Newark Bay Study - Passaic River Public Digital Library
Newark Bay Study - Passaic River Public Digital Library
Newark Bay Study - Passaic River Public Digital Library
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1-33<br />
locations indicate that OCDD is still prevalent in the sub-surface sediments (Figure 1-15). It is<br />
important to use caution in the interpretation of the vertical profiles given the gaps in the data in<br />
deeper layers, in particular in the upper section of the <strong>Bay</strong> between RM1 and RM3.<br />
As with TCDD, there is no clear pattern to the lateral distribution of OCDD levels;<br />
concentrations vary independently of the proximity to the shore (Figure 1-16).<br />
Polyaromatic Hydrocarbons (PAHs). Most of the PAHs reported in TSI’s database have<br />
no risk guidelines, as is the case with some PCB congeners. The spatial distribution of total PAHs<br />
(tPAHs) in surface and subsurface sediments are shown in Figure 1-17. In general, the data reveals<br />
that many of the tPAH concentrations are between the ER-L (4000 ng/g) and ER-M (45,000 ng/g)<br />
(as evaluated by Long et al., 1995), and in some cases, there are peaks that are orders of magnitude<br />
higher than the ER-M. Total PAH concentrations decrease from a peak concentration close to<br />
100,000 ng/g near the mouth of the <strong>Passaic</strong> <strong>River</strong>, to an average of 20,000 ng/g in the first two<br />
miles of <strong>Newark</strong> <strong>Bay</strong>, to about 10,000 ng/g in the main channel towards the Kills. There are also<br />
two significant peaks in the longitudinal distribution of PAHs, at RM1.2 and RM2.1. At the mouth<br />
of the <strong>Passaic</strong> <strong>River</strong> and one mile south, tPAH levels remain high in the sub-surface sediments (e.g.,<br />
13 ft below surface), at levels comparable to those measured at the surface. Between RM0.5 and<br />
RM1, tPAHs levels seem to increase with depth at levels that exceed both the ER-L and ER-M<br />
guidelines. In the rest of the <strong>Bay</strong>, unlike the <strong>Passaic</strong> <strong>River</strong> where tPAH concentrations increase in<br />
depth after an initial drop in shallower layers, tPAH levels generally decrease with depth [with the<br />
exception of a location in the middle section of the <strong>Bay</strong> (~RM5.4) where surface and 4-ft deep<br />
sediments have similar tPAH levels]. It is important to use the same note of caution expressed for<br />
dioxins – there are significant data gaps in the vertical profiles for deeper layers, in particular in the<br />
upper section of the <strong>Bay</strong> between RM1 and RM4. As is the case for PCBs and dioxins, tPAHs are<br />
likely candidates to be considered as COPCs/COPECs.<br />
Pesticides. The analysis shown in Figure 1-18 focuses on DDT to illustrate the spatial<br />
distribution of a well-studied pesticide in <strong>Newark</strong> <strong>Bay</strong> sediments. It should not be inferred from this<br />
spatial distribution, however, that other DDT species or other pesticides will necessarily follow the<br />
same pattern as DDT. In any case, the data reveal that surficial sediment DDT concentrations<br />
exhibit a pattern of decreasing concentration from the mouth of the <strong>Passaic</strong> <strong>River</strong> to a location 1.5<br />
miles south of the mouth, in <strong>Newark</strong> <strong>Bay</strong> (upper panel of Figure 1-18); however, between RM3.8