Tagum Study II: Follow-up Study at Two Years of Age After Prenatal Exposure to Mercury

Abstract

ABSTRACT. Objectives. To correlate the presence and levels of total mercury (THg) in cord blood and meconium indicating prenatal exposure with developmental milestones at 2 years and to compare these subjects with controls of comparable age using cognitive adaptive test and clinical linguistic auditory milestone scale (CAT/CLAMS).Methods. In 48 of the original Tagum (T) subjects, cord blood and meconium Hg levels, head circumference (HC) at birth, and duration of breastfeeding were correlated with CAT/CLAMS at 2 years. At 2 years, THg levels using cold atomic vapor absorption spectrometry were determined in the hair of 46 T subjects and 88 Saranggani (S) controls; THg levels in blood were tested in 48 T subjects and 45 S controls. These levels were correlated with CAT/CLAMS. Both groups had standard physical and neurologic examinations, hearing screen using transitory evoked otoacoustic emissions, serum glutamate pyruvate transaminase, and routine urinalysis. A prevalidated Socioeconomic Means Test was given to both groups.Results. The Hg level in cord blood was negatively correlated with CAT/CLAMS at 2 years. The HC at birth was negatively correlated with levels of Hg in hair of T subjects 2 years later. HC at birth and 2 years hence were positively correlated with CAT/CLAMS. The following were significantly higher in S controls than in T subjects: expressive language quotient 82. 569

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“…However, no association was found between mercury concentrations and mental or psychomotor development in two-years old children in the INMA cohort (Llop et al, 2012). Other studies reported adverse effects of mercury on visual responses and linguistic pathways, however levels of exposure were higher than the ones reported in the present work (Ramirez et al, 2003;Yorifuji et al, 2013). …”

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“…Mercury levels measured in hair of controls (mean ± SD: I-Hg: 0.17 ± 0.14 µg/g; OHg: 1.25 ± 0.71 µg/g; T-Hg: 1.23 ± 0.81µg/g), children living in the Hg-exposed area (mean ± SD: IHg: 0.95 ± 0.79 µg/g; O-Hg: 1.36 ± 0.72 µg/g; T-Hg: 2.27 ± 0.83 µg/g) and children working with Hg (mean ± SD: I-Hg: 2.66 ± 6.73 µg/g; O-Hg: 1.55 ± 1.21 µg/g; T-Hg: 4.08 ± 7.07 µg/g) showed a significant increase in exposed versus controls (Bose-O'Reilly et al, 2008). Ramirez et al (2003) investigated the cognitive, linguistic and auditory skills of 48 Philippine children at the age of two years for whom mercury levels in cord blood and meconium at birth and mercury levels of hair and whole blood at the age of 2 years were measured (Tagum Study). The study indicated a correlation of prenatal mercury exposure and lower scores in neurodevelopmental screening tests, especially for the linguistic skills.…”

Assessing exposure risks for freshwater tilapia species posed by mercury and methylmercury

“…In Taiwan, Hsu et al (2007) found that 89 % pregnant woman had blood Hg concentrations exceeding the US National Research Council recommended limit of 5.8 lg L -1 that is correlated significantly with Hg-contaminated fish consumption. Moreover, Jiang et al (2010) found that Hg concentration in meconium of Taiwanese fetuses (79.2 ± 7.3 ng g -1 ) was higher than other sites in Manila of 1.9 ± 2.3 (Ostrea et al 1997) and Tagum of 48.6 ± 43.5 (Ramirez et al 2003). They also highlighted that various daily Hg exposure concentrations for Taiwanese mothers were mainly attributable to varied Hg concentration in fish as well as fish ingestion rate.…”