Seawater pollution

Whilst the book will be of obvious interest to anyone concerned with seawater environmental protection, it is believed that it will also be of interest to other groups of workers, including River Authorities who have to implement legal requirements regarding seawater pollution, oceanographers, fisheries experts and politicians who create and implement environmental policies, and the news media, who are responsible for making the general public aware of environmental matters. 

This chapter summarizes the major environmental sources of marine water pollution in the Asian region, marine water chemistry and its changes under an increasing pollution load. We will discuss also the consequences of seawater pollution to various coastal and marine ecosystems in Asia. 

Water pollution is multifaceted. As there is no (chemically) pure water in nature, what constitutes pollution is a difficult issue. Shall we define nonpolluted water to be that fit for human consumption, i.e., potable or drinkable Well, this is too narrow a definition. Seawater, polluted or not, is undrinkable. How about nonpris-tine But can we really define fhe pristine condition No, we cannot. 

S. Goiinstein, S. Moncheva, F. Toledo, P. Arancibia-Avila, S. Trakhtenbeig, A. Gorinstein, I. Goshev, J. Namiesnik, Relationship between seawater pollution and qualitative changes in the extracted proteins from mussels mytilus galloprovincialis. Sci. Total. Environ. 364, 251-259 (2006). doi 10.1016/j.scitotenv.2005.06.013... 

J. Scott, ed.. Desalination of Seawater by Reverse Osmosis, Pollution Technology Review No. 75, Noyes Data Corp., Park Ridge, N.J., 1981. 

Important applications for titanium have been developed in processes involving acetic acid, malic acid, amines, urea, terephthalic acid, vinyl acetate, and ethylene dichloride. Some of these represent large scale use of the material in the form of pipework, heat exchangers, pumps, valves, and vessels of solid, loose lined, or explosion clad construction. In many of these the requirement for titanium is because of corrosion problems arising from the organic chemicals in the process, the use of seawater or polluted cooling waters, or from complex aggressive catalysts in the reaction. 

At present the Earth s temperature is not in thermal equilibrium, i.e., the net OLR is still not as high as generated net heat. Natural cold sinks in water, ground, and atmosphere slow down the effect of thermal pollution. The main sources of natural cold are in water and ice. The total volume of global water is 1.4 x 1018 m3, of which 94% is seawater while 3 x 1016 m3 (2%) of the water is ice in the form of glaciers and ice fields (Singh and Singh, 2001). 

High salt concentrations up to 15-20% can be found in wastewater from dyestuff industries. Moreover, textile manufacturers located on coastal areas can cause pollution of seawater. The biological treatability of wastewater with a high saline concentration is limited because most of the microorganisms that are able to degrade azo dyes are not active in these conditions, in which the selection of halophilic or halotolerant bacteria capable to degrade azo dyes is necessary [79]. 

The third, and largely unexpected, case appeared as a problem in the analysis of petroleum hydrocarbons in seawater [24]. In this case, petroleum hydrocarbons, picked up presumably in the surface layers or surface film, were carried down by the sampling bottles and were measured as par t of the pollutant load of the deeper waters. While the possibility of absorption and subsequent release is obviously most acute with hydrophobic compounds and plastic samplers, it does raise a question as to whether any form of sampler which is open on its passage through the water column can be used for the collection of surface-active materials. The effects of such transfer of material maybe unimportant in the analysis of total organic carbon, but could be a major factor in the analysis of single compounds or classes of compounds. 

Several round-robin intercalibrations for trace metals in seawater [26-30] have demonstrated a marked improvement in both analytical precision and numerical agreement of results among different laboratories. However, it has often been claimed that spurious results for the determination of metals in seawater can arise unless certain sampling devices and practical methods of sampler deployment are applied to the collection of seawater samples. It is therefore desirable that the biases arising through the use of different, commonly used sampling techniques be assessed to decide upon the most appropriate technique ) for both oceanic baseline and nearshore pollution studies. 

Intercomparison of Sampling Devices and Analytical Techniques Using Seawater from a CEPEX (Controlled, Ecosystem Pollution Experiment) Enclosure... 

Brown and Bellinger [123] have proposed an ultraviolet technique that is applicable to both polluted and unpolluted fresh and some estuarine waters. Humic acid and other organics are removed on an ion exchange resin. Bromide interference in seawater samples can be minimised by suitable dilution of the sample but this raises the lower limit of detection such that only on relatively rich (0.5 mg/1 NO3N) estuarine and inshore waters could the method be used. Chloride at concentrations in excess of 10 000 mg/1 do not interfere. 

To overcome the suppression effect of amines in the determination of ammonia, Hampson [56] investigated the effect of nitrite ions added either as nitrite or as nitrous acid. Figure 5.2 indicates that very considerable suppression by nitrite does occur, although it is not as strong as with any of the amines. Again, it is not great so long as the nitrite N concentration is less than the ammonia N concentration, but rapidly increases as the nitrite concentration exceeds the ammonia concentration. In fact, the nitrite modified method was found to be satisfactory in open seawater samples and polluted estuary waters. 

Halliday et al. [396] have described a simple rapid graphite furnace method for the determination of lead in amounts down to 1 xg/l in polluted seawater. The filtered seawater is diluted with an equal volume of deionised water, ammonium nitrate added as a matrix modifier, and aliquots of the solution injected into a tantalum-coated graphite tube in an HGA-2200 furnace atomiser. The method eliminates the interference normally attributable to the ions commonly present in seawater. The results obtained on samples from the Firth of Forth (Scotland, UK) were in good agreement with values determined by anodic stripping voltammetry. 

The results demonstrate that cadmium can be determined directly the direct determination of copper, manganese, and chromium is also possible, but their application is more limited than cadmium. The lead and nickel determination proved to be the most difficult, since their determination is limited by their low sensitivity and by the overlap of their absorption profiles with the background absorbance generated by seawater matrix. The direct determination of lead and nickel by this technique can be used only for seawater samples taken in coastal or estuarine zones that are quite polluted. 

Krznaric [799] studied the influence of surfactants (EDTA, NTA) on measurements of copper and cadmium in seawater by differential pulse ASV. Adsorption of surfactants onto the electrode surface were shown to change the kinetics of the overall electrode charge and mass transfer, resulting in altered detection limits. Possible implications for studies on metal speciation in polluted seawater with high surfactant contents are outlined. 

In recent years, there has been an increasing level of interest in the use of 234Th/238U disequilibrium in the marine environment to study geochemical processes with short time scales (up to 100 days), particularly those associated with carbon cycling in the oceans [34-36] and the partitioning of pollutants between the dissolved and particulate phases [37,38]. However, the analysis of 234thorium is constrained by its short half-life and its low concentration in seawater, so appropriate analytical techniques must be rapid and sensitive and preferably should allow shipboard analysis. 

During the investigation of pollution in coastal seawaters, Werner and Waldichuk [24] pointed out the need for concentrating and isolating trace amounts of certain substances with a continuous solvent extractor. They constructed a modified Scheibel apparatus by changing the organic solvent cycle system. 

Fuoco et al. [539] has reported the analysis of priority pollutants in seawater using online supercritical fluid chromatography, cryotrap gas chromatogra-phy-mass spectrometry. Using this system polynuclear aromatic hydrocarbons and polychlorobiphenyls were measured in seawater with recoveries better than 75%. 

Boylan and Tripp [76] determined hydrocarbons in seawater extracts of crude oil and crude oil fractions. Samples of polluted seawater and the aqueous phases of simulated samples (prepared by agitation of oil-kerosene mixtures and unpolluted seawater to various degrees) were extracted with pentane. Each extract was subjected to gas chromatography on a column (8 ft x 0.06 in) packed with 0.2% of Apiezon L on glass beads (80-100 mesh) and temperatures programmed from 60 °C to 220 °C at 4°C per minute. The components were identified by means of ultraviolet and mass spectra. Polar aromatic compounds in the samples were extracted with methanol-dichlorome-thane (1 3). 

While the major emphasis in the analysis of phenols in seawater has been on those compounds introduced by industrial processes, as much phenolic material is probably added by the disintegration of fixed algae in the intertidal regions. A high value for total phenols, particularly in coastal waters, cannot be interpreted simply as a high degree of industrial pollution the kinds of phenols present must also be ascertained. 

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