This study provides the first assessment of exposure to several phthalates among a group of Egyptian pre-adolescent girls in relation to their urban/rural status as well as lifestyle behaviors such as food storage in plastic. Although several studies suggest diet as the primary source of phthalate exposure [4
], there are limited studies investigating and comparing phthalate exposure in various countries. Quantifying exposure to endocrine active compounds in developing countries is an important step to understanding how these compounds may impact the health of potentially vulnerable populations.
Concentrations of urinary phthalate metabolites in urban and rural Egyptian girls were fairly similar in comparison to those reported for age-adjusted Americans girls. The major differences appear with MBzP and MiBP. Urinary concentrations of MBzP in both urban and rural Egyptian girls were lower, while the MiBP urinary concentrations among the Egyptian groups were three fold higher, compared to their American counterparts. A study of phthalate metabolites measured in urine collected from pregnant women in Peru found significantly lower creatinine adjusted concentrations of MBzP, MCPP, MEP, and MiBP compared to pregnant US women [25
]. A recent study of a group of pregnant women from Jerusalem, Israel, however, observed a different pattern of exposure when compared to US women, with MBzP urinary concentrations lower and MiBP levels higher in Israeli women [26
]. The findings of the Israel study are similar to the present study, where median MBzP levels were lower but MiBP levels were higher in Egyptian girls compared to US girls. These differences may reflect social and behavioral variances in daily lifestyle between northern African/Middle Eastern and American cultures. Fewer benzyl butyl phthalate (BzBP) containing products such as vinyl flooring may contribute to comparatively low urinary concentrations of MBzP in Egyptian girls. Elevated MiBP concentrations in Egyptians compared to US individuals suggest differential routes of exposure to DiBP, a phthalate commonly used as a plasticizer as well as in inks and paints. Since individuals who reported consuming canned foods as well as storing food in plastic had significantly higher concentrations of MiBP in their urine, food storage and consumption could potentially explain this difference between the Egyptian and US populations. Urinary concentrations of other phthalate metabolites, however, in general do not significantly differ between individuals from Egypt and the US, implicating similar routes of exposure and contact with phthalate-containing products between American and Egyptian girls.
Similar to previous studies, these data indicate that storage of food in plastics is a relevant route of phthalate exposure in Egypt [27
]. With globalization and widespread distribution of phthalate-containing products, contamination in developing countries will become a greater concern and it will be necessary to address manufacturing regulation at the international level.
Considering phthalate's use in a variety of products ranging from toys to pharmaceuticals, the extent of exposure to different phthalate esters will depend on the availability and application in the local community [2
]. In a study concerning levels of urinary phthalate metabolites in samples from a US reference population collected from 1988-1994, rural females appeared to have higher urinary concentrations of MBzP, a metabolite of BzBP, compared to their male and urban counterparts [28
]. In our study, urban individuals had a higher concentration of specific gravity adjusted MBzP than rural individuals, although a significant relationship was not observed for unadjusted concentrations. In India, urban men had significantly higher levels of DEP, DBP, and DEHP compared to rural men as well as decreased reproductive endpoints, potentially explained by a more widespread use of plastic products in urban areas [29
]. In the current study, urban individuals also had significantly higher levels of specific gravity adjusted MiBP, a metabolite of di-isobutyl phthalate, but this relationship was not observed in unadjusted levels. The similar urinary concentrations of MECPP and other DEHP metabolites found in both urban and rural girls may suggest similar routes of exposure. Widespread urbanization and easy accessibility to phthalate-containing products may be closing the gap between rural and urban lifestyles and variable non-occupational exposure to phthalates as well as other environmental contaminants.
Food storage in plastics is becoming ubiquitous in many areas that once utilized ceramic and clay containers, since plastics are inexpensive and widely manufactured. When covariate adjusted means were compared for all measured metabolites, individuals who reported storing food in plastic containers had significantly higher urinary concentrations of MiBP. Therefore lifestyle behaviors such as diet and food storage among girls in Gharbiah, Egypt can directly explain sources of phthalate exposure more than geographical location. When a quantitative analysis was conducted on the amount of phthalates in foodstuffs, traditional hot Egyptian food such as Koushary and Foul Medams served in plastic bags contained detectable levels of the plasticizers DEHP and di-(2-ethylhexyl) adipate [27
]. The amount of phthalates leaching into these warmly served delicacies stored in plastic dishes, cups, and bags depended on the temperature, plastic contact time, as well as fat content. Therefore the type of food stored in plastics may contribute to variable amounts of phthalate exposures in individuals.
The current study has several limitations. First, the relatively small sample size limits the conclusions about the distribution of urinary concentrations of phthalate metabolites between urban and rural Egyptians. The sample size limits the complexity of statistical analyses that could be performed. Additionally, we only measured phthalate metabolites in prepubescent females, who may have a different exposure profile than adult Egyptians. In this initial study, we collected questionnaire data that we thought would elucidate major pathways of phthalate exposure in this population, including food storage behaviors, cooking methods, cosmetic use, cleaning supply use, and residential history. Despite identifying that storage of food in plastic is significantly associated with urinary concentrations of phthalate metabolites, our lack of comprehensive dietary intake data limits our ability to pinpoint specific foods that may be contaminated with phthalates.