磺胺嘧啶對(duì)魚菜共生系統(tǒng)氮元素轉(zhuǎn)化的影響

胡浩東,高 航,胡 振

磺胺嘧啶對(duì)魚菜共生系統(tǒng)氮元素轉(zhuǎn)化的影響

胡浩東,高 航,胡 振*

(山東大學(xué)環(huán)境科學(xué)與工程學(xué)院,山東省水環(huán)境污染控制與資源化重點(diǎn)實(shí)驗(yàn)室,山東 青島 266237)

本文研究了典型抗生素磺胺嘧啶對(duì)實(shí)驗(yàn)室規(guī)模鯉魚-小白菜共生系統(tǒng)生產(chǎn)性能和氮元素轉(zhuǎn)化的影響.結(jié)果表明,磺胺嘧啶使系統(tǒng)鯉魚體重增量提高17%,但小白菜生產(chǎn)性能大幅下降,使得系統(tǒng)氮素利用率由43.66%降至21.20%, N2O轉(zhuǎn)化率由1.02%上升至1.98%.磺胺嘧啶在投加初期對(duì)系統(tǒng)的硝化過程表現(xiàn)出短期抑制效應(yīng),經(jīng)過32d的適應(yīng)期后,實(shí)驗(yàn)組氨氮濃度下降至和對(duì)照組相近水平,系統(tǒng)運(yùn)行后期實(shí)驗(yàn)組氨氧化細(xì)菌豐度相較對(duì)照組提高51.43%.魚體內(nèi)殘余的磺胺嘧啶為35.23μg/kg,符合國家標(biāo)準(zhǔn),但水體中磺胺類藥物抗性基因1、2及1的拷貝數(shù)分別提升至7.23倍、2.74倍和4.12倍.從生產(chǎn)性能及環(huán)境友好性考慮,魚菜共生系統(tǒng)在設(shè)計(jì)及運(yùn)行中應(yīng)減少或避免抗生素的使用,并采取合理的替代措施規(guī)避其風(fēng)險(xiǎn).

魚菜共生；磺胺嘧啶；氮；氨氧化細(xì)菌；抗性基因

據(jù)世界糧農(nóng)組織(FAO)最新統(tǒng)計(jì),2016年世界水產(chǎn)養(yǎng)殖總產(chǎn)量(包括水生植物)達(dá)1.102億t,近15a年均增長率約為5.8%[1].然而,由于魚類對(duì)魚食中氮磷等元素利用效率較低,水產(chǎn)養(yǎng)殖業(yè)的快速發(fā)展,不僅造成了巨大的資源浪費(fèi),還引發(fā)水體富營養(yǎng)化等污染問題,給自然環(huán)境帶來了沉重的壓力[2].近年來,一種新型的水產(chǎn)養(yǎng)殖模式—魚菜共生系統(tǒng),引起廣泛關(guān)注.魚菜共生系統(tǒng)的核心思想是將水培法應(yīng)用于水產(chǎn)養(yǎng)殖中,利用魚類排泄物中的養(yǎng)分培育水生蔬菜,在改善水質(zhì)的同時(shí)收獲作物[3].已有研究表明,魚菜共生系統(tǒng)可以回收魚食中約70%的磷和60%的氮[4-5],并通過出售作物及服務(wù)提升收入[6],實(shí)現(xiàn)了對(duì)資源的更高效利用,具有廣闊的應(yīng)用前景.氮元素的轉(zhuǎn)化是魚菜共生系統(tǒng)中物質(zhì)循環(huán)的關(guān)鍵過程,目前,國內(nèi)外圍繞魚菜共生系統(tǒng)中氮元素利用效率提升開展了廣泛研究,Hu等[7]證明種植根表面積較高的植物可以取得更高的氮元素利用效率(NUE);Zou等[8]的研究表明當(dāng)系統(tǒng)的pH值為6.0時(shí),NUE將達(dá)到最大值.

為了降低魚類感染病害的概率,增加產(chǎn)量,水產(chǎn)養(yǎng)殖業(yè)中預(yù)防性地添加抗生素已成為常規(guī)策略[9].但抗生素的使用會(huì)帶來多方面的風(fēng)險(xiǎn),譬如抗生素通過食物鏈積累,引發(fā)人體過敏或中毒反應(yīng);破壞微生物群落多樣性,加劇水體富營養(yǎng)化[10].同時(shí),有報(bào)道指出水生環(huán)境與陸地環(huán)境中細(xì)菌之間可以進(jìn)行抗性基因的交換,導(dǎo)致部分人類病原體出現(xiàn)耐藥性,降低醫(yī)用抗生素的治愈率[11].國內(nèi)外目前的研究主要著眼于抗生素與水培系統(tǒng)中植物間的相互作用,例如Chuang等[12]發(fā)現(xiàn)小分子量(<300g/mol)的抗生素可以很容易地進(jìn)入萵苣的根和芽,而大分子量(>400g/mol)的抗生素則主要積累于萵苣的根中;Kong等[13]通過實(shí)驗(yàn)表明隨著水培系統(tǒng)中土霉素濃度增加,苜蓿葉子的顏色變?yōu)闇\綠色甚至黃色.抗生素對(duì)作物的類似毒害作用近年來已被廣泛報(bào)道[14],但魚菜共生作為一種新型的水產(chǎn)養(yǎng)殖模式,抗生素對(duì)其系統(tǒng)性能影響尚不明確,亟需開展相關(guān)研究.

因此,本實(shí)驗(yàn)選取磺胺嘧啶為代表性抗生素,重點(diǎn)考察抗生素對(duì)鯉魚-小白菜共生系統(tǒng)生產(chǎn)性能和氮元素轉(zhuǎn)化的影響,并通過化學(xué)計(jì)量和分子生物學(xué)手段,解析磺胺嘧啶對(duì)魚菜共生系統(tǒng)氮元素轉(zhuǎn)化的影響機(jī)制,為魚菜共生系統(tǒng)的設(shè)計(jì)與運(yùn)行提供理論參考和技術(shù)指導(dǎo).

1 材料與方法

1.1 實(shí)驗(yàn)裝置及運(yùn)行

在山東大學(xué)青島校區(qū)環(huán)境科學(xué)與工程學(xué)院植物生長間搭建鯉魚-小白菜共生系統(tǒng),如圖1所示.系統(tǒng)中的魚箱和菜池均使用藍(lán)色不透光PVC材料制成.其中魚箱有效容積為40L,養(yǎng)殖15條重量在35g左右的中華鯉魚(),頂部加蓋以避光并防止鯉魚躍出;菜池有效容積為80L,水面用泡沫制漂浮筏覆蓋,并種植有長勢(shì)相近的48株小白菜幼苗,種植密度為1株/dm2.通過海綿固定幼苗根部,實(shí)驗(yàn)期間每周向菜池水體中補(bǔ)充小白菜生長所需的營養(yǎng)素[15].

圖1 魚菜共生系統(tǒng)示意

實(shí)驗(yàn)期間持續(xù)對(duì)魚箱進(jìn)行0.1m3/h的曝氣,維持溶解氧濃度大于5.0mg/L;每日對(duì)菜池晝夜(16h:8h)交替提供光照,溫度維持在25℃.魚箱及菜池中用水均為自來水,通過蠕動(dòng)泵輸水和重力自然回流實(shí)現(xiàn)系統(tǒng)的水循環(huán),水力停留時(shí)間為2d[16].

共搭建2套裝置,一套參考規(guī)范[17]中建議的投加量(日投魚體重的1‰),在實(shí)驗(yàn)開始的前3d,在魚食中拌餌投加共1.5g磺胺嘧啶,另外一套作為對(duì)照,不投加抗生素.

1.2 分析項(xiàng)目與測試方法

1.2.1 生產(chǎn)指標(biāo) 記錄每日喂食量,并采用稱量法,測定實(shí)驗(yàn)開始前后魚類總重,計(jì)算飼料轉(zhuǎn)化率(FCR)[18].實(shí)驗(yàn)結(jié)束時(shí),采用分光光度法測定葉片中葉綠素含量[19],并稱量菜池中的蔬菜.

1.2.2 物化指標(biāo) 實(shí)驗(yàn)期間每天對(duì)系統(tǒng)溶解氧、水溫、光照強(qiáng)度等理化參數(shù)進(jìn)行監(jiān)測,保障系統(tǒng)持續(xù)穩(wěn)定運(yùn)行.同時(shí)根據(jù)標(biāo)準(zhǔn)方法對(duì)氨氮、亞硝酸鹽氮、硝酸鹽氮等水質(zhì)指標(biāo)進(jìn)行測定[20].參考洪蕾潔等[21]的方法采用液相色譜法對(duì)水體中磺胺嘧啶濃度進(jìn)行測定.參考鄒藝娜等[22]的方法測定并計(jì)算實(shí)驗(yàn)期間系統(tǒng)內(nèi)魚箱和菜池的N2O釋放通量.對(duì)魚食及系統(tǒng)內(nèi)各組分的樣品進(jìn)行預(yù)處理后,使用德國Vario Macro Cube元素分析儀測定其氮元素含量,并根據(jù)化學(xué)計(jì)量平衡分析元素分布[8].依據(jù)標(biāo)準(zhǔn)方法對(duì)鯉魚樣品進(jìn)行處理后,采用液相色譜法測定其磺胺嘧啶含量[23].

1.2.3 微生物群落分析 實(shí)驗(yàn)結(jié)束時(shí)截取小白菜根部,在磷酸鹽緩沖溶液中振蕩分離根際表面附著的懸浮固體,使用離心機(jī)在5000r/min下離心5min后倒去上清液,收集底部的固體,使用德國GIAGEN公司生產(chǎn)的DNeasy PowerSoil Kit試劑盒提取DNA,通過實(shí)時(shí)熒光定量PCR儀對(duì)樣品進(jìn)行PCR擴(kuò)增,進(jìn)而定量氨氧化功能基因的表達(dá)情況,驗(yàn)證磺胺嘧啶影響系統(tǒng)氮循環(huán)的機(jī)理.同時(shí),過濾收集魚箱水體懸浮物,并采用上述方法提取其中的DNA后,對(duì)磺胺類藥物抗性基因1、2、1的表達(dá)情況進(jìn)行定量[24-25].

1.3 數(shù)據(jù)處理與分析

本研究中所有樣品檢測均進(jìn)行3次平行實(shí)驗(yàn),使用Microsoft Excel 2019與SPSS 22.0進(jìn)行數(shù)據(jù)的統(tǒng)計(jì)與分析,最小顯著性水平低于0.05.使用Origin 2018繪制圖形,結(jié)果取3次平行實(shí)驗(yàn)的平均值.

2 結(jié)果與討論

2.1 磺胺嘧啶對(duì)生產(chǎn)性能的影響

實(shí)驗(yàn)開展期間,2套裝置中均未出現(xiàn)魚類疾病或死亡現(xiàn)象;但實(shí)驗(yàn)組小白菜生長速度相對(duì)緩慢,并于實(shí)驗(yàn)中期(15d)開始出現(xiàn)葉片局部泛黃等現(xiàn)象,至實(shí)驗(yàn)結(jié)束時(shí)實(shí)驗(yàn)組中小白菜已全部死亡.

由表1可知,實(shí)驗(yàn)組中鯉魚的進(jìn)食量與飼料轉(zhuǎn)化率均優(yōu)于對(duì)照組,增重相較對(duì)照組提升約17%.這反映了適量抗生素的存在對(duì)魚類生長起到促進(jìn)作用[26].

表1 系統(tǒng)的生產(chǎn)性能對(duì)比

由于磺胺嘧啶抑制了實(shí)驗(yàn)組小白菜葉片中葉綠素的積累,其葉綠素含量遠(yuǎn)低于對(duì)照組,這與趙保真[27]的研究相符合.葉綠素的減少將影響小白菜的光合效率,同時(shí)磺胺類藥物對(duì)小白菜根和芽的生長也存在抑制作用[28],在多種因素的共同作用下,小白菜無法正常生長發(fā)育.因此在魚菜共生系統(tǒng)中,磺胺嘧啶的使用將會(huì)導(dǎo)致蔬菜生產(chǎn)性能大幅下降.

圖2反映了進(jìn)入系統(tǒng)的氮元素的分布情況.化學(xué)計(jì)量分析結(jié)果表明,在對(duì)照組中,進(jìn)入系統(tǒng)的氮元素分別被鯉魚和小白菜攝取17.61%和26.05%,合計(jì)共43.66%的氮素作為產(chǎn)品回收,氮素利用效率(NUE)與文獻(xiàn)報(bào)道結(jié)果相似[5,15].在實(shí)驗(yàn)組中,盡管鯉魚回收的氮素占比為19.42%,略高于對(duì)照組,但由于小白菜產(chǎn)量極低,其氮素回收僅占1.78%,作為產(chǎn)品回收的氮元素合計(jì)占總輸入量的21.20%,遠(yuǎn)低于對(duì)照組.

此外,魚菜共生系統(tǒng)中存在部分氮素以N2O、NH3、N2等氣體形式溢散,其中N2O是重要的溫室氣體,其全球升溫潛能超過CO2的298倍[29].實(shí)驗(yàn)期間,對(duì)照組中以N2O的形式溢散的氮素占總輸入氮的1.02%,與近年文獻(xiàn)報(bào)道中的數(shù)值范圍相近[20,30].但在實(shí)驗(yàn)組中,N2O轉(zhuǎn)化率則達(dá)到了1.98%,約為對(duì)照組的1.94倍.因此,磺胺嘧啶的使用一方面降低了魚菜共生系統(tǒng)對(duì)氮元素的利用效率,造成資源的浪費(fèi);另一方面增加了溫室氣體的排放,對(duì)環(huán)境帶來不利影響.

a.實(shí)驗(yàn)組;b.對(duì)照組

2.2 磺胺嘧啶對(duì)氮元素轉(zhuǎn)化的影響

在有氧情況下,氨氧化細(xì)菌(AOB)將氨氮氧化為亞硝酸鹽是魚菜共生系統(tǒng)中去除氨的主要途徑[31].由圖3(a)可以看出,對(duì)照組中氨氮在前15d內(nèi)緩慢積累,最高達(dá)到0.94mg/L,此后則下降至較低水平,基本維持在0.1~0.2mg/L之間.這一過程反映了在魚菜共生系統(tǒng)的啟動(dòng)階段,氨氮的凈化受限于菜池內(nèi)氨氧化細(xì)菌(AOB)群落的豐度,往往存在一段時(shí)間的適應(yīng)期[31].而這一適應(yīng)期的長短則反映了系統(tǒng)內(nèi)AOB群落適應(yīng)環(huán)境的速度.在實(shí)驗(yàn)組中,氨氮濃度在前20d迅速上升至3.68mg/L,直到32d時(shí)才降至與對(duì)照組相近的水平.實(shí)驗(yàn)組中出現(xiàn)的這一現(xiàn)象表明,磺胺嘧啶的存在使得其AOB群落的活性受到了抑制,從而降低了系統(tǒng)的氨氮氧化速率,這與Song等[32]的研究相符合.而隨著時(shí)間的推進(jìn),AOB群落緩慢恢復(fù)活性,因此在實(shí)驗(yàn)?zāi)┢谄浒钡獫舛戎饾u下降至和對(duì)照組相近的水平.

在魚菜共生系統(tǒng)中,亞硝酸鹽主要來源于氨氮的氧化,而其去除則依賴于亞硝酸鹽氧化菌(NOB)將其轉(zhuǎn)化為硝酸鹽.在實(shí)驗(yàn)的第6d前,對(duì)照組中的亞硝酸鹽濃度保持上升,反映了魚菜共生系統(tǒng)中NOB細(xì)菌群落的適應(yīng)期[31].而在實(shí)驗(yàn)的第6~16d,對(duì)照組中亞硝酸鹽濃度均大致保持下降趨勢(shì),造成這一現(xiàn)象的原因在于隨著AOB群落適應(yīng)期的結(jié)束,其氨氧化速率超過了NOB群落的亞硝酸鹽氧化速率[33],這也恰好對(duì)應(yīng)了圖3(a)中氨氮的下降.此后,伴隨著氨氧化過程和亞硝酸鹽氧化過程的穩(wěn)定,對(duì)照組中亞硝酸鹽的濃度在短暫上升后逐漸下降至0.1mg/L以下,最終保持穩(wěn)定.盡管有報(bào)道稱磺胺類藥物對(duì)水中的NOB群落存在抑制作用[34],但在實(shí)驗(yàn)的前16d,由于亞硝酸鹽的產(chǎn)生受限于AOB群落的活性,實(shí)驗(yàn)組中亞硝酸鹽的變化趨勢(shì)與對(duì)照組大致相同,并未出現(xiàn)更快的累積.然而在16d后,實(shí)驗(yàn)組中亞硝酸鹽氮的濃度迅速上升,最高達(dá)到21.13mg/L,這段時(shí)間AOB群落活性恢復(fù),氨氧化速率上升,亞硝酸鹽迅速積累.由于N2O的釋放量與水中亞硝酸鹽的濃度呈顯著正相關(guān)關(guān)系[35],這也解釋了2.1中實(shí)驗(yàn)組N2O釋放量增加的現(xiàn)象.此后,隨著實(shí)驗(yàn)組中NOB活性上升,水體中累積的亞硝酸鹽被不斷氧化,最終降到了和對(duì)照組相近的水平.

魚菜共生系統(tǒng)中,植物的吸收同化是硝酸鹽去除的重要途徑[36].如圖3(c)所示,在實(shí)驗(yàn)的前期,由于系統(tǒng)中亞硝酸鹽氧化速率較低,實(shí)驗(yàn)組和對(duì)照組中硝酸鹽濃度基本保持在0~3mg/L之間.在20d左右時(shí),隨著NOB群落的活性上升,系統(tǒng)中硝酸鹽開始出現(xiàn)積累,但由于小白菜處于快速生長期,需要吸收大量硝酸鹽[37],硝酸鹽的產(chǎn)生和積累逐漸維持了動(dòng)態(tài)平衡,直至小白菜成熟后,硝酸鹽濃度恢復(fù)緩慢上升的趨勢(shì).然而在實(shí)驗(yàn)組中,由于小白菜的生長受到抑制,無法有效吸收水中的硝酸鹽,因此在26d左右時(shí),隨著NOB群落活性的上升,硝酸鹽在系統(tǒng)中持續(xù)積累.

圖3 系統(tǒng)中氨氮、亞硝酸鹽、硝酸鹽(以N計(jì))及磺胺嘧啶濃度變化

圖3(d)反映了實(shí)驗(yàn)期間實(shí)驗(yàn)組水體中磺胺嘧啶殘余量的變化.由于水解和吸附對(duì)磺胺嘧啶的作用有限,水體中磺胺嘧啶的去除依賴于生物降解過程[38],而AOB分泌的氨單加氧酶在抗生素的生物降解中發(fā)揮著主導(dǎo)作用,因此磺胺嘧啶的變化可以反映系統(tǒng)中AOB的活性[39-40].在實(shí)驗(yàn)前期,實(shí)驗(yàn)組水體中磺胺嘧啶濃度保持在較高水平,未發(fā)生顯著變化,這表明此時(shí)系統(tǒng)中AOB受到磺胺嘧啶的脅迫作用.而在20d后,磺胺嘧啶濃度迅速下降,表明隨著AOB對(duì)磺胺嘧啶的逐漸適應(yīng),其活性的恢復(fù)使得水體中的磺胺嘧啶得到降解,這驗(yàn)證了對(duì)圖3(a)中氨氮變化趨勢(shì)的相關(guān)分析.

實(shí)驗(yàn)結(jié)束時(shí)實(shí)驗(yàn)組與對(duì)照組中氨氧化功能基因的拷貝數(shù)分別為2.65′107與1.75′107.的拷貝數(shù)反映了系統(tǒng)內(nèi)AOB的數(shù)量.可以看出,盡管在實(shí)驗(yàn)初期磺胺嘧啶對(duì)系統(tǒng)內(nèi)AOB存在抑制作用,但在實(shí)驗(yàn)結(jié)束時(shí),實(shí)驗(yàn)組AOB的豐度未低于對(duì)照組,并相較對(duì)照組提高51.43%,說明其活性已得到恢復(fù),這解釋了實(shí)驗(yàn)中后期水體氨氮和磺胺嘧啶濃度的快速下降. Wang等[39]在對(duì)硝化污泥的研究中發(fā)現(xiàn),暴露于磺胺嘧啶后,基因的表達(dá)水平將會(huì)上調(diào),以克服磺胺嘧啶帶來的不利影響.并且,在大部分時(shí)間里,實(shí)驗(yàn)組中氨氮濃度要高于對(duì)照組,這刺激了AOB的生長.兩方面的作用,使得實(shí)驗(yàn)組的AOB豐度在實(shí)驗(yàn)?zāi)┢诔^了對(duì)照組.

2.3 磺胺嘧啶殘余量及其抗性基因表達(dá)

實(shí)驗(yàn)期間,合計(jì)有1.5g磺胺嘧啶進(jìn)入實(shí)驗(yàn)組.但在實(shí)驗(yàn)結(jié)束時(shí),除水體中保留了47.85mg的磺胺嘧啶(占輸入量的3.19%)外,絕大部分磺胺嘧啶均被降解或吸附.魚體內(nèi)的抗生素殘余量平均為35.23μg/ kg,低于《無公害食品水產(chǎn)品中漁藥殘留限量》(NY 5070-2002)[41]中規(guī)定的100μg/kg,對(duì)人體健康的風(fēng)險(xiǎn)較小.對(duì)于攝取的磺胺嘧啶,鯉魚具有排泄出體外,或通過肝臟與肌肉進(jìn)行降解的能力,這降低了鯉魚體內(nèi)的磺胺嘧啶殘余量[42].

圖4反映了系統(tǒng)中磺胺嘧啶抗性基因的表達(dá)情況.在魚箱內(nèi)水體中,磺胺類藥物抗性基因1、2、1均有檢出,其中1、2、1在實(shí)驗(yàn)組中的拷貝數(shù)分別為對(duì)照組的7.23倍、2.74倍和4.12倍,這表明磺胺嘧啶促進(jìn)了魚菜共生系統(tǒng)內(nèi)微生物抗藥性的產(chǎn)生.當(dāng)前學(xué)術(shù)界普遍認(rèn)為,水生病原體和人體病原體之間通過質(zhì)粒等可移動(dòng)遺傳單元構(gòu)成的潛在橋梁,將會(huì)使得水體中細(xì)菌對(duì)抗生素的耐藥性,傳遞到人類病原體中,進(jìn)而對(duì)人體健康帶來威脅[43].可見,在魚菜共生系統(tǒng)中,抗生素的使用會(huì)帶來抗性基因表達(dá)等環(huán)境風(fēng)險(xiǎn).考慮到磺胺嘧啶對(duì)魚菜共生系統(tǒng)多方面的負(fù)面影響,在其運(yùn)行管理過程中應(yīng)盡量減少或避免抗生素的使用.如有需要,可采取引入益生菌、噬菌體等作為生物防治劑[44-45],或使用藥用植物及其衍生物作為免疫調(diào)劑等替代措施規(guī)避風(fēng)險(xiǎn)[46].

圖4 系統(tǒng)中磺胺嘧啶抗性基因表達(dá)情況

3 結(jié)論

3.1 磺胺嘧啶的使用會(huì)提高魚類的生產(chǎn)性能,但其對(duì)小白菜的毒害作用會(huì)嚴(yán)重影響小白菜的正常生長發(fā)育,促使其死亡,導(dǎo)致系統(tǒng)對(duì)氮元素的利用效率大大降低,N2O釋放量增加.

3.2 磺胺嘧啶的使用會(huì)在投加初期抑制系統(tǒng)內(nèi)的氨氮氧化過程和亞硝酸鹽氧化過程,隨著時(shí)間推進(jìn), AOB和NOB群落將逐漸恢復(fù)性能.但由于蔬菜的死亡,系統(tǒng)中硝酸鹽得不到有效去除.

3.3 在投加量符合標(biāo)準(zhǔn)的情況下,魚體內(nèi)殘余的抗生素將不會(huì)影響人體健康.但磺胺嘧啶的使用仍然會(huì)導(dǎo)致系統(tǒng)中抗性基因的表達(dá),帶來潛在的健康風(fēng)險(xiǎn).

3.4 考慮到磺胺嘧啶對(duì)魚菜共生系統(tǒng)多方面的負(fù)面影響,在其運(yùn)行管理過程中應(yīng)盡量減少或避免抗生素的使用,如有需要,應(yīng)采取合理的替代措施規(guī)避其風(fēng)險(xiǎn).

[1] FAO. The State of World Fisheries and Aquaculture 2018 - Meeting the sustainable development goals [M]. Rome: FAO, 2018:17-18.

[2] Naylor R L, Goldburg R J, Primavera J H, et al. Effect of aquaculture on world fish supplies [J]. Nature, 2000,405(6790):1017-1024.

[3] Graber A, Junge R. Aquaponic systems: Nutrient recycling from fish wastewater by vegetable production [J]. Desalination, 2009,246(1-3): 147-156.

[4] Cerozi, B S, Fitzsimmons K. Phosphorus dynamics modeling and mass balance in an aquaponics system [J]. Agricultural Systems, 2017,153:94-100.

[5] Zou Y, Hu Z, Zhang J, et al. Attempts to improve nitrogen utilization efficiency of aquaponics through nitrifies addition and filler gradation [J]. Environmental Science and Pollution Research, 2016,23(7):6671- 6679.

[6] Love D C, Fry J P, Li X, et al. Commercial aquaponics production and profitability: Findings from an international survey [J]. Aquaculture, 2015,35:67-74.

[7] Hu Z, Lee J W, Chandran K, et al. Effect of plant species on nitrogen recovery in aquaponics [J]. Bioresource Technology, 2015,188:92-98.

[8] Zou Y N, Hu Z, Zhang J, et al. Effects of pH on nitrogen transformations in media-based aquaponics [J]. Bioresource Technology, 2016,210:81-87.

[9] Sapkota A, Sapkota A R, Kucharski M, et al. Aquaculture practices and potential human health risks: Current knowledge and future priorities [J]. Environment International, 2008,34(8):1215-1226.

[10] Cabello F C. Heavy use of prophylactic antibiotics in aquaculture: a growing problem for human and animal health and for the environment [J]. Environmental Microbiology, 2006,8(7):1137-1144.

[11] Heuer O E, Kruse H, Grave K, et al. Human health consequences of use of antimicrobial agents in aquaculture [J]. Clinical Infectious Diseases, 2009,49(8):1248-1253.

[12] Chuang Y H, Liu C H, Sallach J B, et al. Mechanistic study on uptake and transport of pharmaceuticals in lettuce from water [J]. Environment International, 2019,131:104976.

[13] Kong W D, Zhu Y G, Liang Y C, et al. Uptake of oxytetracycline and its phytotoxicity to alfalfa (Medicago sativa L.) [J]. Environmental Pollution, 2007,147(1):187-193.

[14] Madikizela L M, Ncube S, Chimuka L. Uptake of pharmaceuticals by plants grown under hydroponic conditions and natural occurring plant species: A review [J]. Science of the Total Environment, 2018,636: 477-486

[15] Ru D Y, Liu J K, Hu Z, et al. Improvement of aquaponic performance through micro- and macro-nutrient addition [J]. Environmental Science and Pollution Research, 2017,24(19):16328-16335.

[16] Fang Y, Chen X, Hu Z, et al. Effects of hydraulic retention time on the performance of algal-bacterial-based aquaponics (AA): focusing on nitrogen and oxygen distribution [J]. Applied Microbiology and Biotechnology, 2018,102(22):9843-9855.

[17] SC/T 1084-2006 磺胺類藥物水產(chǎn)養(yǎng)殖使用規(guī)范 [S]. SC/T 1084-2006 Specification for the application of sulfanilamides in aquaculture [S].

[18] Li W, Wei Q W, Luo H. Special collector and count method in a recirculating aquaculture system for calculation of feed conversion ratio in fish [J]. Aquacultural Engineering, 2014,60:63-67.

[19] NY/T 3082-2017 水果、蔬菜及其制品中葉綠素含量的測定:分光光度法 [S]. NY/T 3082-2017 Determination of chlorophyll content in fruits, vegetables and derived products-Spectrophotometry method [S].

[20] 國家環(huán)境保護(hù)總局.水和廢水監(jiān)測分析方法 [M]. 北京:中國環(huán)境科學(xué)出版社, 2002. General Administration of Environmental Protection of the People’s Republic of China. Standard methods for the examination of water and wastewater [M]. Beijing: China Environmental Science Press, 2002.

[21] 洪蕾潔,石 璐,張亞雷,等.固相萃取-高效液相色譜法同時(shí)測定水體中的10種磺胺類抗生素 [J]. 環(huán)境科學(xué), 2012,33(2):652-657. Hong L J, Shi L, Zhang Y L, et al. Simultaneous determination of 10sulfonamide antibiotics in water by solid-phase extraction and high performance liquid chromatography [J]. Environmental Science, 2012, 33(2):652-657.

[22] 鄒藝娜,胡 振,張 建,等.魚菜共生系統(tǒng)氮素遷移轉(zhuǎn)化的研究與優(yōu)化 [J]. 環(huán)境工程學(xué)報(bào), 2015,9(9):4211-4216. Zou Y N, Hu Z, Zhang J, et al. Investigation and optimization of nitrogen transformations in aquaponics [J]. Chinese Journal of Environmental Engineering, 2015,9(9):4211-4216.

[23] GB 1077-1-2008 水產(chǎn)品中17種磺胺類及15種喹諾酮類藥物殘留量的測定液相色譜-串聯(lián)質(zhì)譜法 [S]. GB 1077-1-2008 Simultaneou determination of 17sulfonamides and 15quinolones residues in aquatic products by LC-MS/MS method [S].

[24] Zhi W, Ji G. Quantitative response relationships between nitrogen transformati on rates and nitrogen functional genes in a tidal flow constructed wetland under C/N ratio constraints [J]. Water Research, 2014,64:32-41.

[25] 王 娜,楊曉洪,郭欣妍,等.磺胺類耐藥菌中抗性基因的表達(dá)規(guī)律 [J]. 生態(tài)毒理學(xué)報(bào), 2015,10(5):75-81. Wang N, Yang X H, Guo X Y, et al. Expression patterns ofgenes in sulfonamide-resistant bacteria [J]. Asian Journal of Ecotoxicology, 2015,10(5):75-81.

[26] Mo W Y, Chen Z T, Leung H M, et al. Application of veterinary antibiotics in China's aquaculture industry and their potential human health risks [J]. Environmental Science and Pollution Research, 2017, 24(10):8978-8989.

[27] 趙保真.Cu-磺胺嘧啶單一及復(fù)合污染的生態(tài)毒性效應(yīng)研究 [D]. 新鄉(xiāng):河南師范大學(xué), 2012. Zhao B Z. Study of the ecology toxic effects of single and combined pollution between Cu and sulfadiazine [D]. Xinxiang: Henan Normal University, 2012.

[28] Jin C, Chen Q, Sun R, et al. Eco-toxic effects of sulfadiazine sodium, sulfamonomethoxine sodium and enrofloxacin on wheat, Chinese cabbage and tomato [J]. Ecotoxicology, 2009,18(7):878-885.

[29] Hu Z, Lee J W, Chandran K, et al. Nitrous oxide (N2O) emission from aquaculture: A review [J]. Environmental Science & Technology, 2012,46(12):6470-6480.

[30] Wongkiew S, Popp B N, Khanal S K. Nitrogen recovery and nitrous oxide (N2O) emissions from aquaponic systems: Influence of plant species and dissolved oxygen [J]. International Biodeterioration & Biodegradation, 2018,134:117-126.

[31] Wongkiew S, Hu Z, Chandran K, et al. Nitrogen transformations in aquaponic systems: A review [J]. Aquacultural Engineering, 2017,76: 9-19.

[32] Song Z, Zhang X, Sun F, et al. Specific microbial diversity and functional gene (AOB) analysis of a sponge-based aerobic nitrifying moving bed biofilm reactor exposed to typical pharmaceuticals [J]. Science of the Total Environment, 2020,742: 140660.

[33] Wang L, Wang X, Yang F, at al. Nitrogen removal performance and ammonia- and nitrite-oxidizing bacterial community analysis of a novel industrial waste-based biofilter [J]. Chemical Engineering Journal, 2016,299:156-166.

[34] Chang B V, Chang Y T, Chao W L, et al. Effects of sulfamethoxazole and sulfamethoxazole-degrading bacteria on water quality and microbial communities in milkfish ponds [J]. Environmental Pollution, 2019,252(Pt A):305-316.

[35] Peng L, Ni B J, Ye L, et al. The combined effect of dissolved oxygen and nitrite on N2O production by ammonia oxidizing bacteria in an enriched nitrifying sludge [J]. Water Research, 2015,73:29-36.

[36] Buhmann A, Papenbrock J. Biofiltering of aquaculture effluents by halophytic plants: Basic principles, current uses and future perspectives [J]. Environmental and Experimental Botany, 2013,92:122-133.

[37] 羅 健,程?hào)|山,林東教,等.不同收獲時(shí)期和控氮條件對(duì)水培小白菜硝酸鹽含量的影響 [J]. 生態(tài)環(huán)境, 2005,(4):562-566. Luo J, Cheng D S, Lin D J, et al. Effects of harvesting time and controlled supply of nitrogen on nitrate content of Brassia campestris in hydroponics [J]. Ecology and Environmental Sciences, 2005,(4): 562-566.

[38] Kummerer K. Antibiotics in the aquatic environment - A review - Part I [J]. Chemosphere, 2009,75(4):417-434.

[39] Wang B, Ni B J, Yuan Z, et al. Unravelling kinetic and microbial responses of enriched nitrifying sludge under long-term exposure of cephalexin and sulfadiazine [J]. Water Research, 2020,173:115592.

[40] Dong H Y, Yuan X J, Wang W D, et al. Occurrence and removal of antibiotics in ecological and conventional wastewater treatment processes: A field study [J]. Journal of Environmental Management, 2016,178:11-19.

[41] NY 5070-2002 無公害食品水產(chǎn)品中漁藥殘留限量 [S]. NY 5070-2002 Non-polluted food: Residue limits of fishery drugs in aquatic products [S].

[42] Zhao H, Liu S, Chen J, et al. Biological uptake and depuration of sulfadiazine and sulfamethoxazole in common carp (Cyprinus carpio) [J]. Chemosphere, 2015,120:592-597.

[43] Cabello F C, Godfrey H P, Buschmann A H, et al. Aquaculture as yet another environmental gateway to the development and globalisation of antimicrobial resistance [J]. The Lancet Infectious Diseases, 2016, 16(7):e127-e133.

[44] Verschuere L, Rombaut G, Sorgeloos P, et al. Probiotic bacteria as biological control agents in aquaculture [J]. Microbiology and Molecular Biology Reviews, 2000,64(4):655-671.

[45] Sieiro C, Areal-Hermida L, Pichardo-Gallardo A, et al. A hundred years of bacteriophages: Can phages replace antibiotics in agriculture and aquaculture? [J]. Antibiotics-Basel, 2020,9(8):493.

[46] Awad E, Awaad A. Role of medicinal plants on growth performance and immune status in fish [J]. Fish & Shellfish Immunology, 2017,67: 40-54.

Effect of sulfadiazine on the nitrogen transformation of aquaponic systems.

HU Hao-dong, GAO Hang, HU Zhen*

(Shandong Province Key Laboratory of Water Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Shandong University, Qingdao 266237, China)., 2021,41(4)：1697~1703

In this study, impact of sulfadiazine, one of the typical antibiotics, on the performance and nitrogen transformation of lab scale aquaponic systems were reported. Results showed that sulfadiazine increased the growth of carps () by 17%, but had significant adverse effects on the growth of pakchoi (), which reduced the nitrogen utilization rate of the system from 43.66% to 21.20%, and increased its N2O conversion rate from 1.02% to 1.98%. Sulfadiazine was observed to have short-term inhibitory effects on the nitrification process of the system, however, the ammonia concentration of experimental group was decreased to the similar level as that in the control group after 32 days of adaptation. Furthermore, the abundance of ammonia oxidizing bacteria in the experimental group increased by 51.43% compared with the control group. The residual sulfadiazine in the fish was 35.23μg/kg, which was below the requirement of national standard, but the copies of sulfadiazine resistance genes1,2 and1 in the water increased by 7.23, 2.74 and 4.12 times. Taking the production performance and environmental friendliness into consideration, the use of antibiotics should be reduced or avoided during the design and operation of aquaponic systems and reasonable alternative measures need to be used to avoid antibiotics induced risks.

aquaponic；sulfadiazine；nitrogen；ammonia oxidizing bacteria；resistance genes

X703

A

1000-6923(2021)04-1697-07

胡浩東(1997-),男,山東泰安人,山東大學(xué)碩士研究生,主要從事廢水處理及其資源化利用.

2020-09-08

國家自然科學(xué)基金資助項(xiàng)目(51878388);山東省重大科技創(chuàng)新工程(2019JZZY010411);山東省優(yōu)秀青年基金項(xiàng)目(ZR2020YQ42)

* 責(zé)任作者, 教授, huzhen885@sdu.edu.cn