Osmium is one of the rarer elements in seawater, with typical concentration of ≈10 × 10−15 g g−1 (5.3 × 10−14 mol kg−1). The osmium isotope composition (187Os/188Os ratio) of deep oceans is 1.05, reflecting a balance between inputs from continental crust (≈1.3) and mantle/cosmic dust (≈0.13). Here, we show that the 187Os/188Os ratios measured in rain and snow collected around the world range from 0.16 to 0.48, much lower than expected (>1), but similar to the isotope composition of ores (≈0.2) that are processed to extract platinum and other metals to be used primarily in automobile catalytic converters. Present-day surface seawater has a lower 187Os/188Os ratio (≈0.95) than deep waters, suggesting that human activities have altered the isotope composition of the world's oceans and impacted the global geochemical cycle of osmium. The contamination of the surface ocean is particularly remarkable given that osmium has few industrial uses. The pollution may increase with growing demand for platinum-based catalysts.
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机译：是海水中稀有元素之一，典型浓度为≈10×10 −15 gg −1 （5.3×10 −14 mol kg -1 ）。深海的is同位素组成（ 187 Os / 188 Os比）为1.05，反映了地壳投入（≈1.3）和地幔/宇宙尘埃之间的平衡（ ≈0.13）。在这里，我们表明，在世界范围内收集的雨雪中测得的 187 Os / 188 Os比率在0.16至0.48范围内，远低于预期（> 1），但类似于矿石的同位素组成（≈0.2），矿石经过加工以提取铂和其他主要用于汽车催化转化器的金属。当今的地表海水 187 Os / 188 Os比率（≈0.95）低于深海，这表明人类活动改变了世界海洋的同位素组成，影响了the的全球地球化学循环。鉴于几乎没有工业用途，因此对海洋表层的污染尤为明显。随着对铂基催化剂需求的增加，污染可能会增加。
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