Enrichment of polycyclic aromatic hydrocarbons (PAHs) in mariculture sediments of Hong Kong

Surface and core sediments collected from six fish farms in Hong Kong and from reference sites were investigated for the enrichment and sources of polycyclic aromatic hydrocarbons (PAHs). Moderately high ∑PAH₁₆ levels (123-947 ng g⁻¹, mean: 450 ng g⁻¹) were found in the surface aquaculture sediments. In comparison with the sediments from the reference sites, the average enrichment percentage of total organic carbon (TOC) and PAHs in surface sediments were 21.4 and 43.8%, respectively, and in the core sediments, 24.6 and 73.7%, respectively. Mathematical source apportionment analyses (i.e. isomer ratios, hierarchical cluster analysis, principal components analysis with multiple linear regression analysis) suggested a higher percentage of petrogenic sources in aquaculture sediments. The fish feeds might be the main source of the enriched PAHs in the aquaculture sediments. To our knowledge, this is the first study showing that PAHs in aquaculture sediments could be attributed to human aquaculture activities.     

Towards Understanding the Impacts of the Pet Food Industry on World Fish and Seafood Supplies

The status of wild capture fisheries has induced many fisheries and conservation scientists to express concerns about the concept of using forage fish after reduction to fishmeal and fish oil, as feed for farmed animals, particularly in aquaculture. However, a very large quantity of forage fish is being also used untransformed (fresh or frozen) globally for other purposes, such as the pet food industry. So far, no attempts have been made to estimate this quantum, and have been omitted in previous fishmeal and fish oil exploitation surveys. On the basis of recently released data on the Australian importation of fresh or frozen fish for the canned cat food industry, here we show that the estimated amount of raw fishery products directly utilized by the cat food industry equates to 2.48 million metric tonnes per year. This estimate, plus the previously reported global fishmeal consumption for the production of dry pet food suggest that 13.5% of the total 39.0 million tonnes of wild caught forage fish is used for purposes other than human food production. This study attempts to bring forth information on the direct use of fresh or frozen forage fish in the pet food sector that appears to have received little attention to this date and that needs to be considered in the global debate on the ethical nature of current practices on the use of forage fish, a limited biological resource.     

光合细菌净化养殖池水质的模拟研究

从淡水养鱼池塘底泥中分离得到１株光合细菌。在实验室模拟研究了菌液投加量、光照条件、温度、盐度、常用水产杀虫剂硫酸铜、敌百虫用量对净化养殖池水质效果的影响，结果表明：菌表明：菌液适宜投加量为１０ｍｇ／Ｌ；光照状态下净化效果优于黑暗状态；温度低于１５℃，氯化钠投加量高于１００００ｍｇ／Ｌ，硫酸铜投加量高于０．４ｍｇ／Ｌ，敌百申诉凤加量高于２．０ｍｇ／Ｌ时，净化效果均明显下降。     

新丰江水库欧洲鳗网箱养殖对水质的影响

网箱养殖欧洲鳗使养殖区其周围水体中ＣＯＤ、总氮、总磷等污染物浓度明显升高，尤其大肠杆菌指标不能满足渔业水质标准，富营养化状态这中营养化水平。网箱养鳗过程输入氮的６１．０％，磷的７７．４％都积留于库内，造成局部水域氮磷负荷已明显高于可接受负荷荷甚至拉近危险负荷。     

Evaluating aquacultural use of thermal effluents: An application of system dynamics to environmental problem solving

Given the ecological burden imposed by power plants located in the coastal zone, efforts to improve the marginal benefits realized from their operation are warranted. Indeed, if this source of environmental pollution can be utilized to compensate for past ecological damage, then the benefits will be magnified many-fold.This study addresses the economic feasibility of utilizing heated effluent water from power plants to invigorate the growth of oysters raised under controlled conditions. The preliminary findings indicate that given proper combinations of system capacity, supplemental nutrient supplies, sea water flow and temperature gradients, such an operation is feasible.This is also a demonstration of a viable application of a sophisticated computer modeling approach to environmental problems. System Dynamics a technique pioneered at the Massachusetts Institute of Technology, is applied to evaluate the physical, biological, and economic interrelationships of the aquacultural system variables. It offers many advantages for the environmental manager and researcher, a number of which are realized in the present investigation.     

Energy economy of salmon aquaculture in the Baltic sea

Resource utilization in Atlantic salmon aquaculture in the Baltic Sea was investigated by means of an energy analysis. A comparison was made between cage farming and sea ranching enterprises each with yearly yields of 40 t of Atlantic salmon. A variety of sea ranching options were evaluated, including (a) conventional ranching, (b) ranching employing a delayed release to the sea of young smolts, (c) harvesting salmon both by offshore fishing fleets and as they return to coastal areas, and (d) when offshore fishing is banned, harvesting salmon only as they return to coastal areas where released. Inputs both from natural ecosystems (i.e., fish consumed by ranched salmon while in the sea and raw materials used for producing dry food pellets) and from the economy (i.e., fossil fuels and energy embodied in economic goods and services) were quantified in tonnes for food energy and as direct plus indirect energy cost (embodied energy). The fixed solar energy (estimated as primary production) and the direct and indirect auxiliary energy requirements per unit of fish output were expressed in similar units. Similar quantities of living resources in tonnes per unit of salmon biomass output are required whether the salmon are feeding in the sea or are caged farmed. Cage farming is about 10 times more dependent on auxiliary energies than sea ranching. Sea ranching applying delayed release of smolts is 35–45% more efficient in the use of auxiliary energies than conventional sea ranching and cage farming. Restriction of offshore fishing would make sea ranching 3 to 6.5 times more efficient than cage farming. The fixed solar energy input to Atlantic salmon aquaculture is 4 to 63 times larger than the inputs of auxiliary energy. Thus, cage farming and sea ranching are both heavily dependent on the productivity of natural ecosystems. It is concluded that sustainable development of the aquaculture industry must be founded on ecologically integrated technologies which utilize the free production in marine ecosystems without exhausting or damaging the marine environment.     

Occurrence, distribution and risk assessment of antibiotics at various aquaculture stages in typical aquaculture areas surrounding the Yellow Sea

The pollution of antibiotics commonly existed throughout the entire aquaculture process,but the residues of antibiotics at different aquaculture stages have rarely been studied. This study investigated the occurrence, distribution and risk assessment of antibiotics at different aquaculture stages (the non-aquaculture stage, the early aquaculture stage, the middle aquaculture stage, and the late aquaculture stage) in two typical marine aquaculture areas (Mahegang River and Dingzi Bay) surrounding the YellowSea. Fluoroquinolones and tetracyclineswere commonly used antibiotics in the aquaculture of these areaswith high detection frequencies (17% to 83%). Compared among four aquaculture stages, the highest concentration of antibiotics (9032.08 ng/L) in aquaculture ponds was detected at the late aquaculture stage. And the antibiotic pollution level of natural water was directly related to the aquaculture stages. Similarly, at the aquaculture stages, the detection frequency of antibiotics in sediments was higher than that at the non-aquaculture stage. Based on the correlation analysis, the concentration of main antibiotics in water showed a positive correlation with total nitrogen (p<0.05) and chlorophyll a (p<0.01), while it showed a negative correlation with salinity (p<0.01) in coastal water of the Dingzi Bay. According to the risk assessment,with the development of aquaculture stages, the selection pressure of fluoroquinolones and tetracyclines on resistant bacteria had increased. And the ecological risks caused by sulfonamides and tetracyclines to aquatic organisms had also increased markedly. Overall, this study may provide a reference for formulating regulatory policies regarding antibiotic use at different aquaculture stages.     

Occurrence and distribution of antibiotics in coastal water of the Bohai Bay, China: impacts of river discharge and aquaculture activities

The presence of 21 antibiotics in six different groups was investigated in coastal water of the Bohai Bay. Meantime, to illuminate the potential effects caused by the river discharge and aquaculture activities, wastewater from three breeding plants and surface water from six rivers flowing into the Bohai Bay were also analyzed for the selected antibiotics. The result revealed that measured antibiotics in the North Bobai Bay were generally higher than those in the South, highlighting the remarkable effects of high density of human activities on the exposure of antibiotics in environment. The antibiotics found in the six rivers were generally higher than those in the Bohai Bay reflecting the important antibiotics source of river discharge. This study reveals that the high consumption of some antibiotics in aquaculture activities may pose high ecological risk to the bay.     

在线固相萃取-液相色谱串联质谱法测定污水厂尾水中6种酸性药物

建立了大体积在线固相萃取-液相色谱串联质谱（Online-SPE-LC-MS）检测污水厂尾水中6种酸性药物的方法。10 mL水样采用0.45 μm微孔滤膜过滤后经自动进样器直接在线上样,经Atlantis T3柱（100 mm×4.6 mm×3 μm）富集,Atlantis T3柱（100 mm×2.1 mm×2.6 μm）色谱分离,ESI-/ESI+源同步切换扫描,多反应监测（MRM）模式对布洛芬、酮洛芬、双氯芬酸钠、吲哚美辛、苯扎贝特、卡马西平进行同时定量分析。基于外标法和标准加入法进行分析以消除基质效应。结果显示,6种酸性药物在0.1~200 ng/L范围内线性相关性较好（r≥0.996 4）,检出限（LOD）为0.01~0.16 ng/L,定量限（LOQ）为0.02~0.52 ng/L,加标回收率为94.3%~102%,相对标准偏差（RSD）为0.49%~10.1%。该法采用10 mL大体积进样,前处理简单、快速且重现性好,可有效实现污水厂尾水中6种酸性药物的定量分析。     

复合型人工湿地模型对污水厂尾水的深度净化效果

采用由一级垂直流湿地、连续的4级沉水植物氧化塘和二级垂直流湿地组成的复合型人工湿地处理小城镇污水处理厂尾水。结果表明,在0.13 m3.m-2.d-1水力负荷条件下,模型出水仅ρ(CODCr)和ρ(氨氮)(以NH4+-N计)达到地表Ⅲ类水标准(GB 3838—2002);但当进水ρ(TP)达到《城镇污水处理厂污染物排放标准》(GB18918—2002)一级B标准时,出水ρ(TP)亦达到地表Ⅲ类水标准。当二级垂直流湿地水力负荷调整为0.06 m3.m-2.d-1时,出水ρ(TP)和ρ(TN)最终都达到地表Ⅲ类水标准。认为水体中TN主要通过一级垂直流湿地的过滤吸附和二级垂直流湿地的反硝化作用去除,而TP则主要以一级垂直流湿地中石灰石的吸附沉降方式来去除。