II. Background

Vieques is the largest offshore island in the Commonwealth of Puerto Rico. Vieques is 20 miles long, 4.5 miles at its widest point, and about 33,000 acres (or 51 square miles) in area. Figure 1 shows the location of Vieques and surrounding islands. As the figure illustrates, the nearest island to Vieques is the main island of Puerto Rico, approximately 7 miles to the west. The island of Culebra is roughly 9 miles north. St. Thomas, St. John, St. Croix, and other US Virgin Islands are all 20 miles or more northeast and southeast of Vieques.

Land Use

The detailed map in Figure 2 illustrates land use in Vieques. The western portion of Vieques is the former Naval Ammunition Support Detachment (NASD). Prior to May 2001, the Navy used this 8,200 acres for limited Navy operations (e.g., ammunition storage, rock quarry, communication facilities, and Navy support buildings) (IT Corporation 2000). In May 2001, the Navy transferred most of the NASD to the Isla de Vieques, the Puerto Rico Conservation Trust, and the US Department of the Interior, but retained about 100 acres of the former NASD lands for radar and communication facilities (Navy 2001a). Some NASD areas were leased to local farmers for cattle grazing and other agricultural purposes (see Picture 1).

The central 7,000 acres of Vieques houses the entire residential population of the island, mostly in the towns of Isabel Segunda and Esperanza. Vieques land uses include residential, agricultural, commercial, and industrial. In the past, sugarcane was the principal crop. Other crops have included coconuts, grains, sweet potatoes, avocados, bananas, and papayas. In the 1960s and 1970s, manufacturing was important for the economy, beginning in 1969 with the construction of the General Electric plant (Bermudez 1998). But currently, only minimal manufacturing takes place on the island. Isabel Segunda and Esperanza, however, are home to commercial fishing fleets, and recently tourism has been increasing in economic importance.

Until May 2003⁽¹⁾ , the Navy owned roughly the eastern half of Vieques, which is divided into two sections: the Eastern Maneuver Area (EMA) and the Atlantic Fleet Weapons Training Facility (AFWTF).

• The EMA includes approximately 11,000 acres located immediately east of the residential lands. The Navy uses the EMA periodically for various combat training activities, such as conducting shore landing exercises and small arms training (CH2MHILL and Baker 1999; IT Corporation 2000). Camp Garcia, where Marine Corps and Navy personnel are temporarily stationed on Vieques, is within the EMA (see Picture 2). East of the EMA is the AFWTF (3,600 acres), which is further divided into three smaller sections of land:
  
  
• The western part of AFWTF was formerly known as the Surface Impact Area. Prior to 1978, the area was used as an impact area for artillery. It is heavily vegetated and almost completely undeveloped, except for dirt roads, a few observation posts and towers, and the main observation post (OP-1), located on Cerro Matias on the eastern side (see Pictures 3 and 4).
• The middle portion of AFWTF is the Live Impact Area (LIA), also commonly referred to as the bombing range. This roughly 900-acre tract contains the targets for aerial and naval bombardment. The LIA is sparsely vegetated and contains no structures--only surplus equipment (e.g., tanks, small airplanes, and trailers) the Navy uses as targets (see Pictures 5 and 6).
  
  
• The eastern tip of AFWTF is the Punta Este Conservation Zone. To preserve the unique upland forest scrub and evergreen scrub habitats, no Navy operations take place on this small piece of land. A variety of animals, including roseate terns and sea turtles, visit and nest there (see Picture 7).
  
  

Demographics

ATSDR examines demographic data (i.e., population information) to determine the number of people potentially exposed to environmental chemicals and to determine the presence of any sensitive populations, such as women of childbearing age, children, and the elderly. Demographic data also provide details on population mobility which, in turn, helps ATSDR evaluate how long residents might have been exposed to environmental chemicals.

Table 1 summarizes the 2000 US Census Bureau demographic data for Vieques. As the table shows, the 2000 Census reported that 9,106 people live on Vieques. This figure includes residents on both the residential lands and Navy property. Table 1 also specifies the number of residents in three potentially sensitive populations. According to several anecdotal accounts, the population of Vieques is not highly mobile; many are lifelong residents of the island.

As noted previously, most of the residents of Vieques live in the two largest towns on the island, Isabel Segunda and Esperanza (see Pictures 8 and 9). Although these towns are located relatively close to the Navy property, they are several miles removed from the LIA. Approximately 7.9 miles of Navy owned land provides a buffer zone between the LIA and populated areas of Vieques.

Climate

Vieques lies in the path of the easterly trade winds (i.e., winds blowing from east to west). The climate is tropical-marine, with temperatures averaging about 79 Fahrenheit (26.3 Celsius). Annually, the temperature ranges from an average of 76 Fahrenheit (24.6 Celsius) in February to 82 Fahrenheit (28 Celsius) in August. The average amount of precipitation is about 45 inches a year. The western part of the island receives a higher amount of rainfall (about 50 inches a year) than the eastern part (about 25 inches a year). The rainy season is from August through November while the remainder of the year is drier. Tropical storms are common from June to November (NCDC 1985-1994; Torres-Gonzalez 1989).

African Dust Storms

Through the natural occurrence of African dust storms, Vieques, together with the mainland of Puerto Rico and other Caribbean islands, receive an increase of airborne dust particles in the summer. Each year, large quantities of dust from the Sahara Desert and Sahel region in Africa are transported at high altitudes to the Caribbean Sea and southeastern United States. These dust storms can transport minerals, chemicals, bacteria, fungus spores, and possibly viruses and insects. Recent studies have begun to link declining coral reef health with fungi and bacteria found in African dust (e.g., the soil fungus, Aspergillus, causes a disease in sea fans; USGS 2000). The potential for adverse health effects to occur from African dust storms will be addressed in the Community Health Concerns Section of the Air Pathway Evaluation PHA.

Geology

Vieques was formed from igneous and volcanic rock, mostly granodiorite, quartz diorite, and some lavas which created the bedrock of the island. On most of the western half as well as the central portion of the eastern half of the island, the bedrock is exposed and weathered. Because of the weathering of the bedrock, gravel and sands wash downhill during storms. Over the years this material has gathered in valleys by the ocean, forming alluvial deposits (see text box for definition). Other portions of Vieques have ancient marine deposits from a time when the island was submerged. Today these deposits reveal areas with some limestone, sandstone, siltstone, and other sedimentary rocks at the surface. ATSDR's PHA focused on the soil pathway describes the geology and soils of Vieques in greater detail (ATSDR 2003).

Naval Operational History

The Navy has occupied portions of Vieques since 1941. In 1960, the Navy established targets on Vieques and began bombing practice (Navy 1990). The use of the LIA for air-to-ground and ship-to-shore training increased after the closing of the Culebra Island range in the mid-1970s.

Many different types of explosive and non-explosive ordnance (e.g., bombs, flares, rockets, projectiles, and small arms) have been used at Vieques. ATSDR's PHA focused on the soil pathway describes the types of military ordnance in greater detail (ATSDR 2003). Generally, Naval training exercises are most frequent in February and August with fewer exercises in April, May, November, and December. Range utilization statistics data from 1983 to1999 indicate that the Navy and other parties conducted exercises on Vieques between 159 and 228 days per year, with the total number of days not varying considerably from one year to the next. On average, 1,862 tons of ordnance were used at Vieques annually between 1983 and 1998. This ordnance, on average, contained 353 tons of high explosives (Navy 1999). ATSDR's PHA focused on the air pathway will describe ordnance use on Vieques in greater detail.

Two types of explosives were commonly used at Vieques (Young 1978). One explosive is made from organic nitrated compounds (i.e., only carbon, hydrogen, oxygen, and nitrogen). Examples include 2,4,6-trinitrotoluene (TNT), cyclotrimethylene trinitramine (RDX), cyclotetramethylene tetranitramine (HMX), tetryl, Explosive D, Composition B (RDX and TNT), Octol (HMX and TNT), and Composition A-3 (RDX and wax). The second kind of explosive contains aluminum in addition to the organic nitrated compounds. Examples include Tritonal (TNT and aluminum), H-6 (TNT, RDX, and aluminum), and Torpex (TNT, RDX, and aluminum).

Live ordnance has not been used on Vieques since April 19, 1999, when two 500-pound bombs were accidentally dropped near an observation post (OP-1) on the LIA, killing a civilian guard. In January 2000, the decision was made that the Navy could resume training on Vieques. The training is limited to 90 training days per year and the use of nonexplosive ordnance only. In May 2000, the Navy resumed training.

ATSDR Involvement at Vieques

Since its 1999 receipt of the petition requesting an evaluation of public health issues on Vieques, ATSDR has worked extensively to characterize the extent of environmental contamination and potential health effects and to respond to community needs. The following is a summary of ATSDR's past involvement on Vieques:

• Site visits. Since 1999, teams of ATSDR scientists and community involvement specialists have visited Vieques more than 10 times. These visits included site familiarization, identification of health concerns, collection of relevant site information, and collection of fish and shellfish for analysis. During two of the site visits, ATSDR personnel extensively toured the former NASD, EMA, and AFWTF, which included a ground and aerial tour of the LIA.
• Community involvement. Defining community concerns is an essential step in the public health assessment process. To define specific environmental health issues of concern, ATSDR met several times with individuals, families, and many other residents of Vieques. ATSDR has also met with elected officials, physicians, nurses, school educators, fishermen, leaders of women's groups, pharmacists, and businessmen. Among other discussion topics, ATSDR inquired how the agency can most effectively provide public health information to the community. ATSDR plans to continue such community involvement activities at Vieques.
• Health education. Throughout the community involvement process, ATSDR has worked with physicians, nurses, and school officials to provide educational materials and to support the overall public health of Vieques residents. To date, the agency has hosted four physician workshops and one nurses' training workshop covering the various aspects of environmental health, including procedures for taking an exposure history The agency has also facilitated community education sessions on cancer. ATSDR intends to provide additional education sessions that will address topics such as air quality and asthma, nutrition and wellness, and environmental health.

In addition to the previous list of activities on Vieques, ATSDR has assessed the following public health issues:

• In October 2001, ATSDR released a PHA addressing contamination in drinking water supplies and groundwater (ATSDR 2001a). This report concluded that the public drinking water supply on Vieques poses no public health hazard. However, high nitrates and nitrites, most likely resulting from agricultural pollution, in one private drinking water well indicate a health concern for children and pregnant women if they drank water from that well. The report evaluates these health issues in greater detail. Copies are available by contacting ATSDR (1-888-42-ATSDR) and from records repositories on Vieques. The repositories are located at Biblioteca Publica (Calle Carlos Lebrum, Vieques), the Vieques Conservation and Historical Trust (Flamboyan Street, Vieques), and at the University of Puerto Rico's School of Public Health (San Juan, Puerto Rico).
• In July 2001, ATSDR, the Ponce School of Medicine, and the Centers for Disease Control and Prevention (CDC) sponsored an expert panel review to address whether an association existed between place of residence (Vieques or Ponce Playa) and morphological cardiovascular changes among fishermen. A second review by experts showed no indication of abnormal heart function attributable to pericardial thickening. The report summarizing the expert panel review was released in October 2001 (ATSDR and PSM 2001). Copies are available by contacting ATSDR (1-888-42-ATSDR).
• ATSDR continues to evaluate the public health implications of exposure to air contaminants. In a PHA released for public comment in November 2002, ATSDR addressed potential health issues resulting from air releases from the LIA, including wind-blown dust and the use of practice bombs, live bombs, and various other munitions.
• In February 2003, ATSDR released a PHA addressing public health implications from exposures to soils on Vieques (ATSDR 2003). ATSDR addressed exposures that the residential population might typically experience as well as exposures that individuals who lived on the LIA between April 1999 and May 2000 might have experienced. This document concluded that there is no evidence that residents are being exposed to harmful levels of contamination in the soil.

¹ As of May 2003, the former Navy portions of Isla de Vieques are under the control of the U.S. Fish and Wildlife Service.