Newark Bay Study - Passaic River Public Digital Library

1-38
Individual sediment core vertical profiles for DDT (Figure 1-19) also reveal that
measurements in sediment cores were in most cases limited to shallow layers (0 to 6 ft), except near
the mouth of the Passaic River, where DDT levels in deeper sediments (14 ft) could be four times
higher than in the surface layer (e.g., stations 96A-NWB and 81A-NWB). Notwithstanding that
DDT levels in deep sediments (4 ft) of south Newark Bay may also be elevated (e.g., station 70A-
NWB), the high concentrations at the surface suggest the existence of possible on-going sources.
Metals. Of the metals that are available in the database, the spatial distribution of mercury,
chromium, lead, nickel, arsenic, and cadmium in surface and sub-surface sediments of Newark Bay
and the Kill van Kull are shown in Figures 1-20 through 1-25. Unlike in the lower Passaic River
where metal levels often exceed the ER-M guidelines, only levels of mercury and to a lesser extent
chromium and nickel are in excess of the ER-M in Newark Bay.
Mercury concentrations in surface as well as in deeper sediments exceed both the ER-L (150
ng/g) and ER-M (710 ng/g) throughout Newark Bay into the Kill van Kull (Figure 1-20); the
detected concentrations are between 5 to 20 times higher than the medium and low range of
ecological effects. As is the case with other contaminants, there are large gaps in mercury
measurements in the sub-surface sediments, in particular, between RM1.5 and RM4. A preliminary
inspection of the 1976 surface grab sample data of Suszkowski (1978) indicates that mercury levels
at that time were similar in magnitude to the results shown on Figure 1-20, generally on the order of
1000 – 10,000 ng/g. Inspection of results from a limited number of borings failed to reveal a
consistent pattern, though a more detailed review of these data is warranted. It should be noted that
an assessment effort is currently being conducted to better evaluate Berry’s Creek as a potential
source of mercury into Newark Bay. The result of the evaluation will ultimately be integrated into
the modeling effort.
Throughout Newark Bay, chromium concentrations in the surface sediment are between the
ER-M (370,000 ng/g) and ER-L (81,000 ng/g) values (Figure 1-21). The ER-M is exceeded only
once in the Kill van Kull area. In deeper sediments, levels of chromium are somewhat lower than in
the surface sediment, except at locations closer to the mouth of the Passaic River, where deep
sediments (12 ft) show elevated chromium concentrations in excess of the ER-M value.
Suszkowski’s (1978) surface grab sample results from 1976 were comparable in magnitude, though
some results were higher than the concentrations of Figure 1-21, with a number of samples having
chromium levels in excess of the ER-M.
Except in the proximity of the mouth of the Passaic River, the levels of lead in Newark Bay
surface sediment generally remain between the ER-M (218,000 ng/g) and ER-L (46,700 ng/g) values
(Figure 1-22). Also, in spite of the apparent decrease in lead concentrations in the lower section of
Newark Bay, between RM5.5 and RM6.5, there is an apparent surge in lead concentration in the