The changes in atmospheric As, Bi, Sb and Se over central Greenland after the Industrial Revolution

Abstract

Trace metals records in Greenland snow and ice core samples showed anthropogenic influences on atmospheric environment after the Industrial Revolution. However, those records were available for only a few elements such as lead (Pb), copper (Cu), zinc (Zn), cadmium (Cd) and thallium (Tl), because most of trace metals in ice cores exist in extremely low level of pg/g level. In this research, we present the records of arsenic (As), bismuth (Bi), antimony (Sb) and selenium (Se) recovered from the 70.3 m long ice core drilled at Greenland summit in 1989 as part of the European Eurocore program. These records revealed the changes in those elements from 1760 to 1965 A.D. The concentrations of As, Bi, Sb and Se determined from Greenland Eurocore samples are 1.4~22.2 pg/g, 0.03~0.5 pg/g, 0.2~1.8 pg/g, and 17.8~62.4 pg/g, respectively. These values are comparable to those of other Arctic snow samples. The changes in the concentrations of As, Bi and Sb showed slight increases until mid-19th century, and then commonly revealed abrupt concentration peaks during 1890-1930s while Al concentration decreased for the same period. After 1930s, the concentrations of As, Bi and Sb steadily increased again. These patterns are more prominent in EFc values records. The EFc values for the early 20th century were even higher than those after 1950s. During the 20th century, the primary anthropogenic source for As, Bi and Sb were non-ferrous metals production and fossil fuel combustion, and they increased rapidly after 1950s. Therefore the large increases in As, Bi and Sb concentrations for the early 20th century seemed to be due to not only anthropogenic emissions but also additional natural emission such as volcanic eruptions. Se concentration, differently from other trace elements, steadily increased over whole period of the 19th century, dipped for the first half of 20th century before reaching its maximum value at mid-1940s, and then decreased rapidly after 1950s. The natural Se is largely contributed by biogenic emission, while the anthropogenic Se is dominantly emitted from fossil fuel combustion. Therefore the decrease in Se concentration after 1950s was most likely to be due to the changes in bioactivities.