Dynamics of dimethylsulfide and dimethylsulfoniopropionate produced by phytoplankton in the Chinese seas - Distribution patterns and affecting factors

Distribution of dimethylsulfide (DMS) and/or particulate dimethylsulfoniopropionate (DMSPp) concentrations in the Jiaozhou Bay, Zhifu Bay and East China Sea were investigated during the period of 1994 - 1998. Both DMS and DMSPp levels showed remarkable temporal and spatial variations. High values occurred in the coastal or shelf waters and low values in the offshore waters. The highest levels were observed in spring or summer and lowest in autumn. DMS or DMSPp distribution patterns were associated with water mass on a large geographical scale, while biological and chemical factors were more likely influential on smaller-scale variations. Diatoms could play an important role in total DMS or DMSPp abundance in coastal waters. Nitrate was found to have a two-phase relationship with DMSPp concentrations: positive when nitrate concentration was lower than 1 mumol/L, and negative when it was above. Anthropogenic factors such as sewage input and aquaculture also showed influences on DMS or DMSPp concentration.

A nitrogen budget of the Changjiang river catchment

Based on 1997-1998 field investigations in the Changjiang river mouth, rain sampling from the river's upper reaches to the mouth, historical data, and relevant literature, the various sources of Total Nitrogen (TN) and Dissolved Inorganic Nitrogen (DIN) in the Changjiang river catchment and N transport in the Changjiang river mouth were estimated. The export fluxes of various form of were mainly controlled by the river runoff, and the export fluxes of NO3-N, DIN and TN in 1998 (an especially heavy flood year) were 1438 103 tonnes (t) yr(-1) or 795.1 kg km(-2) yr(-1) 1746 10(3) t yr(-1) or 965.4 kg km(-2) yr(-1) and 2849 10(3) t yr(-1) or 1575.3 kg km(-2) yr(-1), respectively. The TN and DIN in the Changjiang river came mainly from precipitation, agricultural nonpoint sources, N lost from fertilizer and soil, and point sources of industrial waste and residential sewage discharge, which were about 56.2% and 62.3%, 15.4% and 18.5%, 17.1% and 14.4%, respectively, of the N outflow at the Changjiang river mouth; maximum transport being in the middle reaches.

Organic carbon source and burial during the past one hundred years in Jiaozhou Bay, North China

Organic carbon (OC), total nitrogen (TN), and Pb-210 in core sediment were measured to quantify the burial of organic carbon and the relative importance of allochthonous and autochthonous contributions during the past one hundred years in Jiaozhou Bay, North China. The core sediment was dated using Pb-210 chronology, which is the most promising method for estimation of sedimentation rate on a time scale of 100-150 years. The variation of the burial flux of organic carbon in the past one hundred years can be divided into the following three stages: (1) relatively steady before 1980s; (2) increasing rapidly from the 1980s to a peak in the 1990s, and (3) decreasing from the 1990s to the present. The change is consistent with the amount of solid waste and sewage emptied into the bay. The OC:TN ratio was used to evaluate the source of organic carbon in the Jiaozhou Bay sediment. In the inner bay and bay mouth, the organic carbon was the main contributor from terrestrial sources, whereas only about half of organic carbon was contributed from terrestrial source in the outer bay. In the inner bay, the terrestrial source of organic carbon showed a steady change with an increase in the range of 69%-77% before 1990 to 93% in 2000, and then decreased from 2000 because of the decrease in the terrestrial input. In the bay mouth, the percentage of organic carbon from land reached the highest value with 94% in 1994. In the outer bay, the sediment source maintained steady for the past one hundred years.

Response of the diatom flora in Jiaozhou Bay, China to environmental changes during the last century

The diatom flora in a 164 cm long sediment core obtained from Jiaozhou Bay (Yellow Sea, China) was analyzed in order to trace the response of diatoms to environmental changes over the past 100 years. The sediment core was dated by Pb-210 and Cs-137 and represented approximately 100 years (1899-2001 A.D.). The flora was mainly composed of centric diatoms (59-96%). The concentration of diatoms declined sharply above 30 cm (after similar to 1981 A.D.), while the dominant species changed from Thalassiosira anguste-lineatus, Thalassiosira eccentria, Coscinodiscus excentricus, Coscinodiscus concinnus and Diploneis gorjanovici to Cyclotella stylorum and Paralia sulcata. Species richness decreased slightly, and the cell abundance of warm-water species increased. We argue that these floral changes were probably caused by climate change in combination with eutrophication resulting from aquaculture and sewage discharge. (c) 2007 Elsevier B.V. All rights reserved.

Changes in nitrogen and phosphorus and their effects on phytoplankton in the Bohai Sea

Systematic studies of the changes in dissolved inorganic nitrogen (DIN) and dissolved inorganic phosphorus (DIP) and their effects on phytoplankton over the last 30 years in the Bohai Sea are presented. The amount of sewage disposal, use of fertilizer and the Huanghe River runoff were found to have a significant influence on the DIN or DIP concentrations in the Bohai Sea over the last 30 years. Moreover, the changes in DIN and DIP resulted in changes in the limiting nutrients of phytoplankton in the Bohai Sea from nitrogen in the early 1980s to nitrogen-phosphorus in the late 1980s, and then to phosphorus after the 1990s. In addition, changes in nitrogen and phosphorus had a significant effect on the phytoplankton community structure. The half saturation constant (K (s)) was used to evaluate the effect of nutrients on the phytoplankton community structure in the Bohai Sea over the last 30 years. Cell abundance percentages of dominant phytoplankton species with high K (s) values for phosphorus and low K (s) values for nitrogen have decreased since the 1980s, while those of dominant phytoplankton species with low K (s) values for phosphorus and high K (s) values for nitrogen increased during this period.

Assessment of metal contamination in surface sediments of Jiaozhou Bay, Qingdao, China

An assessment of metal contamination in surface sediments of the Jiaozhou Bay, Qingdao, one of the rapidly developing coastal economic zones in China, is provided. Sediments were collected from 10 stations and a total of 15 heavy metals were analyzed. Concentrations of metals show significant variability and range from 210 to 620 ppm for Ti, 2.7 to 23 ppm for Ni, 4.2 to 28 ppm for Cu, 5.2 to 18 ppm for Pb, 12 to 58 ppm for Zn, 0.03 to 0.11 ppm for Cd, 5 to 51 ppm for Cr, 1.5 to 9.9 ppm for Co, 5.3 to 19 ppm for As, 12 to 32 ppm for Se, and 19 to 97 ppm for Sr. Based on concentration relationships and enrichment factor (EF) analyses, the results indicate that sediment grain size and organic matter played important roles in controlling the distribution of the heavy metals in surface sediments of the Jiaozhou Bay. The study shows that the sediment of the Jiaozhou Bay has been contaminated by heavy metals to various degrees, with prominent arsenic contributing the most to the contamination. The analysis suggests that the major sources of metal contamination in the Jiaozhou Bay are land-based anthropogenic ones, such as discharge of industrial waste water and municipal sewage and run-off. Notably, the elevated heavy metal concentrations of the Jiaozhou Bay sediments could have a significant impact on the bay's ecosystem. With the rapid economic development and urbanization around the Jiaozhou Bay, coastal management and pollution control should focus on these contaminant sources, as well as provide ongoing monitoring studies of heavy metal contamination within the bay.

污泥处理经济评价和污泥堆肥中氧气监测与动态分析

With the continually increase both in the amount of wastewater disposal and in the treatment rate, more and more sewage sludge has been produced. An economic estimate was taken on the different sewage sludge disposal and treatment technologies, and led to the conclusion that compost is an effective way to make sewage sludge harmless, stable and resourceable. Normally, there are several ways to treat sewage sludge, such as landfill, compost, incineration and so on. These technologies will cost 300-1000 Y per ton of sludge. Among those ways, landfill is the cheapest one and operates easily, however, it just postpones the pollution instead of eventually eliminating the pollution; The amount of the sludge will reduce dramatically after incineration, while incineration will take a very high investment in the beginning, at the same time, it's very hard to maintain running; Sewage sludge will be resourceful after composting treantment, thus makes up the treatment cost, makes composting is the most economical way. Compost production is safe when correctly used, compost is a important way to treat sewage sludge. Oxygen is an important control factor in aerobic composting that has great effects on temperature and microorganisms. The gas gathering and transfering system of an online oxygen monitoring system for composting were bettermented to prolong the monitoring system's running period. The oxygen concentration changes in various aerobic composting stage were studied, and conclusions came to that oxygen concentration changes much faster in the oxygen concentration increasing stage than that in the declining stage; the better the aerobic condition is, the sooner the monitoring system starts to work. The minimal oxygen concentration during a ventilation cycle often falls at the beginning, then ascends in the composting period; at the same time, oxygen concentration changes fast in the early composting stage(temperature increasing stage), much slower in the middle stage(continouns thermophilic stage),and seldom changes in the late composting stage(temperature declining stage). With the help of the oxygen realtime-online monitoring system, oxygen concentrations was measured. During the composting period, water contents was analyzed after sampled. It's found that water contents (WC) and Oxygen concentration can both influence the composting process, and the control rule varies in the various composting stages. Essentially, the rule that water and oxygen control the composting process comes from water counterchecks the oxygen transferring to the composting substrate. The most influential factor to the WC and to the oxygen is the components in the composting pile. In the temperature increasing stage, seldom microorganisms exist in the composting pile with low activity, thus oxygen can meet with microorganisms' need, and WC is the dominant factor. In the high temperature (continouns thermophilic) stage, composting process is controlled by WC and oxygen, essentially by WC, at the same time, their influence somehow is not remarkable. In the temperature declining stage, WC and oxygen influence the composting process little. It's also found that the composting process will differ even if under the same components, thus to equably mix the components can avoid WC focusing in some place and let the composting pile to be aerobic. In one sentence, aerobic state is the most important factor in the composting process, suitable bulking material will be useful to the composting control.

贵阳城市污水、河流及养鱼水域抗生素的地球化学行为

抗生素是广泛应用于人类和动物疾病治疗的药物，近年来在养殖业中抗生素更是常常作为动物催长剂。这些抗生素会通过人畜排泄物、药品的丢弃、污水排放、农业废物堆积等途径进入到环境中。环境中抗生素的残留会导致细菌耐药性的产生、微生态平衡的破坏，以及对生态环境和人类难以预知的影响。抗生素污染是近十年来才在国际上引起注意的新型环境问题，目前研究非常薄弱，要深入认识抗生素的环境影响特征就迫切需要对抗生素在环境中的迁移、归宿等地球化学行为进行针对性的研究。本文研究了贵阳城市污水、南明河及乌江渡水库中氯霉素（CAP）、土霉素（OTC）、四环素（TC）和金霉素（CTC）的环境地球化学特征，包括抗生素的分布、迁移特征及影响因素，并分析了贵阳市动物源性食品中抗生素的残留特征，探讨了环境因素对抗生素稳定性及吸附/解吸的影响，以期了解抗生素在环境中的降解、迁移等环境行为的特征，并据此评价抗生素的环境影响特点，为认识抗生素的污染特点、发展相应的控制、治理措施提供科学依据。主要内容包括： 1. 对环境样品中CAP和TCs的前处理过程和检测方法进行了优化。对水样的前处理采用固相萃取的方法，对土壤和沉积物的前处理采用EDTA-McIlvaine振荡萃取、SAX-HLB净化富集的方法；选择HPLC-UV作为分析的手段，对样品中的4种抗生素进行了检测，各化合物得到了很好的分离，该方法简便、快捷、重现性好。 2. 证实了抗生素在城市污水中的普遍存在。贵阳城市污水中以CAP的污染最为突出，其含量明显高于广州地区的城市污水；污水中四环素类药物（TCs）的含量和大多数欧美国家及地区城市污水中TCs的含量相当。这一结果证明，污水中抗生素的污染非常严重，对地表水环境形成严重的威胁。污水中抗生素的来源包括：人服用抗生素药物以及食用含有抗生素残留的食品之后的排泄物；食品中残留的抗生素随剩余食品的丢弃而进入污水。污水中抗生素的含量都具有明显的季节变化规律，冬春季含量明显高于夏秋季，我们认为这与各季节用水量和疾病特点有关。污水中抗生素的大量存在说明：1）抗生素存在滥用的现象，特别是CAP可能存在严重的违法使用，这一现象应当重视；2）污水中的抗生素会威胁水环境质量，应加强处理和控制技术。 3. 证明了城市河流受到多种来源的抗生素影响，其中城市污水是最重要的源，而且抗生素在河流中呈现一定的持久性。南明河上游河段中抗生素的来源包括郊区城镇污水、养鱼场、制药厂污水排放及地表垃圾。城市污水是抗生素的一大排放源，受其影响，排污口下游的河段受到的抗生素污染尤为严重，此外还有来自下游郊区城镇和农业污水的影响。对南明河中抗生素的来源及行为特点的剖析表明：1）抗生素在南明河的水和沉积物中具有不同的分布特征：河水中以CAP的污染最为严重，各水样中CAP的含量基本都高于TCs；而大部分沉积物中TCs的含量都高于CAP。CAP和TCs在水－沉积物之间的分布特征表明，它们在水环境中的地球化学行为明显受到吸附/解吸特点的影响，CAP的亲水性强，而TCs的亲粒性强。2）虽然在养殖业中已禁止使用CAP，但河水和污水中CAP的大量存在，这一结果揭露了CAP仍然存在大量违法使用的事实。3）河水中抗生素含量的季节差异明显，冬春季抗生素的含量高于夏秋季，其原因主要是夏秋季河水流量大，对河水中抗生素的稀释作用强。沉积物中抗生素的含量没有明显的季节变化规律，各季节抗生素的平均含量差异较小。4）受污水影响，各季节排污口下游的南明河水受到的抗生素污染尤为严重，污水口上下游之间的含量差异明显。沉积物在冬季受城市污水的影响大，在排污口下游的抗生素的含量明显高于上游，而春、夏、秋季受污水影响不明显。这可能是因为在春、夏和秋季其它污染源的影响较大，因此污水的影响强度减弱。夏季上游沉积物中CAP的含量甚至高于下游，原因一方面是因为夏季城市污水中抗生素含量低，对南明河的影响减小，另一方面可能因为夏季雨水多、水量大，将上游的地表垃圾以及积累在小河沟中的垃圾冲刷到南明河中，而这些工业及生活垃圾通常是抗生素的一大来源。 抗生素在河流中呈现了一定的持久性，在20 km的范围内水和沉积物显示了明显的污染水平，可能会对水生生态以及流域的环境造成一定的影响。此外，贵阳市南明河两岸的农田通常是用河水进行灌溉的，从而可能使抗生素的污染危及到食物链，对人体的健康有潜在的威胁。 4. 由于食品（如鱼肉、猪肉等）中残留的抗生素是污水中抗生素的重要来源，因此我们研究了养殖业（水产养殖区）中抗生素的环境行为特点，还研究了常见动物源性食品中抗生素的残留特点。对养鱼区的研究表明，养鱼饲料中含有大量的抗生素，是养鱼区水环境中抗生素的来源。由于饲料的颗粒大，且河水流速快，因此饲料中的抗生素不会对水体造成很大的影响，但是在网箱区的沉积物中形成了高含量的残留，除此以外，在乌江渡主航道的河心沉积物中抗生素的含量也相当可观。这说明该区水产养殖的抗生素主要影响沉积物，且相应的污染不是局部的，而会影响到整个养鱼区。从沉积物中抗生素平均含量的季节差异来看，各季TCs的用药量可能不同，秋季的用量可能最大，而其它季节用量相当；CAP在每个季节的用量可能相当。尽管分析的饲料中CAP的含量高于TCs，但在各季节乌江渡水库主航道沉积物中TCs的含量几乎都远高于CAP，这是由于TCs比CAP更易存在于沉积物中。乌江渡水库上下游主航道沉积物中抗生素的含量差异日益减小，说明了乌江渡水库的污染已日益严重。这些抗生素虽然暂时被固定在了沉积物中，活性相对较小，但是在外界条件的影响下，它们的吸附/解吸作用是可以改变的。因此，乌江渡沉积物中高含量的抗生素残留对水生生态环境具有潜在的威胁。 对贵阳市动物源性食品（鱼肉、猪肉和牛奶）中抗生素的残留特征的分析表明，这些食品中普遍残留有高含量的抗生素，被人食用后，其中的抗生素也会被人体摄入，一部分抗生素会随着人的排泄物而进入到污水中，并最终进入环境中；另一部分抗生素会积蓄在人体中，到一定浓度后就会对人体造成伤害。鲩鱼、鲫鱼、鲤鱼、鳙鱼和鲢鱼中CAP、OTC、TC和CTC的平均含量范围分别在57.1～365.5 µg/kg、37.0～60.7µg/kg、34.3～72.4 µg/kg和22.3～68.0 µg/kg之间。秋季的长吻鲍、团头鲂、鲈鱼、长江洄鱼、对虾、黄鳝、泥鳅和猪肉中CAP、OTC、TC和CTC的平均含量分别为88.1 µg/kg、76.8 µg/kg、343.7 µg/kg和34.2 µg/kg；牛奶中的含量分别为4.2 µg/L、1.6 µg/L和2.5 µg/L和22.0 µg/L。 5. 确定了抗生素的稳定性、吸附/解吸作用与各因素的关系，据此可以探讨环境中抗生素的行为特点及机理，并为环境中抗生素的污染防治提供依据。在短时的加热中，TCs发生了部分降解，而CAP却几乎没有发生分解，说明烹饪过程中的加热不能去除食品中的抗生素，这些抗生素则会进入到人体和污水中。当pH在2～8之间时，TCs的性质较稳定；CAP在pH＝1～10的范围内性质都比较稳定。地表和地下水体的pH一般为7左右，说明了水环境中TCs受pH的影响小，而CAP几乎不受影响。在6个月的时间内，TCs在3种介质中都发生了不同程度的降解，但仍有大部分残留；CAP几乎没有发生明显的降解，这说明CAP和TCs的污染具有一定的持久性。TCs的吸附/解吸受颗粒物粒径的影响大，粒径越小，吸附越强；CAP不受影响。这证明了在环境中CAP更易以水溶态的形式存在，而TCs更易吸附在沉积物中。颗粒物中CaCO3含量越高，TC和CTC的吸附越强，证明CaCO3可以用来增强TC、CTC的吸附，这为环境中抗生素的治理提供了一条思路。