Heavy/toxic metals have been widely investigated in the Antarctic. However, there are rare reports on arsenic up to now. Here, we analyzed a 1,800-year record of arsenic concentration in lake sediments affected by  penguin droppings. We found that arsenic enriches in the penguin dropping sediments with 12.41 ± 0.45 ug/g (on dry weight), which is about two times higher than the one in the background sediments with absence of penguin. Historical change in arsenic concentration was ound to significantly correlate with the fluctuation of penguin number, indicating that penguin activity will result in the enrichment of arsenic somewhere in the maritime Antarctic.