Véron A J, Church T M, Flegal A R
Géosciences de l'Environnement, CNRS UMR6536, CEREGE, Provence, France.
Environ Res. 1998 Aug;78(2):104-11. doi: 10.1006/enrs.1998.3856.
In the early 1980s, Patterson and colleagues demonstrated that most lead in oceanic surface waters had an anthropogenic origin. Their discovery occurred during the phasing out of leaded gasoline in North America initiated in the previous decade. The corresponding decrease in the anthropogenic lead emissions, verified by Pb/210Pb ratios, accounted for the systematic decline in lead concentrations in surface waters of the western Sargasso Sea. Subsequent changes in anthropogenic lead inputs to the western Sargasso Sea surface waters have been documented by measurements of lead concentrations, isotopic compositions (206Pb/207Pb, 208Pb/206Pb), and Pb/210Pb ratios in precipitation and seawater for the period of 1981 to 1994. These data indicate the easterly trade winds are now the primary source of atmospheric lead in Bermuda, and they confirm that the decline of lead concentrations in the North Atlantic is associated with the phasing out of leaded gasoline in North America and western Europe over the past decade. Moreover, temporal variations in the relative contribution of industrial lead inputs from the two sides of the North Atlantic over that period can be quantified based on differences in their isotopic composition. The transient character of those isotopic signatures also allows calculations of pollutant lead penetration rates into the mixed layer and upper thermocline of the western Sargasso Sea.
20世纪80年代初，帕特森及其同事证明，海洋表层水中的大多数铅都源自人为活动。他们的这一发现是在北美于前一个十年开始逐步淘汰含铅汽油期间出现的。通过铅/210铅比率得到证实的人为铅排放的相应减少，解释了马尾藻海西部表层水中铅浓度的系统性下降。1981年至1994年期间，通过对降水和海水中铅浓度、同位素组成（206铅/207铅、208铅/206铅）以及铅/210铅比率的测量，记录了随后人为铅输入到马尾藻海西部表层水的变化情况。这些数据表明，东风信风现在是百慕大气中铅的主要来源，并且证实了北大西洋铅浓度的下降与北美和西欧在过去十年中逐步淘汰含铅汽油有关。此外，基于其同位素组成的差异，可以量化该时期来自北大西洋两侧的工业铅输入相对贡献的时间变化。这些同位素特征的瞬态特性还使得能够计算污染物铅进入马尾藻海西部混合层和上温跃层的渗透率。
