The Effects of Arsenic Poisoning in the early inhabitants of the Azapa Valley, Chile
1
2
Gwyn Madden and Bernardo Arriaza
1
2
( Grand Valley State University, University of Tarapaca).
Figure 1. (Above) Map of sites in the study.
Table 1. (Right) Age and presence or absence of birth defects
observed in the study group.
Figure 3. Playa Miller 7
radiograph, inset shows
the mummified remains.
Case Number
Age
Polydactyl
Spina Bifida
Cleft Palate
Club Foot
Eye Malformations
Syndactly
Disjoined Hip
AZ 6 T190
fetal to newborn
Absent
Not Obs.
Not Obs.
Absent
Absent
Absent
Not Obs.
AZ 6 T9
1 year
Absent
Absent
Absent
Absent
Present
Absent
Possible
AZ 6 T170 Y 4/4
newborn
Absent
Not Obs.
Absent
Absent
Not Obs.
Absent
Not Obs.
AZ 6 T-28 I 1/1
newborn to 6 months
Not Obs.
Not Obs.
Not Obs.
Not obs
Absent
Not Obs.
Not Obs.
AZ 115 T3
6 months
Absent
Not Obs.
Absent
Absent
Absent
Absent
Not Obs.
AZ 115 T12
6 months
Absent
Not Obs.
Absent
Absent
Absent
Absent
Not Obs.
AZ 115 T3 A
newborn
Not Obs.
Not Obs.
Absent
Not obs
Absent
Not Obs.
Not Obs.
AZ 71 T140
6 months
Absent
Absent
Absent
Absent
Absent
Absent
Absent
AZ 71 T310
fetal to newborn
Absent
Not Obs.
Not Obs.
Absent
Absent
Absent
Not Obs.
AZ 71 T167
6 mon
Absent
Not Obs.
Not Obs.
Absent
Not Obs.
Absent
Not Obs.
AZ 75 T86
9 months-1 year
Absent
Absent
Not Obs.
Absent
Not Obs.
Absent
Absent
AZ 140 T54
6 months
Absent
Not Obs.
Absent
Absent
Absent
Absent
Not Obs.
AZ 141 Desc 07
newborn
Absent
Absent
Absent
Absent
Not Obs.
Absent
Absent
AZ 141 T54
12-18 months
Not Obs.
Absent
Absent
Not obs
Absent
Not Obs.
Absent
AZ 141 T47 A
4-6 months
Absent
Not Obs.
Not Obs.
Absent
Absent
Absent
Not Obs.
AZ 141 T42
newborn
Absent
Absent
Not Obs.
Absent
Absent
Absent
Absent
AZ 141 T40
1 year
Absent
Absent
Absent
Absent
Absent
Absent
Absent
AZ 141 T35
1-2 years
Absent
Absent
Present
Absent
Absent
Absent
Absent
Lluta 54 T13
6 months-1 year
Not Obs.
Not Obs.
Not Obs.
Not obs
Absent
Not Obs.
Not Obs.
Lluta 54 T18
newborn to 6 months
Not Obs.
Not Obs.
Not Obs.
Not obs
Not Obs.
Not Obs.
Not Obs.
Lluta 54 T25
fetal
Absent
Absent
Not Obs.
Absent
Absent
Absent
Absent
Lluta 54 T28
6 month
Not Obs.
Not Obs.
Present
Not obs
Absent
Absent
Not Obs.
San Lorenzo
6 months-1.5 years
Not Obs.
Not Obs.
Not Obs.
Not obs
Absent
Not Obs.
Not Obs.
PLM 7 6094
newborn to 6 mon
Not Obs.
Not Obs.
Not Obs.
Not obs
Not Obs.
Not Obs.
Not Obs.
Cam 8 T25
1 year
Absent
Absent
Absent
Absent
Absent
Absent
Absent
Cam 8 T19 A
fetal
Not Obs.
Not Obs.
Not Obs.
Not obs
Not Obs.
Not Obs.
Not Obs.
Cam 8 T22
fetal
Absent
Not Obs.
Not Obs.
Absent
Not Obs.
Not Obs.
Not Obs.
Cam 9
9 months-1 year
Absent
Absent
Absent
Absent
Possible
Absent
Absent
BN 273
indeterminant
Not Obs.
Not Obs.
Not Obs.
Not obs
Not Obs.
Not Obs.
Not Obs.
BN 1263
newborn to 6 months
Absent
Absent
Absent
Absent
Absent
Absent
Absent
S/Ref 1972
fetal to newborn
Not Obs.
Not Obs.
Not Obs.
Not obs
Not Obs.
Not Obs.
Not Obs.
Abstractt
Arriaza (2005) hypothesized the possibility that the Chinchorro of ancient Chile began mummification of the dead due to high numbers of
infant death. The Arica Region is understood to have maintained a high level of natural arsenic in the ground water from prehistory
through the present. Between the San Jose and Camarones Rivers the arsenic levels range from 20-100 times over that considered
acceptable by the World Health Organization. This project investigated evidence of arsenic poisoning and the affects on mortality of 30
infants (neonate to 18 months) from five cemeteries in the ancient Azapa Valley. Arsenic poisoning is known to cause miscarriage,
stillbirth, and potentially several birth defects including polydactyly, syndactyly, spina bifida, cleft palate, cleft lip, club foot, orbital
malformations, and disjoined hip. Obvious differential diagnoses exist in terms of miscarriage, stillbirth, infant death, and all noted birth
defects. Although increased frequency in any one or all of these would be suggestive of arsenic poisoning. The Chinchorro mummies
were so extensively reconstructed that observation of their remains specifically were not possible; as well as radio-opacities due to the
clay used in their construction. Therefore, naturally mummified remains of their Azapa Valley descendents were observed radiologically in
their place. As the level of arsenic has remained high through time, the morbidity and mortality seen in the Chinchorro descendents
mirror that seen in the Chinchorro themselves. Our findings indicate that ancient Arica populations faced high levels of perineonatal
mortality, although congenital defects are not seen at a high frequency. We suggest that ancient infants of similar
ages from the Azapa Valley and the Camarones site in particular be tested for arsenic intake as further evidence to support or reject the
arsenic hypothesis put forward by Arriaza (2005).
Figure 8. Lluta 54 T25 radiograph
Figure 9. Lluta 54 T13 radiograph
Background
The Chinchorro of Chile’s Atacama Desert were the first culture known to practice artificial mummification from 5000 BC to 1100 BC
(Arriaza 1995; Aufderheide et al. 1993; Standen 1997). A great deal of research has been undertaken to describe the culture in terms of
subsistence, technology, health, methods of mummification, and reasons behind creating these very intricate mummies. Three potential
driving factors have been postulated in the search to understand why the Chinchorro chose to partake in this energy intensive task,
including religion, social rank, and love of children. As these were sedentary hunter-gatherers, it is believed that status would likely not
have had much of an affect on the decision to mummify. Many of the mummies are children, which is also unusual outside of societies
using ascribed status to rank individuals. Religion is always a possibility, however unlike Egyptian mummification, there was no written or
pictoral evidence left to define the potential religious purpose of mummification. That leaves the love of children theory to be explained.
Arriaza (2005) has suggested that the Chinchorro mummified their deceased children as part of the grief process. As many Chinchorro
children were mummified, a potential cause for the increased mortality was sought. In 2005, Arriaza put forward the hypothesis that high
levels of natural arsenic may have been responsible for this increase in infant mortality. In the Camarones Valley where artificial
mummification first began, arsenic rates are around 1000 ug/L. The World Health Organization states that up to 10 ug/L are acceptable.
It is understood that levels of arsenic over 800 ug/L affect fetal growth and cause an increase in stillbirth and infant mortality. As fetal
growth is affected, it is assumed that an increase in birth defects would also be present including polydactyly, syndactyly, spina bifida,
cleft palate, cleft lip, club foot, orbital malformations, and disjoined hip. The current study was conducted to search for indicators which
suggest arsenic poisoning may have been a motivator for artificial mummification.
Figure 2. Morro 1-5 14, Chinchorro radiograph
Figure 5. Camarones 9 T25
radiograph, inset shows
mummified remains.
Methodology
Radiographic analysis of 11 mummies and 20 mummy bundles was undertaken searching for age at death and presence or absence of
birth defects (polydactyly, syndactyly, spina bifida, cleft palate, cleft lip, club foot, orbital malformations, and disjoined hip). Thirty one
infants were selected from five sites including Camarones, Azapa, Lluta, Playa Miller, San Lorenso, and three individuals of unknown
provenience (Table 1). Age of the individuals in the sample was determined using dental calcification (Mincer et al. 1993) when possible,
and length of long bones (Johnston 1962). Long bone length was taken on exposed bones, excluding the epiphyses, in mm with digital
Mitutoyo calipers.
Figure 10. Azapa 6 T190 radiograph
Figure 11. Lluta 54 T28 radiograph
In this study, polydactyly is defined as the presence of more than the usual 10 digits on the hands and feet, while syndactyly is the
absence of one or more of the usual 10 digits. Spina bifida refers to lack of closure of the neural arches of the sacrum, S1-S3 (S4 and S5
are normally open). Failure to close completely at the midline of the palate is characteristic of cleft palate. Cleft lip can occur alone or
with cleft palate, but is represented as a lack of closure of the soft tissue in the naso-maxillary area. Orbital malformations are more
subjective, but may be associated with Trisomy 21 (Aufderheide and Rodriguez-Martin 1998). Finally, disjoined hip is a congenital
disorder in which the affected individual displays aplasia of the lunate surface of the acetabulum, a false acetabulum, flattening of the
femoral head, and shortening of the femoral neck (Aufderheide and Rodriguez-Martin 1998:69).
Figure 4. Camarones 8 T22 radiograph
Results
While miscarriage, stillbirth, or neonate (28 days following birth) mortality may be suggestive of arseniasis in this sample, it seems that
there is no increase in the number of birth defects. However, a few of the birth defects are not recognizable in individuals of such young
ages including spina bifida and disjoined hip due to fusion occurring in later age groups. Given disarticulation, flexion of the body, and
lack of development of the femur head and vertebrae, spina bifida disjoined hip was unobservable in most cases. No cases of spina bifida
or disjoined hip were noted. Polydactyly, syndactyly, and club foot were not observable in many cases; mummified tissue may be present
within the bundles but disarticulation of the skeletons was noted on radiography. In those cases where the hands and feet were
observable, no cases of polydactyly, syndactyly, or club foot were noted. Individual AZ 141 T35 shows a potential case of cleft palate,
while Lluta 54 T28 (Figure 11) represents a possible case of cleft lip. In the case of Lluta 54 T28, skin shrinkage may be a differential for
the soft tissue change. One case of malformed orbits was present, AZ 6 T9 (Figure 13). One individual of 31 presents with a
malformation and two others with potential birth defects from three separate cemeteries. This represents a total of 97% of the sample
population free from birth defects.
Conclusion
The next step is three fold, first to determine the number of infants present in each population to calculate infant mortality rates. The
second step will be to sample older children and adults to widen the search for the birth defects described in the study. It is possible that
individuals suffering from birth defects may not have died around the time of birth. This will allow us to have a better understanding of
the potential association of birth defects and arsenariasis. The final step will include sampling of skeletal tissue to determine the amount
of arsenic present in the bone. This final study will be carried out by Arriaza and colleagues at the University of Tarapaca.
Figure 6. Camarones 8 T19A radiograph
Figure 7. Camarones 8 T25
radiograph, inset shows
mummified remains.
Acknowledgements
Research and Development, GVSU
Padnos International Center, GVSU
Department of Anthropology, GVSU
University of Tarapaca, Arica, Chile
Museo Arqueologica San Miguel de Azapa, Arica, Chile
Tim Elrod, GVSU student assistant
Figure 12. Azapa 141 Desc 07 radiograph
Figure 13. Azapa 6 T9 radiograph
References
Arriaza, BT
2005 Arseniasis As An Environmental Hypothetical Explanation For The Origin Of The Oldest Artificial Mummification Practice In The World. Chungara 37:255-260.
1995 Beyond Death. The Chinchorro Mummies of Ancient Chile. Smithsonian Institution Press, Washington D.C.
Aufderheide, A, I Munoz, and B Arriaza
1993 Seven Chinchorro Mummies and the Prehistory of Northern Chile. American Journal of Physical Anthropology 91:189-201.
Aufderheide, A and C Rodriquez-Martin
1998 The Cambridge Encyclopedia of Paleopathology. Cambridge University Press, Cambridge.
Johnston, FE
1962 Growth of the Long Bones of Infants and Young Children at Indian Knoll. Human Biology 23:66-81
Mincer, HH, EF Harris, and HE Berryman
1993 The A.B.F.O. Study of Third Molar Development and its Use as an Estimator of Chronological Age. Journal of Forensic Sciences 38:379-90.
Standen, V
1997 Temprana Complejidad Funeraria en la Cultura Chinchorro: Norte de Chile. Latin American Antiquity 8:134-156.
World Health Organization
2005 Http://www.who.int/mediacentre/factsheets/fs210/en/