| Children’s exposure to environmental chemicals has given rise to wide public concern over its potential harzards during the past two decades. Children are far more vulnerable than adults, due to differences in metabolic capacity. The unique ways in which they interact with the environment and their immature developmental physiology mean that they generally receive a higher dose of toxicant within the relatively safe range of environmental exposure for adult. Additionally, children tend to spend more time outdoors, such as playing sports, so they are breathing more outdoor air compared to adult.The stage of infant and early childhood is also a critical period for the rapid growth and development of several biological systems.Pyrethroids are broadly used in agriculture, forest, textile industry, and public health programs world widely. Phthalates are used as plasticizers in PVC plastics. Since the phthalate plasticizers are not chemically bound to PVC, they can leach, migrate or evaporate into indoor air, atmosphere, foodstuff and other materials, etc. Humans are exposed through ingestion, inhalation, and dermal exposure during their whole lifetime, thus it is significance meaning of exploring the relationship between the environmental chemicals and infant growth development.[Objectives]1. To evaluate the bioload of pyrethroids and phthalates in infants by measuring the concentrations of urinary metabolites;2. To evaluate the levels of the infants growth development;3. To analyze the relationship between urinary level of pyrethroid and phthalate metabolites and growth development, such as body mass index (BMI) in subjects;4. To provide the data for the health risk assessment of pyrethroids and phthalates exposure in rural infants. [Methods]1. A total of449one-year old infants took part in this investigation during June2010to January2011in a country of Jiangsu Province. Interviews and physical examinations were used to assess environmental and physical risk factors.2. The body length, weight, head circumference, chest circumference and developmental quotient were measured according to standard procedures, body mass index (BMI, kg/m2) was calculated.3. Spot urine were collected, the common pyrethroid metabolites, cis-Cl2CA, trans-Cl2CA and3-PBA were measured with gas chromatography-mass spectrometry (GC-MS), the phthalates metabolites, including MBP, MEP, MMP, MiBP, MCPP, MECPP, MEHHP, MEHP and MEOHP were analyzed by liquid chromatography-mass spectrometry/mass spectrometry (LC-MS/MS).4. The percentile, median and geometric mean (GM) were used to describe the distribution of interesting indicators. One-way analysis of variance, t-tests, and other appropriate statistics were used to compare the variation of different subgroups. The potential affecting factors of urinary level of metabolites or indicators for growth development were reviewed with multiple regression analyses. The logarithmic transform of selected original data, such as urinary level of metabolites, were done if necessary.[Results]A total of449infants were involved in this investigation.The results showed that the pyrethroid metabolites were detected in99.1%of the urine specimens. The detectable ratio of cis-Cl2CA, trans-Cl2CA and3-PBA were70.4%,97.6%and84.2%, respectively. The median levels of urinary metabolites were cis-Cl2CA,0.19μg/L; trans-Cl2CA,0.95μg/L and3-PBA,0.40μg/L, which were significantly higher than those reported by researches in other countries. The boys had a higher level of urinary metabolites than girls, however there was no statistically significant difference (P>0.05). Furthermore, a significant seasonal variation in the excretion of urinary metabolites was found, which showed higher levels in summer than winter (P<0.05). The infants who live in the rural area had the highest level of urinary cis-and trans-Cl2CA compared with who live in the suburb or town (P<0.05). It also showed that the urinary pyrethroid metabolites of infants were associated with several factors, including their house location (such as far away from the cropland), the condition of general ventilation and the peeled plaster,, the use of insecticide indoor and their hand-mouth action.Phthalates metabolites were detected in the urine of virtually all infants. The median levels were as follows:MBP,14.15μg/L; MEP,9.03μg/L; MMP,1.14μg/L; MiBP,11.81μg/L; MCPP,0.53μg/L; MEHP,1.51μg/L; MECPP,22.58μg/L; MEHHP,5.59μg/L; MEOHP,3.83μg/L. The detectable ratios were100.00%,98.00%,61.10%,100%,51.00%,87.70%,100.00%,99.80%and99.60%, respectively. It was noted that there existed a positive relation among these phthalates metabolites (Spearman r=0.093-0.982)(P<0.05). The infants who had hand-mouth actions had a higher level of MBP and MCPP than other infants. The infants who often ate food packed with edible plastic had a higher level of phthalates metabolites than the other infants. It was noted that urinary LMWP of infants was related to the ventilation condition of their houses and consumption of food packed with edible plastic(P<0.05).The body weight, length, head circumference, chest circumference, BMI and DQ of these infants were11.16±1.47kg,77.02±2.84cm,46.00±1.52cm,47.08±2.14cm,18.81±2.18and86.90±11.29, respectively.The statistics showed that growth development, such as body weight and BMI, was negatively related to the level of of pyrethroid metabolite or phthalates metabolites among these infants (P<0.05).The two-factor studies showed that there is no interaction effect between the pyrethroid metabolite and phthalates metabolite.The multiple linear regression analysis showed that BMI of these infants was affected by their urinary pyrethroid metabolites levels, birth body weight, the gender, the education level and income of their parents.[Conclusion]This study showed that there was a widespread exposure to pyrethroids and phthalates among infants.The exposure level of pyrethroids among these infants in China was significantly higher than those reported in the other counties, while the exposure level of phthalates was a bit lower.The growth development of these infants was related to the exposure to pyrethroids and phthalates. The potential advese effects of long-term exposure to such environmental chemicals should be concerned. |
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