Newark Bay Study - Passaic River Public Digital Library

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