A Survey of Environmental¹⁴C Levels in Hong Kong

Abstract

As an industrialized city, Hong Kong annually consumes a large amount of fossil fuel. In addition, the Daya Bay Nuclear Power Plant in Shenzhen, Guangdong Province, has just begun operation 20 km from Hong Kong. These factors suggest that it may be appropriate and significant to examine the variation of atmospheric 14C levels in Hong Kong. We have collected and tested a variety of samples from different parts of Hong Kong: terrestrial annual grasses, marine plants and atmospheric CO2. We measured their 14C activity and compared it with that of cassia oil samples from Guangxi Province, China. The values obtained indicate that environmental 14C levels in the Hong Kong region agree with those found in Guangxi, both of which are significantly higher than the levels predicted by Povinec, Chudý and Šivo (1986).

14C Level At Mt Chiak and Mt Kyeryong in Korea

“…The fitting results are tabulated in Table 2. Korea (1950-1970[Guryong], 1979-1995[Bugok], 1975, 1999 In fact, the decrease rate of the bomb peak is faster in the first years after 1965 than later on, since the ocean surface reservoir is gradually filled up with 14 C from the atmosphere. Our data and Nordkapp and Vermunt's data gives τ = ~13.5 yr, which is a little faster than the value in Table 2, when fitted using data at the interval 1964-1970 AD.…”

“…Chiak-f from a different red pine tree at Bugok also shows a strong correlation with Chaik-d1 and Chaik-d2 in 1998, , 1985, 1983, 1981, and 1972). Finally, Kyerong-1 from a different red pine tree at Baekamdong shows a strong correlation with Kyerong-2-1 and Kyerong-2-2 in 1999, 1995, 1992, 1983, 1981, 1973, 1971, 1969, and 1967). Therefore, our cross-dated tree-ring series show strong cross-correlations and are accurately identified in terms of their year.…”

“…Since 1945, nuclear weapons tests have led to an increase in atmospheric ∆ 14 C. The atmospheric ∆ 14 C concentration in the northern hemisphere has approached a peak value of about twice the natural atmospheric ∆ 14 C concentration. Since then, the excess atmospheric 14 C has diffused into other reservoirs (mainly to the oceans) and, following the Limited Test Ban Treaty of 1963, the excess atmospheric 14 C has decreased exponentially (Povinec et al 1986;Leung et al 1995). However, the peak value, the time of peak value, and the speed of exponential decay for ∆ 14 C show differing trends in different latitudes.…”

Apparent ages of suspended sediment and soil erosion of the Pearl River (Zhujiang) drainage basin

“…Within the Pearl River drainage basin, the Δ 14 C values of surface soil were positive in DHS, HS and Hong Kong, Guangxi and other places [23], exhibiting the effect of the "bomb" 14 C. Moreover, the Δ 14 C values of plants were almost identical in the whole drainage basin [23], which showed that the whole basin had been subject to the same intensity of the "bomb" 14 C influence [8].…”