Summary

In 1999, a resident of Vieques asked (that is, petitioned) the Agency for Toxic Substances and Disease Registry (ATSDR) to determine whether the Navy's operations on Vieques expose residents to unhealthy levels of environmental contaminants. For the last 2 years, ATSDR has studied this issue extensively. The results of those studies appear in a series of reports known as public health assessments (PHAs). This PHA evaluates the soils of Vieques and addresses the public health implications of exposure to them. ATSDR's findings and the reasons supporting them are documented throughout this report, but the main conclusions are identified below.

Soil Characteristics

ATSDR evaluated the general soil characteristics of Vieques to identify:

1. Whether the soils of Vieques have elevated levels of metals or other chemicals.
2. Whether the soils of Vieques show evidence of contamination by Navy training activities.

To answer these questions, ATSDR evaluated the general soil characteristics of Vieques in several ways.

• Soil sample analyses were grouped based upon their underlying parent material (the geologic units or rock formations), and the general chemical characteristics of those soils throughout the island were compared and contrasted. ATSDR concludes that the composition of the soils of Vieques including their constituent metal content is strongly influenced by the parent material (underlying geologic units) from which those soils are derived.
• The quality of the soil on Vieques was compared with sediment on the mainland of Puerto Rico and with the soil of the United States. ATSDR concludes that even though the maximum level of some of the metals detected in Vieques soil is moderately elevated in comparison to soil elsewhere (Puerto Rico and the United States), the levels are not inconsistent with what one would expect from soils also underlain by igneous or volcanic rocks.
• The levels of metals in the soils of the Live Impact Area (LIA) were examined to determine if they had been affected by Navy training activities. To do this, ATSDR utilized two different approaches: (1) to compare concentrations of chemicals detected at the LIA to the remainder of Vieques and (2) to compare concentrations of chemicals detected at the LIA to background (naturally occurring) soil samples in the former Naval Ammunition Support Detachment (NASD). ATSDR concludes that it appears that the soils of the LIA have been influenced by Navy training activities and do contain elevated levels of heavy metals. However, the concentrations of the chemicals in the soil are not at levels that pose an adverse health threat (see the Public Health Evaluation section).
• The soil analyses were examined for spatial trends (i.e. progressive trends or gradients from east to west) that might reflect contaminant migration from the LIA into the residential area. ATSDR concludes that the analyses do not detect spatial trends and thus do not supply supporting evidence for airborne transportation and deposition of contaminants into the residential area.

Public Health Evaluation

ATSDR identified two potential pathways of human exposure to chemicals in the soil of Vieques:

1. Residents and visitors of Vieques can contact the soil in the residential portion of the island.
2. Individuals can contact the soil when they enter the LIA.

ATSDR evaluated whether incidental ingestion or dermal contact with the soil would result in harmful health effects from either exposure pathway.

• ATSDR concludes that the residents of Vieques are not being exposed to harmful levels of chemicals in the soil on Vieques. The levels of metals and other chemicals detected on Vieques are too low to be of health concern for both adults and children.
• ATSDR concludes that the protestors who occupied portions of the LIA from April 1999 to May 2000 were not exposed to harmful levels of chemicals in the soil. The levels of metals and other chemicals detected at the protestor camps on the LIA were too low to be of health concern for both adults and children.

Overall Conclusions

Based upon a thorough evaluation of the soils of Vieques, including the soils of the residential area as well as the LIA, ATSDR concludes that Navy training activities have elevated the levels of some metals in soil at the LIA, however, residents and visitors of Vieques are not being exposed to harmful levels of contamination in those soils.