Crustaceans, arsenic

Crown thioethers, coordination chemistry, 35 3 (CIO4), 43 226 Crude oil, vanadium in, 35 99 Crustaceans, arsenic in, 44 150, 167, 168, 170 Cryoscopic measurements, sulfuric acid and, 1 390-391... 

The NPN fraction contains other interesting compounds, such as small peptides. Most of them contribute to flavor besides this, they have a powerful antioxidant activity. Betaines are a special group of compounds that contribute to the specific flavors of different aquatic organisms homarine in lobster and glycine-betaine, butiro-betaine, and arsenic-betaine in crustaceans. Arsenic-betaine has the property of fixing arsenic into the structure, giving a useful method for studying water contamination. 

Inorganic arsenic salts are also present in pesticides, herbicides, fungicides, paints, and tobacco plants. If transmitted to water, they accumulate in fish, mollusks, crustaceans, and algae (Johansen et ah, 2000). Transformed into organic salts, they reach the gastrointestinal tract via food and are delivered to liver, spleen, kidneys, and lungs. Arsenic is deposited in skin, nails, and hair. 

The application of high-sensitivity ICP-MS detectors coupled to HPLC has enabled the detection of trace arsenic compounds present in marine animals. Thus, arsenocholine has been reported as a trace constituent (<0.1% of the total arsenic) in fish, molluscs, and crustaceans (37) and was found to be present in appreciable quantities (up to 15%) in some tissues of a marine turtle (110). Earlier reports (46,47) of appreciable concentrations of arsenocholine in some marine animals appear to have been in error (32). Phosphatidylarsenocholine 45 was identified as a trace constituent of lobster digestive gland following hydrolysis of the lipids and detection of GPAC in the hydrolysate by HPLC/ICP-MS analysis (70). It might result from the substitution of choline with arsenocholine in enzyme systems for the biogenesis of phosphatidylcholine (111). 

Preliminary experiments in which HPLC/ICP-MS techniques have been used to monitor arsenic transformations within planktonic crustaceans feeding on a cultured unicellular alga containing arsenosugars at high concentrations have also been unable to demonstrate the production of arsenobetaine (98). Clearly there is much scope for work in this area. 

A. C. Chapman, On the presence of compounds of arsenic in marine crustaceans and shell fish, Analyst, 51 (1926), 548-563. 

The concentrations of the three arsenicals (75-77) were determined in 37 marine organisms comprising algae, crustaceans, bivalves, fish and mammals by high-performance liquid chromatography/inductively coupled plasma mass spectrometry (HPLC/ICPMS) [170]. All three organoarsenics, which occurred at pg/kg concentrations, were detected in 25, 23 and 17 of the 37 samples analyzed, respectively. The limits of detection were 2-3 pg/kg dry mass. The data illustrate that all three compounds are common minor constituents in practically all marine samples. 

Rattanachongkiat, S., Millward, G. E., Foulkes, M. E. Determination of arsenic species in fish, crustacean and sediment samples from Thailand using high performance bquid chromatography (HPLC) coupled with inductively coupled plasma mass spectrometry (ICP-MS). J Environ Monit 2004, 6, 254-261. 

R represents hydrogen atoms, or aliphatic or aromatic organic radicals and X represents an electronegative atom or radical (F, Cl, Br, I, OH, etc.). Arsenous acid is an example of the most oxidized member of Category I, in which one finds, as derivatives, tetraalkyl arsonium compounds, cacodyl derivatives, and esters of arsenous acids. Arsenic acid is an example of the most oxidized members of Category II, and trimethyl arsine oxide (CHjjjAsO is an example of one of the lowest oxidation states. The practically nontoxic compound arsenobetaine is the main form of arsenic in most species of fish and crustaceans (Edmonds and Francesconi 1988). 

The main organic arsenicals in marine fish and crustaceans, arsenobetaine and arsenocholine, are absorbed to a high extent and rapidly excreted via urine. Due to the fast renal elimination they are supposed to be of little toxicity. However, it is almost impossible to make general statements about the toxicity of organic arsenicals because each compound has to be examined separately. In fact there is a considerable lack of data concerning the specific toxicological data about organoarsenic compounds. 

Although marine animals contain many arsenic compounds, most species contain arsenobetaine as the major arsenical. Fish tend to have a simple pattern of arsenic compounds dominated by arsenobetaine. The silver drummer Kyphosus sydney-anus, however, contains trimethylarsine oxide as its major arsenical (25). Crustaceans also generally contain arsenobetaine as a high percentage of their total arsenic. It should be noted, however, that most work on fish and crustaceans has examined the muscle tissue, and the pattern of compounds may be more complex in other tissues (88). 

Environmental fate and behavior, bioavailability, and toxicity of arsenic vary dramatically with the chemical forms (species) in which arsenic exists. While inorganic arsenite [As(III)] and arsenate [As(V)] are highly toxic, mono-methylarsonic acid [MMA(V)] and dimethylarsinic acid [DMA(V)] are less toxic, and predominant arsenic species present in most crustacean types of seafood are essentially nontoxic (1,5-8). Thus, assessments of environmental impact and human health risk sPictly based on measurements of total element concenfiation are not reliable. It is important to identify and quantify individual chemical species of the element (i.e., chemical speciation). 

In tissues of chondrichthyans (fish with a cartilaginous skeleton, such as sharks and rays), many species of marine fish (cod, flatfish, mackerel, herring, salmon and others), crustaceans (e.g. lobsters, shrimps and crabs) and molluscs (e.g. mussels and scallops), arsenobetaine is the main arsenic organic compound. 

The industrial and pharmacological applications of chitin and chitosan have been known for many years and have become an important industrial pursuit because these materials have the three advantages of being abundant, nontoxic, and biodegradable. Chitin and chitosan are produced on an industrial scale from the shells of crustaceans. Chitosans are strong chelators of arsenic and heavy cations, and are used for this purpose in wastewater treatment and in the paper industry (Da Sacco and Masotti, 2010). They have many other applications, however, particularly in the biomedical field, either unaltered or after chemical transformation (depolymerization, alkylation. 

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