A comparison of fish tissue mercury concentrations from homogenized fillet and nonlethal biopsy plugs

The use of biopsy plugs to sample fish muscle tissue for mercury analyses is a viable alternative to lethal sampling; however, the practice has yet to be widely implemented in routine monitoring due to concerns about variability of mercury concentrations in fish muscle tissues. Here we examine distribution of mercury in fillets of four fish species (Walleye, Northern Pike, Smallmouth Bass and Lake Trout), suitability of left/right side of fillet for biopsy sampling, and appropriateness of re-using a biopsy punch. The results showed that average mercury concentrations in left and right fillets of fish are similar. Mercury concentrations in biopsy plug samples, taken from the anterior dorsal area of the fish fillet, were statistically equivalent to the mercury concentrations in homogenized fillets. There was no discernible cross contamination between samples when a biopsy punch was reused after washing in hot soapy water, and as such, biopsy punches can be recycled during sampling to reduce the sampling cost. If a tissue mass collected from a specific site on the fillet is insufficient, then we suggest sampling corresponding locations on the other fillet rather than sampling two adjacent sites on one fillet to obtain more tissue. The results presented here can improve the accuracy of fillet biopsy plug sampling, minimize fish mortality for mercury monitoring, and reduce labor and material costs in monitoring programs.     

Municipal wastewater-induced histopathological lesions in gills of freshwater fish Labeo rohita – A SEM study

The fingerlings of fish Labeo rohita were subjected to chronic (15, 30, and 60 days) and recovery (60 days) experiments for histopathological studies using sublethal concentrations (35.4%, 26.6%, and 17.7% v/v) of municipal wastewater of Tung Dhab drain, Amritsar, India. Control fish were maintained for same exposure periods using tap water. Scanning electron microscopic studies exhibited dose- and duration-dependent alterations on gill surface ultra-structure. Control fish exhibited functionally normal gills with normal mean degree of tissue change. Fifteen different types of lesions were identified out of which 9, 5, and 1 were of the stage I, II, and III, respectively. The mean degree of change values in the treated groups ranged from 14.8 ± 0.5 (17.7%, 15 days) to 116. ± 17 (35.4%, 60 days) demonstrated gill damages of slight to irreparable lesions. The recorded alterations were epithelial lifting and intraepithelial edema, reduction of water spaces, lamellar fusion, lamellar telangiectasia, swelling and fusion of filaments, sloughing of lamellar epithelium, hypertrophy and hyperplasia of mucous and chloride cells, and necrotic lamellae. The recovery experiments showed positive improvement as the intensity of damage was less than recorded for 60 days of treatment. This study clearly indicated toxicity of drain water to fish at cellular and organ level. The study recommends environmental agencies to make and enforce decisions regarding improvement of water quality of Tung Dhab drain, and further incorporating histopathological studies as an analytical tool.     

镉致背角无齿蚌消化腺组织损伤及调节消化腺和斧足的抗氧化酶活性

采用酶学和组织学方法,研究了镉(Cd)对背角无齿蚌(Anodonta woodiana)消化腺和斧足组织中超氧化物歧化酶(SOD)和过氧化氢酶(CAT)活性和组织形态结构的影响.Cd浓度设置为4.22、8.43、16.86、33.72和67.45 mg·L-1,处理时间为24 h、48 h、72 h和96 h.结果显示,与对照组相比,同一时间随着Cd浓度的增加,消化腺中SOD和CAT活性,在24 h呈现升高的趋势;96 h消化腺中SOD活性逐渐升高,差异极显著(p0.01);48 h和72 h呈现先升后降的趋势.斧足中SOD和CAT在72 h和96 h时活性升高明显,差异显著或极显著(p0.01,p0.05).Cd浓度67.45 mg·L-1处理24 h,消化腺组织细胞结构变化不明显;在48 h以后,消化管间结缔组织松散,腺体结构损伤严重,上皮细胞形态结构异常,细胞界限模糊,甚至消失;细胞膜肿胀、变形;有的细胞核碎裂、明显肿胀甚至消失,上皮细胞部分与基膜分离、脱落;斧足组织未出现显著变化和损伤.研究表明,消化腺在酶活性和组织结构上对镉的反应较快且更具规律性,而且具有明显的时间和剂量效应关系.但是,斧足对镉的胁迫反应与消化腺相比较为迟缓,说明组织之间对重金属的敏感性具有差异性.     

好氧处理工艺传质强化的机理与应用研究

依据惯性效应理论研究了传统污水好氧处理工艺传质强化过程.研究表明,提高传统工艺曝气均匀度和控制多相物系中微涡漩的离心惯性效应,可有效促进物相接触传质和相界面更替,为活性污泥(或生物膜)有机底质与氧气进行生化反应提供良好动力条件,从而提高反应效率,缩短生化反应历程.该工艺在试验及实际工程应用中氧利用率最高可达48%,COD容积负荷8.1-9.0 kg/(m3@d).在处理屠宰废水的实际应用中,当气水比为12∶1,水力停留时间4 h,进水COD Cr浓度800-2200 mg/L,CODCr负荷达8-9 kg/(m3@d)时,COD Cr去除率平均达95%,BOD 5去除率大于97%,SS去除率在95%以上.     

丹参冠瘿组织培养特性及培养动力学研究

研究了丹参冠瘿组织悬浮培养过程的培养特性及细胞的生长和丹参酮的合成规律,并建立了丹参冠瘿组织生长、底物消耗和产物积累的分相动力学模型,模型计算结果与实验值吻合较好．丹参冠瘿组织悬浮培养系,由淡黄色、近圆形、ｄ ５～１０ ｍｍ 的颗粒组成,培养液纯清;丹参冠瘿组织生长周期Ｔ＝２０ ～２５ ｄ,３ ～７ ｄ 近似为指数生长期, 比生长速率μ＝０ ．１６ ｄ－１ ,７ ～１３ ｄ 近似为恒速生长期,生长速率ｄＣＸｄｔ ＝ ０．６９ ｇ Ｌ－１ ｄ－１ ;１３～２１ ｄ 为减速生长期．ｄ ２１ 达最大生物质量浓度ＣＸ,ｍａｘ ＝１０．９ ｇ Ｌ－１ , 丹参酮积累质量浓度Ｃｐ＝ ８．４ ｍｇ Ｌ－１ ．     

两种通气组织不同的水稻品种根表铁膜的形成及砷吸收积累的差异（Differences of Iron Plaque Formation and As Accumulation between Two Rice Cultivars with Different Aerenchyma Tissue）

采用土壤盆栽试验方法,比较了两种通气组织结构不同的水稻品种(扬稻6号和农垦57)根表铁膜的形成及其吸收积累As的差异.结果表明,通气组织结构不同对水稻根表铁膜的形成及其对As的吸收积累有显著影响.通气组织结构发达的扬稻6号根表铁膜数量和铁膜中As含量均显著高于农垦57,扬稻6号根表铁膜量为431.53g·kg-1,铁膜中As含量达到220.2mg·kg-1,分别是农垦57的1.3和1.7倍.发达的通气组织结构显著抑制了As由水稻地下部到地上部的转运以及地上部对As的吸收:扬稻6号地上部As含量为10.77mg·kg-1,显著低于农垦57(12.85mg·kg-1);扬稻6号对As的转移系数(TF)为0.067,仅为农垦57的73.6%.     

Occurrence and dietary exposure assessment of PFOS and PFOA in cultured Trachinotus ovatus in China

In this study, investigation was conducted into concentrations of perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA) in Chinese farmed Trachinotus ovatus between 2014 and 2015 using a modified QuEChERS (Quick, Easy, Cheap, Effective, Rugged and Safe) and ultra fast liquid chromatography-tandem mass spectrometry (UFLC-MS/MS) method. The tissue distribution (muscle, skin, liver, kidney and gill) in Trachinotus ovatus was also assessed. The detection frequencies of PFOS and PFOA in fish were 92% and 3%, respectively, and the mean concentrations were 0.392 and 0.015 μg/kg wet weight. The analysis of PFOS distribution in different tissues in Trachinotus ovatus showed the following trend: skin> gill> kidney> liver> flesh. Results revealeded farmed Trachinotus ovatus in China to generally be contaminated with PFOS. Moreover, the average daily intake for Chinese urban residents calculated on the basis of pollution content was 0.268 ng/kg body weight/d (PFOS) and 0.014 ng/kg body weight /d (PFOA), respectively. Both hazard ratio values were less than 1, indicating that exposure levels of PFOS and PFOA through Trachinotus ovatus consumption may not lead to adverse health effects in the Chinese population.     

汞污染地区粮食对大鼠脑组织氧化损伤影响

应用典型汞矿和典型化工厂粮食对大鼠进行暴露,研究了大鼠脑组织中MAD、SOD、GSHPx以及脑汞含量的变化情况。结果表明,与对照组相比,经过7d暴露后,清镇组大鼠及万山组大鼠脑汞蓄积均出现显著性差异(清镇,p<0.05;万山,p<0.01)。生理生化指标结果表明,暴露3d后,清镇组脑组织GSHPx与对照组相比有显著差异(p<0.05);暴露7d后,万山组脑组织GSHPx及MDA与对照组相比有显著性差异(GSHPx,p<0.05;MDA,p<0.01),清镇组脑组织各指标与对照组相比均有显著性的差异(p<0.05),证明经7d暴露后,大鼠脑组织中已产生脂质过氧化损伤。进而表明上述两处典型汞污染地区汞污染极为严重,可能已经通过食物链严重影响到当地公众健康与安全。     

曝气强化微生物功能菌修复黑臭水体

从成都市三道沟黑臭底泥中分离出一株能以底泥有机质为碳源和能源生长的土著微生物功能菌HC-1,经鉴定该菌株为不动杆菌（Acinetobacter）。在实验室条件下,以三道沟黑臭底泥为研究对象,采用微生物功能菌强化底泥有机质降解来修复黑臭水体的方法。研究了底泥曝气和上覆水曝气对黑臭水体修复效果的影响。研究表明,投加土著微生物功能菌并结合底泥曝气能够明显改善上覆水水质,加快底泥的修复。使用间歇曝气协同土著微生物功能菌作用时效果和连续曝气相近,且可降低运行成本。实验15 d后,上覆水COD、NH3-N和TP去除率分别达67.6%、71.6%和92.2%,底泥有机质的降解速率提高了30%,底泥微生物活性增加5倍。     

气相色谱法测定鱼组织中的久效磷

采用气相色谱法氮磷检测器测定鱼肉和内脏中的久效磷含量。鱼肉或内脏匀浆后，用正己烷洗涤，二氯甲烷提了，以内标法定量分析，方法简单，灵敏，准确。当取鱼组织0．5g时，方法检测限为0．002mg/kg，加标回收率为72．6％－83．3％，相对标准差在3．3％－7．0％之间。