畜禽粪便中抗生素污染特征及堆肥化去除研究进展

养殖业抗生素的大量使用导致了畜禽粪便中多种抗生素残留,畜禽粪便成为了环境中抗生素污染的重要来源.本文总结了畜禽粪便中多种抗生素复合污染现状及其在土壤中的生态毒理效应,综述了堆肥化技术去除畜禽粪便中抗生素的影响因素和研究进展.堆肥化技术研究显示:针对不同种类抗生素的特性差异,控制堆肥过程的相关参数,提高堆肥化处理技术去除效果,是解决畜禽粪便多种抗生素污染问题的关键.     

畜禽养殖业主要废弃物处理工艺消除抗生素研究进展

随着集约化畜牧养殖业的不断发展,抗生素被广泛用作饲料添加剂以控制畜禽疾病和促进畜禽生长.用于畜禽养殖业中的抗生素绝大部分都不能被动物体所完全吸收,而是以原形或代谢物的形式随动物的粪便排出体外,然后通过各种途径进入到土壤和水体中,给人类健康带来巨大威胁.本文综述了好氧堆肥、厌氧发酵、高级氧化和人工湿地对畜禽粪便和养殖废水中抗生素的去除效果,重点讨论了不同运行参数对处理工艺去除抗生素的影响,最后根据现行研究仍存在的问题提出今后的工作建议,为畜禽养殖业抗生素污染的控制提供参考.     

猪粪堆肥过程中四环素类抗生素的生物转化及降解研究进展

四环素类抗生素(TCs)是畜禽养殖业中一类重要的兽药。随着畜禽养殖集约化,越来越多的抗生素经畜禽机体代谢进入环境,导致了对人类健康和生物安全等的危害。堆肥是无害化去除畜禽粪便中TCs的常见方法,能最大程度削减畜禽粪便中TCs的残留。笔者根据国内堆肥处理猪粪中抗生素残留的现状,结合国内外猪粪堆肥化技术的最新研究进展,从TCs生物转化、生物和非生物降解途径,阐述了猪粪堆肥过程中环境因子的调控、微生物群落结构与组成的变化和TCs的生物降解机制,旨在为未来畜禽粪便无害化、肥料资源化利用提供理论依据和技术参考。     

农村固体废弃物中抗生素及耐药基因的赋存及风险管理

全球范围内抗生素抗性的传播扩散严重威胁人类健康。固体废弃物中的生活垃圾、污泥和畜禽粪便是抗生素及耐药基因的重要储库。针对新型环境污染物抗生素和耐药基因,综述了农村固废中抗生素及耐药基因的赋存和传播扩散,阐述了农村固废中抗生素及细菌耐药的生态风险、控制管理和消除方法,并结合目前抗生素及耐药基因的污染状况,对今后研究重点进行了展望。     

兽药抗生素环境风险控制管理政策探析

抗生素作为兽药和饲料添加剂广泛用于世界各国的畜禽养殖,造成环境中抗生素/抗性基因传播扩散问题日益突出,严重威胁到生态环境和人类健康。笔者梳理了国内外在兽药抗生素登记、使用、标准以及防控计划等各环节的管理政策,从不同角度分阶段提出了我国兽药抗生素环境风险控制管理政策建议,包括:建立兽药环境监管机制,从源头控制抗生素抗性基因污染;制定兽药抗生素环境风险评估导则,从登记环节规避环境与健康风险;加快制定粪便和污水中抗生素/抗性基因的控制标准,从使用末端消除污染;加强含有抗生素的粪便处置与管理,限制抗生素/抗性基因的环境溢出;推广生态有机农业的开展,以期为我国兽药抗生素的环境管理提供基础支撑。     

兽用抗生素在土壤环境中的行为及其生态毒理效应研究进展

目前全球至少有70%左右的抗生素被用于畜牧业和水产养殖业,这些抗生素大多不能被动物完全吸收,以母体或代谢物的形式排出动物体外的抗生素约占用药量的40～90%,排出体外的抗生素大多随粪便等进入环境尤其是土壤环境中并在其中累积.为了明确兽用抗生素对环境中生物等的影响,合理评价兽用抗生素的环境风险,论文就土壤环境中兽用抗生素的来源,兽用抗生素在土壤环境中的吸附、迁移、降解以及对环境中生物的影响等方面进行了综述,在此基础上提出了今后的重点研究方向.     

抗生素及其抗性基因在环境中的污染、降解和去除研究进展

随着抗生素及其抗菌产品的广泛应用,自然和人工环境中的抗生素残留带来的危害引起人们关注.本文基于最新文献,综述了国内外抗生素及其抗性基因的污染水平和来源、它们之间的关系和传播机理以及这类污染物的降解和去除技术.现有研究表明,抗生素及其抗性基因的污染已遍布水、土壤、大气等介质,而在以污水处理厂和固废填埋场为代表的人工环境中,其污染水平更高.抗生素残留诱导产生抗性基因,其在环境中传播扩散与水平基因转移(Horizontal Gene Transfer,HGT)和微生物群落结构组成有关.抗生素和抗性基因在环境中自然降解过程受基质类型、光照、温度和微生物种群等因素的影响,其中光照是影响其降解的重要因子;而在人工处理系统中,紫外消毒和生化降解对抗生素及其抗性基因有较好的去除效果,但并非全部有效.建议今后加强对特定环境中抗生素和抗生素抗性基因的扩散规律和高效降解去除等方面的机理和工艺研究,进而有效控制其环境含量,降低其污染水平.     

兽药抗生素对土壤微生物群落的影响

兽药抗生素广泛应用于畜禽养殖业,用于预防、治疗动物疾病及促进动物生长。然而,养殖过程中使用的抗生素不能被动物完全吸收,其中40%～90%以母体或其代谢物的形式排出动物体外并随畜禽粪便进入土壤环境,对土壤微生物群落结构和功能产生影响。在汇总了畜禽粪便和土壤中兽药抗生素的残留特征之后,概述了抗生素对土壤微生物群落结构和功能的影响以及微生物产生的污染诱导群落耐性。重点探讨了抗生素微生物毒性的影响因素和近年来对微生物共耐性方面的研究,并对未来的研究方向及目标提出了建议。     

环境中抗生素及其生态毒性效应研究进展

近年来,越来越多的抗生素类药物用于在医疗、畜禽和水产养殖业。由于其机体代谢率低,大部分以原药或代谢物的形式经由尿液和粪便排出体外进入环境中,造成抗生素在水体和土壤等环境介质中的残留。这些残留的抗生素会导致潜在的环境风险,其中最严重的是会诱发和传播各类抗生素抗性基因(antibiotic resistance genes,ARGs),进而对人类健康产生威胁。本文介绍了环境中抗生素的来源,归趋和残留状况,并且对其所引起的生态毒性效应以及ARGs进行总结,最后指出了目前研究中存在的问题,并对未来研究进行了展望。     

畜禽养殖排放的雌激素对周边水体环境的影响

环境雌激素是一大类化学物质,它们能够干扰生物体内激素的合成、分泌、转运、活性等,或与生物体内激素结构相似而发挥激素作用,对生物体的生长、繁殖及行为产生不利影响。环境雌激素包括天然雌激素及人工合成类雌激素。随着国内畜禽养殖的规模与数量的不断扩大,养殖场成为了一个很大的环境雌激素的产生源,其环境风险应得到相应的重视。目前对畜禽养殖过程中环境雌激素的产生量以及雌激素进入环境后的迁移转化行为已有很多的研究,包括野外的调查与实验室内机理研究。畜禽养殖过程产生的大量雌激素进入环境后能够被土壤吸附及微生物降解。室内的静态平衡吸附实验、土柱迁移试验及降解研究均表明雌激素进入环境后绝大部分迅速被吸附到土壤颗粒或悬浮胶体、沉积物颗粒上,同时发生转化与生物降解,由此推断其对周边环境中的雌激素贡献很小。然而,野外调查结果却表明实际情况下雌激素的迁移性高于理论期望值。因此,畜禽养殖对周边环境中雌激素的贡献量的大小尚未明确。本论文综述了畜禽养殖过程中环境雌激素的排放情况,结合国内外的调查研究,阐述了畜禽养殖产生的环境雌激素在土壤及水体中的迁移与降解行为,探讨了影响准确评估畜禽养殖排泄物对周边水体中雌激素贡献大小的因子,并提出了今后应开展原位吸附与迁移的实验,重点考虑天然有机质及抗生素等共存物质对雌激素环境行为的影响,建立综合模型来估算不同时期养殖场对周围水环境雌激素的贡献量的建议。     

土壤环境中四环素类抗生素残留及抗性基因污染的研究进展(Tetracycline Residues and Tetracycline Resistance Gene Pollution in Soil: A Review)

近年来,致病菌耐药性的增加和扩散已成为全世界关注的热点问题,而人类医疗和畜禽养殖业抗生素的滥用正不断加剧这一问题.众多研究表明土壤环境作为一个巨大的抗性基因储存库,在抗性微生物和抗性基因的传播中起重要的作用,具有潜在的生态与健康风险.在总结国内外最新研究基础上,对土壤环境中典型抗生素-四环素类抗生素的主要污染源以及其在土壤中的基本环境行为等进行了分析,并探讨了土壤中四环素类抗性基因的来源、迁移和扩散及分子检测手段等问题.我国作为抗生素的生产和消费大国,抗生素污染问题较其他国家更为严重,而国内相关研究才刚刚起步,迫切需要开展有关环境中抗生素和抗生素抗性基因污染的系统研究.     

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.     

Effects of adding biochar on tetracycline removal during anaerobic composting of swine manure

Residual antibiotics in manure pose a potential threat to public and ecological health when the manure is released to the environment via land application of manure as fertiliser. Anaerobic composting has the potential to decrease antibiotic concentrations prior to land application. We therefore investigated the degradation of the antibiotics tetracycline (TC) and oxytetracycline (OTC) during anaerobic composting under different conditions. All composting treatment conditions were able to effect significant decreases in the antibiotic concentrations, though without biochar antibiotic residues remained. TC and OTC were removed more efficiently when the compost was treated at 55°C than treatments at 35°C or 25°C. Adding biochar significantly and rapidly decreased the antibiotic concentrations in the compost samples. After 15 days of treatment with biochar at 55°C, 100% of TC and OTC had been removed from the manure. The marked ability of biochar to remove the antibiotics was primarily attributed to adsorption of TC and OTC by the biochar. However, the addition of biochar may also have altered the microbial community structures within the compost and accelerated microbial degradation of the antibiotics.     

A review on anammox process for the treatment of antibiotic-containing wastewater: Linking effects with corresponding mechanisms

• Anammox is promising for nitrogen removal from antibiotic-containing wastewater. • Most antibiotics could inhibit the anammox performance and activity. • Antibiotic pressure promoted the increase in antibiotic resistance genes (ARGs). • Antibiotic-resistance mechanisms of anammox bacteria are speculated. Antibiotic is widely present in the effluent from livestock husbandry and the pharmaceutical industry. Antibiotics in wastewater usually have high biological toxicity and even promote the occurrence and transmission of antibiotic resistant bacteria and antibiotic resistance genes. Moreover, most antibiotic-containing wastewater contains high concentration of ammonia nitrogen. Improper treatment will lead to high risk to the surrounding environment and even human health. The anaerobic ammonium oxidation (anammox) with great economic benefit and good treatment effect is a promising process to remove nitrogen from antibiotic-containing wastewater. However, antibiotic inhibition has been observed in anammox applications. Therefore, a comprehensive overview of the single and combined effects of various antibiotics on the anammox system is conducted in this review with a focus on nitrogen removal performance, sludge properties, microbial community, antibiotic resistance genes and anammox-involved functional genes. Additionally, the influencing mechanism of antibiotics on anammox consortia is summarized. Remaining problems and future research needs are also proposed based on the presented summary. This review provides a better understanding of the influences of antibiotics on anammox and offers a direction to remove nitrogen from antibiotic-containing wastewater by the anammox process.     

Antibiotic resistance genes in manure-amended paddy soils across eastern China: Occurrence and influencing factors

• Manure fertilization resulted in antibiotic residues and increased metal contents. • The tet and sul genes were significantly enhanced with manure fertilization. • Soil physicochemical properties contributed to 12% of the variations in ARGs. • Soil metals and antibiotics co-select for ARGs. Pig manure, rich in antibiotics and metals, is widely applied in paddy fields as a soil conditioner, triggering the proliferation of antibiotic resistance genes (ARGs) in soil. However, comprehensive studies on the effects of manure fertilization on the abundance of ARGs and their influencing factors are still insufficient. Here, pig manure and manure-amended and inorganic-amended soils were collected from 11 rice-cropping regions in eastern China, and the accumulation of antibiotics, metals, and ARGs was assessed simultaneously. The results showed that manure fertilization led to antibiotic residues and increased the metal content (i.e., Zn, Cu, Ni, and Cr). Tetracycline and sulfonamide resistance genes (tetM, tetO, sul1, and sul2) were also significantly enhanced with manure fertilization. According to variance partitioning analysis, the most important factors that individually influenced ARGs were soil physicochemical properties, accounting for 12% of the variation. Significant correlations between soil nutrients and ARGs indicated that manure application enhanced the growth of resistant microorganisms by supplying more nutrients. Metals and antibiotics contributed 9% and 5% to the variations in ARGs, respectively. Their co-occurrence also increased the enrichment of ARGs, as their interactions accounted for 2% of the variation in ARGs. Interestingly, Cu was significantly related to most ARGs in the soil (r = 0.26–0.52, p<0.05). Sulfapyridine was significantly related to sul2, and tetracycline resistance genes were positively related to doxycycline. This study highlighted the risks of antibiotic and ARG accumulation with manure fertilization and shed light on the essential influencing factors of ARGs in paddy soils.     

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。     

基于小流域尺度的目标抗生素排放量估算方法——以梅江流域为例

抗生素的大量使用和排放造成的环境污染和生态风险问题日益突出,抗生素排放量的估算是评价流域内抗生素污染程度的重要指标,但目前抗生素排放量估算方法尚不完善。本研究以梅江流域为例,建立了适合小流域尺度的典型抗生素排放量估算方法,计算了四环素类抗生素(TCs)向不同环境相的排放量并分析了其主要来源。结果表明:2016年梅江流域TCs排放量为8 558.1 kg,不同行政区抗生素排放量差异较大,其中梅江镇受人口密度及养殖密度影响,抗生素排放量最大,高达1 224.4 kg;同时流域内不同抗生素的排放量也有所不同,其大小顺序为强力霉素(DXC)土霉素(OTC)四环素(TC)金霉素(CTC);TCs受排放源、排放途径等因素影响,以进入环境水相及土壤相为主,其中进入水相中的抗生素主要来自人类及生猪粪便,进入土壤相中的抗生素主要来自生猪及三黄鸡粪便。梅江小流域抗生素具有潜在的生态风险,应加强抗生素使用管理。该研究为我国小尺度流域目标抗生素排放量的估算提供了十分有效的方法。     

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)     

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。     

畜禽养殖场排放物病原微生物危险性调查

以粪大肠菌群和沙门菌为指标,采集江苏省内10家不同养殖类型畜禽养殖场的排放物及其周边水、土样共37个进行观察与计数,同时分析排放污水中大肠杆菌的耐药性以及禽畜排泄物对土壤和水体耐药细菌数的影响.结果表明:调查的10家养殖场中有9家粪便未经无害化处理直接排放到水体或施于农田,且排放物的粪大肠菌群数全部严重超标,沙门菌检出率达19%,施新鲜粪肥的土壤中粪大肠菌群数(MPN,最大可能数)在105 g-1以上,水体中分离出的大肠杆菌表现出多重耐药性,抗生素抗性细菌总数也远高于未施新鲜粪肥的土壤及水体.