Association between the Concentrations of Metallic Elements in Maternal Blood during Pregnancy and Prevalence of Abdominal Congenital Malformations: The Japan Environment and Children’s Study

Abdominal congenital malformations are responsible for early mortality, inadequate nutrient intake, and infant biological dysfunction. Exposure to metallic elements in utero is reported to be toxic and negatively impacts ontogeny. However, no prior study has sufficiently evaluated the effects of exposure to metallic elements in utero on abdominal congenital malformations. The aim of the present study was to evaluate associations between metallic elements detected in maternal blood during pregnancy and congenital abdominal malformations. Data from participants in the Japan Environment and Children’s Study was used in the present study, and contained information on singleton and live birth infants without congenital abnormalities (control: n = 89,134) and abdominal malformations (case: n = 139). Heavy metals such as mercury (Hg), lead (Pb), cadmium (Cd), and trace elements of manganese (Mn) and selenium (Se) were detected in maternal serum samples during mid- and late-gestation. Infant congenital abnormalities were identified from delivery records at birth or one month after birth by medical doctors. In a multivariate analysis adjusted to account for potential confounders, quartiles of heavy metals and trace elements present in maternal blood were not statistically correlated to the prevalence of abdominal congenital malformations at birth. This study is the first to reveal the absence of significant associations between exposure levels to maternal heavy metals and trace elements in utero and the prevalence of abdominal congenital malformations in a large cohort of the Japanese population. Further studies are necessary to investigate the impact of exposure to heavy metals and trace elements via maternal blood in offspring after birth.

Bioavailability and Solubility of Heavy Metals and Trace Elements during Composting of Cow Manure and Tree Litter

Objectives. To characterize the total content of heavy metals (Cd, Cr, Cu, Hg, Mo, Ni, Pb, and Zn) and trace elements (As and Se) of interest, their bioavailability and solubility during the composting of cow manure and tree litter in piles inoculated with beneficial microorganism (IBM), or not inoculated (NBM), on the university campus of the Universidad Nacional Agraria La Molina (UNALM). Methods. The investigation evaluated composting in six piles, three IBM piles and three NBM piles, for 120 days. Every 30 days, a composite sample was taken from each pile. The raw materials used were cattle manure and tree litter. The variables analyzed were the total concentrations (content) of metals and trace elements of interest, extracted with diethylenetriaminepentaacetic acid/pentatetic acid (DTPA) (for the bioavailability study) and extracted with deionized water (for the solubility study). Results. The average values (n = 3) of the total content (mg·kg−1) on day 120 in IBM were in the following order: Zn (404.33) > Cu (86.33) > Pb (71.2) > Cr (34.33) > As (28.0) > Ni (13.83) > Mo (2.86) > Se (1.38) > Cd (1.32) > Hg (0.39) and in NBM: Zn (466.0) > Cu (112.23) > Pb (73.23) > Cr (35.33) > As (29.67) > Ni (14.37) > Mo (3.23) > Se (1.55) > Cd (1.38) > Hg (0.38). The values complied with the Austrian Compost Standard for Landscaping and Land Rehabilitation and the Peruvian Standard for Nonorganic Agriculture. Significant differences were observed in some elements ( p < 0.05) between 0 and 120 days in both types of pile (IBM and NBM). Conclusions. For nonorganic agriculture in Peru, urban compost is recommended, whereby raw organic materials are inoculated with beneficial microorganisms during the composting process to reduce the bioavailability of Cu and Zn, as these elements showed less bioavailability than noninoculated piles. The composting process for both piles (IBM and NBM) reduced the solubility in Cu, Pb, and Zn.