Concentration. of Al, , Cu, F , Mo, i, and Zn were d termined u.ing atomic absorption pectrometry in a dirnent c re taken from Lake Tahoe, alifomia-Ncvada, in 1991. The pattern o their concentration with d pth may reveal in ormati n about antm po enic inpu diagenetic fact ,rs and changes in ourc of sedim n . Pb-210 datin of the ediments by D. Edgington revealed that there were three change in sedimentation rate. Th edimcntation rate was .24 cm/yr in the lo er pan of th core from cm t about 10-11cm ( ~ 1840 to I 920). Thi ru her rate can be attributed to higher ero ion rate. related to the deforestation of the virgin timber ar und the lake as a consequence of nearby mining activiti . The edimentation rate dccreas d to 0.10 cm/yr b tween l 20 and 1966. During thi tim , th 1 al mining had stopped and forest had been allowed to grow nd human activities in the lake ba. in were marginal. The third chang occurred after l 66 wher the sedimentation rate increa d to 0.24 cm/yr. This change oc urred becaus of higher ro ion du to con tructi n acti jti around th basjn high r productivity in th lake du to nutr:i nt inpuc and diagenetic remobilization. Biogenic activitie ha e been a major concern in tbi area. B m uring th lo -onignition (LOO, the am unt of organics in the diments may be approximat d wjth depth. Th LOT . uggest that the organic content ha. increa din recent times as a consequenc of the higher nutrient inpu . The j Jubie fra tion (which w not dis I ed. with HN03 and H l) i fairly con tant up co a depth of about 6 cm, whi h corresponds with the mor recent chang in sedimentation rate. bove this the in. o]uble fraction decre e hewing dilution by organic matter and other ph c . The increase in edimentation rat due to defore ation did not c.han e the pe of material d.imented, onJ th amount brought in. The concentration of AJ with depth in th edimentary column is e . ntialJy constant. Thu , chan · in sedimentation rat did not affect the 1 c ntent in chis core. ince I i as o iated ith aJumin • iticate , all metal cone ntratio wer compared to AJ tor move the eff ec of variou dilutan . The u and V analyze. are. imi lar to Al in that they showed no pattern. om ther metal h w a di tinctive po!Jution-typ profil with an increas in concentration in more recent ediments. Pb and Zn both how th teady increase, however, Pb reache a maximum at a deeper depth than Zn. Any anthropo enic input for the remainder of the m taJ tudied j overwhelmed by djagenic pro . ses. F and Mn are depo. ited a olid Fe/Mn oxide . As the organic matter decompose o ygen i removed re ultin in the reduction and com uen di elution offirt Mn at about 3 cm th n F at 4 5 m depth. pon further burial, the F and Mn++ in the pore waters diffu. es upward, get. oxidized and reprecipitates as the r spective o ide just above acb one's redox boundary yielding large peaks in their ediment concentrations. Cr Mo and i were mo t probably carried to th edim n with th e pb , and w re rcdi tributed uring cliagen · re ulting in diagen tk-typ concentration profiJcs with depth.