back global monitoring index
back to chemicals index
back to factsheets index|
|
back global monitoring indexback to chemicals indexback to factsheets index |
 |
IPEN Body Burden Community Monitoring Handbook Polycyclic Aromatic Hydrocarbons (PAHs)Chemical Name: PAHs is a group of compounds consisting of two or more fused aromatic rings. CAS Number: Properties: Solubility in water: 0.00014 -2.1 mg/L at 25ºC; vapour pressure: mm Hg at 25°C; log KOW: 4.79-8.20 Discovery/Use: Most of these are formed during incomplete combustion of organic material and the composition of PAHs mixture varies with the source(s) and also due to selective weathering effects in the environment. Persistence/Fate: Persistence of the PAHs varies with their molecular weight. The low molecular weight PAHs are most easily degraded. The reported half-lives of naphthalene, anthracene and benzo(e)pyrene in sediment are 9, 43 and 83 hours, respectively, whereas for higher molecular weight PAHs, their half-lives are up to several years in soils/sediments. The BCFs in aquatic organisms frequently range between 100-2000 and it increases with increasing molecular size. Due to their wide distribution, the environmental pollution by PAHs has aroused global concern. Toxicity: The acute toxicity of low PAHs is moderate with an LD50 of naphthalene and anthracene in rat of 490 and 18000 mg/kg body weight respectively, whereas the higher PAHs exhibit higher toxicity and LD50 of benzo(a)anthracene in mice is 10mg/kg body weight. In Daphnia pulex, LC50 for naphthalene is 1.0 mg/L, for phenanthrene 0.1 mg/L and for benzo(a)pyrene is 0.005 mg/L. The critical effect of many PAHs in mammals is their carcinogenic potential. The metabolic actions of these substances produce intermediates that bind covalently with cellular DNA. IARC has classified benz[a]anthracene, benzo[a]pyrene, and dibenzo[a,h]anthracene as probable carcinogenic to humans. Benzo[b]fluoranthene and indeno[1,2,3-c,d]pyrene were classified as possible carcinogens to humans. Source: UNEP Chemicals, Regional Reports of the Regionally Based Assessment of Persistent Toxic Substances Program (2002) Available from: http://www.chem.unep.ch/pts UNEP Chemicals 11-13, chemin des Anemones CH-1219 Chatelaine, GE Switzerland. 
IPEN Body Burden Community Monitoring Handbook - 2003 |
|