ACCESS NUMBER: 11957

STUDY TITLE: Marine Debris Point Source Investigation: Padre Island National 

Seashore March 1994-September 1995 

REPORT TITLE: Marine Debris Point Source Investigation: Padre Island National 

Seashore March 1994-September 1995 

CONTRACT NUMBER: 11957 

SPONSORING OCS REGION: Gulf of Mexico 

APPLICABLE PLANNING AREA: Gulf of Mexico 

FISCAL YEAR OF PROJECT FUNDING: 1995 

COMPLETION DATE OF REPORT: July 1996 

COST: FY 1995: $30,000

PROJECT MANAGER: John E. Miller 

AFFILIATION: National Park Service, Padre Island National Seashore 

ADDRESS: 9405 South Padre Island Drive, Corpus Christi, Texas 78418 

PRINCIPAL INVESTIGATORS*: John E. Miller and Darrell L. Echols 

KEY WORDS: Gulf of Mexico; Padre Island National Seashore; barrier island; marine 

debris; point source polluters; plastic debris; commercial fishing 

BACKGROUND: Padre Island is a barrier island located on the southeastern coast of 

Texas. Created by the Congress of the United States in 1962, Padre Island National 

Seashore (PINS) is the longest undeveloped beach in the United States -- 68 miles in 

length. Although similar in many ways to other National Seashores, PINS is atypical 

because of the large quantity of garbage that washes onto its shoreline. At times, the 

shoreline is inundated by as much as one ton of debris per linear mile. The primary 

reason for this large accumulation of debris is the convergent currents occurring off the 

park’s coastline. Because of these currents, any item discarded into the Gulf of Mexico 

has the potential of washing onto the PINS shoreline. Marine debris represents the 

foremost natural resource management problem at the National Seashore and includes 

aesthetics and impacts to marine mammals, birds and reptiles from entanglement and 

ingestion. Additionally, toxic chemicals and medical waste wash ashore and pose a 

safety hazard to the visiting public. With the signing of the Plastics Act in 1987, the 

United States joined 39 other nations in ratifying Annex V of the International 

Convention for the Prevention of Pollution from Ships, known as MARPOL. This treaty 

bans the dumping of plastics by vessels at sea. It also limits the dumping of other 

vessel -- generated garbage to specific distances from shore. In the Gulf of Mexico, the 
ACCESS NUMBER: 11957

treaty expressly prohibits the discharge of any vessel generated garbage. Because of 

the sheer amount of plastics and other debris washing onto the PINS shoreline, we 

questioned whether MARPOL regulations are working. The amount of garbage 

washing onto PINS will not be reduced, nor will the overall problems of marine debris in 

the Gulf of Mexico be adequately addressed, unless point sources are identified. The 

objective of the seven-year long PINS research was to identify point sources and to 

furnish the results to state and federal agencies concerned with the health of the Gulf of 

Mexico. 

OBJECTIVE: To analyze the numbers of specific debris items associates with the 

offshore oil and gas industry per month for 18 months (March 1, 1994 -September 30, 

1995). 

DESCRIPTION: Based on findings from previous marine debris studies conducted at 

Padre Island National Seashore (PINS), methods were developed to identify and 

assess the magnitude of marine point source pollution in the Gulf of Mexico. In 

February 1994, PINS began an investigation to connect the amount of garbage washing 

onto the beach from specific sources. This project involved a 7 days/week survey of 16 

miles of shoreline between March 1, 1994 until September 30, 1995. During this time, 

42 specific items were collected from the tidal area. Thirteen items associated with 

offshore oil and gas platforms were identified. These items were compiled in 

partnership with the Minerals Management Service and the Offshore Operators 

Committee (whose members include major oil and gas companies operating the Gulf of 

Mexico). ARCO Oil and Gas Company conducted a marine debris survey in 1990 to 

assess offshore operator compliance with U.S. Coast Guard regulations under 

MARPOL Annex V. ARCO’s study developed a list of items that is representative of 

platform debris. A list of items associates with the shrimping industry was developed 

through communications with the United States Coast Guard and conversations with 

individuals familiar with the shrimping industry in the Gulf of Mexico. Fifteen items were 

selected and targeted for the investigation. Before beginning, items were grouped into 

two categories -- probable and suspected. “Probable” items were unique and specific to 

the shrimping industry; “suspected” items were those that appeared in great numbers 

during the same time that the probable items washed ashore. Fourteen items from an 

unknown source were selected for long-term analysis of marine debris composition and 

accumulation at PINS. These items may be associated with shipping, recreational 

boating, beach visitation, or land-based non-point sources (e.g., landfills, storm drains, 

etc). 

SIGNIFICANT CONCLUSIONS: Environmental factors directly influence the amount of 

daily debris accumulation. PINS research indicates that mathematical extrapolation of 

data from infrequent surveys is inaccurate. Additionally, PINS research indicates that 

debris collected from the backshore area of there beach is not post-MARPOL Annex V 

garbage. Results from this research indicate that point source violators can be 

identified. The research indicates that the shrimping industry is directly responsible for 

30 percent of garbage that washes into the PINS survey area. They are suspected of 

contributing an additional 35 percent. We have also shown that the offshore oil and gas 
ACCESS NUMBER: 11957

industry is suspected of contributing 13 percent of the garbage that accumulated in the 

PINS survey area. Taken together, over 70 percent of most items that wash ashore are 

contributed by identifiable point sources. 

STUDY RESULTS: During the sample period, 63,410 debris items were collected from 

the 16-mile transect. Thirteen items associated with the offshore oil and gas industry 

numbered 8,063 (13% of the total), 14 items from an unknown source totaled 13,382 

(21% of the total), and the items associates with the commercial shrimping industry 

numbered 41,965 (66% of the total). In the offshore oil and gas category, the most 

abundant items included strip lumber (3,781), plastic straps (2,042) and five-gallon 

containers (3,781). Of the items that are considered to be probable shrimping items, a 

total of 18,751 were collected. Of these items the most abundant were rubber gloves 

(10,178), onion sacks (3,150) and scoops (2,484). In the “suspected” shrimping 

category, 23,214 items were collected. The most abundant were one-gallon milk 

containers (8,689), incandescent light bulbs (4,125) and glass condiment bottles 

(3,418). Items collect in the “unknown source” category contained the greatest number 

of items in the following: green quart bleach bottles (4,880), one-quart oil containers 

(2,479), and balloons and ribbons (2,340). Compared to previous survey’s, the 

percentages of each category did not significantly change nor did the types and 

amounts of abundant items within each category change significantly either. 

STUDY PRODUCT: Marine Debris Point Source Investigation, March 1994-September 

1995. 1996. OCS Study MMS 96-0023. U.S. Dept. of the Interior, Minerals 

Management Service, Gulf of Mexico OCS Region, New Orleans, LA, and U.S. Dept. of 

the Interior, National Park Service, Padre Island National Seashore, Corpus Christi, TX. 

38 pp. 

*P.I.’s affiliation may be different than that listed for Project Managers.