Contamination with seawater

Nickel is usually alloyed with elements including copper, chromium, molybdenum and then for strengthening and to improve corrosion resistance for specific applications. Nickel-copper alloys (and copper-nickel alloys see Section 53.5.4) are widely used for handling water. Pumps and valve bodies for fresh water, seawater and mildly acidic alkaline conditions are made from cast Ni-30% Cu type alloys. The wrought material is used for shafts and stems. In seawater contaminated with sulfide, these alloys are subject to pitting and corrosion fatigue. Ammonia contamination creates corrosion problems as for commercially pure nickel. 

Capodaglio, G., Scarponi, G., P. Cescon. Lead contamination of seawaters with different anthropic influence. Ill International Conference "Environmental Contamination", Venice, Sept. 1988, pp. 505-407. 

The first aim of this work was to study the influence of an unwashed membrane filter on the cadmium, lead, and copper concentrations of filtered seawater samples. It was also desirable to ascertain whether, after passage of a reasonable quantity of water, the filter itself could be assumed to be clean so that subsequent portions of filtrate would be uncontaminated. If this were the case, it should be possible to eliminate the cleaning procedure and its contamination risks. The second purpose of the work was to test the possibility of long-term storage of samples at their natural pH (about 8) at 4 °C, kept in low-density polyethylene containers which have been cleaned with acid and conditioned with seawater. 

NSP has been reported from the southeastern coast of the U.S., the Gulf of Mexico, and New Zealand (Ishida et al., 1996). Few cases of NSP occur in the U.S. because of comprehensive monitoring programs that periodically sample shellfish and the waters where shellfish are harvested. If shellfish or seawater samples are contaminated with brevetoxins, harvesting is stopped until the shellfish have depurated the toxin and are again safe to eat. 

Gerba, C. P., Wallis, C., and Melnick, J. L. (1977a). Application of photodynamic oxidation to the disinfection of tapwater, seawater, and sewage contaminated with poliovirus. Photochem. Photobiol. 26, 499-504. 

The half-life with respect to chemical transformation of CH3I in seawater at 20°C was determined to be 20 days, as compared to about 200 days in freshwater (reaction with H20 yielding CH3OH). In a case of a groundwater contamination with several alkyl bromides, Schwarzenbach et al. (1985) reported the formation of dialkyl sulfides under sulfate-reducing conditions in an aquifer. They postulated that in an initial reaction, primary alkyl bromides reacted with HS" by an SN2 mechanism to yield the corresponding mercaptans (thiols) ... 

Reverse Osmosis/Electrodialysis. Very recently, Perdue and co-workers have developed a novel process in which reverse osmosis (RO) is used to remove water from seawater and electrodialysis (ED) is used to desalt seawater. The coupled RO/ED process was developed initially by Koprivnjak et al. (2006) to purify RO-concentrated samples of DOM from freshwaters, which are nearly always contaminated with sulfuric acid (H2S04) and silicic acid (H4Si04). It was possible to remove nearly all H2S04 and H4Si04 from such samples with an average 85% overall recovery of DOC. 

Chlorine is applied in a number of forms from chlorine gas to hypochlorite solution. It is important that the source of chlorine is not contaminated. For example, chlorine gas has been found to be contaminated with carbon tetrachloride, hypochlorite that is stored for a long time gradually breaks down to give chlorate, and hypochlorite generated electrolytically from seawater or brine with a high bromide content can have high concentrations of bromate. 

Several more hours were necessary to establish the lack of significant man-caused radioactive contamination of seawater and bottom sediments accordingly, the monitoring program was re-oriented toward discovering initial indices of marine environment contamination. Underwater radiation monitoring complex PRM-K with 1-... 

To avoid the risk of contamination by seawater, either through direct contamination of the samples or contamination of the magma by assimilation of contaminated material, many authors disregard samples with very low osmium concentrations. Unfortunately, this approach does not remove the inherent ambiguity of interpretation, and it may simply bias the sampling. What is clearly needed are independent measures of very low levels of magma chamber and sample contamination. 

CCI3F (F-11) and CCI2F2 (F-12) shows the bucket samples to be free of contamination. The extraction flask is filled by attaching a stainless steel funnel (1 L) to the flask and filling the funnel with seawater from the bucket. About 650 mL of water is aspirated into the flask without allowing any air to enter. The flask is then pressurized with 15 psi of zero air. The results are equal volumes of air and water equilibrated at 25 °C and 1-atm pressure. Containing the sample under positive pressure reduces contamination... 

The depth at which the water collection bottles are placed provides the hydrostatic driving force to fill the bottles with seawater through the connecting polyethylene tubing. The bottle is designed to fill with seawater from the bottom to the top to carefully exclude air. Thus, the collected seawater can be analyzed for oxygen, pH, salinity, and trace metals. The apparatus is constructed of polyethylene or polypropylene materials to reduce potential trace metal contamination to the sample. The only items not made from plastics are the weights. 

Regarding Diphyllobothrium tapeworms, an increased number of human cases of diphyllobothriasis due to Diphyllobothrium latum was recorded in Europe 48 new cases in France and Switzerland in 2001-2002, contracted by consuming freshwater fish from Leman lake (Dupouy-Camet and Peduzzi 2004 AFSSA 2004). Also, the consumption of seawater fish contaminated with plerocercoid larvae of marine Diphyllobothrium species (Chai et al. 2005) led to human diphyllobothriasis. For instance, D. pacificum (from sea-lions) infects humans in coastal zones of Chile,... 

Depending on the use of the fuel, ash composition has a considerable bearing on whether or not detrimental effects will occur. However, distillate fuels tend to contain only negligible amounts of ash but pick up ash-forming constituents during transportation from the refinery. Water transportation, in particular, presents many opportunities for fuel oils to be contaminated with ash-forming contaminants (seawater, dirt, and scale rust). 

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