Optical properties of rainbow trout lenses after in vitro exposure to polycyclic aromatic hydrocarbons in the presence or absence of ultraviolet radiation

The optical properties of rainbow trout lenses were investigated after in v itro exposure to polycyclic aromatic hydrocarbons (PAHs) and ultraviolet (U V) irradiation. both because PAHs frequently contaminate aquatic environmen ts and because UV exposure has generally increased with the decline of the ozone layer. Lenses were exposed to UV irradiation for 12 hr while immersed in culture medium, UV irradiation, with or without the presence of PAHs, w as accomplished with one WA and one UVB photoreactor lamp to yield a photon fluence rate of 9.27 mu mol m(-2) s(-1) UVA (UVA:UVB 10.8, radiant exposur e of 13.4 Jcm(-1)), Individual PAHs studied were fluorene, fluoranthene and benzo(a)pyrene. In addition, lenses were exposed to a solution of creosote , a wood preservative used in the aquatic environment that contains many PA Hs. All PAH exposures, including creosote, were carried out either in the d ark or concurrently with UV irradiation. A scanning laser monitor system wa s used to evaluate the optical properties of lenses for up to 236 hr after the UV/PAH treatments. Mean focal length variability (FLV) increased with t ime after concurrent exposure to UV irradiation and high concentrations of either fluoranthene (4900 nM). benzo(a)pyrene (265 nM) or creosote (70 mu g ml(-1)), with FLV values ranging from, 0.21-0.41, 0.21-0.64 and 0.15-0.22 mm, respectively. 72 hr after termination of the UV/PAH treatment. UV irrad iation alone or exposure to PAHs in the dark brought about no changes in th e optical properties of lenses. Also, fluorene in the presence or absence o f UV had no effect, even at concentrations as high as 128 mu M. Lenses were also unchanged by 12 hr exposures in the dark to solutions of either fluor ene, fluoranthene, benzo(a)pyrene or creosote that had been previously UV i rradiated for 12 hr, This meant that photomodified products of the individu al PAHs or creosote were not cataractogenic and emphasized that simultaneou s exposure to UV and PAHs or creosote was necessary for the increased FLV. The results point for the first time to an interaction between UV irradiati on and PAHs as a potential contributing factor to cataract formation in fis h. (C) 2000 Academic Press.