In utero exposure to fluoride and cognitive development delay in infants.

The objective of this study was to evaluate the association between in utero exposure to fluoride (F) and Mental and Psychomotor Development (MDI and PDI) evaluated through the Bayley Scale of Infant Development II (BSDI-II) in infants. The sample included 65 mother-infant pairs. Environmental exposure to F was quantified in tap and bottled water samples and F in maternal urine was the biological exposure indicator; samples were collected during the 1st, 2nd and 3rd trimester of pregnancy. The mean values of F in tap water for the 1st, 2nd and 3rd trimester were 2.6±1.1mg/l, 3.1±1.1mg/l and 3.7±1.0mg/l respectively; above to 80% of the samples exceeded the reference value of 1.5mg/l (NOM-127-SSA1-1994). Regarding F in maternal urine, mean values were 1.9±1.0mg/l, 2.0±1.1mg/l and 2.7±1.1mg/l for the 1st, 2nd and 3rd trimester respectively. The infants with MDI and PDI scores less than 85 points were 38.5% and 20.9% respectively. After adjusting for potential confounding factors (gestational age, age of child, marginalization index and type of water for consumption), the MDI showed an inverse association with F levels in maternal urine for the first (ß=-19.05, p=0.04) and second trimester (ß=-19.34, p=0.01). Our data suggests that cognitive alterations in children born from exposed mothers to F could start in early prenatal stages of life.

DNA Damage in Vicia faba by Exposure to Agricultural Soils from Tlaxcala, Mexico.

The aim of this research was to quantify some POPs, such as p,p' DDT, p,p' DDE, and PCBs in agricultural soils of Tlaxcala, Mexico and evaluate their capacity for eliciting DNA damage, using Vicia faba as bioindicator. The values of ΣDDTs and ΣPCBs ranged from 8-24 to 118-26,983 µg/kg, respectively. The samples T1 (HQ = 9.3) and T2 (HQ = 53.9) showed concentrations of ΣPCBs higher than Canadian guidelines (SQGE = 500 µg/kg). The genotoxicity testing produced percentages of DNA fragmentation higher than negative control and statistically significant (p < 0.05), both in agricultural soils and organic extracts. The soils T2, T3, N4, and N5 showed a DICA from 2.6 to 3.1 times, statistically higher (p < 0.05) than negative control. In general, the agricultural soils have greater genotoxic capacity than the organic extracts, suggesting a potential risk to biota that depends upon this ecosystem.

Assessment of dioxin-like soil contamination in Mexico by enzyme-linked immunosorbent assay.

In this work, we describe the results of a preliminary soil assessment program for the detection of dioxins at different sites in Mexico performed by immunoassay. We studied five different sectors considered relevant sources of dioxins: Anaversa and Tekchem industrial areas where organochlorine pesticides were manufactured and released by accidental explosions, secondary smelters, brick kilns, and rural dwellings. In the context of the Agency for Toxic Substances and Disease Registry (ATSDR) guidelines, only the brick kilns sites can be considered as low-risk areas. The dioxin concentrations detected in the vicinity of the Anaversa and Tekchem chemical plants and secondary smelters exceed the screening level of 0.05 ppb set by the ATSDR, and therefore further site-specific studies are needed. The dioxin levels found in all soot samples from indigenous dwellings where wood is used for indoor cooking were above the evaluation level. Considering that the studied areas are representative examples of dioxin sources in less developed countries, our work demonstrates the useful application of dioxin immunoassays as a tool for dioxin screening for environmental assessment programs in developing countries.