[ORGANOPHOSPHORUS FLAME RETARDANTS - TOXICITY AND INFLUENCE ON HUMAN HEALTH]. / FOSFOROWE ZWIAZKI ORGANICZNE ZMNIEJSZAJACE PALNOSC - TOKSYCZNOSC I WPLYW NA ZDROWIE LUDZI.

Organophosphorus flame retardants (flame retardants, FRs) have been used for several decades in many industries, including the production of dyes, varnishes, adhesives, synthetic resins, polyvinyl chloride, hydraulic fluids, plastics and textiles. Their importance in recent times has increased due to i.a., significantly reduced use of polybrominated diphenyl ethers (PBDEs) - persistent organic pollutants, dangerous for the environment. The aim of this study was to review the available literature data concerning phosphorous FRs primarily for neurotoxic, fertility, reproductive and carcinogenic effects. The analysis concerned the following most commonly used substances: tris(2-ethylhexyl)phosphate (TEHP), tris(2-butoxyethyl)phosphate (TBEP), triphenyl phosphate (TPP), tris(2-chloroethyl)phosphate (TCEP), tetrakis(hydroxymethyl)-phosphonium chloride (THPC), tributyl phosphate (TBP), tricresyl phosphate (TCP), tris(2-chloroisopropyl)phosphate (TCPP), tris(1,3-dichloroisopropyl)phosphate (TDCP) and tetrakis(hydroxymethyl)phosphonium sulphate (THPS). In animal studies neurotoxic effects were found after exposure to TBEP, THPC, TBP and TCP, while in humans they were observed only after exposure to TCP. TCEP, THPS, TBP, TCP and TDCP caused disorders in fertility and/or fetal development of animals. Adverse effects on reproduction in humans may be caused by TPP, TCP, and TDCP. In laboratory animals the development of tumors was observed after high doses of TEHP, TCEP, TBP and TDCP. None of these compounds is classified as a human carcinogen. The environmental toxicity of phosphate FRs is low (except for TPP, TCEP and TBEP). They are not stable compounds, in living organisms they are metabolised and quickly excreted. Therefore, they can be used as an alternative to PBDEs.

Selected oxidative stress parameters after single and repeated administration of octabromodiphenyl ether to rats.

OBJECTIVES: Octabromodiphenyl ether (OctaBDE) was used as a flame retardant applied mostly in the manufacture of plastics utilized in the electrical and electronic industries. Owing to its long half-life and being regarded as an environmental pollutant, OctaBDE, like other polybrominated diphenyl ethers, has been classified as a persistent organic pollutant (POP). This study was carried out to assess the effects of oxidative stress (redox homeostasis) induced in rats by OctaBDE. MATERIAL AND METHODS: Female Wistar rats exposed intragastrically to OctaBDE at single (25, 200 or 2000 mg/kg b.w.), or repeated (0.4, 2, 8, 40 or 200 mg/kg/day) doses during 7-28 days were used in the experiment. Selected oxidative stress parameters were determined in the liver and blood serum. RESULTS: Administration (single or repeated) of OctaBDE to rats resulted in the impaired redox homeostasis, as evidenced by the increased levels of reduced (GSH) and oxidized (GSSG) glutathione in the liver, the reduced total antioxidant status (TAS) in serum and the increased concentration of malondialdehyde (MDA) in the liver. After multiple doses of OctaBDE, elevated activity of glutathione transferase (GST) in the liver was also noted. CONCLUSIONS: After repeated administration of OctaBDE at the lowest dose (0.4 mg/kg/day), changes were observed in the parameters (MDA, TAS, GSSG) indicative of oxidative stress.

Octabromodiphenyl ether - porphyrogenicity after repeated administration to rats.

OBJECTIVES: Octabromodiphenyl ether (OctaBDE) is a flame retardant which has been withdrawn from common use due to its negative effect on the environment. The literature data regarding its toxicity addresses its effect on liver function, the endocrine and reproductive systems, as well as its developmental toxicology aspects. The aim of this study was to investigate the effect of repeated administration of OctaBDE on heme biosynthesis in rats. MATERIALS AND METHODS: The study was performed on female Wistar rats. OctaBDE was administered intragastrically at four different doses (2, 8, 40 or 200 mg/kg/day) for 7, 14, 21 or 28 days. The following measures of heme synthesis disturbance were used: urinary excretion of porphyrins, liver concentration of porphyrins, the activity of delta-aminolevulinate synthase (ALA-S) and delta-aminolevulinate dehydratase (ALA-D) in the liver. RESULTS: After 28 days of exposure, lower ALA-S and ALA-D activity was observed in the liver. Additionally, increased concentrations of high carboxylated porphyrins (octa- and heptacarboxyporphyrins) were found in the liver: from 2- to 10-fold after the 2 mg/kg/day doses and from 4- to 14-fold after the 8-200 mg/kg/day doses. The porphyrogenic effect of OctaBDE was also evidenced by augmented, dose-dependent and exposure time-dependent, concentrations of total porphyrins in urine (2-7.5-fold increase) and their urinary excretion (2-9-fold increase). Tetracarboxyporphyrins predominated in the urine; their concentrations increased 2.5-10 fold. CONCLUSIONS: The study revealed that repeated exposure to OctaBDE affects heme biosynthesis and the levels of porphyrins. The lowest effective level which induced changes in porphyrin concentration was 2 mg/kg/day.

The effect of short-term intoxication of rats with pentabromodiphenyl ether (in mixture mimic commercial products).

Until quite recently, pentabromodiphenyl ether (PentaBDE) was most commonly used as a flame retardant. Due to the considerably long atmospheric half-life of PentaBDE and its contribution to environmental pollution, it is categorized as a persistent organic pollutant (POP). As the data on the toxicity of PentaBDE is rather scarce, its potential acute toxicity was the subject of this study. PentaBDE was administered intragastrically to female rats, in a single dose (25, 200 or 2000 mg/kg b.w.). PentaBDE administered to rats disturbed redox homeostasis, which was manifested by lower total antioxidant status (TAS) in serum and by higher liver glutathione reduced (GSH) concentration. The toxic effect of PentaBDE intensified lipid peroxidation. On histopathological examination, administration of the highest PentaBDE dose (2000 mg/kg b.w.) was seen to induce symptoms of fatty liver. PentaBDE caused an increase in relative liver mass, cytochromes P-450 (after two highest doses), a dose-dependent increase in the activity of CYP lA (12-26 fold) and CYP 2B (5-6 fold) as well as the levels of CYP lAl (16-50 fold) and CYP 4A (2-3 fold) in liver.

Toxicity of penta- and decabromodiphenyl ethers after repeated administration to rats: a comparative study.

Until recently, pentabromodiphenyl (PentaBDE) and decabromodiphenyl (DecaBDE) ethers were commonly used as flame retardants in a wide array of products, mostly in the production of plastics utilized in the electric, electronic and textile industries. The aim of this study was to compare the toxicity of PentaBDE and DecaBDE after their repeated (7-28 days) intragastric administration to rats. The compounds were given at doses of 2, 8, 40 or 200 mg/kg/day (PentaBDE) and 10, 100 or 1,000 mg/kg/day (DecaBDE). The repeated administration of PentaBDE disturbed redox homeostasis, which was manifested by lower total antioxidant status and increased activity of glutathione reductase in serum and higher concentrations of glutathione reduced and malondialdehyde in the liver. The occurrence of these effects was not observed after DecaBDE administration. The results of histopathological examination showed fatty degeneration after administration of the highest dose of PentaBDE. The repeated administration of PentaBDE also caused the increase in relative liver mass, dose-dependent increase in the activity of CYP 1A (EROD) and CYP 2B (PROD), 7-12- and 2-8-fold, respectively, as well as enhanced level of CYP 1A1 (5-30-fold) and CYP 4A (2-4.5-fold). The administration of DecaBDE induced much less pronounced changes: a maximum 2.8-fold increase in the activity of CYP 1A, a twofold increase in CYP 2B, and no alterations in other parameters under study. Contrary to DecaBDE, PentaBDE disturbed redox homeostasis, and induced liver microsomal enzymes. Fatty degeneration in liver caused by this compound was also found.