FINAL DATA REPORT

FOR THE

VIEQUES ISLAND BIOTA SAMPLING PROJECT

VIEQUES ISLAND, PUERTO RICO

PREPARED BY

NATIONAL OCEANIC AND ATMOSPHERIC ADMINISTRATION

NATIONAL OCEAN SERVICE

OFFICE OF RESPONSE AND RESTORATION

AND

RIDOLFI Inc.

NOAA’s Office of Response and Restoration
FINAL DATA REPORT

FOR THE

VIEQUES ISLAND BIOTA SAMPLING PROJECT

VIEQUES ISLAND, PUERTO RICO

Prepared by

National Oceanic and Atmospheric Administration

National Ocean Service

Office of Response and Restoration

and

RIDOLFI Inc.

July 2006

NOAA’s Office of Response and Restoration
INFORME FINAL DE DATOS

PARA EL

PROYECTO DE MUESTREO BIOTA EN LA ISLA DE VIEQUES

ISLA DE VIEQUES, PUERTO RICO

Preparado por

Administración Nacional Oceánica y Atmosférica

Servicio Nacional de Océanos

Oficina de la Respuesta y la Restauración

y

RIDOLFI Inc.

Julio 2006

NOAA’s Office of Response and Restoration
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ACKNOWLEDGEMENTS

This study was funded wholly by NOAA. The crab samples for this study were collected with the

assistance of individuals from the U.S. Fish and Wildlife Service, the U.S. Environmental

Protection Agency, and the Puerto Rico Environmental Quality Board. A U.S. Navy expert in 

unexploded ordnance accompanied the sampling team into areas where public access is

restricted.

RECONOCIMIENTOS

Este estudio fue financiado en su totalidad por la Administración Nacional Oceánica y

Atmosférica (NOAA, por sus siglas en inglés). Las muestras de cangrejos para este estudio se

recolectaron con la colaboración de miembros del Servicio de Pesca y Vida Silvestre de

EE.UU., la Agencia de Protección Ambiental de EE.UU. y la Junta de Calidad Ambiental de

Puerto Rico (JCA). Un experto en materiales explosivos de la Marina de EE.UU. acompañó al

equipo de recolección de muestras en las zonas donde está restringido el acceso al público.
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CITATION

National Oceanic and Atmospheric Administration and RIDOLFI Inc. (NOAA and Ridolfi).

2006. Final Data Report for the Vieques Island Biota Sampling Project, Vieques Island, Puerto 

Rico. NOAA, National Ocean Service, Office of Response and Restoration. Seattle, WA.

CONTACT INFORMATION

For more information about this report or to obtain a copy, please visit

<HTTP://mapping.orr.noaa.gov/website/portal/vieques/projectscrab.html> or contact Mike

Buchman, NOAA/NOS/OR&R at (206) 526-6340.
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EXECUTIVE SUMMARY

In June 2005, the National Oceanic and Atmospheric Administration (NOAA) Office of

Response and Restoration (ORR) conducted an investigation of land crab (Cardisoma guanhumi)

and fiddler crab (Uca spp.) from Vieques Island, Puerto Rico. Assistance was provided by the

U.S. Fish and Wildlife Service (USFWS), the U.S. Environmental Protection Agency (USEPA),

the Puerto Rico Environmental Quality Board (EQB), and RIDOLFI Inc. under contract to

NOAA. The primary purpose of the investigation was to characterize concentrations of explosive

compounds, polychlorinated biphenyls (PCBs), organochlorine pesticides, and trace elements in

land and fiddler crab. In addition, the Agency for Toxic Substances and Disease Registry 

(ATSDR) has used the land crab data presented in this report to write a Public Health 

Consultation (PHC), which is included in this report as Appendix H. Prior, limited investigations

have been conducted by the ATSDR, the USFWS, and researchers from the University of Puerto 

Rico: this investigation was designed in part to build upon those previous efforts.

Results from the evaluations by ATSDR and NOAA will assist the USFWS in determining 

whether selected refuge areas can be opened to crab harvesting. In the future, the U.S. Navy, the

USEPA, and the Puerto Rico EQB may also use portions of the land and fiddler crab data, as

appropriate, in a full human health and ecological risk assessment for portions of Vieques Island.

From the 1940s until 2003, a portion of Vieques Island was used for military training exercises

(gunfire and bombing). In 2001, the U.S. Navy transferred ownership of approximately 3,000

hectares (7,500 acres) of land on the west end of the island to the municipality of Vieques, the

Puerto Rico Conservation Trust, and the USFWS. On May 1, 2003, the U.S. Navy ceased all

military operations on and around the island and transferred its property on the east end of the

island (approximately 5,800 hectares [14,575 acres]) to the USFWS. The land on the east end of

the island and the land controlled by the USFWS on the west end of the island were then 

designated a national wildlife refuge. Approximately 9,300 Puerto Ricans live in the residential

section of the island, which lies between the east and west ends. Land crab are an important

subsistence resource to these islanders.
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For the current investigation, land and fiddler crab were sampled from mudflats, mangrove

wetlands, coastal forested areas, and sandy areas on the east and west ends of Vieques Island.

Land crab were collected because of their importance in the diet of the island’s residents. Fiddler

crab were collected because they live in similar habitats, yet represent a slightly different

pathway in the food web and serve as an additional indicator species for potential contaminant

uptake. Because of their small size, a composite sample of fiddler crab also represents a far

greater number of individuals per sampling station than is possible with the land crab.

Five to six individual land crab were collected from each of 12 sampling locations, which mainly

represented potential or known harvest areas. Two reference locations of similar habitat were

also sampled. Three composite samples of fiddler crab were collected at each of 12 sampling 

locations and one reference location: no fiddler crab were present at the on-island, Blue Horizon

reference site. Following sample collection, the land crab and fiddler crab were processed and 

shipped according to the methods described in the Final Sampling and Analysis Plan for the

Vieques Island Biota Sampling Project. Individual whole body land crab samples and composite,

whole-body fiddler crab samples were analyzed for explosive compounds, PCBs, organochlorine

pesticides, and trace elements. A limited number of land crab samples were subdivided into 

exoskeleton (i.e., the carapace and other parts of the shell) and soft tissue-only samples and these

fractions were analyzed separately for trace elements. All analytical data were independently 

reviewed and validated to ensure their usability.

The fiddler crab data were compared to conservative ecological screening benchmarks; these

conservative values provide a high degree of confidence that contaminant concentrations that do

not exceed the benchmarks will not pose substantial adverse risk. Conversely, contaminant

concentrations in excess of the conservative benchmarks do not necessarily indicate a definitive

problem, but indicate the need for more detailed evaluations. Some of the benchmarks are

specific to the protection of crab; when crustacean-specific benchmarks were not available,

benchmarks protective of wildlife that eat contaminated prey (birds or small mammals) were

used. Land crab data were also compared to just the crustacean-specific benchmarks, which 

include all organic benchmarks, cadmium, mercury, and vanadium.
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Results generally indicate minimal occurrence of organic chemicals. Concentrations of many 

organic chemicals were below the sample-specific method detection limits (MDLs), and many of

the detected values were just slightly above the MDLs. Explosive compounds were not detected 

in any land or fiddler crab. PCB compounds were detected in samples from only one area:

Aroclor 1260 was found in a single land crab sample from Laguna Kiani, while Aroclor 1254 

was found in all three fiddler crab composites from that sampling location. PCB concentrations

in the crab samples, however, were well below the conservative ecological screening benchmark.

PCBs have been reported by the U.S. Navy in the groundwater at Laguna Kiani in the past.

Unlike other organics, organochlorine pesticides, predominantly DDT and its metabolites, were

detected in multiple land and fiddler crab samples. Levels of total DDT were generally higher in

fiddler crab than in land crab, but there was concordance between the two species in the general

pattern of sites having the highest average concentrations. Laguna Kiani, Red Beach, Blue

Beach, and Bahia Tapon displayed higher concentrations of total DDT in both land and fiddler

crab. The composition of DDT compounds does not suggest ongoing releases. These results are

similar to those found in previous investigations.

The second most commonly detected pesticide was chlordane and its related compounds.

Chlordane compounds were detected near the MDL in land crab from half of the sampling areas,

including the on-island Blue Horizon reference location. Total chlordane (the sum of eight

compounds) was detected at concentrations usually near the MDL in fiddler crab from all

sampling locations except Mosquito Bay, including samples from the Humacao Wildlife Reserve

reference location on mainland Puerto Rico. Again, there was concordance between the two 

species, with Laguna Kiani and Bahia Tapon having the highest total chlordane levels.

The occurrence of other pesticides was generally limited and sporadic. Aldrin, endrin, and

dieldrin were detected at one to two sites each. Mirex was observed in most land crab and all

fiddler crab samples only from the Live Impact Area (LIA). No pesticide concentrations in land

or fiddler crab exceeded any ecological screening benchmarks.

As in previous investigations, trace elements were ubiquitously detected in both land and fiddler

crab samples across all sampling locations. The widespread detection of numerous trace
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elements in crab samples likely reflects exposure to elements naturally occurring in soil,

sediment, groundwater, and surface water. Elevated levels, especially those significantly greater

than the reference site, tend to suggest the potential for exposure to anthropogenic sources. In

general, the results are variable. Differences were observed both within and among sampling 

areas, from element to element, and between the two crab species. However, there were

observations of concordance between the two species that tend to suggest consistent exposures.

In land crab, average concentrations of beryllium, iron, mercury, selenium, thallium, uranium,

vanadium, and zinc were either not different among locations or were not significantly greater

than concentrations at the reference locations. For all other trace elements, at least one area had 

significantly greater concentrations than were observed at a reference location. However, in 

some cases this was because of elevated concentrations measured in a single crab.

In its PHC, the ATSDR concluded that levels of PCBs, organochlorine pesticides, and trace

elements found in land crab were much lower than levels reported in the scientific literature as

causing harmful health effects. Therefore, the ATSDR does not expect harmful health effects to 

occur in adults and children as a result of eating land crabs from Vieques Island. DDE

concentrations were also below the Food and Drug Administration’s regulatory limit for shellfish 

consumption.

The land crab data were also screened against ecological screening benchmarks for cadmium,

mercury, and vanadium meant to be protective of other crustacean species. All concentrations of

mercury were below the ecological screening benchmark. Vanadium concentrations were either

below the MDL or above the screening benchmark. Average vanadium among areas did not

differ from means observed from either reference though, suggesting that vanadium levels may 

represent baseline conditions. The cadmium benchmark was exceeded in four samples from three

sampling locations (Boca Quebrada, Laguna Kiani, and the LIA). Levels in crab from the LIA

were significantly greater than those from either reference. This ecological screening indicates

that the possibility of adverse impacts to land crab due to the body burden of cadmium, and

perhaps vanadium, cannot be eliminated for some specific areas.
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One land crab from each sampling area was dissected into exoskeleton and soft tissue fractions,

which were analyzed separately for trace elements. The purpose was to evaluate the two

fractions for indications of preferential bioconcentration. In general, more compounds were

detected in the soft crab tissue than in the exoskeleton. The exoskeletons did not contain

beryllium, mercury, or selenium. Concentrations of half of all detected trace elements were

greater in the exoskeleton than in the soft tissue; concentrations of barium, calcium, chromium,

and magnesium were at least an order of magnitude greater. Average cadmium, copper, silver,

and zinc concentrations were three to ten times higher in the soft tissue.

Concentrations of beryllium, manganese, mercury, nickel, thallium, and uranium in fiddler crab 

did not exceed ecological screening benchmarks in any samples. No benchmarks were available

for cobalt, iron, and silver. Concentrations of ten trace elements measured in fiddler crab 

exceeded ecological screening benchmarks in one or more samples. Of these, aluminum, arsenic,

vanadium, and zinc exceeded wildlife screening benchmarks in all samples from all sampling 

areas, including the reference location. Concentrations of barium, cadmium, chromium, copper,

and selenium exceeded screening benchmarks to varying degrees and at various locations. Lead 

concentrations exceeded the benchmark at only one location (Laguna Kiani). Three of the

compounds that exceeded benchmarks (cadmium, lead, and selenium) were not detected in the

Humacao Wildlife Reserve reference samples at concentrations above the benchmarks.

The occurrence of PCBs in both land crab and fiddler crab from Laguna Kiani, which is

coincident with past reports by the US Navy of PCBs in groundwater at this same site,

demonstrate that PCBs at this location are bioavailable and capable of entering the food web.

The co-occurrence of maximum concentrations of other contaminants in these same samples for

both species suggests that other contaminant releases may be occurring within this area as well.

Although the concentrations of organics reported here are below screening benchmarks, the

limited extent of sampling in this preliminary study makes it difficult to draw firm conclusions

regarding the degree of risk that releases at this site may pose. Further characterization of the

nature and extent of releases at this site is recommended as part of the ongoing remedial

investigation or as monitoring to verify the effectiveness of removal actions.
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The concordance observed between the two species in some contaminants detected may indicate

exposure pathways at other sites as well. Examples include mirex, arsenic, and cadmium

observed at the LIA and total DDT at Blue Beach, Red Beach, and Bahia Tapon. Although 

values were below screening benchmarks, these observations demonstrate an exposure

mechanism for these areas.

The screening-level assessment presented in this report should not be viewed as a full ecological

risk assessment. This screening assessment applied conservative assumptions about exposure

that are not necessarily realistic or appropriate for characterizing actual risk. Instead, it offers a

high level of confidence in determining situations where a low probability of adverse impacts are

present, and facilitates determining the need for, and degree of, further investigation. The

screening-level assessment acknowledges that any chemical concentrations exceeding the

conservative benchmark values may be considered potentially hazardous, although they are not

necessarily so until further, more realistic, site-specific assessments determine this. The

preliminary screening of crab chemical body burdens presented here cannot eliminate the

possibility that some analytes may be present at levels sufficiently high to cause adverse impacts

to crab. To fully identify and characterize potential risk to the environment, further analysis of

appropriate portions of these data, as well as evaluations for other ecological receptors, may be

warranted, particularly with regard to PCBs, total DDT, and some trace elements. The need for

additional evaluation, as applicable, should be determined in the human health and 

environmental risk assessment activities required for the ongoing remedial investigation of sites

on Vieques Island.
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RESUMEN EJECUTIVO

En junio de 2005, la Oficina de la Respuesta y la Restauración de la Administración Nacional

Oceánica y Atmosférica (ORR, NOAA, por sus siglas en inglés, respectivamente) llevó a cabo 

una investigación sobre el cangrejo terrestre (Cardisoma guanhumi) y el cangrejo violinista (Uca 

spp.) en la Isla de Vieques, Puerto Rico, en colaboración con el Servicio de Pesca y Vida

Silvestre de EE.UU. (USFWS, por sus siglas en inglés), la Agencia de Protección Ambiental de

EE.UU. (USEPA, por sus siglas en inglés), la Junta de Calidad Ambiental de Puerto Rico (JCA)

y RIDOLFI Inc. bajo contrato con NOAA. El propósito principal de la investigación fue definir

las concentraciones de compuestos de explosivos, policlorobifenilos (PCB), pesticidas

organoclorados y oligoelementos en los jueyes y en los cangrejos violinistas. Además, la

Agencia para Sustancias Tóxicas y Registro de Enfermedades (ATSDR, por sus siglas en inglés)

ha utilizado los datos obtenidos del cangrejo terrestre presentados en este informe para redactar

una Consulta de Salud Pública (CSP), que se incluye en este informe como Apéndice H.

Anteriormente, ATSDR, USFWS e investigadores de la Universidad de Puerto Rico han

realizado investigaciones limitadas: esta investigación fue diseñada en parte para ampliar estos

esfuerzos previos.

Los resultados de las evaluaciones de ATSDR y NOAA ayudarán a USFWS a determinar si las

áreas de refugio seleccionadas pueden abrirse para la cría de cangrejos. En el futuro, la Marina

de EE.UU., USEPA y JCA de Puerto Rico también pueden utilizar porciones de los datos sobre

el cangrejo terrestre y sobre el cangrejo violinista, según el caso, en una completa evaluación de

los riesgos para la salud humana y la ecología en áreas de la Isla de Vieques.

Desde los años 1940 hasta 2003, una parte de la Isla de Vieques se utilizó para ejercicios de

entrenamiento militar (fuego de artillería y bombardeos). En 2001, la Marina de Estados Unidos

traspasó la propiedad de aproximadamente 3.000 hectáreas (7.500 acres) de tierra en el extremo 

occidental de la isla al municipio de Vieques, al Fideicomiso de Conservación de Puerto Rico y a

USFWS. El 1o de mayo de 2003, la Marina de Estados Unidos suspendió todas las operaciones

militares en y alrededor de la isla y traspasó su propiedad en el extremo oriental de la isla

(aproximadamente 5.800 hectáreas [14.575 acres]) a USFWS. Las tierras del extremo oriental de

la isla y las controladas por USFWS en el extremo occidental de la isla se declararon entonces
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refugio natural nacional. Aproximadamente 9.300 puertorriqueños viven en la zona residencial

de la isla, que se extiende entre los extremos oriental y occidental.

Para la presente investigación, se recolectó muestras de jueyes y de cangrejos violinistas en 

marismas, manglares, zonas boscosas costeras y áreas arenosas de los extremos oriental y 

occidental de la Isla de Vieques. Se recolectó jueyes debido a su importancia en la dieta de los

residentes isleños. Se recolectó cangrejos violinistas porque viven en hábitats similares, aunque

representan una vía ligeramente diferente en la red alimenticia y sirven como especie indicadora

adicional de la captación de contaminantes potenciales. Debido a el pequeño tamaño de los

cangrejos violinista, una muestra compuesta del cangrejo violinista también representa un 

número mucho mayor de individuos por estación de muestreo que la posible con el cangrejo

terrestre.

Se recolectó entre cinco y seis especimenes de jueyes en cada uno de los 12 sitios de muestreo,

los cuales representaron principalmente zonas conocidas o potenciales para la captura, más dos

sitios de referencia de hábitat similar. Se recolectó tres muestras compuestas de cangrejos

violinistas en cada uno de los 12 sitios de muestreo y en un sitio de referencia: no hubo cangrejos

violinistas presentes en el sitio de referencia Blue Horizon en la isla. Tras la recolección de las

muestras, los jueyes y los cangrejos violinistas fueron procesados y enviados de acuerdo con los

métodos descritos en el Plan Definitivo de Análisis y Muestreo para el Proyecto de Muestreo 

Biota en la Isla de Vieques. Se analizó muestras individuales del cuerpo entero de jueyes y 

muestras compuestas de cangrejos violinistas para hallar compuestos de explosivos, PCB,

pesticidas organoclorados y oligoelementos. Un número limitado de muestras de jueyes se

subdividió en muestras de exoesqueleto (es decir, el caparazón y otras partes duras externas) y 

muestras de tejido blando solamente y se analizaron en forma independiente para hallar

oligoelementos. Todos los datos del análisis se revisaron y validaron independientemente para

asegurar su efectividad.

Los datos sobre el cangrejo violinista se compararon con puntos de referencia conservadores de

comprobación ecológica; tales valores conservadores proporcionan un alto grado de confianza en 

cuanto a que las concentraciones de contaminantes que no exceden los puntos de referencia no

plantean riesgos desfavorables significativos. Por el contrario, las concentraciones de
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contaminantes que superan los puntos de referencia conservadores no necesariamente indican 

problemas, pero señalan la necesidad de evaluaciones más detalladas. Algunos de los puntos de

referencia son específicos para la protección del cangrejo; se usó puntos de referencia protectores

de la vida silvestre que consume presas contaminadas cuando no hubo disponibilidad de puntos

de referencia específicos para crustáceos. Los datos sobre los jueyes también se compararon con

los puntos de referencia específicos para crustáceos solamente, los cuales incluyen todos los

compuestos orgánicos, cadmio, mercurio y vanadio.

Los resultados en general indican mínima presencia de químicos orgánicos. Las concentraciones

de muchos químicos orgánicos estuvieron por debajo de los límites de detección por método 

específico a la muestra (LDM) y muchas de las detecciones estuvieron apenas ligeramente por

encima de los LDM. No se detectó compuestos de explosivos en los jueyes ni en los cangrejos

violinista. Se detectó compuestos de PCB en las muestras de una sola área: se descubrió 

Aroclor 1260 en una sola muestra de juey en Laguna Kiani, mientras se halló Aroclor 1254 en 

todos los tres compuestos de cangrejos violinistas en ese sitio de muestreo. Sin embargo, las

concentraciones de PCB en las muestras de cangrejos estuvieron bien por debajo de los puntos

de referencia conservadores ecológica. En el pasado, la Marina de Estados Unidos ha informado

acerca de presencia de PCB en las aguas subterráneas de Laguna Kiani.

Se detectó pesticidas organoclorados, predominantemente DDT y sus metabolitos, en muchas

muestras de jueyes y de cangrejos violinistas. Los niveles de DDT total fueron generalmente más

altos en los cangrejos violinistas que en los jueyes, pero hubo concordancia entre las dos especies

en el patrón general de los sitios que tenían las concentraciones promedio más altas. Laguna

Kiani, Red Beach, Blue Beach y Bahía Tapón mostraron concentraciones más altas de DDT total

tanto en jueyes como en cangrejos violinistas. La constitución de los compuestos de DDT no

sugiere emisiones continuas. Estos resultados son similares a los concluidos en investigaciones

precedentes.

El segundo pesticida más comúnmente encontrado fue el clordano y sus compuestos

relacionados. Se detectó compuestos del clordano cercanos a los LDM en los jueyes de la mitad 

de las áreas de muestreo, incluyendo el sitio de referencia Blue Horizon en la isla. El clordano 

total (la suma de sus ocho compuestos) se detectó en concentraciones generalmente cercanas a
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los LDM en los cangrejos violinistas de todos los sitios de muestreo, excepto en Mosquito Bay,

incluyendo muestras del sitio de referencia Reserva Natural de Humacao, en tierra firme de

Puerto Rico. Una vez más, hubo concordancia entre las dos especies, donde Laguna Kiani y

Bahía Tapón tuvieron los niveles más altos de clordano total.

La incidencia de otros pesticidas por lo general fue limitada y esporádica. Se detectó aldrino,

endrino y dieldrino en uno o dos sitios cada uno. Se observó mirex en la mayoría de muestras de

jueyes y en todas las muestras de cangrejos violinistas solamente en la Zona de Tiro. Ninguna

concentración de pesticidas en los jueyes o cangrejos violinistas excedió los puntos de referencia

ecológica.

Como en investigaciones anteriores, se detectó en todas partes oligoelementos tanto en las

muestras de jueyes como en las de cangrejos violinistas en todos los sitios de muestreo. La

extensa detección de numerosos oligoelementos en las muestras de cangrejos parece reflejar

exposición a elementos que se presentan de forma natural en el suelo, sedimentos, aguas

subterráneas y superficiales. Los elevados niveles, especialmente los significativamente mayores

al sitio de referencia, tienden a sugerir el potencial para exposición a fuentes antropogénicas. En 

general, los resultados son variables. Se observó diferencias dentro y entre las áreas de muestreo,

de elemento a elemento y entre las dos especies de cangrejos. Sin embargo, hubo observaciones

de concordancia entre las dos especies que tienden a sugerir exposiciones constantes.

En los jueyes, las concentraciones promedio de berilio, hierro, mercurio, selenio, talio, uranio,

vanadio y zinc no fueron diferentes entre sitios o no fueron significativamente mayores que las

concentraciones en los sitios de referencia. Para todos los demás oligoelementos, por lo menos

un área tuvo concentraciones significativamente mayores que las que se observaron en un sitio 

de referencia. Sin embargo, en algunos casos esto ocurrió debido a las elevadas concentraciones

medidas en un solo cangrejo.

En su CSP, ATSDR concluyó que los niveles de PCB, pesticidas organoclorados y 

oligoelementos encontrados en los jueyes fueron mucho más bajos que los reportados en la

literatura científica como causantes de efectos perjudiciales para la salud. Por consiguiente,

ATSDR no espera que se presenten efectos perjudiciales para la salud en adultos y niños como 
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resultado del consumo de jueyes en la Isla Vieques. Las concentraciones de DDE también 

estuvieron por debajo del límite reglamentario de la Administración de Drogas y Alimentos de

Estados Unidos para el consumo de mariscos.

También se compararon los datos obtenidos de los jueyes con los s de referencia ecológica en

cuanto a cadmio, mercurio y vanadio considerados protectores de otras especies de crustáceos.

Todas las concentraciones de mercurio estuvieron por debajo de los puntos de referencia

ecológica. Las concentraciones de vanadio estuvieron por debajo de los LDM o por encima del

punto de referencia. El vanadio promedio entre áreas no fue diferente de las medias observadas

en una u otra referencia, sugiriendo que los niveles de vanadio pueden representar condiciones

iniciales. Se excedió el punto de referencia de cadmio en cuatro muestras de tres sitios de

muestreo (Boca Quebrada, Laguna Kiani y la Zona de Tiro). Los niveles en los cangrejos de la

Zona de Tiro fueron significativamente mayores que los de una u otra referencia. Esta

investigación ecológica indica que la posibilidad de impacto desfavorable para el cangrejo 

terrestre debido a la carga corporal de cadmio, y tale vez vanadio, no puede eliminarse para

algunas áreas específicas.

Un juey de cada área de muestreo se diseccionó en exoesqueleto y fracciones de tejido blando,

los cuales fueron analizados en forma independiente para hallar oligoelementos. El propósito fue

evaluar las dos fracciones en busca de indicadores de bioconcentración preferencial. En general,

se detectó más compuestos en el tejido blando del cangrejo que en el exoesqueleto, el cual no

contuvo berilio, mercurio ni selenio. Las concentraciones de la mitad de todos los

oligoelementos detectados fueron mayores en el exosqueleto que en el tejido blando; las

concentraciones de bario, calcio, cromo y magnesio fueron por lo menos un orden de magnitud 

mayor. Las concentraciones promedio de cadmio, cobre, plata y zinc fueron tres a diez veces más

altas en el tejido blando.

Las concentraciones de berilio, manganeso, mercurio, níquel, talio y uranio en el cangrejo

violinista no superaron los puntos de referencia ecológica en las muestras. No hubo puntos de

referencia ecológica disponibles para cobalto, hierro y plata. Las concentraciones de diez

oligoelementos medidos en el cangrejo violinista excedieron los puntos de referencia ecológica

en una o más muestras. De éstos, aluminio, arsénico, vanadio y zinc excedieron los puntos de
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referencia ecológica de vida silvestre en todas las muestras de todas las áreas de muestreo,

incluyendo el sitio de referencia. Las concentraciones de bario, cadmio, cromo, cobre y selenio 

excedieron los puntos de referencia ecológica a grados variantes y en diversos sitios. Las

concentraciones de plomo excedieron el punto de referencia en solo un sitio (Laguna Kiani).

Tres de los compuestos que excedieron los puntos de referencia ecológica (cadmio, plomo y 

selenio) no fueron detectados en las muestras de referencia de la Reserva Natural de Humacao en 

concentraciones por encima de los puntos de referencia ecológica.

La incidencia de PCB tanto en el juey como en el cangrejo violinista de Laguna Kiani, que

coincide con informes anteriores sobre PCB de la Marina de Estados Unidos en aguas

subterráneas en este mismo sitio, demuestran que PCB en este lugar es biodisponible y capaz de

entrar en la red alimenticia. La copresencia de máximas concentraciones de otros contaminantes

en estas mismas muestras para ambas especies sugiere que las emisiones de otros contaminantes

se pueden estar presentando también dentro de esta área. Aunque las concentraciones de

orgánicos reportadas aquí están por debajo de los puntos de referencia ecológica, el grado

limitado de muestreo en este estudio preliminar hace difícil sacar conclusiones firmes e relación 

con el grado de riesgo que puedan plantear las emisiones en este sitio. Además la definición de la

naturaleza y grado de las emisiones en este sitio se recomienda como parte de una investigación 

correctiva continuada o como monitoreo para verificar la eficacia de las acciones de remoción.

La concordancia observada entre las dos especies en algúnes contaminantes detectado puede

indicar trayectorias de exposición en otros sitios también. Los ejemplos incluyen mirex, arsénico 

y cadmio en la Zona de Tiro y DDT total en Blue Beach, Red Beach y Bahía Tapón. Aunque los

valores estuvieron por debajo de los puntos de referencia ecológica, estas observaciones

demuestran un mecanismo de exposición para estas áreas.

La evaluación presentada en este informe no debe considerarse como una evaluación completa

de riesgos ecológicos. Esta evaluación aplicó suposiciones conservadoras acerca de la exposición 

que no son necesariamente reales o adecuadas para definir el riesgo real. Más bien, ofrece un alto

nivel de confianza en la determinación de situaciones donde la baja probabilidad de impacto 

desfavorable está presente, y facilita determinar la necesidad de, y el grado de, más

investigación. Este evaluación reconoce que las concentraciones químicas que superan los
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valores de referencia conservadores pueden considerarse potencialmente peligrosas, aunque no 

lo sean necesariamente hasta que otras evaluaciones más realistas, específicas al sitio lo 

determinen. La comprobación preliminar de los residuos de tejido de cangrejo presentes aquí no 

puede eliminar la posibilidad de que algunos analitos puedan estar presentes en niveles los

suficientemente altos para causar impacto desfavorable al cangrejo. Para identificar y definir

completamente el riesgo potencial al medio ambiente, se justifica más análisis de las porciones

correspondientes de estos datos, como también evaluaciones de otros receptores ecológicos,

particularmente con respecto a PCB, DDT total y algunos oligoelementos. La necesidad de

evaluación adicional, cuando proceda, debe determinarse en las actividades de evaluación de

riesgos para la salud humana y para la ecología requeridas para la investigación correctiva

continuada de los sitios en la Isla de Vieques.
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TABLE OF CONTENTS

EXECUTIVE SUMMARY....................................................................................................... iii

RESUMEN EJECUTIVO ..........................................................................................................ix

1.0 INTRODUCTION..............................................................................................................1

1.1 Purpose of the Investigation............................................................................................1

1.2 Site Location...................................................................................................................2

1.3 Site Characteristics..........................................................................................................2

1.3.1 Habitat Description...................................................................................................2

1.3.2 Site Geology.............................................................................................................2

1.4 Site History.....................................................................................................................4

1.5 Previous Biological Investigations..................................................................................5

1.5.1 University of Puerto Rico Study (Deya and Dias 1999) ............................................5

1.5.2 USFWS Study (Lopez 2002) ....................................................................................6

1.5.3 ATSDR Study (ATSDR 2003) .................................................................................7

2.0 DESCRIPTION OF THE STUDY......................................................................................8

2.1 Study Design ..................................................................................................................8

2.1.1 Species Selection......................................................................................................8

2.1.2 Sample Location Selection .......................................................................................9

2.1.3 Contaminants of Potential Concern.........................................................................11

2.2 Sample Collection.........................................................................................................12

2.2.1 Field Methods ........................................................................................................12

2.2.2 Sample Processing..................................................................................................13

2.2.3 Sample Analyses....................................................................................................14

2.2.4 Deviations from the Sampling and Analysis Plan....................................................15

2.3 Quality Assurance Summary.........................................................................................16

3.0 DATA SUMMARY .........................................................................................................18

3.1 Development of Screening Benchmark Values..............................................................18

3.2 Land Crab Results.........................................................................................................20
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3.2.1 Explosive Compounds............................................................................................21

3.2.2 Polychlorinated Biphenyls......................................................................................21

3.2.3 Organochlorine Pesticides......................................................................................22

3.2.4 Trace Elements.......................................................................................................24

3.2.5 Sample Area Comparisons......................................................................................25

3.3 Fiddler Crab Results .....................................................................................................29

3.3.1 Explosive Compounds............................................................................................29

3.3.2 Polychlorinated Biphenyls......................................................................................29

3.3.3 Organochlorine Pesticides......................................................................................30

3.3.4 Trace Elements.......................................................................................................31

3.3.5 Sample Area Comparisons......................................................................................34

3.4 Comparisons to Previous Studies..................................................................................37

4.0 CONCLUSIONS..............................................................................................................38

5.0 REFERENCES.................................................................................................................41
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LIST OF TABLES

Table 2-1. Sample Identification and Description

Table 3-1. Ecological Screening Benchmarks

Table 3-2. Vieques Island Land Crab Whole Body Data Summary

Table 3-3. Vieques Island Land Crab Whole Body Average Values

Table 3-4. Vieques Island Land Crab Exoskeleton vs. Tissue-Only Data Summary

Table 3-5 Summary of Differences, Relative to Reference, and Exceedances of Crustacean 

ESBs in Land Crab

Table 3-6. Vieques Island Fiddler Crab Whole Body Data Summary

Table 3-7. Vieques Island Fiddler Crab Whole Body Average Values

Table 3-8. Summary of Differences, Relative to Reference, and Exceedances of ESBs in Fiddler Crab

LIST OF FIGURES

Figure 1-1. Site Location and Sampling Areas

Figure 2-1. Area 1 – Downgradient from SWMU 7

Figure 2-2. Area 2 – Downgradient from AOCs J and R

Figure 2-3. Area 3 – Laguna Kiani

Figure 2-4. Area 4 – Laguna Kiani South 

Figure 2-5. Area 5 – Boca Quebrada

Figure 2-6. Area 6 – Laguna Playa Grande

Figure 2-7. Area 7 – Mosquito Bay

Figure 2-8. Area 8 – Puerto Ferro

Figure 2-9. Area 9 – Red Beach 

Figure 2-10. Area 10 – Blue Beach 

Figure 2-11. Area 11 – Bahia Tapon 

Figure 2-12. Area 12 – Live Impact Area

Figure 2-13. Area 13 – Blue Horizon Reference

Figure 2-14. Area 14 – Humacao Wildlife Reserve, Main Island Reference
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Figure 3-1. Vieques Island Land and Fiddler Crab Data – Cadmium

Figure 3-2. Vieques Island Land and Fiddler Crab Data – Lead

Figure 3-3. Vieques Island Land and Fiddler Crab Data – Selenium

Figure 3-4. Mean Fiddler Crab Residues Significantly Greater than Reference and Exceeding ESBs

LIST OF APPENDICES

Appendix A. Photographs

Appendix B. Analytical Results for All Samples

Appendix B-1. Vieques Is. Land Crab Results

Appendix B-2. Vieques Is. Land Crab Results, Exoskeleton vs. Tissue Only

Appendix B-3. Vieques Is. Fiddler Crab Results

Appendix C. Data Validation Report and Review Memoranda

Appendix D. Quality Assurance Report

Appendix E. Land Crab Trace Element and Total DDT Statistical Analysis

Appendix F. Fiddler Crab Trace Element and Total DDT Statistical Analysis

Appendix G. Land Crab Exoskeleton and Tissue-Only Sample Analysis

Appendix H. ATSDR Public Health Consultation
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LIST OF ABBREVIATIONS AND ACRONYMS

AOC Area of Concern

ATSDR Agency for Toxic Substances and Disease Registry

CERCLA Comprehensive Environmental Response, Compensation and Liability Act

EQB Environmental Quality Board (Puerto Rico)

ERED Environmental Residue Effects Database

ESB ecological screening benchmark

FDA Food and Drug Administration

GC gas chromatography

km kilometer

LIA Live Impact Area

MDL method detection limit

mi mile

μg/kg micrograms per kilogram

mg/kg milligrams per kilogram

MRL minimal risk level

MS/MSD matrix spike/matrix spike duplicate

NOAA National Oceanic and Atmospheric Administration

NOAEL no observed adverse effects level

NPL National Priorities List

ORR Office of Response and Restoration (NOAA)

PCB polychlorinated biphenyl

PHC Public Health Consultation

PVC polyvinyl chloride

QAPP quality assurance project plan

QA/QC Quality Assurance/Quality Control

RBC risk-based criteria

RCRA Resource Conservation and Recovery Act

RfD reference dose

RI Remedial Investigation
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SAP sampling and analysis plan

SWMU Solid Waste Management Unit

TOXRES Toxicity/Residue (database)

TRV toxicity reference value

USACE U.S. Army Corps of Engineers

USEPA U.S. Environmental Protection Agency

USFWS U.S. Fish and Wildlife Service
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TABLE OF CONTENTS

EXECUTIVE SUMMARY....................................................................................................... iii

RESUMEN EJECUTIVO ..........................................................................................................ix

1.0 INTRODUCTION..............................................................................................................1

1.1 Purpose of the Investigation............................................................................................1

1.2 Site Location...................................................................................................................2

1.3 Site Characteristics..........................................................................................................2

1.3.1 Habitat Description...................................................................................................2

1.3.2 Site Geology.............................................................................................................2

1.4 Site History.....................................................................................................................4

1.5 Previous Biological Investigations..................................................................................5

1.5.1 University of Puerto Rico Study (Deya and Dias 1999) ............................................5

1.5.2 USFWS Study (Lopez 2002) ....................................................................................6

1.5.3 ATSDR Study (ATSDR 2003) .................................................................................7

2.0 DESCRIPTION OF THE STUDY......................................................................................8

2.1 Study Design ..................................................................................................................8

2.1.1 Species Selection......................................................................................................8

2.1.2 Sample Location Selection .......................................................................................9

2.1.3 Contaminants of Potential Concern.........................................................................11

2.2 Sample Collection.........................................................................................................12

2.2.1 Field Methods ........................................................................................................12

2.2.2 Sample Processing..................................................................................................13

2.2.3 Sample Analyses....................................................................................................14

2.2.4 Deviations from the Sampling and Analysis Plan....................................................15

2.3 Quality Assurance Summary.........................................................................................16

3.0 DATA SUMMARY .........................................................................................................18

3.1 Development of Screening Benchmark Values..............................................................18

3.2 Land Crab Results.........................................................................................................20
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3.2.1 Explosive Compounds............................................................................................21

3.2.2 Polychlorinated Biphenyls......................................................................................21

3.2.3 Organochlorine Pesticides......................................................................................22

3.2.4 Trace Elements.......................................................................................................24

3.2.5 Sample Area Comparisons......................................................................................25

3.3 Fiddler Crab Results .....................................................................................................29

3.3.1 Explosive Compounds............................................................................................29

3.3.2 Polychlorinated Biphenyls......................................................................................29

3.3.3 Organochlorine Pesticides......................................................................................30

3.3.4 Trace Elements.......................................................................................................31

3.3.5 Sample Area Comparisons......................................................................................34

3.4 Comparisons to Previous Studies..................................................................................37

4.0 CONCLUSIONS..............................................................................................................38

5.0 REFERENCES.................................................................................................................41
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LIST OF TABLES

Table 2-1. Sample Identification and Description

Table 3-1. Ecological Screening Benchmarks

Table 3-2. Vieques Island Land Crab Whole Body Data Summary

Table 3-3. Vieques Island Land Crab Whole Body Average Values

Table 3-4. Vieques Island Land Crab Exoskeleton vs. Tissue-Only Data Summary

Table 3-5 Summary of Differences, Relative to Reference, and Exceedances of Crustacean 

ESBs in Land Crab

Table 3-6. Vieques Island Fiddler Crab Whole Body Data Summary

Table 3-7. Vieques Island Fiddler Crab Whole Body Average Values

Table 3-8. Summary of Differences, Relative to Reference, and Exceedances of ESBs in Fiddler Crab

LIST OF FIGURES

Figure 1-1. Site Location and Sampling Areas

Figure 2-1. Area 1 – Downgradient from SWMU 7

Figure 2-2. Area 2 – Downgradient from AOCs J and R

Figure 2-3. Area 3 – Laguna Kiani

Figure 2-4. Area 4 – Laguna Kiani South 

Figure 2-5. Area 5 – Boca Quebrada

Figure 2-6. Area 6 – Laguna Playa Grande

Figure 2-7. Area 7 – Mosquito Bay

Figure 2-8. Area 8 – Puerto Ferro

Figure 2-9. Area 9 – Red Beach 

Figure 2-10. Area 10 – Blue Beach 

Figure 2-11. Area 11 – Bahia Tapon 

Figure 2-12. Area 12 – Live Impact Area

Figure 2-13. Area 13 – Blue Horizon Reference

Figure 2-14. Area 14 – Humacao Wildlife Reserve, Main Island Reference
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Figure 3-1. Vieques Island Land and Fiddler Crab Data – Cadmium

Figure 3-2. Vieques Island Land and Fiddler Crab Data – Lead

Figure 3-3. Vieques Island Land and Fiddler Crab Data – Selenium

Figure 3-4. Mean Fiddler Crab Residues Significantly Greater than Reference and Exceeding ESBs

LIST OF APPENDICES

Appendix A. Photographs

Appendix B. Analytical Results for All Samples

Appendix B-1. Vieques Is. Land Crab Results

Appendix B-2. Vieques Is. Land Crab Results, Exoskeleton vs. Tissue Only

Appendix B-3. Vieques Is. Fiddler Crab Results

Appendix C. Data Validation Report and Review Memoranda

Appendix D. Quality Assurance Report

Appendix E. Land Crab Trace Element and Total DDT Statistical Analysis

Appendix F. Fiddler Crab Trace Element and Total DDT Statistical Analysis

Appendix G. Land Crab Exoskeleton and Tissue-Only Sample Analysis

Appendix H. ATSDR Public Health Consultation
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LIST OF ABBREVIATIONS AND ACRONYMS

AOC Area of Concern

ATSDR Agency for Toxic Substances and Disease Registry

CERCLA Comprehensive Environmental Response, Compensation and Liability Act

EQB Environmental Quality Board (Puerto Rico)

ERED Environmental Residue Effects Database

ESB ecological screening benchmark

FDA Food and Drug Administration

GC gas chromatography

km kilometer

LIA Live Impact Area

MDL method detection limit

mi mile

μg/kg micrograms per kilogram

mg/kg milligrams per kilogram

MRL minimal risk level

MS/MSD matrix spike/matrix spike duplicate

NOAA National Oceanic and Atmospheric Administration

NOAEL no observed adverse effects level

NPL National Priorities List

ORR Office of Response and Restoration (NOAA)

PCB polychlorinated biphenyl

PHC Public Health Consultation

PVC polyvinyl chloride

QAPP quality assurance project plan

QA/QC Quality Assurance/Quality Control

RBC risk-based criteria

RCRA Resource Conservation and Recovery Act

RfD reference dose

RI Remedial Investigation
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SAP sampling and analysis plan

SWMU Solid Waste Management Unit

TOXRES Toxicity/Residue (database)

TRV toxicity reference value

USACE U.S. Army Corps of Engineers

USEPA U.S. Environmental Protection Agency

USFWS U.S. Fish and Wildlife Service
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1.0 INTRODUCTION

This document describes an investigation of chemical residues in land crab (Cardisoma 

guanhumi) and fiddler crab (Uca spp.) tissue samples collected from Vieques Island, Puerto

Rico. Crab samples were collected in June 2005 and sent to an analytical laboratory for chemical

analysis. The samples were analyzed for explosive compounds, polychlorinated biphenyls

(PCBs), organochlorine pesticides, and selected trace elements.

As a natural resource trustee, NOAA provides scientific support to the USFWS, the USEPA, the

U.S. Navy, and the EQB for the investigation and cleanup of Vieques Island. Through its

participation, NOAA is working to protect coastal resources, mitigate threats to those resources,

and restore their ecological function when needed. This investigation was conducted by the

National Oceanic and Atmospheric Administration (NOAA) Office of Response and Restoration 

(ORR) with assistance from the U.S. Fish and Wildlife Service (USFWS), the U.S.

Environmental Protection Agency (USEPA), the Puerto Rico Environmental Quality Board 

(EQB), and RIDOLFI Inc. under contract to NOAA. This study was wholly funded by NOAA.

1.1 Purpose of the Investigation

The primary purpose of the investigation was to characterize chemical concentrations in land and

fiddler crab from Vieques Island. Although limited crabbing was allowed as a test in an area

around Red Beach in June to July 2005 (Diaz pers. comm.), the USFWS currently prohibits the

general harvesting of land crab on refuge lands at Vieques Island.

The USFWS will use the data in this report as one factor in deciding whether selected refuge

areas can be opened to crab harvesting. In the future, the U.S. Navy, the USEPA, and the Puerto 

Rico EQB may also use appropriate portions of the land and fiddler crab data as one component

of human health and ecological risk assessments for sites on Vieques Island. The land crab data

were also provided to the Agency for Toxic Substances and Disease Registry (ATSDR) for use

in a Public Health Consultation (PHC). The PHC document is included in the final draft version 

of this report as Appendix H.
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1.2 Site Location

Vieques Island is approximately 11 kilometers (km) (7 miles [mi]) southeast of the main island 

of Puerto Rico (Figure 1-1). The island, which is approximately 34 km (21 mi) long and 5 km (3

mi) wide, is bordered to the north by Vieques Sound and to the south by the Caribbean Sea.

Mangrove wetlands, coral reefs, and sea grass beds fringe much of the island. Inland lagoons,

streams, and wetland areas provide habitat for crab. The crab samples were collected from a

variety of environments, including mostly mud and sand flats, mangrove wetlands, and coastal

forested areas on the east and west ends of the island.

1.3 Site Characteristics

The habitat types from which samples of land and fiddler crab were collected are briefly

described below, as is the geology of Vieques Island. The site geology was reviewed (using 

information from previous studies) to evaluate whether the minerals in rocks and soils at Vieques

Island could contribute to the trace elements observed in crab samples.

1.3.1 Habitat Description

Land crab were collected from coastal habitat types, including mangrove wetlands, mud and 

sand flats, and wet forested/shrub areas. The mangrove wetlands from which some of the land

and fiddler crab were collected are composed primarily of red, black, or white mangrove trees or

a combination of these species. The mangrove wetlands generally occur as dense thickets along 

tidal shores that are sheltered from high-energy waves. The coastal forested areas, where

additional land crab were collected, are near lagoons or beaches; the dominant tree species in this

habitat type is often mesquite. Additional fiddler crab were collected from mud and sand flats

near the forested areas where land crab were collected.

1.3.2 Site Geology

The bedrock geology of Vieques Island consists primarily of volcanic and volcanoclastic rocks

that were intruded by plutonic rocks (igneous rock that has solidified beneath the Earth's

surface). Limestone is found along the coastal margin of the island (Torres-Gonzáles 1989).

Alluvial sediments, which were deposited by flowing water, are found in the valleys and along
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the coastal fringe; beach/dune deposits are also found along the coastal fringe. The mineral

composition of these deposits can be expected to reflect their volcanic origin.

Upland soil on Vieques Island ranges from shallow to deep and is well drained. Soil that

developed on terraces and alluvial fans is deep and well drained. Volcanically derived soils

predominate on the east end of the island, while plutonic- and alluvial-derived soils predominate

on the west end of the island. Very poorly drained soils are present on the coastal plain within 

swamps and marshes (Soil Conservation Service and University of Puerto Rico 1977).

A geochemical reconnaissance of soils on Vieques Island found locally anomalous

concentrations of copper, primarily along and attributed to a plutonic/volcanic contact zone that

trend southeast from Isabel Segunda and in hydrothermally altered volcanic rocks along the

northern coast (Learned et al. 1973). Additional site investigations have been conducted on the

west end of Vieques Island to establish background concentrations of explosives, PCBs, and

trace elements in abiotic media such as groundwater, soil, surface water, and sediment (CH2M

Hill 2002a); details of those investigations are not included in this report.

Unlike the man-made organic chemicals observed during this study, trace elements can have

both natural sources .In general, many, if not all, of trace elements can be found in natural

materials (e.g., soil, sea salt), and several trace elements are essential nutrients. Analyses from

mainland Puerto Rico indicate that nearly all the trace elements analyzed for in this study have

been observed in various volcanic soils on the mainland (USGS 2001). However, some trace

element levels may sources may be related to human activities. I t is often difficult, however, to

proportionately attribute chemical body burdens in animals between the potential natural and 

anthropogenic sources. Evaluation of spatial patterns is one simple approach often used to gain

some preliminary insight about potential anthropogenic influences, but such attribution is beyond 

the scope of this study. At sites where a screening level assessment indicates the potential for

exposure and adverse impacts, analysis of the surrounding soil sampled at the same time as tissue

sampling is a common subsequent investigational approach to address the causes of elevated 

tissue concentrations.
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1.4 Site History

During the early 1940s, the U.S. Navy acquired approximately 10,000 hectares (25,000 acres) on

the west and east ends of Vieques Island. From the 1940s until 2003, the U.S. Navy used 

Vieques Island for munitions storage and military training exercises, which included naval

gunfire and aerial bombing. In 2001, the U.S. Navy transferred ownership of approximately 

3,000 hectares (7,500 acres) of land on the west end of the island to the municipality of Vieques,

the Puerto Rico Conservation Trust, and the USFWS (USEPA 2004). On May 1, 2003, the U.S.

Navy ceased all military operations on and around the island and transferred its property on the

east end of the island to the USFWS (USEPA 2004). The land on the east end of the island and 

the land controlled by the USFWS on the west end of the island were then designated a National

Wildlife Refuge (some of the land has also been designated as a wilderness area). Any potential

for releases of hazardous substances on these refuge lands is related to their history.

Approximately 9,300 civilian Puerto Ricans live in the residential section of the island, which is

between the two (west and east) refuge sections (USEPA 2005a).

Since 2000, the U.S. Navy has been working with the USEPA to complete an environmental

investigation of the east end of the island under the guidelines of the Resource Conservation and 

Recovery Act (RCRA). The investigations are organized by areas associated with particular

historical activities where releases of hazardous waste or hazardous constituents potentially 

occurred. These areas are known as Solid Waste Management Units (SWMUs) or Areas of

Concern (AOCs).

Investigations of the west end of the island have been and continue to be conducted by the U.S.

Navy and the USEPA under the Comprehensive Environmental Response, Compensation and 

Liability Act (CERCLA). Certain areas of Vieques Island that have been impacted by military

activities plus some of the surrounding waters were placed on the National Priorities List (NPL)

in February 2005 (USEPA 2005b). Subsequently, further environmental investigation of both the

east and west ends of the island began under CERCLA guidance.
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1.5 Previous Biological Investigations

The ATSDR, the USFWS, and individuals from the University of Puerto Rico have all conducted 

limited studies to determine contaminant concentrations in biota from Vieques Island. All of

these studies could be considered preliminary screening efforts because of their limited sampling

areas, small sample sizes, or other factors. All of these studies examined only tissue residues;

none of them examined co-located soils. This section briefly summarizes the methods and results

of these previous investigations. For further details regarding any individual study, the reader is

referred to the original publication of each study.

1.5.1 University of Puerto Rico Study (Deya and Dias 1999)

In November 1999, researchers from the University of Puerto Rico collected approximately 35

fiddler crab from Icacos Lagoon in the Live Impact Area (LIA) on the east end of the island, as

well as 35 fiddler crab from a reference location at Puerto Mosquito (Mosquito Bay) on the south 

side of the island. According to the report, the main objective of the study was “to assess the

potential transport of pollutants from the LIA to other ecosystems through the food chain.”

The samples were divided into two portions representing the extremities (legs and levers) and the

bodies; each portion was analyzed for cadmium, chromium, cobalt, copper, lead, manganese,

nickel, and zinc. Average concentrations of cadmium (8.05 milligrams per kilogram [mg/kg])

and cobalt (35.69 mg/kg) in the Icacos Lagoon crab body sample were 3.5 times greater than

averages from the reference sample. The average copper concentration (499.91 mg/kg) in the

crab body sample from Icacos Lagoon slightly exceeded the concentrations detected in the

reference samples. Conversely, manganese, nickel, and zinc were all detected at greater

concentrations in crab bodies from the reference location than from Icacos Lagoon. Average

manganese and zinc concentrations in the reference samples were approximately twice the

average concentrations of these trace elements in the Icacos Lagoon samples. Chromium

concentrations were similar in both the body and the extremities samples and for both the

sampling and the reference areas Lead was not detected in any sample; the detection limit was

not provided.
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In the crab body samples, the only statistically significant differences appear to be the greater

manganese and zinc concentrations in the reference sample and the greater cadmium

concentration in the Icacos Lagoon body sample. In the crab extremities samples, the only

statistically significant differences appear to be greater concentrations of manganese and nickel

in the reference sample.

With the exception of cobalt in the reference sample, all trace elements were detected at greater

concentrations in the body portion of the fiddler crab samples than in the extremities.

1.5.2 USFWS Study (Lopez 2002)

In 2002, one composite fiddler crab and two individual land crab samples were collected from

mangrove wetlands at Punta Boca Quebrada near SWMU 4, and one composite fiddler crab and

two individual land crab samples were collected from SWMU 6 near Laguna Arenas. Both 

SWMUs are on the west end of the island (Figure 1-1). Three individual land crab samples were

also collected from a reference location at Sandy Point National Wildlife Refuge on St. Croix,

U.S. Virgin Islands.

The purpose of this investigation was to collect preliminary data about the level of contamination

in the prey base for some aquatic birds present on the island. Whole body samples were analyzed 

for PCBs, organochlorine pesticides, and trace elements.

DDT compounds were detected in one land crab sample and the composite fiddler crab sample

collected at SWMU 6. The maximum concentrations of the pesticides p,p’-DDE and p,p’-DDTi

were 0.130 and 0.028 mg/kg, wet weight, respectively. PCBs and other organochlorine pesticides

were not detected in any of the SWMU 4, SWMU 6, or reference crab samples.

Cadmium, lead, and vanadium were detected in crab samples collected from SWMU 4,

SWMU 6, and the Sandy Point reference location. The maximum cadmium concentration (0.656

mg/kg, wet weight) was detected in a land crab sample collected at SWMU 6. The maximum

 

i

p,p’-DDE and p,p’DDT are referred to in this report as 4,4’-DDE and 4,4’-DDT.
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concentrations of lead (4.07 mg/kg, wet weight) and vanadium (0.915 mg/kg, wet weight) were

detected in the composite fiddler crab sample collected from SWMU 6. The report concluded 

that the crab collected from SWMU 6 contained DDT and trace elements, including lead and 

cadmium.

1.5.3 ATSDR Study (ATSDR 2003)

In 2001, the ATSDR collected fish and shellfish samples from six sites on Vieques Island as part

of a public health assessment. The purpose of the public health assessment was to determine

whether the muscle tissue from commonly consumed fish and shellfish contained levels of heavy 

metals and explosive compounds that would adversely affect public health. During this study,

five land crab samples were collected from the north end of the LIA; five were collected adjacent

to the west side of Bahia Salina del Sur; and two were collected from Laguna Kiani on the west

end of the island. In addition, two composite fiddler crab samples were collected from the north

end of the LIA and two were collected from the shore on the west side of Bahia Salina del Sur.

The crab samples were analyzed for explosive compounds and trace elements.

In their study, the ATSDR averaged analyte concentrations detected in the land crab samples

with concentrations detected in other types of shellfish. The study reported the following results:

• Explosive compounds were not detected in the shellfish samples.

• Calcium, chromium, magnesium, potassium, selenium, and sodium were detected in all

of the shellfish samples.

• Aluminum, arsenic, barium, iron, and manganese were detected in 64% to 89% of the

shellfish samples.

• Cadmium, mercury, silver, and vanadium were detected in 34% to 55% of the shellfish 

samples.

The ATSDR study concluded that although trace elements were detected in shellfish, the

concentrations were too low to pose a human health concern.
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2.0 DESCRIPTION OF THE STUDY

2.1 Study Design

This section describes the study design for the June 2005 investigation of Vieques Island land 

crab and fiddler crab.

2.1.1 Species Selection

Land Crab

Land crab were collected for this study because of their importance in the diet of the people of

Vieques Island. Land crab live in mangrove wetlands and other coastal wetlands and forests,

building individual burrows in the soil to protect against predators and warm temperatures

(Taissoun 1974). The poorly drained soil in wetlands and other coastal areas is a habitat

requirement for land crab, because the water retained in their burrows serves as their water

source. If they do not have access to water, land crab will live approximately only three days

(Taissoun 1974). Land crab are primarily vegetarians and become carnivorous only if vegetation,

including leaves, flowers, and fruit, is not available. Crab generally come out to feed at night

when temperatures are cooler, and land crab generally feed within a 100-meter (approximately 

330-foot) radius of their burrows (SMS 2001).

Land crab change morphologically and in color as they mature. Juvenile land crab are dark

brown and grey, and it is difficult to distinguish between the sexes (Taissoun 1974). During the

transitional stage from juvenile to adult, land crab are purple and orange. During this stage,

males can be distinguished from females because one of the front claws on the males is larger

than the other and the shape of the abdomen becomes distinct between the sexes (Taissoun 

1974). Adult crab are blue-lavender in color; in the adults, the features that distinguish the sexes

in the transitional stage become more prominent (Taissoun 1974).

Land crab generally require four years to reach maturity (Hostetler et al. 2003). On Vieques

Island, the spawning season is generally from mid-July to mid-October. The female lays her eggs

and then carries them in her abdomen for approximately two weeks before migrating to shallow

nearshore ocean waters, where she releases the eggs (Hostetler et al. 2003). After releasing her
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eggs, the female returns to a burrow. Female land crab can release multiple clutches of eggs

during one spawning season (Taissoun 1974). The eggs hatch in the nearshore water and the

larvae are then carried to deeper water, where they float for approximately one month until they

mature into juvenile crab. The currents then carry the juvenile crab back to shore, often to an 

area different from where the female released them (Hostetler et al. 2003).

Fiddler Crab

Fiddler crab were selected for this study because they live in habitats adjacent to the land crab,

represent a slightly different pathway in the food web, and serve as an additional indicator species

for the potential uptake of contaminants of concern. Because of the fiddler crab’s small size, a

composite sample of fiddler crabs also represents a far greater number of individuals per sampling 

station than is possible with the land crab. Fiddler crab live in soft sand or mud in mangrove and 

other coastal intertidal wetlands. Although fiddler crab are not consumed by the people of Vieques

Island, they are important in the diets of birds, fish, and other animals present on the island.

At low tide, fiddler crab emerge from their burrows to feed (Grimes et al. 1989). The diet of a

fiddler crab is generally composed of detritus and other organic particles. Fiddler crab mate,

sleep, and hide from predators in burrows that they dig in the mud or sand. After mating, the

female fiddler crab will stay in the burrow for two weeks. The female will then emerge and 

release her hatched eggs into nearby coastal waters (Grimes et al. 1989).

2.1.2 Sample Location Selection

Fourteen locations were sampled for land crab and fiddler crab (Figure 1-1): six locations on the

west end of Vieques Island, six locations on the east side of Vieques Island, plus two reference

locations, one on Vieques Island and one on the main island of Puerto Rico. Sample locations

were selected in close coordination with the USFWS and with input from the federal and 

commonwealth partners, as well as the community. The sampling locations were selected 

primarily to represent a balance of:

• Areas where land crab are actively being harvested; and

• Areas where the USFWS may open refuge property to land crab harvesting in the future.
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The reference location on Vieques Island was selected because it represents an area of similar

habitat, but where exposure to substances released from past military or other activities is

considered unlikely. The reference location on the main island of Puerto Rico was sited in the

Humacao Wildlife Reserve because of its reserve status; because the geology of the reserve is

similar to that of Vieques Island; plus, the location was recommended by the USFWS and the

Puerto Rico Department of Natural Resources. Although the Humacao Wildlife Reserve is in the

general vicinity of the former Frontera Creek Superfund site, that proximity is not expected to be

a factor in this study, because the Frontera Creek Superfund site is part of a separate watershed 

drainage area. The contaminants of concern at the former Frontera Creek Superfund site were

mercury and lindaneii. In 1995, approximately 600 cubic meters (800 cubic yards) of

contaminated soil and sediment were removed from the site (USEPA 2002). In 1998, the

Frontera Creek site was removed from the NPL (USEPA 2002).

The Vieques Island sampling locations and associated figures depicting the locations are:

• West End of Vieques Island

Area 1 (Figure 2-1): Downgradient from SWMU 7

Area 2 (Figure 2-2): Downgradient from AOCs J and R

Area 3 (Figure 2-3): Laguna Kiani

Area 4 (Figure 2-4): Laguna Kiani South

Area 5 (Figure 2-5): Boca Quebrada

Area 6 (Figure 2-6): Laguna Playa Grande

• East End of Vieques Island

Area 7 (Figure 2-7): Mosquito Bay

Area 8 (Figure 2-8): Puerto Ferro

Area 9 (Figure 2-9): Red Beach

Area 10 (Figure 2-10): Blue Beach

Area 11 (Figure 2-11): Bahia Tapon

Area 12 (Figure 2-12): Live Impact Area

 

ii

Lindane was not detected in any land crab samples; mercury was detected, but at an average level that is indistinguishable from any other site.
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The reference sampling locations and associated figures depicting the locations are:

• Vieques Island

Area 13 (Figure 2-13): Blue Horizon Reference

• Mainland Puerto Rico

Area 14 (Figure 2-14): Humacao Wildlife Reserve, Main Island Reference

2.1.3 Contaminants of Potential Concern

Concentrations of DDE, DDT, and trace elements have been detected in crab samples collected 

from the island during previous investigations (Deya and Dias 1999; Lopez 2002; ATSDR

2003). Explosive compounds and PCBs have been measured in groundwater in some areas where

full Remedial Investigations (RIs) have been conducted (CH2M Hill 2002b). In addition, trace

elements, including aluminum, antimony, arsenic, barium, chromium, copper, lead, manganese,

mercury, nickel, selenium, silver, thallium, vanadium, and zinc, have been detected in soil,

sediment, groundwater, or surface water at several sites throughout Vieques Island (CH2M Hill

2002a). These trace elements likely have natural as well as anthropogenic sources.

A target analyte list was developed for this study based on results from the limited prior studies

and giving broad consideration to areas where releases of hazardous substances may have

occurred. The target analyte list included explosive compounds, PCBs, organochlorine

pesticides, and trace elements. Uranium is of interest because depleted uranium rounds have

been used within the LIA. Anticipated laboratory detection limits for the target analytes were

prescreened to confirm that the analyses would yield data capable of being evaluated against

accepted ecological screening benchmarks.

Lipid content was also determined in the tissue samples; however, because the data were not

lipid-normalized, those results are discussed only in the quality assurance report (Appendix D),

not in the main body of this data report.

Section 3 details the number of samples analyzed and the analytes determined in each sample.
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2.2 Sample Collection

Land crab and fiddler crab were collected according to the methods described in the Final

Sampling and Analysis Plan for the Vieques Island Biota Sampling Project (RIDOLFI Inc. and 

NOAA 2005). The field methods used for sample collection and processing are summarized in

Sections 2.2.1 and 2.2.2 of this report. The sample analyses are discussed in Section 2.2.3 and

deviations from the sampling and analysis plan (SAP) are described in Section 2.2.4.

2.2.1 Field Methods

Land crab and fiddler crab samples were collected from adjacent habitat types using several

methods. The fiddler crab samples were composited to obtain sufficient sample mass for the

chemical analyses. Global positioning system coordinates were recorded near the center of each 

sample location. Table 2-1 summarizes the sample identifications and descriptions. Each 

sampling area was photographed during the fieldwork; selected photographs representing the

different habitat types and collection methods are included in Appendix A.

Land Crab Collection Methods

Land crab were collected with traps and by hand from 14 locations. Between nine and 14 wood 

or polyvinyl chloride (PVC) traps were baited with fruit and placed in the entrances of active

burrows at each sample area. Active burrows were identified by the presence of feces and freshly 

piled dirt. The traps were left in place until they were tripped or until sufficient samples had been 

collected from other burrows. In general, the traps were tripped after one to two hours. Traps that

were not tripped within several hours were moved to a different burrow. This process was

repeated until six to seven land crabs with carapaces longer than approximately 6.4 centimeters

(2.5 inches) were collected. Additional sample mass was collected at some sites for use in matrix 

spike/matrix spike duplicate (MS/MSD) analyses performed at the laboratory for the purpose of

quality assurance/quality control (QA/QC). Occasionally, the field crew collected the crabs by

hand if land crab were observed outside of, or in the entrances of, their burrows. Following 

collection, the land crab were sexed and their carapaces were measured in the field. When 

possible, a ratio of three females to three males was collected at each sample area.
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Fiddler Crab Collection Methods

Fiddler crab were collected at 13 locations. The samples were collected using dip nets or by

digging fiddler crabs from their burrows with stainless steel shovels or trowels. Between 33 and 

223 fiddler crabs were collected from each sample location and placed in precleaned glass jars to 

make one composite sample. The number of individuals per composite sample depended on the

size of the fiddler crabs. Individuals were collected until the target minimum mass required for

chemical analysis was reached. Each fiddler crab composite sample weighed approximately 60

to 100 grams (approximately 2 to 3.5 ounces).

Three composite samples were collected from each sample location, with the exception of the

Blue Horizon (Area 13) reference location on Vieques Island. Although this reference location

was searched extensively, no fiddler crab were presentiii. Mosquito Bay, which is sampling Area

7 in this study, has been used previously as a reference location. For over 20 years, the Mosquito 

Bay area has been managed by Puerto Rico as a natural resource (for example, gasoline-powered 

boats are banned). Like some other sample locations, no activities that would have led to 

substantial contaminant releases are known to have occurred in the Mosquito Bay area. For these

reasons, the Mosquito Bay sampling area shares many of the characteristics of a reference

location. However, the Mosquito Bay area was selected because of its implications for land crab 

harvesting: it is believed to be an area that provides land crab for the replenishment of adjacent

areas. Mosquito Bay was not designated as a reference location in the original study design, and

it was deemed inappropriate to make that designation retroactively.

2.2.2 Sample Processing

Land Crab Processing

The land crab samples were rinsed in the field with distilled water to remove sand and other

debris. The samples were measured, sexed, tagged, and placed in a cooler. The land crab were

 

iii

The exact locale originally evaluated and chosen for the on-island reference location had, by the time of sampling, been bulldozed, so no land

crab were present there. In consultation with local partners, and after considerable discussion of alternatives, it was concluded that the Blue

Horizon locale offered the best likelihood of representing an area with minimal anthropogenic impacts. Because of this, and the fact that land crab

were the primary target of this study, an adjacent location within the Blue Horizon region was retained as the on-island reference.
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then placed in a freezer at the USFWS headquarters. After several hours, the land crab samples

were removed from the freezer, rinsed, measured, and sexed again. They were then doublebagged in clean freezer-style polyethylene bags. Both the inner and outer sample bags were

marked in indelible ink with the sample identification number and other sample information. A

custody seal was placed over the opening of each outer bag. The land crab samples were then

stored in a freezer at the USFWS headquarters until frozen. Once the samples were frozen, the

bags were wrapped in bubble wrap, placed in coolers with blue ice, and shipped by courier to the

laboratory under chain-of-custody procedures.

Fiddler Crab Processing

The composite fiddler crab samples were placed in a freezer at the USFWS headquarters. After

several hours, the samples were rinsed over a sieve with distilled water to remove sand and other

debris. The fiddler crabs were counted, sexed, and then placed in new, precleaned glass jars. For

each composite sample, the sample identification number and other sample information were

written in indelible ink on a label that was affixed to the jar, and the labels were covered with 

clear tape. A custody seal was placed across the opening of each jar. The sample jars were stored 

in a freezer at USFWS headquarters until they were shipped. Prior to shipping, the sample jars

were wrapped in bubble wrap, double-bagged in clean polyethylene bags, and placed in coolers

with blue ice, then shipped by courier to the laboratory under chain-of-custody procedures.

2.2.3 Sample Analyses

The land crab and fiddler crab samples were sent to Columbia Analytical Services, Inc. of Kelso,

Washington, for chemical analysis. At the laboratory, whole bodies of five to six land crab from

each sample location were individually homogenized and analyzed for explosive compounds,

PCBs, organochlorine pesticides, and trace elements. The land crab were analyzed as whole body 

samples because the residents of Vieques Island consume the majority of the land crab, including

parts of the shell.

In addition to the whole body analyses, one land crab from each sample location was dissected to 

separate the soft tissue from the exoskeleton (which includes the carapace and all other parts of

the shell). The soft tissue and the exoskeleton fractions were weighed and analyzed separately 
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for trace elements. These samples were analyzed to determine whether concentrations of trace

elements in the whole body crab samples may be due to elevated concentrations sequestered in 

the exoskeletons.

The whole body fiddler crab composite samples were homogenized and analyzed for explosive

compounds, PCBs, organochlorine pesticides, and trace elements.

A list of all compounds for which crab samples were analyzed can be found in Section 3 with the

discussion of results.

2.2.4 Deviations from the Sampling and Analysis Plan

To accommodate conditions encountered in the field, some changes were made to the sampling 

and processing methods described in the final SAP (RIDOLFI Inc. and NOAA 2005). These

changes do not compromise the integrity of the samples or the quality of the analytical data

generated from the samples. Deviations from the SAP are described below:

• An overview photograph of each sampling area and some individual traps and crabs was

taken, instead of photographing each individual trap and crab.

• An attempt was made to place the land crab traps at regular distance intervals, but this

was not always possible due to habitat constraints. At some locations, the traps were

placed wherever active burrows were present so that enough sample material could be

collected to complete the sample for that location.

• Several of the land crab were collected by hand, instead of with a trap, because of the

ease of capture and because at least six land crab specimens were needed from every

sample location.

• Individual fiddler crabs were not identified by species.

• The first attempt to collect land crab at the Humacao Wildlife Reserve (Area 14)

reference location was not successfuliv. As a result, the reference crab samples from this

 

iv The area originally targeted had recently active burrows, but crab within this area had been completely harvested.
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location were collected two weeks after the other samples. Such temporal adjustments are

slight and are not expected to affect the analytical results.

• The land crab generally were collected over a span of several hours rather than overnight.

• Although the sampling effort was extended, fiddler crab were not collected at the Blue

Horizon (Area 13) reference location because suitable habitat was lacking.

• Mosquito Bay (Area 7) was sampled instead of Sun Bay because of permitting issues.

The Mosquito Bay sample location is believed to be similar to Sun Bay and a recruiting 

habitat for land crab.

• The sample area referred to in the SAP as Laguna Arenas was moved to the south end of

Laguna Kiani at the request of the USFWS; the name of the sample area was therefore

changed to Laguna Kiani South (Area 4).

2.3 Quality Assurance Summary

Analytical data quality was evaluated both by the laboratory and independently, as specified in

the quality assurance project plan (QAPP). The independent review and the validation of

laboratory data packages were performed by Validata, LLC, of Seattle, Washington. An 

additional review of explosive compounds data was performed by D.M.D., Inc., of Vashon,

Washington. The validated laboratory data appear in Appendix B. Data validation reports and 

associated memoranda are included as Appendix C. A summary quality assurance report is

included as Appendix D.

Laboratory results were either accepted as received (unqualified) or were qualified. No results

were rejected. Unqualified results are considered valid with respect to the specified procedures

and QA/QC measures and may be used as intended. Results qualified with a J flag are considered 

usable with the understanding that the associated values are estimates because they are so near

the sample-specific method detection limit (MDL). Certain pesticide and PCB results were

flagged by the laboratory as JP, indicating that the result is less than the method reporting limit

and that the gas chromatography (GC) confirmation criteria were not met. Data with the JP flag

have more associated uncertainty and should be used with caution. The data validation report

(Appendix C) defines the data qualifiers.
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The principal measures associated with data quality are precision, accuracy, representativeness,

completeness, and comparability. An evaluation of each of these measures determined that overall

analytical performance and data quality are acceptable (see Appendix D for more detail).

During data evaluation, it became evident that trace element analyses associated with one

preparation batch of land crab exoskeletons actually represented crab soft tissue, not the

exoskeleton. Archived samples from this batch were reprepared and reanalyzed; the revised results

are consistent with other exoskeleton results. Details regarding reanalysis of the land crab 

exoskeleton samples are provided in Appendix G.
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3.0 DATA SUMMARY

This section discusses the results of the chemical analysis of Vieques Island land crab and fiddler

crab samples. The analytical results are presented in milligrams per kilogram (mg/kg) or

micrograms per kilogram (μg/kg) on a wet weight basis. Summary tables are provided in this

section, and the complete laboratory analytical data are provided in several tables in Appendix B.

Statistical analyses of trace element and total DDT data are provided in Appendix E for land crab 

and Appendix F for fiddler crab.

It’s important to note that in comparing analytical results, use of the word “significant” has a

particular meaning within the context of the statistical analyses conducted for land crab

(Appendix E) and fiddler crab (Appendix F). An alpha of 0.05 was applied for significant

findings (a p value lower than this indicates a statistically significant difference exists among 

some sites). Therefore, a concentration described as, for instance, “significantly greater” is one

that exhibits a statistically significant difference from the value to which it is being compared.

In this section, the results of this study are briefly compared to the results from previous

biological investigations where possible, although often data comparability is lacking. The land 

crab results presented here were screened for human health effects by the ATSDR in a PHC

(Appendix H). In addition, this report provides limited screening of the land crab data against

conservative ecological risk benchmarks intended to protect the crab themselves (as opposed to 

consumers of crab). The fiddler crab results presented here are also screened against conservative

ecological risk benchmarks.

In addition to the toxicological evaluation of the data, a spatial evaluation was conducted to

provide further insight into any patterns associated with potentially hazardous substances.

3.1 Development of Screening Benchmark Values

The analytical results were screened against highly conservative benchmark values to establish 

whether any compounds could potentially pose a threat to human or ecological receptors. The

benchmark values used in this screening were identified from various published sources.

Although this screening-level assessment should not be treated as a human health and ecological
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risk assessment, it does offer “a high level of confidence in determining a low probability of

adverse risk” (Suter 1993) to facilitate a determination regarding the need for, and degree of,

further investigation. A screening-level assessment acknowledges that chemical concentrations

in excess of the conservative benchmark values may be considered potentially hazardous.

However, concentrations that exceed the benchmark values are not necessarily hazardous. To 

make that determination, further, more realistic, site-specific assessment is required (USEPA

2001). Ultimately, potential risks can be identified and characterized only after consideration of

site-specific exposure parameters, pathways, endpoints, and other assumptions.

Land crab are a food resource for residents of Vieques Island. Therefore, the analytical results

for land crab were compared to human health screening benchmarks in accordance with values

used by the ATSDR in its PHC and assessments that involve fish and shellfish consumption 

(ATSDR 2003). These human health consumption guidelines are based on the ATSDR’s

Minimal Risk Levels (MRLs), the USEPA’s reference dose (RfD) levels, and USEPA regional

risk-based criteria (RBC) for the protection of human health. An MRL is an estimate of the daily

human exposure to a hazardous substance that is likely to be without appreciable risk of adverse

non-cancer health effects over a specified duration of exposure. These substance-specific

estimates, which are intended to serve as screening levels, are used by ATSDR health assessors

and others to identify contaminants and potential health effects that may be of concern at

hazardous waste sites and that deserve further evaluation. Human health screening benchmarks

and results of the land crab screening-level evaluation are provided in the ATSDR PHC

(Appendix H). For the current study, land crab data were also screened against selected 

ecological benchmarks for cadmium, mercury, and vanadium that are specifically protective for

crustacean species.

Fiddler crab are a common intertidal species important in the ecological food web of Vieques

Island. Therefore, the analytical results for fiddler crab were compared to conservative ecological

threshold values. Consistent with the philosophy of a screening-level assessment, the lowest

available tissue residue limits identified in the literature for the protection of crustacean 

(specifically crab, when available) survival, growth, and reproduction were selected (Table 3-1).

Tissue concentration limits, based on no observed adverse effects levels (NOAELs), were

compiled from the USEPA Toxicity/Residue (TOXRES) database (Jarvinen and Ankley 1999)
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and the U.S. Army Corps of Engineers (USACE) Environmental Residue Effects Database

(ERED) (USACE 2005).

Several resident avian species on Vieques Island, including herons and egrets, have been 

reported to feed on fiddler crab, as have small mammals (Deya and Dias 1999). Therefore, when 

crustacean effects data were not available, the fiddler crab analytical results were compared to

toxicity reference values (TRVs) developed by the Oak Ridge National Laboratory for higherorder wildlife. The TRVs are based on NOAELs for the protection of avian and mammalian 

wildlife species (Sample et al. 1996). These NOAEL-based oral ingestion benchmarks were

developed for multiple wildlife species that represent a range of body sizes and diets; however,

the value selected for comparison in this report was not based on a particular receptor species,

but rather on the lowest available value so as to provide high confidence in the screening. Using 

the lowest value as a benchmark, even if the animal is not a known predator of fiddlers, helps to

ensure that the screening is applicable to the broadest range of actual consumers or predators of

fiddler crab. However, chemical concentrations in fiddler crab that exceed these benchmarks do 

not necessarily indicate a particular risk level. Rather, according to this conservative approach,

“concentrations below the benchmarks should not result in significant effects” to predator

species (Sample et al. 1996). Exceedance of a TRV does not firmly establish that a risk is

present, it merely suggests a potential for risk and indicates that further evaluation is warranted.

Table 3-1 summarizes the ecological screening benchmarks used in this report for evaluating

fiddler crab data.

The maximum detection limits for the data used in this study were below the ecological

benchmarks, indicating that the selected benchmarks are sufficiently low to apply to all the data

generated.

3.2 Land Crab Results

Whole body land crab samples (representing the exoskeleton, soft tissue, and all parts) collected 

from Areas 1 through 12 and two reference locations (Areas 13 and 14) were analyzed for

explosive compounds, PCBs, organochlorine pesticides, and trace elements. Results from these

analyses are summarized in Table 3-2 and provided in Appendix B-1. In Table 3-3, mean values
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for all analytes that were detected at least once are compared between sample locations to aid in

identifying potential spatial patterns. In addition, the exoskeleton and soft tissue fractions of one

land crab sample from each area were analyzed separately for trace elements. Those results are

provided in Table 3-4. Compounds that were not detected above the sample-specific laboratory 

MDL are considered non-detects. The MDL is used to represent the non-detects in averaging 

calculations. Only detected compounds were summed for total DDT and total chlordane.

The results were screened against conservative benchmark values developed for the protection of

human health, as discussed in more detail in the ATSDR PHC (Appendix H). In the case of

organic compounds, cadmium, mercury, and vanadium, ecological screening benchmarks meant

to be protective of the crab themselves are available; therefore, whole body concentrations of

these analytes in land crab were also screened against those benchmarks. The results of that

screening are discussed in Section 3.2.4.

To gain additional insight into the patterns of occurrence of trace elements and total DDT, the

mean levels observed at each area (including reference areas) were tested for statistical

difference to identify those areas that exhibited significantly different averages. Details of these

statistical tests appear in Appendix E, along with graphical representation of mean trace element

and total DDT concentrations for each sample location. The differences are discussed in Section 

3.2.5.

3.2.1 Explosive Compounds

Seventy-three whole body land crab samples were analyzed for 14 explosive compounds. A 74th

sample collected in Red Beach (Area 9) was analyzed for all other analyte groups, but was not

analyzed for explosive compounds due to an inadvertent error by the laboratory. No explosive

compounds were detected at concentrations above the MDLs in any land crab sample.

3.2.2 Polychlorinated Biphenyls

Seventy-four whole body land crab samples were analyzed for nine PCB Aroclor mixtures.

Aroclor 1260 was detected in one sample from Laguna Kiani (Area 3) at an estimated 

concentration of 7.6 μg/kg, which is just above the MDL. In a full RI previously conducted at
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Laguna Kiani on behalf of the U.S. Navy, PCBs were detected in groundwater (CH2M Hill

2002b). No other PCB Aroclor mixtures were detected in any land crab sample at concentrations

above the MDLs.

The ATSDR PHC (Appendix H) discusses human health screening values for PCBs. The

estimated concentration of 7.6 μg/kg in a single sample from Laguna Kiani is less than the levels

reported in the scientific literature as causing harmful health effects.

3.2.3 Organochlorine Pesticides

Seventy-four whole body land crab samples were analyzed for 31 individual pesticide

compounds (Table 3-2, Appendix B-1). Seventeen of the 31 pesticide compounds were detected 

in at least one land crab sample, and detections occurred in samples from all areas, including the

reference locations. Nearly all of the detections were of DDT and its metabolites or chlordane

compoundsv.

The pesticides 4,4’- and 2,4’-DDT, -DDD, and -DDE were the most ubiquitous of the pesticide

compounds; detections ranged from two samples (2,4’-DDE) to 39 samples (4,4’-DDE). DDT

and its metabolites were detected in samples from all sample locations except the Blue Horizon

(Area 13) reference location at concentrations ranging from 0.14 μg/kg to 190 μg/kg. 4,4’DDT

and -DDE had previously been detected in crab tissue samples from Vieques Island at similar

concentrations (Lopez 2002).

Land crab data were statistically tested to determine whether there were differences among the

sexes and whether size was an influencing factor. Neither sex nor size was a significant factor to 

explain differences in total DDT values. The only significant differences were among sampling 

areas.

 

v Chlordane, especially when applied as a commercial pesticide, is a mixture of dozens of individual compounds. There are about 10 individual

compounds that make up the majority of most commercial formulations; the sum of eight compounds has been used in this report to represent

total chlordane.
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Gamma-chlordane, the most prevalent of the chlordane compounds, was detected in 16 samples

representing about half of the sampling areas, including the Blue Horizon reference area.

Chlordane compounds were not detected in six areas.

Other pesticide compounds were detected in samples from four areas, including the Humacao 

Wildlife Reserve (Area 14) reference location. Three cyclo-diene pesticides (aldrin, dieldrin, and 

endrin) were each detected once at low, estimated concentrations that were just above the MDLs.

The samples with these single detections were collected from Bahia Tapon (Area 11) and from

the Humacao Wildlife Reserve. Three other pesticides (endosulfan sulfate, methoxychlor, and

mirex) were each detected in from two to four samples; many of these detections were also at

low, estimated concentrations. These samples were collected from east- and west-end sampling

areas, as well as the Blue Horizon reference location. Mirex was detected in land crab only from

the LIA (Area 12) (and was also found in fiddler crab only from that same area). Although

different compounds were in general detected in different areas, there was a certain degree of

concordance in the occurrence of infrequently detected pesticides: Three of the four areas where

endosulfan sulfate, methoxychlor, and aldrin were detected are also among the areas with the

four highest mean total DDT concentrations. These areas are Laguna Kiani (Area 3), Red Beach 

(Area 9), and Bahia Tapon. Bahia Tapon and Laguna Kiani also were among the areas with the

four highest mean total chlordane concentrations.

The human health screening values for detected pesticides are discussed in the ATSDR PHC

(Appendix H). In summary, the concentrations of detected pesticide compounds are less than 

levels reported in the scientific literature as causing harmful health effects. As reported in the

PHC, DDE levels (average of 0.021 mg/kg) were also well below the Food and Drug 

Administration (FDA) action level of 5 mg/kg for edible portions of fish. Averages from

individual areas were also below health effect levels and FDA guidelines.

Pesticide concentrations in land crab data were also screened against the ecological screening 

benchmarks developed for other crustacean species. All pesticide concentrations were below the

available crustacean ecological screening benchmarks.
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3.2.4 Trace Elements

Seventy-four whole body land crab samples, 14 soft tissue-only samples, and 14 exoskeletononly samples were analyzed for 23 trace elements, which were ubiquitously detected in samples

from all areas, including both reference locations (Tables 3-2 and 3-4, Appendices B-1 and B-2).

To compare the concentrations among locations, data from the individual whole body land crab 

samples were averaged by compound for each location (Table 3-3). For substances that were not

detected, the sample-specific laboratory MDL value was used in generating the mean.

More than half of all 23 trace elements were detected in all whole body samples. The widespread 

detection of numerous trace elements in land crab samples likely reflects exposure to elements

naturally occurring in soil, sediment, groundwater, and surface water (CH2M Hill 2002a). Some

of these trace elements are in fact essential nutrients (e.g., copper, calcium, magnesium)

(Terwilliger and Ryan 2001; van Holde et al. 2001). Extreme values though, such as those

significantly greater than values observed from a reference, may indicate potential anthropogenic

sources. Certain trace elements had previously been reported in a limited number of land crab

tissue samples (Lopez 2002; ATSDR 2003).

Results of the land crab exoskeleton-only and soft tissue-only analyses for trace elements are

summarized in Table 3-4 and provided in Appendix B-2. Exoskeletons were analyzed to evaluate

whether certain trace elements may be preferentially bioconcentrated in the skeleton. In addition,

it was thought that these data might provide additional insight into the levels of whole body

residue burdens. In general, more trace elements were detected in the soft crab tissue than in the

exoskeleton; the exoskeleton did not contain beryllium, mercury, or selenium. Concentrations of

half of all trace elements detected in the exoskeleton were greater in the exoskeleton than in the

soft tissue-only samples (ratio greater than 1; see Table 3-4); concentrations of four trace

elements (barium, calcium, chromium, and magnesium) were at least an order of magnitude

greater in the exoskeleton than in the soft tissue-only samples. Because calcium is one

constituent of the carapace, calcium concentrations were, as expected, much greater in the

exoskeleton, averaging 105,657 mg/kg compared to the average soft tissue concentration of

3,844 mg/kg. Mean copper concentrations were higher in soft tissue, however, averaging 50.3 

mg/kg compared to 6.0 mg/kg in the exoskeleton. This copper result was also expected because
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of the biochemistry of crab. A similar pattern of soft tissue concentrations exceeding exoskeleton 

concentrations was observed for cadmium (0.104 mg/kg vs. 0.012 mg/kg); silver (0.073 mg/kg 

vs. 0.013 mg/kg), and zinc (48.1 mg/kg vs. 13 mg/kg).

Trace element concentrations in land crab were also screened against screening benchmarks for

cadmium, mercury, and vanadium developed for other crustacean species. All concentrations of

mercury were below the crustacean ecological screening benchmark. Concentrations of

vanadium were either below the MDL or above the ecological screening benchmark derived 

from shore crab at all areas, except Red Beach (Area 9). Cadmium concentrations exceeded the

benchmark in five cases:

• One crab from Boca Quebrada (Area 5) had a cadmium concentration about two times

the cadmium benchmark value.

• One crab from Laguna Kiani (Area 3) had a cadmium concentration that just barely 

exceeded the cadmium benchmark value.

• Three crab from the LIA (Area 12) contained cadmium concentrations about two to four

times the cadmium benchmark value.

Although the ATSDR concluded that consumption of these crab is not expected to cause harmful

health effects in adults or children, this screening suggests that levels of vanadium and cadmium

observed in land crab might affect the health of the crab themselves. Such differences in apparent

toxicity (human versus crab) can occur because of variations in sensitivity between species,

which can be further related to differences in the biochemistry of specific organisms. Neither the

vanadium nor the cadmium benchmark was derived from studies of land crab. Considering 

species-specific variations in toxicity, it is possible that these benchmarks may under- or overestimate the potential for risk to land crabs.

3.2.5 Sample Area Comparisons

This section discusses the spatial pattern and differences observed in concentrations irrespective

of their absolute value relative to ecological or human health benchmarks. Spatial evaluations of

the data can help raise other insights from the data beyond their toxicological significance.
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Table 3-3 presents average concentrations of analytes detected in land crab for Areas 1 through 

14. In calculating these averages for the trace elements, the MDL was used to represent any nondetect value. Only detected values were summed to generate total DDT. The means for the trace

elements and total DDT were then statistically tested to determine which areas (including the

reference locations) were significantly different from each other. Detailed statistics, along with

graphical representations of the statistical analysis, are presented in Appendix E. Table 3-5

summarizes the statistical analysis.

Organic Compounds

Most of the organic compounds for which land crab were analyzed were either not detected or

were detected infrequently. PCB Aroclor 1260 was detected in one land crab sample from

Laguna Kiani (Area 3). Endosulfan sulfate, methoxychlor, mirex, and aldrin were each detected 

in one or two areas. This low number of detections precludes comparison between areas.

Chlordane-related compounds were observed at half of the areas. When detected, chlordane

concentrations were just above the detection limit, including at the on-island Blue Horizon (Area

13) reference location.

Low concentrations of the pesticide DDT and its metabolites were observed in land crab from all

areas except the Blue Horizon reference location. The greatest average concentrations of total

DDT were found in the crab collected from Laguna Kiani on the island’s west end and from Red 

Beach (Area 9) on the east end, followed by Blue Beach (Area 10) and then Bahia Tapon (Area

11). Table 3-5 presents a statistical analysis of areas for which analytical results were

significantly different (either lower or greater) from results for the two reference areas. As shown 

in Table 3-5, mean total DDT concentrations at Laguna Kiani and Red Beach were significantly

greater than for both reference areas.

Trace Elements

Table 3-5 also summarizes the statistical analysis (Appendix E) of average trace element

concentrations for each area relative to the reference locations. In calculating these averages, the

MDL was used for samples with non-detectable concentrations. Refer to Appendix E for
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graphical representations of each trace element that clearly illustrate deviations from the overall

average.

The reference locations did not exhibit any difference in trace element concentrations with the

exception of barium. Average concentrations of barium in samples from the Humacao Wildlife

Reserve (Area 14) were significantly greater than concentrations of barium in samples from the

Blue Horizon reference area. In general, mean reference values for trace elements were near an

overall average or below. These observations tend to reinforce the appropriateness of the

selection of these locales as reference areas.

Average concentrations of several trace elements in land crab (Table 3-3) appear to be elevated 

(greater than island-wide averages, Table 3-2) at some specific areas. In some cases, however,

this apparent difference derives from the analytical results for a single crab. Examples include

thallium at Red Beach; silver and chromium at Puerto Ferro (Area 8); copper at Mosquito Bay 

(Area 7); and lead at Laguna Kiani. It’s difficult to determine the significance of a single crab 

with greater-than-average concentrations. Clearly, consistent results within a given area would

be a clearer indication of exposure within that locale. Because of the relatively small sample

sizes in this study, however, the singular results should not be immediately dismissed as outliers.

For instance, concordance between the results for a given compound in the two species would be

a broader indication of significant exposure factors within an area.

Samples from Laguna Kiani, Puerto Ferro, downgradient from AOCs J and R (Area 2), Boca

Quebrada (Area 5), and the LIA (Area 12) contained the largest number of trace elements for

which average values were greater than the reference values. Land crab from each of these areas

had four or more trace elements at concentrations that were significantly greater than

concentrations in at least one of the reference locations. SWMU 7 (Area 1) was the only area

where no trace elements were detected in samples at concentrations significantly greater than the

average reference values.

The spatial distribution of specific trace elements is discussed below:

• Mercury and beryllium display a unique pattern: Apparent statistical differences in these

trace elements occurred between samples in which concentrations were below the MDL
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and those in which concentrations were just above the MDL. Mercury concentrations did 

not exceed the crustacean-based screening benchmark in any of the areas. Beryllium had 

the lowest frequency of detection, with a single detection in a sample from downgradient

of AOCs J and R (Area 2).

• In the case of selenium, thallium, uranium, and zinc, no apparent spatial pattern in 

concentrations was observed and the sampling areas did not exhibit significant

differences. Uranium was detected in all land crab samples except two at concentrations

ranging from 0.0017 mg/kg (Blue Beach) to 0.0375 mg/kg (downgradient of AOCs J and 

R); however, concentrations across all areas, including the reference locations, are

statistically indistinguishable.

• Iron and vanadium also display no apparent spatial pattern: Areas that were different

from the reference areas had significantly lower concentrations. Mean vanadium

concentrations from all sampling areas except Red Beach exceeded the crustacean-based 

screening benchmark for vanadium.

• The average cadmium concentration in land crab from the LIA was generally elevated 

above the other locations, and significantly greater than the reference samples. The LIA

was also the only area at which the crustacean-based screening benchmark for cadmium

was exceeded.

• Laguna Kiani was the only area with an average lead concentration significantly greater

than the reference values.

• Average levels of barium in samples from Laguna Kiani South (Area 4) were

significantly greater than the reference values.

• Average levels of nickel in samples from Laguna Playa Grande (Area 6) were

significantly greater than the reference values.

• Average levels of arsenic in samples from Red Beach were significantly greater than the

reference values.

There was some apparent co-occurrence of maximal levels of both organics and trace elements.

The highest average concentrations of arsenic, chromium, iron (on island), lead (detected mostly 
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in one crab), and magnesium were observed at Laguna Kiani, as were the PCB detection, the

second-highest total chlordane result, and the maximum average of total DDT.

3.3 Fiddler Crab Results

Fiddler crab composite samples collected from Areas 1 through 12 and Area 14 were analyzed 

for explosive compounds, PCBs, organochlorine pesticides, and trace elements. The analytical

results are summarized in Table 3-6. Mean values shown in Table 3-7 were calculated for all

analytes and compared among sampling areas to identify potential spatial patterns. Compounds

that were not detected above the laboratory MDLs are considered non-detects. The MDL is used 

to represent the non-detects in averaging calculations. Only detected compounds were summed

for total DDT and total chlordane.

The analytical results are provided in Appendix B-3 and are discussed below. The results were

screened against conservative benchmark values (Table 3-1) developed for the protection of

ecological receptors. The results of that screening are discussed in Section 3.3.4.

To gain additional insight into the patterns of occurrence of trace elements and total DDT, the

mean levels observed at each area (including reference areas) were tested for statistical

difference to identify those areas that exhibited extreme averages. Details of these statistical tests

appear in Appendix F, along with graphical representation of mean trace element and total DDT

concentrations for each sample location. The differences are discussed in Section 3.3.5.

3.3.1 Explosive Compounds

Thirty-nine whole body composite fiddler crab samples were analyzed for 14 explosive

compounds. No explosive compounds were detected in fiddler crab samples at concentrations

above the MDLs.

3.3.2 Polychlorinated Biphenyls

Thirty-nine whole body composite fiddler crab samples were analyzed for nine PCB Aroclor

mixtures. Aroclor 1254 was detected in three samples from Laguna Kiani (Area 3) at

concentrations ranging from 47 to 58 μg/kg. None of these concentrations exceeded the
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ecological screening benchmark for blue crabviof 23,000 μg/kg (USEPA 2005c). PCBs had 

previously been detected in groundwater in this area (CH2M Hill 2002b). No other PCB Aroclor

mixtures were detected in fiddler crab samples at levels above the MDLs.

3.3.3 Organochlorine Pesticides

Thirty-nine whole body composite fiddler crab samples were analyzed for 31 individual pesticide

compounds (Table 3-6). Pesticides were detected in all areas, including the Humacao Wildlife

Reserve (Area 14) reference location. Twenty-two of the individual pesticide compounds

analyzed for were detected in at least one fiddler crab sample:

• Three pesticides were each detected once at low, estimated concentrations: delta-BHC

was detected in a sample from Boca Quebrada (Area 5), while endrin and heptachlor

were detected in samples from Laguna Kiani (Area 3).

• Eight individual compounds (aldrin, beta-BHC, cis-nonachlor, endrin aldehyde, endrin

ketone, gamma-chlordane, mirex, and trans-nonachlor) were each detected in two or three

samples; many of the detections were at low, estimated concentrations. These samples

were collected from both east- and west-end sampling areas, as well as from the

Humacao Wildlife Reserve.

• Five pesticides (alpha-chlordane, dieldrin, endosulfan sulfate, heptachlor epoxide, and 

methoxychlor) were each detected in from six to eight samples; these detections represent

most of the sampling areas, including the Humacao Wildlife Reserve reference location.

• DDT compounds (4,4’- and 2,4’-DDT, -DDD, and –DDE) were the most ubiquitous of

the detected pesticide compounds, occurring in between two samples (2,4’-DDE) and 33 

samples (2,4’-DDT). DDT and its metabolites were detected in samples from all areas,

including the reference location, at concentrations ranging from 0.27 μg/kg to 270 μg/kg.

DDT and DDE had previously been detected in crab tissue samples from Vieques Island 

(Lopez 2002) at similar concentrations.

 

vi

This is a no observed effects level for survival in juvenile blue crab following a 20-day exposure.
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No pesticide compounds were detected at concentrations that exceeded available ecological

screening benchmarksvii. The remaining pesticide compounds were not detected at levels above

the MDLs.

3.3.4 Trace Elements

Thirty-nine whole body composite fiddler crab samples were analyzed for 23 trace elements,

which were ubiquitously detected in samples from all areas, including the reference location 

(Table 3-6). Beryllium was detected in the fewest samples (21), while most other trace elements

were detected in all or nearly all 39 samples.

The widespread detection of trace elements in fiddler crab samples likely reflects their exposure

to elements naturally occurring in soil, sediment, groundwater, and surface water (CH2M Hill

2002a). Some of these trace elements are in fact essential nutrients (e.g., copper, calcium,

magnesium) (Terwilliger and Ryan 2001; van Holde et al. 2001). Extreme values though, such as

those significantly greater than values observed from a reference, may indicate potential

anthropogenic sources and suggest the need for further evaluation to establish their cause.

Certain trace elements had previously been reported in a limited number of fiddler crab tissue

samples (Deya and Dias 1999; Lopez 2002).

Uranium was detected in all fiddler crab samples at concentrations ranging from 0.011 mg/kg at

the downgradient of SWMU 7 (Area 1) sampling location to 0.115 mg/kg at the Boca Quebrada

(Area 5) location. These values do not approach the wildlife TRV screening benchmark for

uranium of 5.98 mg/kg. As shown on Table 3-7, which provides average values for each analyte

at each location, the highest level of uranium occurred in a sample from Boca Quebrada;

however, most locations exhibit concentrations that are relatively consistent. Average

concentrations of uranium in samples from Laguna Kiani South (Area 4), Boca Quebrada, and

 

vii

One sample contained 4,4’-DDE at a concentration roughly twice the benchmark for 4,4’-DDT. DDE is known to be generally less toxic than

DDT, plus limited data from other crustacean species suggest that DDT may be 10 to up to 200 times more toxic than DDE (Lotufo et al. 2000).

Therefore, this single DDE result was not considered significant. This assessment is focused on crabs and does not estimate risk to potential

predators, such as birds.
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Mosquito Bay (Area 7) were all significantly greater than concentrations at the reference

location, but all were well below the screening benchmark.

Ten trace elements (aluminum, arsenic, barium, cadmium, chromium, copper, lead, selenium,

vanadium, and zinc) were detected in multiple samples at concentrations that exceeded available

ecological screening benchmarks:

• Aluminum concentrations exceeded the ecological screening benchmark of 3.8 mg/kg

(wildlife TRV) in all samples; aluminum concentrations ranged from 33.2 mg/kg (Red 

Beach, Area 9) to 1,100 mg/kg (Blue Beach, Area 10).

• Arsenic concentrations exceeded the ecological screening benchmark of 0.25 mg/kg 

(wildlife TRV) in all samples; arsenic concentrations ranged from 0.6 mg/kg

(downgradient of AOCs J and R, Area 2) to 4.01 mg/kg (Red Beach).

• Barium concentrations exceeded the screening benchmark of 17.2 mg/kg (wildlife TRV)

in 29 samples representing all locations except Red Beach and Bahia Tapon (Area 11);

barium concentrations ranged from 4.19 mg/kg (Red Beach) to 122 mg/kg (downgradient

of AOCs J and R).

• Cadmium concentrations exceeded the screening benchmark of 0.13 mg/kg (lobster

NOAEL) in 12 samples from Areas 1, 3, 6, 10, and 12; cadmium concentrations ranged 

from 0.013 mg/kg (Mosquito Bay) to 0.557 mg/kg (Laguna Kiani, Area 3). However, the

average cadmium concentration across all areas (0.118 mg/kg) did not exceed the

benchmark.

• Chromium concentrations exceeded the screening benchmark of 0.83 mg/kg (wildlife

TRV) in 30 samples representing all locations except downgradient of AOCs J and R;

chromium concentrations ranged from 0.27 mg/kg (downgradient of AOCs J and R) to

7.89 mg/kg (Blue Beach).

• Copper concentrations exceeded the screening benchmark of 38.9 mg/kg (wildlife TRV)

in 26 samples representing all locations except Areas 1 and 2; copper concentrations

ranged from 26.7 mg/kg (downgradient of SWMU 7) to 73.1 mg/kg (Laguna Kiani).
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• Lead concentrations exceeded the screening benchmark of 0.94 mg/kg in three samples

collected from one area, making lead unique among the trace elements with exceedances.

Lead concentrations ranged from 0.08 (Mosquito Bay) to 9.72 mg/kg (Laguna Kiani) and

exceeded the screening benchmark in the three samples from Laguna Kiani, where the

average lead concentration was 8.13 mg/kg; the next highest area average was 0.55

mg/kg.

• Selenium concentrations exceeded the screening benchmark of 0.33 mg/kg (wildlife

TRV) in 14 samples representing Areas 5, 6, 9, 10, 11, and 12; selenium concentrations

ranged from 0.12 mg/kg (downgradient of AOCs J and R) to 0.83 mg/kg (Laguna Playa

Grande, Area 6). However, the average concentration across all areas (0.35 mg/kg) was

only slightly greater than the benchmark.

• Vanadium concentrations exceeded the screening benchmark of 0.2 mg/kg (shore crab 

NOAEL) in all samples but one; vanadium concentrations ranged from 0.2 mg/kg (Red 

Beach) to 3.2 mg/kg (Blue Beach).

• Zinc concentrations exceeded the screening benchmark of 12 mg/kg (wildlife TRV) in all

samples; zinc concentrations ranged from 18.8 mg/kg (Red Beach) to 36.5 mg/kg (Boca

Quebrada).

Of the ten trace elements discussed above, all of which exceeded screening benchmarks in 

multiple samples, only cadmium, lead, and selenium were not detected at concentrations above

the screening benchmarks in reference samples from the Humacao Wildlife Reserve (Area 14).

It is important to note that, in the absence of tissue residue screening benchmarks for the

protection of crab themselves, the screening benchmark values used for many of these

compounds are wildlife TRVs. These TRVs are developed for the protection of avian and 

mammalian wildlife that may eat contaminated prey. These TRVs represent a dietary

benchmark; as applied here, the entire diet is assumed to be fiddler crab, all of the diet is

assumed to be contaminated at the maximum analyte concentration detected, and 100% of any

contaminant is assumed to be assimilated from the diet. It is recognized that these are overly

conservative exposure assumptions. Some trace elements may nonetheless warrant further sitespecific evaluation to determine whether they pose a threat to crab and tp other ecological
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receptors. Additional data regarding the concentration of trace elements in co-located abiotic

media (for example, soil) will also help put these results into context.

3.3.5 Sample Area Comparisons

This section discusses the spatial pattern and differences observed in concentrations irrespective

of their absolute value relative to ecological or human health benchmarks. Spatial evaluations of

the data can help raise other insights from the data beyond their toxicological significance.

Table 3-7 presents average concentrations of analytes detected in fiddler crab for Areas 1 

through 12 and 14. In calculating these averages for the trace elements, the MDL was used to 

represent any non-detect value. Only detected values were summed to generate total DDT. The

means for the trace elements and total DDT were then statistically tested to determine which

areas (including the reference location) were significantly different from each other. Detailed

statistics, along with graphical representations of the statistical analysis, are presented in 

Appendix F. Table 3-8 summarizes the statistical analysis.

Organic Compounds

Differences in the concentrations of organic substances measured in the fiddler crab were

generally similar to those for the land crab, with most substances either not detected or detected 

at similar concentrations among all locations. As was the case for land crab, PCBs (in this case,

Aroclor 1254) were detected in fiddler crab samples collected only from Laguna Kiani (Area 3).

The pesticide DDT and its metabolites were detected at more locations than in the land crab 

samples; however, the greatest concentrations were found at Laguna Kiani, Red Beach (Area 9),

and Bahia Tapon (Area 11), similar to the case for land crab. Only concentrations of total DDTs

from Bahia Tapon and Red Beach were significantly greater than concentrations in the reference

samples.

Trace Elements

Table 3-8 summarizes the results of statistical testing (Appendix F) for trace elements. Figure 3-

4 illustrates the mean concentrations identified on Table 3-8 as both significantly greater than

concentrations at the reference location and in excess of ecological screening benchmarks. Refer
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to Appendix F for graphical representations of each trace element that clearly illustrate

deviations from the overall average. Additional data plots in Appendix F also indicate the

variability within sampling areas for select trace elements.

Average concentrations of nearly all trace elements (excepting magnesium, mercury, and 

thallium) determined in samples from Areas 1 through 12 were different from concentrations for

the reference location (either greater or lower) for at least one area. However, differences in 

those trace element concentrations that also exceeded conservative ecological screening 

benchmarks are of most interest.

Ten trace elements were detected in at least one sample at concentrations that exceeded an 

ecological screening benchmark:

• Concentrations of aluminum, arsenic, vanadium, and zinc exceeded ecological screening 

benchmarks in every sample (including the reference sample). Average concentrations of

aluminum were significantly greater than the reference mean at Boca Quebrada (Area 5)

and Blue Beach (Area 10); average concentrations of arsenic at Laguna Kiani, Red 

Beach, Bahia Tapon, and the LIA (Area 12) were greater than the reference mean;

average concentrations of vanadium at Laguna Playa Grande (Area 6) and Blue Beach 

were greater than the reference mean; and average concentrations of zinc at Laguna

Kiani, Boca Quebrada, Red Beach, and Bahia Tapon were significantly greater than the

reference mean.

• Concentrations of cadmium, lead, and selenium did not exceed the ecological screening 

benchmarks at the reference locations, but concentrations detected at one to four sample

areas were significantly greater than the reference mean. Concentrations of cadmium,

lead, and selenium in land crab and fiddler crab are presented on Figures 3-1, 3-2, and 3-

3, respectively, relative to the applicable ecological screening benchmarks. The average

selenium concentration exceeded the reference value at Laguna Playa Grande, Blue

Beach, Bahia Tapon, and the LIA. The average cadmium concentration was greater than 

the reference mean at Blue Beach, the LIA, and Laguna Kiani. The average lead 

concentration at Laguna Kiani was greater than the reference mean and also exceeded the

ecological screening benchmark.
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• Average concentrations of barium, chromium, and copper exceeded ecological screening 

benchmarks at one to three sites and were greater than the reference mean. The average

concentrations of chromium at Blue Beach; of barium downgradient from SWMU 7 

(Area 1) and downgradient from AOCs J and R (Area 2); and copper at Laguna Kiani,

Boca Quebrada, and Laguna Playa Grande were all greater than the mean observed at the

reference location.

Magnesium, mercury, and thallium were the only trace elements for which no such statistical

differences were observed among any of the sampling areas. Cobalt and nickel were the only 

trace elements for which any significant differences were less than the reference. Cobalt, iron,

and silver have no ecological screening benchmark.

Samples from Laguna Kiani, Boca Quebrada, and Blue Beach contained the largest number of

trace elements for which average values were greater than the reference values. Land crab from

each of these areas had six or more trace elements at concentrations that were significantly 

greater than concentrations at the reference locations. Puerto Ferro was the only area where no

trace elements were detected in samples at concentrations significantly greater than the average

reference values.

Overall, three of the sampling areas had samples with trace element concentrations that exceeded 

ecological screening benchmarks, but the averages for those trace elements were not

significantly different from the reference values:

• Laguna Kiani South (Area 4);

• Mosquito Bay (Area 7); and

• Puerto Ferro (Area 8).

Given that these results exceeded ecological screening benchmarks but not the reference values,

these results may represent a regional baseline condition.
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3.4 Comparisons to Previous Studies

Because of differences in sample processing, the results from this study cannot always be

directly compared to results from previous studies. Deya and Dias (1999) dissected the fiddler

crabs. The fiddler crabs associated with data reported by the ATSDR (2003) were not rinsed of

sand and mud, and the land crab results were reported with the results for other shellfish in the

ATSDR study. Only the land and fiddler crab data from Lopez (2002) are directly comparable

with the data reported here.

Lopez (2002) reported detectable concentrations of DDT compounds and cadmium, lead, and

vanadium. The DDT level observed by Lopez (28 μg/kg) is comparable to the maximum

presented here (25 μg/kg), and DDE values in Lopez (130 μg/kg in land crab and 54 μg/kg in

fiddler crab) are also within the range of values presented here. Cadmium data reported by Lopez

for fiddler crab are within the range of values reported here. Cadmium concentrations in three of

the four land crab samples analyzed by Lopez are lower than the average cadmium values

reported here. Lopez reported slightly greater cadmium concentrations in one land crab sample

(0.656 mg/kg) than the maximum (0.557 mg/kg) reported here. For lead and vanadium, values

reported by Lopez fall within the range of values reported here.

Deya and Dias (1999) focused on selected trace elements (cadmium, chromium, cobalt, copper,

lead, manganese, nickel, and zinc). The trace element data presented by Deya and Dias for

fiddler crab represent different tissues than the whole body composite data presented here. Deya

and Dias generally reported higher levels of trace elements (excepting copper and manganese)

and used Mosquito Bay as a reference location for comparison to the values determined in 

samples taken from the LIA. Similar to the results reported here, no consistent trends were

observed in trace element concentrations by sampling area.
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4.0 CONCLUSIONS

This report summarizes analytical results for Vieques Island land and fiddler crab sampled by 

NOAA in June 2005. All analytical data were independently reviewed and validated to ensure

their usability. Land crab sample results were compared to conservative human health screening 

values in the ATSDR PHC (Appendix H). Land crab results were also screened in this report

against ecological benchmarks meant to be protective of the crab themselves. Fiddler crab

sample results were evaluated against conservative ecological screening benchmarks, as

summarized in this report. Benchmarks for the protection of crab themselves were used when 

available. Benchmarks meant to protect wildlife that may prey on fiddler crab were applied when

crustacean-based benchmarks were not available.

The ATSDR prepared a PHC using the data reported here to evaluate potential human health

impacts from eating land crab. The ATSDR determined that the levels of PCBs, organochlorine

pesticides, and trace elements found in land crab are much lower than levels reported to cause

harmful health effects. Concentrations were also below appropriate FDA regulatory contaminant

limits for shellfish consumption. The ATSDR does not expect that adults or children will

experience harmful health effects from eating land crab from Vieques Island.

While the ATSDR’s evaluation focused on human health aspects of the land crab data, NOAA

used the data to determine whether contaminants could pose a risk to the land crab themselves.

There appears to be little contamination of crab by the organic contaminants analyzed for in this

study. No explosive compounds were detected in any land or fiddler crab. Few PCB compounds

were detected, and the detections occurred only in samples from Laguna Kiani (Area 3). Aroclor

1260 was detected in one land crab sample while Aroclor 1254 was detected in all fiddler crab 

composite samples from Laguna Kiani. It is noteworthy that the PCB detections occurred at the

same area where PCBs had previously been detected in groundwater (CH2M Hill 2002b).

Laguna Kiani is one of the few sampling areas with sufficient assessment data to allow

comparisons among various environmental media and the body burdens reported here. Although 

PCBs were detected in crabs from Laguna Kiani, the results did not exceed the human or

ecological screening benchmark values.
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Pesticides were also rarely observed, excepting DDT metabolites and chlordane compounds,

which were both detected in multiple land crab and fiddler crab samples. Many of the detections

were at low, estimated concentrations just above the MDLs. No pesticide concentrations in crab 

exceeded ecological screening values intended for the protection of crustaceans. The

composition of DDT compounds does not suggest ongoing releases. There was general

concordance in the spatial pattern of exposure for the two crab species: The four highest average

total DDT concentrations in both land crab and fiddler crab were observed at Laguna Kiani, Red 

Beach (Area 9), Blue Beach (Area 10), and Bahia Tapon (Area 11). Laguna Kiani and Bahia

Tapon also had the highest total chlordane levels. Other pesticides were detected infrequently, at

just one or two locations. Mirex, however, was observed in most land crab and all fiddler crab 

samples from the LIA (Area 12) and was not detected at any other sampling area. Although

mirex concentrations in crab were below the crustacean screening benchmark, the co-occurrence

of this compound in multiple samples from both species is noteworthy because it demonstrates

an exposure pathway in this area.

Trace elements were ubiquitously detected in both land crab and fiddler crab samples.

Concentrations were generally greater in fiddler crab than in land crab. In land crab, no

differences were observed in average trace element concentrations between the two reference

locations (excepting barium). In general, reference values were average or low, indicating that

the reference locations were appropriately selected.

In land crab, concentrations of mercury did not exceed the crustacean-based ecological

benchmark in any sampling area. Concentrations of vanadium exceeded the crustacean-based 

ecological benchmark in all areas except Red Beach, but there were no differences among the

averages. Cadmium concentrations in samples from the LIA were elevated, were significantly 

different from cadmium concentrations in the reference samples, and exceeded the ecological

benchmark for crustaceans. Average lead concentrations in land crab were significantly greater

than the reference values at only one sampling area, Laguna Kiani. No differences were observed 

in average land crab residues of iron, selenium, thallium, uranium, and zinc among sampling 

areas, nor were concentrations of these trace elements in land crab significantly greater than in 

the reference samples.
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Ten trace elements exceeded conservative ecological screening benchmarks in fiddler crab:

aluminum, arsenic, barium, cadmium, chromium, copper, lead, selenium, vanadium, and zinc.

Concentrations of some of these elements exceeded benchmarks at all sampling areas, including

the reference location, while others (such as lead at Laguna Kiani) exceeded their respective

benchmark at only one sampling area. Concentrations of cadmium, lead, and selenium exceeded 

benchmarks in some samples, but not at the reference location, and were detected at levels

significantly greater than the reference means. These observations tend to suggest that exposure

of these trace elements at these sampling areas may include non-natural sources in addition to 

natural sources. Trace elements exceeded benchmarks but were not different from the reference

at three locations: Laguna Kiani South (Area 4), Mosquito Bay (Area 7), and Puerto Ferro (Area

8). Exposures at these sites may represent a regional baseline conditions that results in body

burdens greater than the conservative benchmarks applied here.

There were several instances of concordance between trace element levels in the two species;

elevated concentrations were observed in both species for lead at Laguna Kiani; cadmium at the

LIA; and arsenic at Laguna Kiani, the LIA, and Red Beach. Total DDT was greatest in both 

species at Laguna Kiani, Red Beach, Blue Beach, and Bahia Tapon. Both species from Laguna

Kiani and Bahia Tapon also had the highest total chlordane averages. Concordance between the

two species provides a consistent indication of exposure.

This data report includes a screening-level assessment of land and fiddler crab samples from

Vieques Island. This preliminary screening indicates that some analytes may be present at levels

sufficiently high that the possibility of adverse impacts to crab cannot be eliminated. To fully 

identify and characterize potential risks to human health and ecological receptors, further

analysis of land and fiddler crab, as well as other ecological receptors, may be warranted,

particularly with regard to organochlorine pesticides and trace elements. The need for additional

analyses should be evaluated as applicable, as part of the ongoing human health and ecological

risk assessment activities required for the Remedial Investigations of sites on Vieques Island.
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5.0 REFERENCES

Agency for Toxic Substances and Disease Registry (ATSDR). 2003. Public Health Assessment:

Fish and Shellfish Evaluation, Isla de Vieques Bombing Range, Vieques, Puerto Rico.

Agency for Toxic Substances and Disease Registry.

CH2M Hill. 2002a. Final Soil, Groundwater, Surface Water, and Sediment Background 

Investigation Report. Norfolk, VA: Department of the Navy, Atlantic Division.

CH2M Hill. 2002b. Final Expanded Preliminary Assessment/Site Investigation Phase II Seven 

Sites. Norfolk, VA: Department of the Navy, Atlantic Division.

Deya, A.M., and E. Dias. 1999. Biomagnification of Carcinogenic Metals in Crab Tissue,

Vieques, Puerto Rico. University of Puerto Rico. March 1999.

Diaz, Oscar. 2005. Personal communication with Michael Buchman. 21 Nov 2005.

Grimes, B.H., M.T. Huish, J.H. Kerby, D. Moran, and E. Pendleton. 1989. Species: Life

Histories and Environmental Requirements of Coastal Fishes and Invertebrates (MidAtlantic), Atlantic Marsh Fiddler. Vicksburg, MS and Washington D.C.: U.S. Army Corps of

Engineers and U.S. Fish and Wildlife Service.

Hostetler, M.E., F.J. Mazzotti, and A.K. Taylor. 2003. Blue Land Crab (Cardisoma guanhumi).

Gainesville, Florida: University of Florida, Institute of Food and Agricultural Sciences.

Jarvinen, A.W., and G.T. Ankley. 1999. Linkage of Effects to Tissue Residues: Development of

a Comprehensive Database for Aquatic Organisms Exposed to Inorganic and Organic

Chemicals. Published (hard copy) by the Society for Environmental Toxicology and

Chemistry (SETAC) and online by the USEPA. Website accessed October 2005:

http://www.epa.gov/med/Prods_Pubs/tox_residue.htm.

Learned, Robert E., G.R. Grove, and R. Boissen. 1973. A geochemical reconnaissance of the

Island of Vieques, Puerto Rico. US Geological Survey and Puerto Rico Department of

Natural Resources. Open-file report 73-155 (order no. 1866).
NOAA ORR and Final Data Report for the

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Lopez, F. 2002. Contaminant Levels in Crabs from Two Solid Waste Management Units on 

Vieques National Wildlife Reserve. U.S. Fish and Wildlife Service, Caribbean Field Office,

Boqueron, Puerto Rico.

Lotufo, G.R., et al. 2000. Comparative toxicity and toxicokinetics of DDT and its major

metabolites in freshwater amphipods. Environ. Toxicol. Chem. 19(2):368-379

Marsh, Sherman P. 1992. Analytical results for stream sediment and soil samples from the

Commonwealth of Puerto Rico, Isla de Culebra, and Isla de Vieques. U.S. Geological Survey 

Open-File Report 92-353A.

RIDOLFI Inc. and the National Oceanic and Atmospheric Administration (RIDOLFI Inc. and 

NOAA). 2005. Final Sampling and Analysis Plan for the Vieques Island Biota Sampling 

Project. Seattle, WA; NOAA, National Ocean Service, Office of Response and Restoration.

Sample, B.E., D.M. Opresko, and G.W. Suter II. 1996. Toxicological Benchmarks for Wildlife:

1996 Revision. Oak Ridge National Laboratory (ORNL), Oak Ridge, TN.

Schellekens, J.H., J. Joyce, A.A. Smith, and D.K. Larue. 1991. Tectonics and mineral deposits of

the Caribbean, in Schellekens, J.H., ed., 105h Annual Symposium on Caribbean Geology:

Mayaguez University of Puerto Rico, Department of Geology.

Smithsonian Marine Station (SMS). 2001. Animals of the Indian River Lagoon: Cardisoma 

guanhumi (blue land crab). Available at: Smithsonian Marine Station at Fort Pierce

http://www.sms.si.edu/irlspec/Cardis_guanhu.htm (accessed September 23, 2005).

Soil Conservation Service and University of Puerto Rico. 1977. Soil survey of Humacao Area,

Eastern Puerto Rico. January.

Suter II, G.W. 1993. Ecological Risk Assessment. Lewis Publishers. Chelsea, MI.

Taissoun, E. 1974. The Land Crab of Venezuela. Maracaibo, Venezuela: University of Zulia,

Center for Biological Investigations. 48 pp.

Terwilliger, N. B., and M. Ryan. 2001. Ontogeny of Crustacean Respiratory Proteins. Integrative

and Comparative Biology 41(5):1057-1067.
NOAA ORR and Final Data Report for the

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Torres-Gonzáles, Sigfredo. 1989. Reconnaissance of the Ground-Water Resources of Vieques

Island, Puerto Rico. U.S. Geological Survey Water-Resources Investigations, Report 86-

4100.

U.S. Army Corps of Engineers (USACE). 2005. Environmental Residue Effects Database

(ERED). Website accessed October 2005: http://el.erdc.usace.army.mil/ered/.

U.S. Environmental Protection Agency (USEPA). 2001. ECO Update: The Role of ScreeningLevel Risk Assessments and Refining Contaminants of Concern in Baseline Ecological Risk 

Assessments. Pub 9345.0-14. EPA 540/F-01/014. June 2001.

U.S. Environmental Protection Agency (USEPA). 2002. More In-Depth Site Details: Frontera

Creek. August 2002. Available at: http://www.epa.gov/Region2/superfund/npl/0202550c.pdf

(accessed October 31, 2005).

U.S. Environmental Protection Agency (USEPA). 2004. Vieques Island, Puerto Rico – Sectors.

Available at: USEPA Region 2, Vieques, http://www.epa.gov/Region2/vieques/sectors.htm

(accessed August 11, 2005).

U.S. Environmental Protection Agency (USEPA). 2005a. NPL site narrative at listing Atlantic

Fleet Weapons Training Area-Vieques. Available at: USEPA National Priorities List,

http://www.epa.gov/superfund/sites/npl/nar1719.htm (accessed August 11, 2005).

U.S. Environmental Protection Agency (USEPA). 2005b. EPA proposes the Atlantic Fleet

Weapons Training Area on Vieques and Culebra for inclusion on the Superfund National

Priorities List. Available at: USEPA Region 2 News & Speeches 2004,

http://www.epa.gov/Region2/news/2004/04129.htm (accessed August 11, 2005).

U.S. Environmental Protection Agency (USEPA). 2005c. Toxicity/Residue Database,

http://www.epa.gov/med/Prods_Pubs/tox_residue.htm (accessed 2005).

U.S. Navy. 2005. Vieques public website: East Vieques Island. March 2005. Available at: U.S.

Navy, Installation Restoration Program, http://public.lantopsir.org/sites/public/vieques/East%20Site%20Info/about.aspx (accessed August 11, 2005).
NOAA ORR and Final Data Report for the

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U.S. Geological Survey. 2001. Geology, geochemistry, geophysics, mineral occurrences, and 

mineral resource assessment for the Commonwealth of Puerto Rico. Walter J Bawiec, ed.

USGS Open File Report 98-38 (on CD-ROM).

Van Holde, K. E., K. I. Miller, and H. Decker. 2001. Hemocyanins and Invertebrate Evolution. J.

Biol. Chem. 276(19):15563-15566.
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TABLES
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FIGURES
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APPENDIX A

Photographs
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APPENDIX B

Analytical Results for All Samples
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APPENDIX C

Data Validation Report and Review Memoranda
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APPENDIX D

Quality Assurance Report
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APPENDIX E

Land Crab Trace Element and Total DDT Statistical Analysis
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APPENDIX F

Fiddler Crab Trace Element and Total DDT Statistical Analysis
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APPENDIX G

Land Crab Exoskeleton and Tissue-Only Sample Analysis
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APPENDIX H

ATSDR Public Health Consultation
Carlos M. Gutierrez

Secretary, U.S. Department of Commerce

Vice Admiral Conrad C. Lautenbacher, Jr., USN (Ret.)

Under Secretary for Oceans and Atmosphere and NOAA Administrator

John H. Dunnigan

Assistant Administrator for NOAA Oceans and Coasts