ASAM CYANURAT, KEMBARAN MELAMINE

Asam cyanurat, senyawa yang serupa dengan melamine. Biasa dipakai sebagai pelunak/conditioner air di kolam renang. Juga banyak dipakai sebagai bahan pencemar pet foods. USDA dan FDA lembaga resmi amerika serikat yang mengatur perdagangan produk pangan dan produk pertanian, menyatakan efek melamine dan produk serupa (asam cyanurat) terhadap manusia belum diketahui. Demikian pula interaksi melamine dan asam cyanurat terhadap manusia belum jelas. namun dilaporkan 16 pets mati dan ratusan lainnya sakit dan sebagian mati, yang diduga terkait erat dengan tainted pet foods (pet foods tercemar oleh asam cyanurat). Tanpa ada penyelidikan lebih lanjut. Asam cyanurat dan melamine banyak dipakai sebagai bahan pencemar pada gluten gandung dan protein konsentrat beras. Dimana gluten dan protein konsentrat beras sebagai bahan baku utama pet foods.

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Metabolism/Pharmacokinetics of MELAMINE

Absorption, Distribution & Excretion:
… A single oral dose of 0.025 mCi (0.38 mg) [14C]melamine /was administered/ to adult male Fischer 344 rats. Within the first 24 hr, 90% of the administered dose was excreted in the urine. Negligible radioactivity appeared in breath and feces. There was little difference in blood, liver or plasma concentrations of 14C, suggesting that melamine distributes in body water. The only organs showing radioactivity levels much higher than plasma were the kidney and bladder. The bladder level was by far the highest, a finding probably due either to back diffusion from urine or to contamination of bladder tissue with urine. Virtually no residual radioactivity was observed in tissues examined at 24 hr or later. The elimination-phase half-life calculated from plasma data, 2.7 hr, was in good agreement with the urinary-excretion half-life of 3.0 hr. The renal clearance of melamine was 2.5 mL/min.
[Mast RW et al; Food Chem Toxicol 21 (6): 807-10 (1983) ]**PEER REVIEWED** PubMed Abstract

… Following oral administration of 250 mg/kg melamine to rats, 50% of the mother compound was excreted with the urine within 6 hrs. … Crystals found in the urine were composed of dimelamine monophosphate, amounting to nearly 20% of the administered dose. After feeding melamine to dogs, 60 – 86.5% of the mother compound was recovered in the urine within 24 hrs. …
[European Chemicals Bureau; IUCLID Dataset, Melamine (CAS # 108-78-1) p.79 Available from the Database Query page at: http://ecb.jrc.it/esis/esis.php as of June 26, 2007. ]**PEER REVIEWED**

Doses of 2.4 g/kg cause diuresis & elimination of fine crystals of dimelamine monophosphate in urine.
[Lefaux, R. Practical Toxicology of Plastics. Cleveland: CRC Press Inc., 1968., p. 330]**PEER REVIEWED**

After administration of a single oral dose of 0.38 mg (14)C-melamine to adult male Fischer 344/N rats, 90% of the administered dose was excreted in the urine within the first 24 hours. Negligible radioactivity was detected in exhaled air and feces; and radioactivity was concentrated in the kidney and bladder. Virtually no residual radioactivity was observed in tissue after 24 hours or more. Chromatography of the radioactivity found in plasma or urine indicated that melamine is not metabolized in rats.
[IARC. Monographs on the Evaluation of the Carcinogenic Risk of Chemicals to Man. Geneva: World Health Organization, International Agency for Research on Cancer, 1972-PRESENT. (Multivolume work)., p. V39 340 (1986)]**PEER REVIEWED**

sources: Hazardous Substances Data Bank

MELAMINE On Human Health Effects:

Evidence for Carcinogenicity:
Evaluation: There is inadequate evidence in humans for the carcinogenicity of melamine. There is sufficient evidence in experimental animals for the carcinogenicity of melamine under conditions in which it produces bladder calculi. Overall evaluation: In making the overall evaluation, the Working Group noted that a non-DNA reactive mechanism by which melamine produced urinary bladder tumors in male rats occurred only under conditions in which calculi were produced. Melamine is not classifiable as to its carcinogenicity to humans (Group 3).
[IARC. Monographs on the Evaluation of the Carcinogenic Risk of Chemicals to Man. Geneva: World Health Organization, International Agency for Research on Cancer, 1972-PRESENT. (Multivolume work)., p. 73 336 (1999)]**PEER REVIEWED**

Human Toxicity Excerpts:
/HUMAN EXPOSURE STUDIES/ HUMAN SUBJECTS WERE GIVEN PATCH TESTS WITH MELAMINE. NO EVIDENCE OF EITHER PRIMARY IRRITATION OR SENSITIZATION WAS FOUND.
[Bingham, E.; Cohrssen, B.; Powell, C.H.; Patty's Toxicology Volumes 1-9 5th ed. John Wiley & Sons. New York, N.Y. (2001)., p. 4:1337]**PEER REVIEWED**

/SIGNS AND SYMPTOMS/ SUMMARY TOXICITY STATEMENT: ACUTE… MODERATE VIA ORAL ROUTE. MODERATE= MAY CAUSE REVERSIBLE OR IRREVERSIBLE CHANGES TO EXPOSED TISSUE, NOT PERMANENT INJURY OR DEATH; CAN CAUSE CONSIDERABLE DISCOMFORT.
[Sax, N.I. Dangerous Properties of Industrial Materials. 5th ed. New York: Van Nostrand Rheinhold, 1979., p. 791]**PEER REVIEWED**

/CASE REPORTS/ DERMATITIS HAS BEEN REPORTED FROM MFR OF MELAMINE FORMALDEHYDE RESINS & GLUES. IT IS PROBABLE THAT THESE CASES WERE CHIEFLY DUE TO FORMALDEHYDE OR INTERMEDIATE REACTION PRODUCTS OF FORMALDEHYDE & MELAMINE.
[Bingham, E.; Cohrssen, B.; Powell, C.H.; Patty's Toxicology Volumes 1-9 5th ed. John Wiley & Sons. New York, N.Y. (2001)., p. 4:1337]**PEER REVIEWED**

Probable Routes of Human Exposure:
MELAMINE ITSELF DOES NOT SEEM TO BE IMPORTANT INDUSTRIAL HAZARD EXCEPT IF DECOMP BY HEAT. …SKIN SHOULD BE KEPT FREE FROM UNREACTED RESINS…
[International Labour Office. Encyclopedia of Occupational Health and Safety. Volumes I and II. New York: McGraw-Hill Book Co., 1971., p. 852]**PEER REVIEWED**

NIOSH (NOES Survey 1981-1983) has statistically estimated that 43,104 workers (6,239 of these are female) are potentially exposed to melamine in the US(1). Occupational exposure to melamine may occur through inhalation and dermal contact with this compound at workplaces where melamine is produced or used. Monitoring data indicate that the general population may be exposed to melamine via ingestion of contaminated food(SRC).
[(1) NIOSH; NOES. National Occupational Exposure Survey conducted from 1981-1983. Estimated numbers of employees potentially exposed to specific agents by 2-digit standard industrial classification (SIC). Available at http://www.cdc.gov/noes/ as of Jun 26, 2007. ]**PEER REVIEWED**

Source: Hazardous Substances Data Bank : http://toxnet.nlm.nih.gov/cgi-bin/sis/search/r?dbs+hsdb:@term+@na+Melamine