Arsenic, cadmium and lead are well-known environmental contaminants, and their toxicity at low concentration is the target of scientific concern. In this study, we aimed to identify the potential effects of prenatal heavy metal exposure on the birth outcomes among the Myanmar population. This study is part of a birth-cohort study conducted with 419 pregnant women in the Ayeyarwady Division, Myanmar. Face-to-face interviews were performed using a questionnaire, and maternal spot urine samples were collected at the third trimester. Birth outcomes were evaluated at delivery during the follow up. The median values of adjusted urinary arsenic, cadmium, selenium and lead concentration were 74.2, 0.9, 22.6 and 1.8 μg/g creatinine, respectively. Multivariable logistic regression revealed that prenatal cadmium exposure (adjusted odds ratio (OR) = 1.10; 95% confidence interval (CI): 1.01–1.21; p = 0.043), gestational age (adjusted OR = 0.83; 95% CI: 0.72–0.95; p = 0.009) and primigravida mothers (adjusted OR = 4.23; 95% CI: 1.31–13.65; p = 0.016) were the predictors of low birth weight. The present study identified that Myanmar mothers were highly exposed to cadmium. Prenatal maternal cadmium exposure was associated with an occurrence of low birth weight.

Invasion of contiguous forests by a giant bamboo (Moso bamboo, Phyllostachys pubescens) has the potential to induce changes in the chemical characteristics of soils due to the high growth rate of this species. We evaluated the impact of bamboo invasion into hinoki cypress (Chamaecyparis obtusa) forests on soil properties under varying conditions of shoot density at three study sites (Kanpachi, Seto, and Noguchi) in central Japan. We established three successive quadrats along bamboo invasion (allotted to a bamboo stand, a mixed stand of bamboo and hinoki, and a hinoki stand) at every site. Then, we measured the density and basal area of bamboo and hinoki shoots. Surface soil was sampled from each quadrat to analyze pH, water content, and exchangeable cation contents. The values of soil pH were significantly higher in the mixed stands than the hinoki stands at all sites, showing positive correlations with exchangeable Ca contents in the soil. Exchangeable K and Mg contents in the soil of the mixed stand showed significant differences compared with the hinoki stand only in Seto, but these values in the mixed stand were similar to those in the bamboo stand. This characteristic is consistent with the invasion degree determined from the density ratio of living bamboo culms to living hinoki trunks: Seto > Kanpachi > Noguchi. We conclude that increases in the soil pH due to bamboo invasion into hinoki forests resulted in distinct and sensitive changes in the soil chemistry.

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