چكيده لاتين :
Introduction
Before the advent of Holocene, the subsistence of all hominines was hunting and gathering.
Different biomes have been occupied by Homo sapiens during late Pleistocene. Due to the fact that
subsistence-related activities in a given patch are aimed at adapting to a pack of specific
characteristics, the ways to reach this goal could be called adaptive strategies. There is ample
evidence supporting the assumption that inter-biome (or inter-patch) differences had had dramatic
impacts on hunter-gatherers’ various ways of life, generally speaking, and the dependence of
Pleistocene foragers upon local environmental characteristics was heavier than horticulturalists or
even hunter-gatherers of later periods.
Some models in the framework of human behavioral ecology have been developed in order to
grasp different foragers’ behaviors (decision making). These models are based upon optimality for
the most part. Foragers could decide which way to choose to acquire a resource among other
options, each with its costs and returns. The optimal way is the one with the least cost and the most
benefit (return). Finally, foraging optimally would increase individual or group fitness.
Materials and Methods
For investigating on subsistence strategies of Pleistocene hunter-gatherers, a framework should be
constructed based upon anthropological and evolutionary ecological models. In this light,
archaeological finds could be analyzed and explained. Generalized models, built upon the studies of
contemporary hunter-gatherer bands from the ecological viewpoint are analyzed in this paper. The
degree to which these models are consistent with data recovered from Pleistocene archaeological
sites is equivocal and under scrutiny. To answer such questions, more and more archaeological
study is needed. In this paper, bibliographic analysis has adopted to assess the relationship between
foragers and the natural environment.
Discussion and Results
Statistical works of researchers on contemporary hunter-gatherers and some inadequate
archaeological evidence imply that foragers’ subsistence-related activities have been regularly
related to the environmental parameters with a good accuracy. Pioneers such as Binford have
pointed to insolation, effective temperature, and the distribution of solar heat as the ultimate causes
(and the most important one) of diversity in biomes and consequently, in foragers’ subsistence; but
one should keep in mind that absorbing more solar heat, higher temperatures, and higher Net
Primary Productivity (NPP) will not necessarily result in more accessible food to the human
foragers, especially the prehistoric ones. In biomes with higher NPP, such as tropical rainforests, a
great deal of energy will be invested in structural maintenance (tree trunks) and the capture of
sunlight (taller and taller trunks), therefore, the food available to foragers is not that much; whereas
in some regions with lower NPP (e.g. African savannah) more energy will be dedicated to
reproductive or storage organs of plants which are widely edible for human foragers. Based on this,
human foragers tended to live on the edges of dense forests (ecotones) and not the jungles inappropriate soil quality and soil pollution of the region. However, chromium has the most
considerable value, 2.75. Average value of EF is less than 2 for arsenic, cobalt and vanadium
proving that the region does not show enrichment for the aforesaid elements. Enrichment index
values for cadmium, chromium, copper, nickel, lead and zinc are between 2 to 5 indicating average
enrichment of these samples than other metals. Since enrichment element of these sample are higher
than 2, they have anthropogenic source.
According to Pearson correlation coefficient, there is a high correlation between nickel and
chromium, scandium and cobalt, vanadium and chromium, and zinc and copper and lead indicating
the equal source or similar geochemical behavior of the elements toward each other. Since
vanadium is considered as one the oil pollution indices, it can be concluded that high pollution of
this element and chromium around the region comes from petroleum.
Conclusions
The findings from the present study show that soil surrounded Kermanshah Refinery is polluted to
some elements. According to the values of geo accumulation in the studying area, elements nickel
and chromium have pollution. The finding from enrichment factor indicates the average enrichment
of the region soil by chromium and lead. Besides, enrichment factor higher than 2 for lead and
copper proves anthropogenic interference factors in the region pollution. The results from pollution
bar for chromium, nickel, zinc, copper and lead is more than 1 indicating soil pollution to these
metals. Pearson correlation coefficient reveals that there is a high correlation among vanadium,
cobalt, chromium, and nickel proving same origin. Making zoning map of heavy metal density in
the region soil demonstrates that high density of the elements in some stations is related to
petroleum producing installations and storage tank. Cluster analysis shows the division of the
elements into 7 clusters. Besides, the elements with structural relationship are related in next
subcategories. Clusters 6 and 7 together indicate the same origin for these elements. Since
vanadium is derived from oil compound, it can be concluded that chromium and nickel pollution
have the same pollution origin with oil compounds. Factor analysis introduces three main factors in
which the first factor with total 40/1% of total variance is the most effective factor in density of the
soil elements. This factor has a high positive correlation with Sc, V, Ni, Cr, and Co proving the
same density origin with petroleum compound.
