. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. C •| 5 <? .0 Q. 001 y = 0 0057x + 0 0059' R2 = CR y = 00112x-0004 R2 = 0 95. 10 %C Figure 1. Top: Depth profiles of lead concentration (mg/g sediment) in cores from Childs River, Quashnet River, and Sage Lot Pond, average of two cores. indicates a layer with much lower organic content. Bottom: Lead concentration vs. the % carbon in cores of sediment for nil three estuaries. CR = Childs River, QR = Quashnet River, SLP — Sage Lot Point. peaked as a result of the use of leaded
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. C •| 5 <? .0 Q. 001 y = 0 0057x + 0 0059' R2 = CR y = 00112x-0004 R2 = 0 95. 10 %C Figure 1. Top: Depth profiles of lead concentration (mg/g sediment) in cores from Childs River, Quashnet River, and Sage Lot Pond, average of two cores. indicates a layer with much lower organic content. Bottom: Lead concentration vs. the % carbon in cores of sediment for nil three estuaries. CR = Childs River, QR = Quashnet River, SLP — Sage Lot Point. peaked as a result of the use of leaded gasoline. Ph concentrations decreased after 1973, when the United States banned the addition of lead to gasoline for automotive fuel. There is a near-surface peak of Pb concentrations in the uppermost layers of sediments in the Childs River profile (as well as in those of the other two estuaries I. This feature is unexplained; we speculate that lead sources from recent increases in boat traffic might be responsible because the use of leaded gasoline in boats was not officially banned until 1995. Further, there could be increased leaching of Pb deposited in roads and roadsides. The depth profiles for Pb vary among the estuaries; for exam- ple, the Quashnet River profile shows a marked trough at 11- 15cm (Fig. 1, top middle). This trough in Pb concentrations was associated with a significant decrease in organic content. It is difficult to compare Pb loads to the different estuaries by just comparing Pb concentrations; we must also account for possible differences in sediment accretion. To get a better comparison of lead inputs into the three estuaries, we calculated the total inventory of Pb received by each estuary, across the time period represented by the top 31 cm in the sediment cores (Fig. 1, top). The total lead per volume of sediment per core section was calculated by using data on porosity of the sediment (6). The Pb inventory in the Childs River sediment was g
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Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
