Distribution and abundance of large floating plastic in the north-central Gulf of Mexico

Marine Pollution Bulletin Warwick, R. M. (1988a). Analysis of community attributes of the macrobenthos of Frierfjord/Langesundfjord at taxonomic levels higher than species. Mar. Ecol. Prog. Ser. 46, 167-170. Warwick, R. M. (1988b). Effects on community structure of a pollution gradient--summary. Mar. Ecol. Prog. Set. 46, 167-170. Weston, D. P. (1990). Quantitative examination of macrobenthic community changes along an organic enrichment gradient. Mar. Ecol. Prog. Ser. 61,233-244.

MarinePollutionBulletin,Volume24, No. 12,pp. 598-601, 1992. Printedin GreatBritain.

Windom, H. L., Tenore, K. T. & Rice, D. L. (1982). Metal accumulation by the polyehaete Capitella capitata: influences of metal content and nutritional quality of detritus. Can. Jour. Fish andAqu. Sci. 39, 191196. Zajac, R. N. & Whitlach, R. B. (1988). Population ecology of the polychaete Nephtys incisa in Long Island Sound and the effects of disturbance. Estuaries 11 (2), 117-133.

0025-326X/92$5.00+0.00 © 1992PergamonPressLtd

Distribution and Abundance of Large Floating Plastic in the North-Central Gulf of Mexico KAREN M. LECKE-MITCHELL and KEITH MULLIN NOAA, National Marine Fisheries Service, Southeast Fisheries Science Center, P.O. Drawer 1207, Pascagoula, MS 39568-1207, USA

Aerial surveys were conducted in the north-central Gulf of Mexico from June 1988 to May 1989. Sightings of marine debris and specifically large floating plastics were recorded during these surveys. Five study areas off the Louisiana coast were monitored and seasonal distribution and densities were estimated. Each study area contained plastic throughout the year. The estimated densities of plastic were largest in the offshore areas (4 & 5) and smallest in the inshore areas (1 & 3). Seasonally, density of plastic was smallest in the summer and largest in the fall. The reasons for the differences in seasons and study areas are not apparent but the amount of plastic in each area and season could be affected by variations in currents, winds, discharge from rivers, and human activity.

During beach clean-ups of US coastal shores, plastic has been the dominant item found. Nationwide in 1988 and 1989, plastics comprised over 60% of more than 850 metric t of debris (e.g. plastic, paper, metal, glass, wood, rubber, and cloth) collected from coastal beaches. In the Gulf of Mexico, volunteers in Louisiana alone picked up over 50 metric t of debris on just over 100 km of coastal beaches. Of the debris collected in both years, over 75% was plastic (National Beach Clean-up Results, 1988, 1989). Each year in US waters, seabirds, marine mammals and other wildlife die due to ingestion of plastics or 598

entanglement in marine debris. Also, marine debris is a hazard to boaters. Boaters are put at risk by floating debris when propellers become entangled in debris and their boat becomes disabled. In December 1988, MARPOL (Marine Pollution) Annex V went into effect. This prohibits the dumping of plastics into any body of water and it also stipulates the distance from shore other garbage is allowed to be thrown overboard (Kearney, A. T. Inc., 1989). The US EPA Gulf of Mexico Program located at Stennis Space Center in Bay St. Louis, Mississippi has gone forward with a proposal for special area designation for the Gulf of Mexico to be established in 1993. The criteria for special area designation encompass characteristics of the area's oceanographic and ecological conditions and vessel traffic. If an area is designated as a special area under MARPOL Annex V then dumping of any kind would not be allowed. As of July 1991, the Gulf of Mexico was designated as a special area. After a fifteen month acceptance period, the special area designation will become effective six months after the acceptance period which is April 4, 1993. It will then be illegal to dispose of waste anywhere in the Gulf of Mexico. Other areas which are designated as special areas include the Mediterranean, Baltic, Black and Red Seas and the Persian, Oman and Aden Gulfs (Gulfwatch, 1990). During a cooperative project with the Minerals Management Service (Dept. of Interior), we documented the presence of large (anything as large or larger than 23 cm in diameter) floating plastic during aerial

Volume 24/Number 12/December 1992

surveys on the continental shelf in the Gulf of Mexico from June 1988 through May 1989. The primary objective of the project was to study the relationship of sea turtles to oil platforms (Lohoefener et al., 1990). Our purpose here is to report on the abundance and distribution of floating plastic sighted. The results of this study could be used to compare to data collected in the future so that compliance with MARPOL Annex V may be measured or to monitor the persistence of debris in the Gulf. Five study areas were selected to include a wide range of depths (6-120 m) on the continental shelf off the Louisiana coast (Fig. 1, Table 1). The number and distribution of oil platforms were also important considerations in the size and orientation of the study areas. A DeHavilland (DHC-6) Twin Otter aircraft was used as the study platform. It was modified with a

plexiglass bubble on each side of the aircraft and provided two observers with excellent downward, forward and lateral viewing capabilities. The surveys were flown at an altitude of 229 m and at approximately 204 km h -1. Line transects of each area were surveyed four times each month. Sightings of plastic within 630 m of each side of the transect line by the two observers were recorded on a laptop computer using a BASIC data acquisition program. The computer was interfaced with a LORAN-C unit and the latitude and longitude were automatically recorded with each sighting. Data were pooled by season (summer, June-August; fall, September-November; winter, December-February; spring, March-May). For each season and study area, the density (b) of plastic was estimated using i replicate transects and a strip transect estimator as follows (Burnham et al., 1980):

92:0~;

88:30 ,30:29

30:29.

28: OOl 5 ~ J 92: O~J

SUMMER

28:00 30

88

Fig. 1 Locations of large plastic (.) in summer.

92:0~ 30:29

fl8:30 30:29

'I ,I.IW 28:00 92:05

¸

FALL

28:00 88:30

Fig. 2 Locations of large plastic (.) in fall. TABLE 1 Density of large floating plastic (D in pieces 100 km2). Area 1 se(b)

Season

b

Summer Fall Winter Spring

7.7 12.5 16.9 20.4

1.6 1.7 9.0 5.2

/~ 20.7 44.9 32.3 29.0

Area 2 se(b)

13

Area 3

9.0 8.4 16.1 5.3

7.9 34.1 13.6 28.9

Area 4

se(b)

13

1.4 8.6 3.1 17.5

11.4 69.5 52.6 37.8

se(l~)

13

2.8 14.6 10.2 5.6

19.1 77.2 55.3 38.6

Area 5

se(O) 4.1 33.8 26.8 11.5

599

Marine Pollution Bulletin 92 : 05 30 : 28

i

~

~

~

~

~

88 : 30 30 : 29

.g 5

[':~']

Wl

NTER

28:0( 92:05

28:00 88:30 Fig. 3 Locations of large plastic (.) in winter.

92:05

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g

SPRING

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Fig. 4 Locations of large plastic (.) in spring. R

Z l b, [)i --

~

ni 2liw '

i=1 R i=l

R

E ti(bi=

k

I~(R

-

1)

i=1

where, l was the transect length; n, the number of pieces of plastic; w, the strip width (i.e. 630 m) and R, the number of transects. Large floating plastic was ubiquitous in every study area during each season (Figs 1-4). In general, each season the estimated densities of plastic in Areas 4 and 5 were the largest, and Areas 1 and 3 had the smallest estimated densities of plastic (Table 1). Areas 4 and 5 had the deepest water depths and were located most distant from land. The densities of plastic in Areas 4 and 5 were as much as 6 times larger than they were in Areas 1 and 2. Areas 1 and 3 had shallowest water depths and were located closest to land. In Area 2, the densities of plastic were between those of Areas 4 and 5, and those of Areas 1 and 3. Area 2 was of intermediate depth and distance from land (Figs 1-4). 600

The density of plastic in each study area was the smallest in the summer and except for Area 1, was largest in the fall. Seasonally, the density of plastic in Area 4 was 6 times larger in fall than in summer. The densities in Areas 3 and 5 were about 4 times larger in fall than in summer. The reasons for these differences between study areas and seasons are not apparent. However, the amount of plastic in each area and season could be affected by variations in currents, winds, discharge from rivers and human activity. The study areas were located near major shipping lanes, major river deltas (Mississippi and Atchafalaya) and they also contained many oil platforms. Commercial shrimping and recreational boating activities are also prevalent in these areas. There are approximately 1.5 million private boats, 4500 oil rigs and 6000 shrimp vessels in the Gulf of Mexico (US Coast Guard; NMFS, Southeast Fisheries Center). Our data indicate that large amounts of debris associated with these activities are discarded into the Gulf of Mexico. The debris we surveyed was floating and visible from an altitude of 229 m. Our study did not deal with debris which was too small to see, sinks, or dissipates in the water. We thank R. Lohoefener, W. Hoggard, C. Roden and C. Rogers at the NMFS Pascagoula Laboratory for help in collecting the data; B. Taggart,

Volume 24/Number 12/December 1992 E Wheling, and M. White of the NOAA Aircraft Operations Center for Lohoefener,R., Hoggard,W., Mullin, K., Roden, C. & Rogers,C. (1990). Association of sea turtles with petroleum platforms in the northpiloting the Twin Otter; and B. Avent of the Minerals Management Service, New Orleans, the COTR for the project was alwaysa greathelp. central Gulf of Mexico. OCS Study/MMS 90-0025. US Dept. of the The data for this paper was collected under interagency agreement Interior, Minerals Mgmt. Service, Gulf of Mexico OCS Regional Office,New Orleans, LA. 14-12-0001-30398 between the Minerals ManagementService and the O'Hara, K. J. & Debenham, P. (1989). Cleaning America's beaches: National Marine Fisheries Service. 1988 national beach clean-up results. Center for Marine Conservation, 1725 DeSales Street, NW, Washington, DC. pp. 79-87. Burnham, K. E, Anderson, D. R. & Laake, J. L. (1980). Estimation of O'Hara, K. J. & Younger, L. K. (1990). Cleaning North America's beaches: 1989 beach clean-up results. Center for Marine Condensity from the line transect sampling of biological populations. servation, 1725 DeSales Street, NW, Washington, DC. pp. 113-118. Wildl. Monogr. 72. Gulfwatch (1990). EPA study supports special area designation for gulf. US Department of Transportation, US Coast Guard (1991). Boating Statistics 1990. p. 4. 2(2), 2. Kearney/Centaur Division (1989). Dealing with garbage under Weber, M., Townsend, R. T. & Bierce, R. (1990). Environmental quality in the Gulf of Mexico, a citizen's guide. Center for Marine ConMARPOL Annex V: examplesof complianceapproachesused by the servation, 1725 DeSalesStreet, NW, Washington, DC. p. 41. shipping industry. NOAA/NMFS Contract No. 52ABNF800132.

Marine Pollution Bulletin, Volume 24, No. 12, pp. 601-606, 1992. Printed in Great Britain.

0025-326X/92 $5.00+0.00 @ 1992 Pergamon Press Ltd

A New Certified Reference Material for the Quality Control of Trace Elements in Marine Monitoring: Cod Muscle (CRM 422) PH. Q U E V A U V I L L E R * , G. N. KRAMERI" and B. G R I E P I N K *

*Commission of the European Communities, Community Bureau of Reference (BCR), rue de la Loi 200, 1049 Brussels, Belgium t Commission of the European Communities, Central Bureau for Nuclear Measurements, Steenweg op Retie, 2440 Geel, Belgium

Analyses of fish tissues are routinely carried out by a number of laboratories to monitor the levels of contamination of the marine environment and food by toxic elements, e.g. by heavy metals. To improve and control the quality of such determinations, the Community Bureau of Reference (BCR) has organized a certification campaign which enabled us to produce a reference material (cod muscle CRM 422) certified for its contents of As, Cd, Cu, Fe, Hg, I, Mn, Pb, Se, and Zn. This material was collected in the southern part of the North Sea, carefully prepared (filleted and crushed under liquid nitrogen) and its homogeneity and long term stability were verified. This paper presents the certification work performed.

Information from monitoring programmes form the basis for national and international policies; they provide insight in the effectiveness of measures which have been taken and also the basic information for strategic decisions for environmental protection. This information is expensive: a rapid estimate of the

monitoring costs in the North Sea amounted to up to 20 million ECU per yr. The economic impact of the measures which may be taken on the basis on this information can even be higher. Wrong decisions may give rise to unacceptable damage to the North Sea ecosystem. The improvement of analytical capability and the harmonization of marine monitoring is a necessity; the aspect of quality assurance in marine monitoring is now being considered in the frame of a 'holistic approach' where all aspects of Q A (from collection to final determination) should be dealt with (Quevauviller et al., 1992a; Griepink et al., 1992). In this programme, the use of reference materials play a major role for the validation of the analytical methods applied. The C R M described in this p a p e r completes a series of C R M s produced to support analyses related to the marine environment and in particular: mussel tissue C R M 278 (Griepink & Muntau, 1988), sediment C R M 277 (Griepink & Muntau, 1988) and seawater C R M 403 (Quevauviller et al., 1992b). This new material ( C R M 422) has been certified for those trace elements which are of most interest (As, Cd, Cu, Fe, Hg, I, Mn, Pb, Se, and Zn). 601