The inventories of ¹³⁷Cs (503 ± 34 Bq.m⁻²), ²⁴¹Am (11.3 ± 1.2 Bq.m⁻²), ²⁴¹Pu (33.7 ± 3.4 Bq.m⁻²), ²³⁸Pu (6.82 ± 0.87 Bq.m⁻²) and ^239+240Pu (113.0 ± 5.9 Bq.m⁻²), sum of ²³⁹Pu (100 ± 11 Bq.m⁻²) and ²⁴⁰Pu (14.5 ± 1.7 Bq.m⁻²), in the Gambier archipelago (23°S) of the French Polynesia, are well higher the global fallout at this latitude, in unequal proportions for the different radionuclides. (²⁴⁰Pu/²³⁹Pu)_AR (AR: atomic ratio) of 0.0394 ± 0.0062, and (²⁴¹Pu/²³⁹Pu)_AR of (2.03 ± 0.39)10⁻⁴, confirm that the overwhelmingly dominant source of these radionuclides comes from local fallout during the 1970s of the French atmospheric tests of Moruroa and Fangataufa located nearly 400 km from Gambier. The signatures of the local fallout were deduced from the excess of its inventory in ¹³⁷Cs and from the mixing lines established from the signatures of the global fallout, some of the test sites and the isotopic ratios measured in Gambier. Signatures obtained are 2.0 ± 0.4 for ¹³⁷Cs/^239+240Pu, 0.045 ± 0.008 for ²³⁸Pu/^239+240Pu, 0.031 ± 0.009 for ²⁴¹Am/^239+240Pu, 0.092 ± 0.027 for ²⁴¹Pu/^239+240Pu, 0.0163 ± 0.0049 for (²⁴⁰Pu/²³⁹Pu)_AR, (0.78 ± 0.23)10⁻⁴ for (²⁴¹Pu/²³⁹Pu)_AR. The concordance of the mixing lines of the [(²⁴⁰Pu/²³⁹Pu)_AR, (²⁴¹Pu/²³⁹Pu)_AR] and the linear regression of these ratios measured in the stratosphere (40°S) during the 1970s, indicates that the signatures of the close-in deposition are also those of the stratospheric injections of the French tests. The signatures of stratospheric fallout in the Southern Hemisphere were evaluated by considering that the fission energy of these injections represents 11% and that of the Northern Hemisphere represents 89% and that the isotopic ratios of stratospheric injections remained the same over the period 1970–1974. The activity ratios deducted are 21.9 ± 0.1 in ¹³⁷Cs/^239+240Pu, 0.11 ± 0.05 in ²³⁸Pu/^239+240Pu, 1.03 ± 0.12 in ²⁴¹Pu/^239+240Pu and 0.35 ± 0.04 in ²⁴¹Am/^239+240Pu. The associated atom ratios are 0.157 ± 0.011 for (²⁴⁰Pu/²³⁹Pu)_AR and (8.33 ± 0.48)10⁻⁴ for (²⁴¹Pu/²³⁹Pu)_AR. These signatures appear to be consistent with the results of the inventories at Hiva Oa, located more than 1,000 km north of both French test sites, and with those found in the Australian continent, in regions not impacted by UK-test debris. The proportions of close-in tropospheric fallout from the French tests are about 90% in Gambier. They represent a proportion in the inventories of 40% for the ¹³⁷Cs, 60% for ²⁴¹Am and in the range between 80 and 90% for Pu isotopes.

的清单^137个CS（503±34 Bq.m ^-2），²⁴¹ AM（11.3±1.2 Bq.m ^-2），²⁴¹浦（33.7±3.4 Bq.m ^-2），²³⁸浦（6.82±0.87贝。 m ^-2 ) 和^239+240 Pu (113.0 ± 5.9 Bq.m ^-2 )，²³⁹ Pu (100 ± 11 Bq.m ^-2 ) 和²⁴⁰ Pu (14.5 ± 1.7 Bq.m ^-2 ) 的总和，在法属波利尼西亚的甘比尔群岛（南纬 23 度）在该纬度的全球辐射量要高得多，不同放射性核素的比例不等。( ²⁴⁰ Pu/ ²³⁹ Pu) _AR(AR: 原子比) 为 0.0394 ± 0.0062，( ²⁴¹ Pu/ ²³⁹ Pu) _AR为 (2.03 ± 0.39)10 ^-4，证实这些放射性核素的主要来源来自 1970 年代法国大气的局部沉降Moruroa 和 Fangataufa 的测试距离甘比尔近 400 公里。局部沉降的特征是从其在¹³⁷ Cs中的库存过剩以及根据全球沉降的特征、一些测试地点和在 Gambier 中测量的同位素比率建立的混合线推断出来的。¹³⁷ Cs/ ^239+240 Pu获得的签名为 2.0 ± ^0.4，238 Pu/ ^239+240为 0.045 ± 0.008浦，0.031±0.009 ²⁴¹ AM / ^{239 + 240}莆，0.092±0.027 ²⁴¹ PU / ^{239 + 240}莆，0.0163±0.0049为（²⁴⁰ PU / ²³⁹莆）_AR，（0.78±0.23）10 ^-4为（²⁴¹ Pu/ ²³⁹ Pu) _AR。[( ²⁴⁰ Pu/ ²³⁹ Pu) _AR , ( ²⁴¹ Pu/ ²³⁹ Pu) _AR混合线的一致性]和1970年代在平流层（40°S）中测得的这些比率的线性回归表明，近地沉积的特征也是法国试验的平流层注入的特征。考虑到这些注入的裂变能占 11%，北半球的裂变能占 89%，并且在 1970-1974 年期间平流层注入的同位素比率保持不变，评估了南半球平流层沉降的特征。扣除的活度比在¹³⁷ Cs/ ^239+240 Pu 中为 21.9±0.1，在²³⁸ Pu/ ^239+240 Pu 中为0.11±0.05，在²⁴¹ Pu/ ^239+240 Pu 中为1.03±0.12，在± 0.35 中为 0.35²⁴¹上午/ ^239+240浦。( ²⁴⁰ Pu/ ²³⁹ Pu) _AR的相关原子比为 0.157 ± 0.011 ，( ²⁴¹ Pu/ ²³⁹ Pu) _AR的相关原子比为(8.33 ± 0.48)10 ^-4。这些特征似乎与位于法国两个试验场以北 1,000 多公里的 Hiva Oa 的清单结果以及在澳大利亚大陆未受英国试验碎片影响的地区发现的结果一致。来自法国测试的近距离对流层沉降物在甘比尔的比例约为 90%。它们在库存中的比例为¹³⁷ Cs的 40 %，²⁴¹ Cs 的 60%Am 和 Pu 同位素的范围在 80% 和 90% 之间。