The ecological effects of oil pollution on littoral communities

scallop settlement and culture it seems possible that this method could be of value both to the investigator of this important species and as a basis for commercial culture. Moreover, in the work performed at Loch Sween, the live boxes were suspended at one depth only, but by the suspension of 'stacks' of live boxes at different depths a much higher productivity may be possible.

E. J. PERKINS E. GRIBBON

Marine Laboratory, University of Strathclyde, Garelochhead, Dunbartonshire, Scotland.

Marine Waste Deposits near New York The effects of effluent discharges and sludge dumping in New York Harbor and New York Bight have been surveyed. Total carbon content, loss on ignition, and lead and copper concentrations prove to be the most useful parameters for mapping the distribution o~ wastes in bottom deposits. Waste deposits are widely distributed in the coastal ocean around cities. Although commonly ignored, they may have a major influence in environmental quality in coastal areas. Their distribution on the continental shelf (New York Bight) and in New York Harbor was mapped in 1970 to learn more about them. The areas included in this survey were New York Harbor (390 km 2) and part of the New York Bight (1,000 km-"), the area near the harbour entrance. Mapping waste deposits within this large area demanded that the characteristic criteria were selected to obtain the maximum amount of data. The desired characteristics for diagnostic criteria included: (a) readily interpretable index of waste abundance; (b) simple, rapid determination; (c) relatively inexpensive analysis; (d) good reproducibility, relative standard deviation + 10 per cent or better; (e) constituent abundant in wastes with low abundance in natural sediments. For this project the abundance of organic matter and minor element composition (Cu, Cr, Pb, Ag) were selected as the most informative parameters. The uppermost few centimetres of the deposits were sampled in various parts of New York Harbor and the adjacent New York Bight. Sediment samples from the New York Bight area were collected by personnel of the Sandy Hook Marine Laboratory, National Oceanic and Atmospheric Administration. Sediments from New York Harbor were collected by personnel from the Marine Science Research Center, State University of New York, Stony Brook. In every instance only superficial deposits were sampled.

Organic Matter Two measures of the abundance of organic matter were chosen for mapping waste deposits: (1) loss on ignition and (2) total carbon content. Both are relatively simple to determine in sediment and are easily reproducible in the laboratory. Loss on ignition values for chemically pure compounds were within 1 per cent of the predicted results, indicating that all the organic matter was destroyed during the heating in air at 550°C for 4-8 h. Relative

standard deviation was also l per cent or less. Carbonate compounds (calcium carbonate, sodium carbonate) analysed under these conditions had weight losses of 0.3-0.9 per cent, indicating that they did not decompose at 550°C. The loss on ignition technique works well in clean sands and provides a useful data to delineate carbonrich waste deposits on the continental shelf. Sediments ~ !

~:: !:.'.,.'.','~

: . ,.,..... ~" .i.:.

v

~..

:........

.....

..

•. . . . . .I .

~

~ . .

. . . .. .. . .

'.'.'.'.'"

" ' "

.:.." :'

"

+0 57 HARBOR

I

~016

x

t4o 3o'

+ +

SANDY

x

x

~

078+

x

HOOK

x

2

~+

,~

/-- " ~

/ ~ ~ -9+o'+

~'~2.s'--~*.;

o.~i=o.,

x ÷ / ~

~--I~

//IS+

045'

xOI6

)

~7/x.

,**.,.'L,-~-..-,,,o46

x

x

3ore

x

I I

• 0.14

x

Fig.

1

Total York

carbon Bight.

x

\

\ c

7}oi~0'

2.5-5.0% 0.5 - 2.5 %

5.0%

II I II

l I I fl I i I 5

STATUT1EMILES

I

x

>

•

,,

Ill

~

• +

x < 0.5%

÷ ,.~¢"~"~.~,",,

400 20'

[ I

T O T A L CARBON

•

35e

,,

x

"

x

x

0.20

028

\ \

~

concentrations

73~L40

in

,.

deposits

from

New

beyond the influence of waste disposal activities had loss on ignition values averaging 1.2 per cent. Within officially designated disposal areas the waste deposits had loss on ignition values as high as 13.8 per cent and averaged 6.0 per cent. If we assume that an ignition loss exceeding 5 per cent (four times the background values) indicates the presence of wastes, the area of New York Bight obviously covered by wastes containing volatile matter is about 45 km 2 (17 square statute miles). The area apparently covered by dredged wastes (39 km :) is about seven times as large as the area apparently covered by sewage sludges (6 km'-'). Within New York Harbor, the abundance of finegrained sediment limited the utility of the loss on ignition technique owing to possible interferences from partial decomposition of these minerals. For this area, the total carbon concentrations were taken as the 61

primary index of waste abundance. Carbonate-carbon was typically less than 0.2 per cent (Gross, 1971). These deposits are also the major source of materials dredged from the harbour and dumped in the dredged waste disposal area. In the harbour deposits, highest total carbon concentrations were found in the waterways adjoining the East River, in the Lower Hudson River and in Newark Bay. Areas affected by strong tidal current (East River) and wave action (Lower New York Bay) were nearly devoid of carbon-rich deposits. Of the approximately 390 km ~ of New York Harbor, these data indicate that approximately 160 km ~ (41 per cent of the harbour area) are covered by carbon-rich deposits containing more than 2 per cent carbon, with a median concentration of 5.6 per cent. The total carbon concentration of the sands in Lower Bay near the harbour entrance is somewhat lower than the median concentration of total carbon in sands on the continental shelf. In some of the samples collected in Raritan Bay and Lower New York Bay, the finegrained carbon-rich deposits were lying above layers of dead shell on hard sand. This evidence suggests, although it does not prove, that the fine-grained wastes now cover areas that were formerly hard-sand bottoms. Additional work, including coring of the deposits, is necessary to determine the recent history of these harbour areas. Results of these analyses (Fig. 1) indicate that the wastes on the offshore disposal sites are generally close to the designated disposal areas. Dredged wastes which occupy the largest area are within 5 km of the designated spot although slightly displaced toward the entrance to the harbour. The carbon-rich deposits are displaced about 1 km from the designated disposal site for sewage sludges. They, too, lie closer to the harbour. No samples were available to determine if the 'Cellar Dirt' site (used for disposal of construction wastes and rubble) could be detected on the basis of carbon content. The results of this study generally confirm the results obtained by Pearce (1969) although the waste-affected areas are somewhat different in size and shape. These results do not, however, provide any compelling evidence of movement of carbon-rich wastes towards either the Long Island or New Jersey coasts. There are, indeed, isolated scattered samples containing high total carbon concentrations lying between the waste disposal areas and the harbour entrance, It is possible but not demonstrated that these isolated occurrences result from shoreward movement of wastes following their discharge in the designated disposal areas. It is also possible that they result from improper disposal operations, such as errors in navigation, illegal dumping or leaky barges passing over the area in transit to the disposal site. The second possibility would appear the most likely in the absence of more compelling data indicating waste movement.

Diagnostic minor elements Previous studies showed that several elements were present in the wastes at concentrations in excess of those observed in sediments or ancient rocks unaffected by waste disposal activities (Gross, 1970; Gross et al, 1971). Elements most useful for detecting the presence of in62

dustrial wastes were chromium, copper, lead and tin (Fig. 2). ! C"

CHROMIUM

"

'

' " ....

M

I

'

~

.....

~'1

"

.......

•

s

I

,

. . . . . . .

'1

+ x ~ _

c

--

I

E

•

-

COPPER M

•

+

-

m

•

S C I

+$

LEAD M

x

S C

'~

S,LVER t Fig. 2

S

"/,m~l-~,, I

n

,,~,,i

,

I 0.0001

X + • A

A lid

IO 0.001

I

[

I

SHALE SAND MARINE PLANTS SEWAGE SLUDGE

I ''''j

i

I00 0.01

,

,

.....

1

I000 PPM 0.1%

Median concentration value (indicated by vertical line) range, and limits for 70 per cent of samples analysed (shown by heavy bar) for samples of superficial deposits in New York Harbor and New York Bight. (C-continental shelf sediment, 1-inner harbour deposits, M-deposits near 'mud' disposal area, S-deposits near sewage sludge disposal area). Typical concentrations are shown for shales, sands, and marine plants (Bowen, 1966) and sewage sludges (Gross, 1970). Question marks indicate the detection limits for the various elements.

Optical emission spectrochemical techniques were used because of the ease of making analyses, their sensitivity for these metals and ability to determine the total elemental concentration of about 24 elements regardless of the chemical form of the elements in the dried samples (Gross, 1970). Although tin was easily detectable in the sewage sludges it was frequently below detection limits in the harbour sediments and waste deposits and therefore not usable for this purpose. Silver, however, was easily detectable and occurred in concentrations greatly in excess of those observed in normal sediments, soils or marine organisms and was, therefore, included in the survey. Lead was easily detected in the waste deposits and in most of the harbour deposits (Fig. 3). The lead concentrations in these deposits were 20 times higher than in normal shales and about 50 times greater than the concentrations in marine plants. It is also interesting to note that the lead concentrations in sewage sludges and harbour deposits are not significantly different. The detection limit for lead in the samples was about 109 ppm. This itself provides a useful index for the presenc~ of waste deposits. If lead was detectable in the sands, it apparently indicated the presence of waste deposits. Silver, like lead, is easily detected in the waste deposits and in sewage sludges, but was found to be detectable in only two samples of continental shelf sediment. Silver in the deposits was more useful in marking the boundaries of the dredged waste deposits than for the sewage sludge deposits where it was detected only in the immediate vicinity of the designated disposal site. Copper and chromium were easily detected in all samples analysed (Fig. 2) and the waste deposits contained generally more of these elements than sediments well outside the boundaries of the waste disposal operations. But for chromium, the background concentrations