长三角地区池塘养殖水产品体内农药类污染与食用风险评价

为了解池塘养殖水产品体内的农药污染情况,以便为水产品质量评价及保障当地居民的饮食健康提供科学依据,本研究采用气相色谱质谱联用法(GC-MS)对长三角地区13个养殖池塘中5类(蟹类、鳖类、蚌类、虾类、鱼类)水产品体内9种有机磷农药(OPPs)、8种有机氯农药(OCPs)以及4种拟除虫菊酯类农药(SPs)进行了检测,并初步分析了其污染来源。结果表明,水产品体内3类农药均有检出,但残留水平均不高,OPPs残留总量为未检出至299 ng·g-1(dw),三唑磷、伏杀硫磷、喹硫磷和毒死蜱较易在水产品体内蓄积;OCPs残留总量为16~82 ng·g-1(dw),主要污染物为六六六(HCHs),主要来自历史残留;SPs残留总量为44~89 ng·g-1(dw),主要污染物为高效氯氟氰菊酯。水产品体内的农药污染可能与养殖池塘中的沉积物污染密切相关。5类水产品体内3类农药的总风险指数(HI)为0.0020~0.046,远小于1,因此,长三角地区由3类农药造成的健康风险处于安全水平。     

Community-Based Technology Transfer in Rural Aquaculture: The Case of Mudcrab Scylla serrata Nursery in Ponds in Northern Samar,Central Philippines

Finding aquaculture development approaches to open up livelihood opportunities for the rural poor and in mainstreaming smallholder fish farmers to reduce poverty remain a challenge. This paper examines the community-based technology transfer mechanism of mudcrab nursery in ponds and its socioeconomic impacts on smallholder mudcrab growers in Northern Samar, Philippines. Results indicated that the technology is a viable enterprise done by a straight culture system method, which is the rearing of crablets from <1.0 to 4.0 cm for 42 days, or by-phases. However, technology adoption hinges on many factors like area ownership, farm distance from household, and market including the type of strategy needed to enhance technology uptake. Collaboration among research and development institutions and local partners is critical in training and empowering rural communities to adopt aquaculture technologies.

Electronic supplementary material

The online version of this article (doi:10.1007/s13280-014-0528-5) contains supplementary material, which is available to authorized users.     

Simulated Impacts of Climate Change on Current Farming Locations of Striped Catfish (Pangasianodon hypophthalmus; Sauvage) in the Mekong Delta,Vietnam

In Vietnam, culturing striped catfish makes an important contribution to the Mekong Delta’s economy. Water level rise during rainy season and salt intrusion during dry season affect the water exchange and quality for this culture. Sea level rise as a consequence of climate change will worsen these influences. In this study, water level rise and salt water intrusion for three sea level rise (SLR) scenarios (i.e., +30, +50, and +75 cm) were simulated. The results showed that at SLR +50, the 3-m-flood level would spread downstream and threaten farms located in AnGiang, DongThap and CanTho provinces. Rising salinity levels for SLR +75 would reduce the window appropriate for the culture in SocTrang and BenTre provinces, and in TienGiang’s coastal districts. Next to increasing dikes to reduce the impacts, the most tenable and least disruptive option to the farming community would be to shift to a salinity tolerant strain of catfish.     

微生物絮凝法处理养鱼污水

以枯草杆菌为絮凝产生菌,优化养鱼污水对其培养条件,探讨其降解污水有机物效果及增殖变化,并讨论分析絮凝活性分布、成分组成。结果表明：pH 6.7～7.8、碳氮比20～40、COD≥85 mg/L养鱼污水（灭菌）培养该菌36 h,其培养液（2 mL投量）对高岭土悬液的絮凝率达39.5%,养鱼污水COD去除率达47.2%,絮凝菌生长良好;该絮凝菌其絮凝活性物质是菌体分泌物,成分主要为多糖。     

螺旋藻增氧系统处理养殖污水与预测模型研究

针对滨海水产养殖区水质差,溶解氧不足造成对虾死亡的问题,以对虾养殖污水为实验对象,分别进行了螺旋藻在不同盐度梯度(0‰、10‰、15‰、20‰、25‰、30‰和35‰)和BOD5浓度水平(20 mg/L(平均)、40 mg/L(上限)、180mg/L(对照)以及不同投藻量(0、50、100和150 mg/L)情况下的增氧效果实验研究,并进一步构建了预测投加螺旋藻后水体中DO等因素变化的数学模型。实验结果表明,螺旋藻在20‰盐度下生物量增长最快,增氧效果在低污染水质条件下效果较好,最佳投藻量为100 mg/L。经过验证,模型拟合度较高,可以用来预测一定水质条件下螺旋藻增氧效果,对今后采用螺旋藻增氧处理养殖污水具有指导意义。     

组合式水生植物净化系统对Cu、Pb和Cd的去除与生物富集特征

选取再力花、美人蕉、水烛、旱伞草、梭鱼草、慈姑、菖蒲、水葫芦和大藻9种植物作为实验植物,构建成以高效净化重金属污染水体为主要功能的组合式水生植物高效净化系统（人工湿地＋生态浮床＋水生植物塘3个处理单元串联而成）,研究不同处理单元中水生植物对重金属Cu、Pb和cd的去除能力及富集特征。结果表明,该净化系统经过为期60d的连续运行,对Cu、Pb和Cd的去除率较为稳定,可分别达到Cu93．5％～96．1％、Ph94．5％～95．2％和Cd95．6％～97．4％,3种重金属出水浓度均可达到GB3838-2002Ⅲ类水排放要求;其中人工湿地单元对重金属去除贡献率最高,Cu、Pb和Cd分别为54．15％、33．61％和44．84％,其次为生态浮床处理单元,Cu、Pb和Cd的去除贡献率分别为38．61％、51．42％和38．56％,而水生植物塘主要起到深度处理作用,对Cu、Pb和cd的去除贡献率分别为7．24％、14．97％和16．6％。9种植物在系统运行期间,生长状况良好,且重金属累积量较高,尤其是生物塘系统中的水葫芦和大藻,实验期间其重金属生物富集系数（BCF）均在200以上。所选植物不同部位对3种重金属的吸收富集能力均表现为根最强。     

尾矿库伴生放射性污染清除水平估算研究

通过RESRAD程序模拟估算了某尾矿库伴生放射性污染清除水平,同时对尾矿库中的232 Th模拟估算参数进行设定,并对剂量约束限值的确定、照射情景分析、照射途径设定、模式参数设定、计算机模拟估算清除水平及估算结果分析等进行了分析研究。结果表明,此尾矿库中232 Th及其长寿命子体所致最大年有效剂量约为10.7mSv/a,超出了预设的0.25mSv/a的剂量约束限值;致癌风险0.023 5,远超出人们的可接受水平;当在剂量约束限值为0.25mSv/a时,此尾矿库土壤中的232 Th清除水平为0.047Bq/g。通过分析表明,该尾矿库开放前,必须采取一定措施,进行清除工作。     

组合式水生植物净化系统对Cu、Pb和Cd的去除与生物富集特征

选取再力花、美人蕉、水烛、旱伞草、梭鱼草、慈姑、菖蒲、水葫芦和大薸9种植物作为实验植物,构建成以高效净化重金属污染水体为主要功能的组合式水生植物高效净化系统(人工湿地+生态浮床+水生植物塘3个处理单元串联而成),研究不同处理单元中水生植物对重金属Cu、Pb和Cd的去除能力及富集特征。结果表明,该净化系统经过为期60 d的连续运行,对Cu、Pb和Cd的去除率较为稳定,可分别达到Cu 93.5%~96.1%、Pb 94.5%~95.2%和Cd 95.6%~97.4%,3种重金属出水浓度均可达到GB3838-2002Ⅲ类水排放要求;其中人工湿地单元对重金属去除贡献率最高,Cu、Pb和Cd分别为54.15%、33.61%和44.84%,其次为生态浮床处理单元,Cu、Pb和Cd的去除贡献率分别为38.61%、51.42%和38.56%,而水生植物塘主要起到深度处理作用,对Cu、Pb和Cd的去除贡献率分别为7.24%、14.97%和16.6%。9种植物在系统运行期间,生长状况良好,且重金属累积量较高,尤其是生物塘系统中的水葫芦和大薸,实验期间其重金属生物富集系数(BCF)均在200以上。所选植物不同部位对3种重金属的吸收富集能力均表现为根最强。     

Antibiotic resistance and genetic diversity of Escherichia coli isolates from traditional and integrated aquaculture in South China

This study investigated antibiotic resistance profiles including antibiotic resistance frequencies, resistance genes and resistance patterns in Escherichia coli strains isolated from traditional and integrated aquaculture systems in South China by using antibiotic susceptibility testing and real time polymerase chain reaction (PCR) technique. The E. coli isolates were found to be resistant to at least one antibiotic among 12 antibiotics. Higher resistance frequencies to ampicillin, sulfamethoxazole, trimethoprime, streptomycin and tetracycline were found compared to the rest antibiotics. Among the 10 tetracycline resistance genes detected in the resistant isolates, the most prevalent tetracycline resistance genes were tetA, tetW and tetB with the frequency of 69.7%, 63.5% and 21.9%, respectively. Three sulfonamide resistance genes were detected in these resistant isolates, with their detection frequencies in the following order: sul2 (55.3%) > sul3 (28.2%) > sul1 (6.2%). Four resistance genes mainly encoding extended-spectrum β-lactamases (ESBLs) were detected in these resistant isolates, with the detection frequencies of blaTEM (28.4%) > blaOXA (9.7%) > blaCTX (9.3%) > blaCARB (5.2%) > blaSHV (0.0%). It was found that the integrated aquaculture system exhibited generally higher prevalence of antibiotic resistance than the traditional aquaculture system. An integrated aquaculture system could facilitate development of bacterial resistance and spread of the antibiotic resistance genes, and consequently become an important reservoir of resistance genes.     

循环水养殖系统中流化床生物滤器净水效果影响因素

为优化流化床生物滤器的工作性能,采用新型填料玻璃珠作为滤器的基质,并将其应用于罗非鱼循环水养殖系统,研究了玻璃珠粒径、床层膨胀率、碱度和氨氮负荷4个可控因素对其处理养殖废水效果的影响。结果表明,流化床生物滤器挂膜23d后生物膜成熟稳定,当床层膨胀率低于160％时,床层增高和填料流失现象不明显。选用0．2～0．4mm粒径的玻璃珠为填料时,对TAN和NO2--N的去除率显著高于以0．4～0．6mm玻璃珠为填料的滤器;随着床层膨胀率的提高,滤器对TAN和NO2--N的去除率逐渐下降,但对TAN的去除负荷有一定的提高;碱度和TAN负荷的增加有利于滤器的硝化作用。流化床生物滤器对养殖水体中的TAN的平均去除负荷和NO2--N的去除率分别可以达到（673．11±23．26）g／（m3·d）和（90．24±3．45）％,显示出较好的硝化性能。