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551.
Belias CV Bikas VG Dassenakis MJ Scoullos MJ 《Environmental science and pollution research international》2003,10(5):287-295
GOAL, SCOPE AND BACKGROUND: Over the last decade Greece has become a leading country in the EU as concerns the cage farming of seabream and seabass. A strong debate has risen, however, about the environmental impacts of aquacultures in the coastal areas. The present paper deals with this problem and it is based on measurements of physico-chemical parameters in the water column, particulate matter and sediments in the area of Astakos Gulf, a coastal embayment in western Greece where three big fish farms are currently operating. METHODS: Water samples were collected by using Hydro-Bios sampling bottles, whereas a prototype sediment trap was installed under a fish cage for the collection of particulate matter. Temperature, dissolved oxygen, pH and salinity were measured in situ using portable equipment. Nutrients were determined by standard spectrophotometric methods. Trace metals were determined by Atomic Absorption Spectrometry. Dissolved organic carbon was determined by a Shimadzu 5000A carbon analyzer, whereas organic carbon in sediments was determined titrimetrically. RESULTS AND DISCUSSION: No clear eutrophication incidents have been identified, although the water column near the fish farms was enriched in nutrients and organic carbon. A sludge 'blanket' covers considerable parts of the seabed and is enriched in colloidal organic carbon and trace metals (Cd, Cu, Fe and Zn) that come from unused fish food. The biodegradation of this sludge leads to the development of anoxic conditions followed by the formation of undesirable gases, precipitation or remobilization of metals and the extinction of benthic fauna. CONCLUSION: The operation of fish farms at the coastal area of Astakos Gulf, and probably in similar Mediterranean gulfs, affects the marine environment, particularly in the vicinity of the cages. The most significant influence concerns the near-bottom water layer. The environmental impacts depend on the amount of food given to fishes, the mode of feeding, the fish density in cages, the annual production and the years of unit operation. The hydrology and the geomorphology of the area are also critical factors for its environmental quality. RECOMMENDATION AND OUTLOOK: The success of the fish-farming sector in the Mediterranean is accompanied by environmental and, in some extents, by social and marketing problems. These problems, derived from the rapid development of fish farming, can be solved only through an integrated management, using methods such as environmental impact assessment, risk assessment, economic evaluation, vulnerability assessments, resource accounting, cost-benefit analysis and outcome-based monitoring. 相似文献
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Seasonal Fluctuation in Heavy Metal Pollution in Iran´s Siahroud River - A Preliminary Study (7 pp) 总被引:1,自引:0,他引:1
Charkhabi AH Sakizadeh M Rafiee G 《Environmental science and pollution research international》2005,12(5):264-270
Background The management of its available water resources has become a key issue for Iran. During the last few decades, the water quality
of Siahroud River in the coastal plain of the Caspian Sea in Gilan Province in Northern Iran has significantly degraded. The
scarcity of water has been compounded by rapid population growth and increasing pollution from fertilizers, pesticides, and
municipal and industrial wastes. One of the sources of this degradation is the movement of heavy metals from the river's watershed
into the various water systems supported by the river, including the water system for Rasht City.
Methods To study the magnitude of heavy metal pollution in the Siahroud River, seven heavy metals including Zn, Cu, Pb, Cd, Mn, Fe,
and Ni were measured in duplicate from replicated water samples collected over five consecutive seasons and analyzed by Atomic
Absorption Spectrometry. In situ measurements of pH were taken with the samples and total organic carbon (TOC) was analyzed
by IR gas measurement.
Results The results demonstrated that four of the seven heavy metals including Pb, Fe, Cd, and Mn exceeded permissible safe levels
as established by the United States Environmental Protection Agency. Multivariate factor analysis suggested that industrial
land-use was the main contributing factor for the high levels of Fe and Mn in the Siahroud River, whereas, Cd was principly
from agricultural activities in the watershed. The data also suggested that pH and TOC had an important role in the behaviour
of Pb and Mn, and that the elevated levels of these two heavy metals in Siahroud River was the consequence of other anthropogenic
sources. Only negligible levels of Zn, Cu and Ni were detected. Finally, all the sampling stations were subjected to cluster
analysis. The results indicated that three different zones could be distinguished according to the levels of pollution. In
addition, it was shown that the urban areas did not have a significant impact on the heavy metal pollution in the river. This
observation stems from the fact that the data from the sampling stations before and after Rasht City were not significantly
different.
Recommendation . Preventive measures need to be undertaken in the land-use systems and watersheds of the Siahroud River to reduce the pollution
levels of Pb, Cd, Mn and Fe. 相似文献
556.
宝应县土壤重金属的污染调查 总被引:1,自引:0,他引:1
以宝应县农田土壤重金属调查为依据,采用污染指数法对土壤质量进行评价,分析土壤重金属污染原因,提出防治措施。 相似文献
557.
东京根霉对重金属Cr^3+、Mn^2+和Zn^2+的吸附研究 总被引:5,自引:0,他引:5
张建梅 《环境污染治理技术与设备》2006,7(8):64-68
利用固定化发酵中产生的废菌体——东京根霉(Rhizopustonkinesis)去除废水中Cr^3+、Mn^2+和Zn^2+,研究了预处理、pH、温度、金属离子初始浓度、吸附时间等条件对吸附量的影响。结果表明,用NaOH浸泡4—6h、在pH=5—6,温度25-35℃时吸附效果最好,用Langmuir、Freundlich和Temkin方程对其吸附等温线进行拟合,相关性都比较好;用不同的吸附动力学方程描述东京根霉吸附金属离子的最优和最次模型分别为Elovich方程和一级扩散方程,双常数方程和抛物线扩散方程拟合介于前二者之间。 相似文献
558.
Klumpp A Ansel W Klumpp G Belluzzo N Calatayud V Chaplin N Garrec JP Gutsche HJ Hayes M Hentze HW Kambezidis H Laurent O Peñuelas J Rasmussen S Ribas A Ro-Poulsen H Rossi S Sanz MJ Shang H Sifakis N Vergne P 《Environmental science and pollution research international》2002,9(3):199-203
EuroBionet, the 'European Network for the Assessment of Air Quality by the Use of Bioindicator Plants', is an EU-funded cooperative project currently consisting of public authorities and scientific institutes from 12 cities in 8 countries. In 2000, the bioindicator plants tobacco (Nicotiana tabacum Bel W3), poplar (Populus nigra 'Brandaris'), spiderwort (Tradescantia sp. clone 4430), Italian rye grass (Lolium multiflorum italicum) and curly kale (Brassica oleracea acephala) were exposed to ambient air at 90 monitoring sites according to standardised methods. Visible injuries and growth parameters were assessed and the accumulation of toxic substances in leaves determined. The exposure of tobacco resulted in a gradient with low levels of ozone-induced foliar injury in N and NW Europe, and medium to high values in the southern and central regions. The results of heavy metal and sulphur analyses in rye grass samples generally showed low to very low sulphur and low to medium heavy metal concentrations in leaves. In some cities, however, local hot spots of heavy metal contamination were detected. Analyses of the PAH contents in curly kale leaves gave low to medium values, with locally elevated levels at traffic-exposed sites. 相似文献
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