可利用磷含量偏低的难题开拓一条生物学途径。     

畜禽环境中抗生素的去除及其风险评估

抗生素作为饲料添加剂广泛应用于畜禽养殖业,造成养殖环境抗生素大量蓄积,尤其是在畜禽粪便中,长期的积累不仅污染养殖场内土壤环境,残留的抗生素还会随畜禽粪便进入周边水体及农田环境,威胁农作物及人体健康。目前,国内相关研究主要集中在抗生素的降解工艺及降解规律方面,而对其去除效率的影响因素及风险评价研究相对较少。笔者综述了国内外抗生素的降解转化及去除方式等的研究进展,并概述了抗生素在畜禽环境中的生态风险评估的研究现状,为抗生素的高效去除、风险预估及畜禽粪便资源化安全利用提供理论基础和技术支撑。     

四环素类抗生素和铜复合污染对猪粪厌氧消化的影响

兽用抗生素和矿物元素添加剂可起到预防动物疾病、促进动物生长、提高饲料转化率等作用,因此被广泛应用于畜禽养殖业。本研究以猪粪中温厌氧消化为研究目标,采用全自动甲烷潜势测试系统,考察了一定浓度的四环素(TC:30 mg·kg~(-1)dry weight,DW)、土霉素(OTC:50 mg·kg~(-1)DW)和金霉素(CTC:15 mg·kg~(-1)DW)对厌氧累积产甲烷量和日产甲烷速率的影响。结果表明,TC、OTC和CTC对猪粪中温厌氧消化累积产甲烷量和日产甲烷速率均有促进作用(累积产甲烷总量提高比例分别为7.9%、0.4%和5.4%)。另外,采用超高效液相色谱-四极杆串联质谱对猪粪厌氧消化前后样品中四环素类抗生素及其代谢产物进行了分析。结果表明,液相中的四环素类抗生素在猪粪厌氧消化过程中得到了明显的去除,去除率达到90%~100%;而固相中只有金霉素和差向异构金霉素有明显的去除效果,去除率分别为41.69%和41.58%。采用Tessier连续提取法对猪粪厌氧消化前后样品中5种形态的铜包括可交换态、碳酸盐结合态、铁锰氧化结合态、有机物结合态、残渣态进行了分析,结果表明,猪粪厌氧消化后,可交换态、碳酸盐结合态和铁锰结合态的铜浓度比厌氧消化前分别降低了1%~9%、0.1%~3%、12%~19%,而有机态和残渣态的铜浓度却在厌氧消化后分别增加了15%~35%、1%~2%。厌氧消化后,70%~80%的铜都是以有机铜的形态存在。铜逐渐从不稳定态转化为相对稳定的有机态和残渣态铜,因此,厌氧消化过程使铜从可生物利用态转变为不可生物利用态,趋于稳定化。     

Environmental effects and risk control of antibiotic resistance genes in the organic solid waste aerobic composting system: A review

• ARGs were detected in livestock manure, sludge, food waste and fermentation dregs. • The succession of microbial community is an important factor affecting ARGs. • Horizontal transfer mechanism of ARGs during composting should be further studied. Antibiotic resistance genes (ARGs) have been diffusely detected in several kinds of organic solid waste, such as livestock manure, sludge, antibiotic fermentation residues, and food waste, thus attracting great attention. Aerobic composting, which is an effective, harmless treatment method for organic solid waste to promote recycling, has been identified to also aid in ARG reduction. However, the effect of composting in removing ARGs from organic solid waste has recently become controversial. Thus, this article summarizes and reviews the research on ARGs in relation to composting in the past 5 years. ARGs in organic solid waste could spread in different environmental media, including soil and the atmosphere, which could widen environmental risks. However, the conventional composting technology had limited effect on ARGs removal from organic solid waste. Improved composting processes, such as hyperthermophilic temperature composting, could effectively remove ARGs, and the HGT of ARGs and the microbial communities are identified as vital influencing factors. Currently, during the composting process, ARGs were mainly affected by three response pathways, (I) “Microenvironment-ARGs”; (II) “Microenvironment-microorganisms-ARGs”; (III) “Microorganisms-horizontal gene transfer-ARGs”, respectively. Response pathway II had been studied the most which was believed that microbial community was an important factor affecting ARGs. In response pathway III, mainly believed that MGEs played an important role and paid less attention to eARGs. Further research on the role and impact of eARGs in ARGs may be considered in the future. It aims to provide support for further research on environmental risk control of ARGs in organic solid waste.     

猪粪和锯末联合堆肥的中试研究

以 3种配比的猪粪和锯末为原料 ,进行了联合堆肥中试研究。一次发酵采用温度反馈通气量控制的静态好氧堆肥系统 ,周期 1 5d ;二次发酵采用定期翻堆自然腐熟 ,周期 30d。试验分析了堆制过程中温度、含水率、有机质、pH值的变化。对堆肥产物的腐熟度和养分分析表明 ,3种配比的堆肥产物均可达到腐熟度要求。猪粪养分含量越高 ,产物养分越高。通过堆肥工艺的优化控制和加水措施 ,猪粪和锯末联合堆制可以在 4 5d内获得高质量的有机肥 ,具有良好的应用前景。     

畜禽有机肥对典型蔬果地土壤剖面重金属与抗生素分布的影响

采集不同类型的畜禽有机肥及施用后的土壤,测定其重金属浓度,同时利用超声波提取-SPE—LC／MS／MS方法分析土壤中14种抗生素的污染特征,研究长期施用畜禽有机肥对典型蔬果地土壤剖面重金属与抗生素分布的影响。结果表明,猪粪、羊粪、鸡粪3种畜禽有机肥中最易造成土壤污染的是猪粪,Cu、Zn和Cd含量分别为197．0、947．0和1．35mg·kg-1。不同土地利用方式下,施用有机肥均使重金属在土壤剖面呈现表聚现象,以设施菜地最为突出,Zn和Cd积累明显,0—20cm土层含量分别为203和0．48mg·kg-1。不同土地利用方式下,14种抗生素的含量与组成在土壤剖面上存在明显分异,随土层深度增加含量迅速下降,但在〉80～100cm土层仍有检出;设施菜地表层土壤抗生素含量为39．5μg·kg-1,积累和残留明显高于林地和果园,特别是四环素类和氟喹诺酮类,含量分别为34．3和4．75μg·kg-1。可见,农田土壤长期大量施用畜禽有机肥可引起重金属和抗生素的复合污染,具潜在生态风险。     

木薯渣堆肥及其对难溶性磷的活化试验研究

试验以干鸡粪、米糠、堆肥返料作调理剂,同时加入不同含量的磷矿粉,对木薯渣进行好氧堆肥,研究木薯渣堆肥过程中堆肥理化性质的变化及木薯渣堆肥对难溶性磷的活化作用。试验设置磷矿粉加入量10％（T1）、15％（T2）、20％（T3）和不加磷矿粉（CK）四个处理,干鸡粪、米糠、堆肥返料的添加量均为10％、15％和20％。在堆肥过程中,四个处理均在55℃以上高温持续了25d,超过了国家规定的标准。在堆肥结束时,各处理水分含量均降至30％左右,pH升高至弱碱性,淀粉降解率均在90％以上,水溶性碳（DOC）含量均降至10g.kg。以下,达到了基本腐熟的标准。证明木薯渣通过堆肥能达到稳定无害化状态。在堆肥结束时,T1、T2、T3有效磷增加量分别为12．58、12．81、12．96g.kg-1,对磷矿粉的活化率分别为23．53％、17．07％、14．50％,T1活化效果最好。研究结果表明木薯渣堆肥对难溶性磷有一定的活化作用,可为解决堆肥资源化产品中植物可利用磷含量偏低的难题开拓一条生物学途径：     

Efficacy of woody biomass and biochar for alleviating heavy metal bioavailability in serpentine soil

Crops grown in metal-rich serpentine soils are vulnerable to phytotoxicity. In this study, Gliricidia sepium (Jacq.) biomass and woody biochar were examined as amendments on heavy metal immobilization in a serpentine soil. Woody biochar was produced by slow pyrolysis of Gliricidia sepium (Jacq.) biomass at 300 and 500 °C. A pot experiment was conducted for 6 weeks with tomato (Lycopersicon esculentum L.) at biochar application rates of 0, 22, 55 and 110 t ha^?1. The CaCl₂ and sequential extractions were adopted to assess metal bioavailability and fractionation. Six weeks after germination, plants cultivated on the control could not survive, while all the plants were grown normally on the soils amended with biochars. The most effective treatment for metal immobilization was BC500-110 as indicated by the immobilization efficiencies for Ni, Mn and Cr that were 68, 92 and 42 %, respectively, compared to the control. Biochar produced at 500 °C and at high application rates immobilized heavy metals significantly. Improvements in plant growth in biochar-amended soil were related to decreasing in metal toxicity as a consequence of metal immobilization through strong sorption due to high surface area and functional groups.     

牛粪发酵过程中抗生素耐药基因及相关菌群组成变化规律

随着规模化奶牛养殖迅速发展,牛粪带来的环境污染问题日益严重。实验探究牛粪及其堆肥过程中养分变化、抗生素耐药基因消减情况以及细菌群落演替规律,探讨细菌菌群与养分、抗生素耐药基因之间的相关性。采集牛粪及其堆肥过程样品,测定样品中养分、检测抗生素耐药基因相对丰度,采用16S r RNA高通量测序技术研究牛粪堆肥过程细菌群落变化。结果表明,从新鲜牛粪(组FM)到发酵牛粪(组C),样品中有机质含量下降,全氮和全磷含量有不同程度增加,全钾(TK)显著升高(P<0.05)。堆肥发酵后,抗生素耐药基因erm B、tet M、bla CTX-M和aac(6')-Ib-cr的相对丰度呈现不同程度的下降,而基因sul1相对丰度增加。高通量测序结果表明,在门水平,各组均以Firmicutes、Proteobacteria和Bacteroidetes这3个菌门为主,在属水平,各组具有不同的优势物种,其中发现Bacteroides、Paeniclostridium和Pseudomonas等7个潜在病原菌属的相对丰度在堆肥后有效降低。通过相关性分析发现,潜在病原菌属与基因tet M和sul1呈显著正相关(P<0.05),此外,大部分优势菌属与养分TK有显著相关性(P<0.05)。研究结果表明,牛粪经堆肥发酵后,病原菌相对丰度有效降低,抗生素耐药基因相对丰度的下降与细菌菌群结构变化存在相关关系。     

Field evaluation of intensive compost application on Cd fractionation and phytoavailability in a mining-contaminated soil

A field experiment was conducted to investigate the effect of chicken manure compost on the fractionation of cadmium (Cd), soil biological properties and Cd uptake by wheat in a soil affected by mining activities in Hubei province, China. Compost was applied at five levels (0, 27, 54, 108, 216 t ha^?1), and winter wheat (Triticum aestivum L.) was chosen as an indicator plant. Results showed that the application of compost increased soil pH and the content of total phosphorus and organic matter. Soil biological properties such as microbial biomass carbon, invertase, protease, urease and catalase activities were significantly enhanced by 0.24–3.47 times after compost application. Sequential extraction indicated that compost amendments decreased the acid-extractable Cd by 8.2–37.6 %, while increased the reducible and oxidisable Cd by 9.2–39.5 and 8.2–60.4 %, respectively. The addition of 27–54 t ha^?1 compost reduced Cd content in wheat stems and seeds by 69.6–75.0 % and 10.3–18.4 %, respectively. However, only 25.5–26.5 % reductions in Cd content in wheat stems were observed in 108–216 t ha^?1 compost amendments, and no significant decrease was detected for seeds. This study suggests that although compost is a suitable organic amendment to improve soil fertility and biological activities, the addition of compost should be moderated by an appropriate rate to optimize the use of compost for the reclamation of metal-contaminated soils at field scale.     

Antibiotic resistome mostly relates to bacterial taxonomy along a suburban transmission chain

• The α-diversities of resistome were lower in manure and compost than in soils. • There were significant correlations between the resistome and bacterial taxonomy. • Bacterial taxonomy was the highest in explaining resistome variances. Antibiotic resistance genes comprising antibiotic resistome are of great concern due to their increase in the environment. Recent evidence of shared resistomes between soils and animal husbandry has imposed potential risks to human health. However, the correlation between a given community’s resistome and bacterial taxonomic composition is controversial. Here, a transmission chain of resistomes from swine manure to compost and compost-amended soil were analyzed in five suburban areas of Beijing, China, with unamended agricultural soils as control soils. Antibiotic resistomes and bacterial taxonomic compositions were distinct between (I) manure and compost; and (II) compost-amended and control soils. In manure, compost, and compost-amended soils, the β-diversity of the resistome and bacterial taxonomic composition was significantly correlated, while no correlation was detected in control soils. Bacterial taxonomic composition explained 36.0% of total variations of the resistome composition, much higher than environmental factors. Together, those results demonstrated that antibiotic resistome was closely related to bacterial taxonomic composition along the suburban transmission chain.     

高温堆肥碳氮循环及腐殖质变化特征研究

堆肥化处理，是指依靠自然界广泛分布的细菌、放线菌、真菌等微生物，对有机物有控制地进行生物降解，使之转化为腐殖质的生物化学处理技术。作者采用畜禽粪便条垛式高温堆肥实验方法，研究了堆肥过程中碳氮循环及腐殖质变化特征。结果表明，堆肥过程中，碳素和氮素变化最大，表现为二者总量的减少，其中以碳素总量减少较多，氮素总量次之，从而导致碳氮质量分数比降低。腐殖酸总量、胡敏酸和富里酸总量均呈下降趋势，但腐殖酸占有机碳的比例以及胡敏酸与富里酸质量分数比却在提高，速效养分含量也在升高，表明堆肥过程是一个有机质数量减少、有机质质量提高的过程。     

菌剂对堆肥的作用及其应用

好氧高温堆肥是一种受微生物控制的有机物降解和转化的过程。在堆肥过程的不同阶段对有机物降解起关键作用的微生物种群不同。接种菌剂可以使堆肥物料快速达到高温、控制堆肥过程中臭气的产生，缩短堆肥腐熟进程；可以有效杀灭病原体和降解有机污染物，提高堆肥质量。堆肥产品含有生物活性的微生物，作物增产效果显著。文章总结了接种菌剂在堆肥过程中的作用和应用效果，提出接种菌剂的研究首先应利用传统微生物研究法和先进的分子生态学技术摸清堆肥过程中微生物活动规律，逐步筛选出所需功能性菌群，在堆肥应用时要确定菌剂的最佳接种时间和接种量。     

石灰预处理对树叶堆肥过程中养分转化的影响

以树叶干质量的0%、1.00%、2.50%和4.00%的石灰预处理树叶,24h后分别将预处理后的树叶与鸡粪联合堆肥,研究不同用量石灰预处理树叶对树叶堆肥过程中养分转化的影响。试验在自制的堆肥反应器内进行,采用间歇式强制通风的方式,进行为期59d的堆肥试验。结果表明:石灰预处理树叶24h可以有效的降低树叶中的有机质质量分数,以4.00%的石灰预处理的树叶其有机质降幅达6.00%;石灰预处理24h后,各处理pH相差不大;EC的变化与pH相似;预处理前后,各处理总氮、总磷和总钾的质量分数相差不大。用石灰预处理后的树叶堆肥有利于堆肥有机质的降解,尤以2.50%石灰预处理的效果最好;有利于堆肥w(C)/w(N)的降低,其降低幅度与石灰用量成正比;有利于减少堆肥过程中氮素的损失,且氮素损失与石灰使用量呈反比;有利于堆肥NH4 -N质量分数的降低;提高堆肥终产品NO3--N的质量分数,其质量分数与石灰用量呈正比;有利于堆肥中钾的浓缩;对堆肥的pH、EC、w(NH4 -N)/w(NO3--N)和总磷的影响不大。综合考虑试验结果后认为,以4.00%石灰预处理的效果最为理想。     

奶牛粪便翻堆式与槽式堆肥过程气体排放规律及养分损失原位监测

为探究奶牛粪便翻堆式与槽式堆肥过程中温室气体和氨气(NH₃)排放规律及养分损失情况,采用原位监测的方法,通过静态采气箱和气体在线监测设备,分别对奶牛粪便翻堆式和槽式堆体开展为期36 d的气体监测。结果表明,翻堆式堆肥过程中甲烷(CH₄)、氧化亚氮(N2_O)和NH₃排放主要集中于翻堆阶段;槽式堆肥过程中CH₄和NH₃排放主要集中于堆肥前期,N2_O排放则主要集中于堆肥中后期。堆体管理措施及物料特性显著影响堆肥气体的排放。翻堆式堆肥过程中翻堆对气体排放的影响大于堆肥理化因子如温度、含水率以及pH值;而槽式堆肥过程中,降低堆体的平均温度可同时减缓堆肥过程中CH₄、二氧化碳(CO₂)和NH₃的释放。从养分损失来看,翻堆式和槽式堆肥过程中碳素总损失量分别占堆肥物料初始总碳含量(TC)的27.16%和21.53%,其中约80%以上的碳素损失来自CO₂-C。而堆肥过程中氮素总损失量分别占堆肥物料初始总氮含量(TN)的18.67%和13.44%,其中约80%以上的氮素损失来源于NH₃N。该研究表明,在保证堆体物料腐熟的前提下,降低翻堆频率可显著减缓翻堆式堆肥过程中温室气体和NH₃的排放;降低槽式堆肥堆体的温度可显著减少堆肥过程中CH₄、CO₂和NH₃的排放。该研究结果对于减少堆肥过程气态污染物排放和养分损失,提高堆肥效率具有重要的指导意义。     

外源铁、磷对堆肥腐熟的影响及“腐殖酸-Fe-P”复合体的形成初探

针对堆肥过程中氮素损失严重,产品品质低下的问题,试验以FeCl3和Ca3（PO4）2（干质量比1∶1）混合物分别按10%（处理A）和15%（处理B）的比例添加到堆肥原料中,以未加任何外源物质的处理作为对照,进行添加外源铁、磷是否会促进堆肥腐熟、提高产品品质的研究。结果表明,与对照处理相比,外源铁、磷对堆肥油菜籽（Brassica napus）发芽率指数影响不大,但产品的氮素含量明显提高,分别高于对照1.42%和1.17%;外源铁、磷加速有机质的分解,有机质分解率分别高于对照处理13%和3.3%;外源铁、磷对堆肥产品腐殖酸结合的Fe含量分别为对照处理的4.4倍和1.98倍,铁结合的磷含量分别为9.12、5.91g·kg-1,对照处理仅为2.21g·kg-1,并通过相关文献讨论,提出堆肥体中可能形成了＂腐殖酸-Fe-P＂三元复合体的假设。从作用和成本上来看,处理A的添加比例较处理B合适。     

Antibiotika (Ivermectin, Monensin) und endokrine Umweltchemikalien (nonylphenol, Ethinylöstradiol) im Boden

The influence of four synthetic chemicals (nonylphenol, ethynyl-estradiol, ivermectin, monesin) on the biomass and on the microbial activity was studied in a laboratory experiment using a typical luvisol derived from loess. The polyether antibiotic monensin, the antiparasitic agent ivermectin and the two environmental chemicals with endocrine effects nonylphenol and ethynylestradiol were chosen because of their toxicity to different organisms and known biological activity. These agents may enter the soil together with sewage sludge or manure. To date, however, the effects on soil have hardly been studied. Selected microbial methods revealed in part very significant effects on the microbial biomass and microbial activity during constant physical (15°C, 50% water holding capicity) and chemical conditions (pH, C_org) 1, 14 and 42 days after contamination.