Presence of Polycyclic Aromatic Hydrocarbons (PAHs) in Apple
in Rural Terrains from Mexico City
Rutilio Ortiz Salinas
•
Gilberto Dı
´
az Gonza
´
lez
•
Beatriz Schettino Bermudez
•
Rey Gutie
´
rrez Tolentino
•
Salvador Vega y Leo
´
n
Received: 27 December 2009 / Accepted: 8 June 2010 / Published online: 3 July 2010
Ó Springer Science+Business Media, LLC 2010
Abstract This paper describes PAH concentrations in
apple crops that are growing in rural terrains in Mexico
City. The concentrations of individual PAHs showed great
variability, there being low and high molecular weight
compounds in dry (high molecular weight for Tlahuac
7.06 lg/g and Milpa Alta 3.96 lg/g) and wet months (high
molecular weight for Tlahuac 11.25 lg/g and Milpa Alta
12.05 lg/g). Some PAHs indicators and cross plot ratios
Ant/(Ant ? Phe) and Flu/(Flu ? Pyr) define fossil fuels
and vegetation combustion as the source of contamination
over the cuticle of the apples. It is likely that deposition
(dry and wet) is the principal source o f contamination over
the apple surface. This study reveals the presence of PAHs
in apples due to the high air contamination of Mexico City.
Keywords Contamination Á Deposition Á PAHs
Polycyclic aromatic hydrocarbons (PAHs) are products of
the incomplete combustion of organic material; other
sources are incineration, fossil fuel combustion and
industrial activities. In general, human activities contribute
high concentrations of these organic compounds in com-
parison to natural sources such as volcanic eruptions, dia-
genesis and natural forest fires (Kipopoulou et al. 1999;Cai
et al. 2007). Some PAHs are carcinogenic and/or muta-
genic; therefore, they may pose a human health threat
(IARC 2000). Several studies have showed the presence of
these compounds on food due to contamination of water,
soil and air by processes of adsorption, deposition and
bioaccumulation, mainly (Martens et al. 1997; Chung et al.
2008).
For some vegetables and fruits, PAHs are found on
surfaces as a result of the atmospheric deposition of par-
ticle bound compounds and the retention of vapor phase
PAHs on the waxy leaf cuticle (Kipopoulou et al. 1999;
Ja
´
nska
´
et al. 2006). In reports related to contamination of
vegetables, these organic contaminants of low molecular
weight (2–3 aromatic ring) are found in higher abundance
because their vapor pressure, water solubility and bio-
availability are greater than heavier PAHs which prefer-
entially are associated with particulate matter (Ja
´
nska
´
et al.
2006).
Mexico City’s government has encouraged sustainable
agricultural activities in rural areas and considers that
agricultural land should be protected from further urban
growth in order to support the recharge of the aquifer under
the city as well as for growing important crops such as
maize, flowers, vegetables and fruit trees (GDF 2003;
Grupo Produce 2006). The government of the Federal
District (the central part of the metropolitan area of Mexico
City) has encouraged the growing of commercial crops
(vegetables, flowers, cactus stems and fruits trees) in rel-
atively rural terrains as an alternative means for conser-
vation of green areas which also helps the recharge of
aquifers in rural areas such as Xochimilco, Tlalpan, Mag-
dalena Contreras, Milpa Alta and Tla
´
huac (Grupo Produce
2006).
The research was conducted in Tlahuac (situated 19° 20
0
and 19° 12
0
north; 98° 56
0
and 99° 04
0
west) at a mean
altitude of 2,500 m mean, an area in the template region of
Mexico. Rain falls almost exclusively between June and
R. O. Salinas Á G. D. Gonza
´
lez (&) Á B. S. Bermudez Á
R. G. Tolentino Á S. Vega y Leo
´
n
Laboratorio de Ana
´
lisis Instrumental, Departamento de
Produccio
´
n Agrı
´
cola y Animal, Universidad Auto
´
noma
Metropolitana Unidad Xochimilco, Calzada del Hueso 1100,
Colonia Villa Quietud, 04960 Coyoaca
´
n, Me
´
xico D.F., Mexico
e-mail: guppyabanico@gmail.com; gdiaz@correo.xoc.uam.mx
123
Bull Environ Contam Toxicol (2010) 85:179–183
DOI 10.1007/s00128-010-0060-7