Pollution Marine environment

EPA. 1979. Microbial degradation of organochlorine compounds in estuarine waters and sediments. Proceedings of Workshop Microbial Degradation Pollution Marine Environment. U.S. Environmental Protection Agency, Office of Research and Development, 443-50, 462-76. Document No. 

Table 28.8 Comparison of the Dissolved Concentrations of Trace Metals (nM) in the Ocean Outfall Seawater off the Tanshui Coast and in Other Heavily Polluted Marine Environments around the World. ...

Dixon DR, Pollard D (1985) Embryo abnormalities in the periwinkle, Littorina saxatilis as indicators of stress in polluted marine environments. Mar Pollut Bull 16 29-33 Dixon DR, Prosser H (1986) An investigation of the genotoxic effects of an organotin antifouling compound [bis(tributyltin) oxide] on the chromosomes of the edible mussel, Mytilus edulis. Aquat Toxicol 8 185-195... 

Malins DC, Myers MS, Roubal WT (1983) Organic free radicals associated with idiopathic liver lesions of English sole Parophrys vetulus) from polluted marine environments. Environ Sci Technol 17 679-685... 

Aldener, M., S.S. Brown, H. Stark, E.J. Williams, B.M. Lerner, W.C. Kuster, P.D. Goldan, P.K. Quinn, T.S. Bates, F.C. Fehsenfeld, and A.R. Ravishankara (2006), Reactivity and loss mechanisms of NO3 and N2O5 in a polluted marine environment Results from in situ measurements during New England Air Quality Study 2002, J. Geophys. Res., Ill, doi 10.1029/2006JD007252. 

The marine environment is highly aggressive. Materials in marine service are constantly exposed to water, corrosive salts, strong sunlight, extremes in temperature, mechanical abuse, and chemical pollution in ports. This climate is very severe on ships, buoys, and navigational aids, offshore stmctures such as drilling platforms, and faciUties near the shore such as piers, locks, and bridges. 

There are numerous examples and instances of pollution in the marine environment and a comprehensive coverage would be beyond the scope of a single article. Only a few case studies are presented here. They are global in character and represent examples where public and scientihc concern has been sufficient to provoke strategies to mitigate and/or prevent such pollution. 

As background, Garrod and Whitmarsh describe market failure with respect to protecting the marine environment. Particular difficulties arise because of the diverse and perhaps conflicting exploitation of the sea and its resources. Thus, pollutants may be released into the marine environment by one sector or industry... 

Despite the attractions of economic forces driving environmental protection, some cautions and failures have been noted. Firstly, the export of hazardous waste to countries where costs for treatment are lower enhances environmental risks during transport and has the potential for transboundary export in the event of pollution. At the same time, the loss of raw material may deprive the home market of an adequate supply of feedstock for the home-based industry. Secondly, there is considerable scepticism that self-regulation of TBT-based antifoulants could be achieved in a timely manner by the shipping industry. This is an instance where the cost benehts to one industry are born by another commercial sector, notably aquaculture. Thus, protection of the marine environment is likely to be aided by economic factors but the role of government, via taxation and standard setting, is not likely to be usurped. Public education and, in turn, pressure, can promote and support corporate environmentalism. 

Three factors influence the rate of corrosion of metals—moisture, type of pollutant, and temperature. A study by Hudson (1) confirms these three factors. Steel samples were exposed for 1 year at 20 locations throughout the world. Samples at dry or cold locations had the lowest rate of corrosion, samples in the tropics and marine environments were intermediate, and samples in polluted industrial locations had the highest rate of corrosion. Corrosion values at an industrial site in England were 100 times higher than those found in an arid African location. 

Consultants are equipped to monitor the quality of freshwater, estuarine and marine environments and can make field measurements of a variety of water-quality parameters in response to pollution incidents. For example, reasons for the mortality of marine shellfish and farmed freshwater fish have been determined using portable water-analysis equipment. Various items of field equipment are, of course, also employed in baseline studies and monitoring, respectively, before and after the introduction of new effluent-disposal schemes. 

Sulphur oxides These (SO2 is the most frequently encountered oxide) are powerful stimulators of atmospheric corrosion, and for steel and particularly zinc the correlation between the level of SO2 pollution and corrosion rates is good However, in severe marine environments, notably in the case of zinc, the chloride contamination may have a higher correlation coefficient than SO2. 

The purity of the zinc is unimportant, within wide limits, in determining its life, which is roughly proportional to thickness under any given set of exposure conditions. In the more heavily polluted industrial areas the best results are obtained if zinc is protected by painting, and nowadays there are many suitable primers and painting schemes which can be used to give an extremely useful and long service life under atmospheric corrosion conditions. Primers in common use are calcium plumbate, metallic lead, zinc phosphate and etch primers based on polyvinyl butyral. The latter have proved particularly useful in marine environments, especially under zinc chromate primers . 

Although the corrosivity may not be high provided the condensed moisture remains uncontaminated, this rarely happens in practice, and in marine environments sea salts are naturally present not only from direct spray but also as wind-borne particles. Moreover, many marine environments are also contaminated by industrial pollution owing to the proximity of factories, port installations, refineries, power stations and densely populated areas, and in the case of ships or offshore installation superstructures by the discharge from funnels, exhausts or flares. In these circumstances any moisture will also contain S, C and N compounds. In addition, solid pollutants such as soot and dust are likely to be deposited and these can cause increased attack either directly because of their corrosive nature, or by forming a layer on the surface of the metal which can absorb and retain moisture. The hygroscopic nature of the various dissolved salts and solid pollutants can also prolong the time that the surface remains moist. 

Koeman, J.H. and van Genderen, H. (1970). Tissue levels in animals and effects caused by chlorinated hydrocarbon insecticides, chlorinated biphenyls, and mercury in the marine environment along the Netherlands coast. FAO Technical Conference on Marine Pollution. Rome, December 1970. 

Walker, C.H. and Johnston, G.O. (1989). Interactive effects of pollutants at the kinetic level Implications for the marine environment. Marine Environmental Research 28, 521-525. 

Monteiro LR, Furness RW. 1995. Seabirds as monitors of mercury in the marine environment. Water Air Soil Pollut 80 851-870. 

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