A case of partial sirenomelia and possible vitamin A teratogenesis

Prenatal echographical findings of a partial sirenomelic fetus are described. An attempt was made to terminate pregnancy by administration of prostaglandin F₂a, but uterine rupture occurred. The teratogenic role of vitamin A ingested by the mother in the penconceptional period is discussed.     

Safety evaluation of cable barriers installation on rural highways in British Columbia

Objective: The objective of this study was to evaluate the safety effectiveness of cable barrier systems installation on rural highway sections in British Columbia, Canada.

Methods: Data on police-attended serious collisions (injury?+?fatality) on a number of rural highway sections in British Columbia, Canada, were used in the analysis. An empirical Bayes (EB) approach was employed to ensure that the evaluation results were reliable and to account for the regression to the mean artifact. Safety performance functions (SPFs) were developed using data collected at similar sites. For both median cable barrier (MCB) and roadside cable barrier (RCB) sections, the evaluation was undertaken using all serious collisions, truck serious collisions, and off-road serious collisions.

Results: For MCB sections, the evaluation results showed statistically significant reductions of 21.7, 53.8, and 34.8% in all serious collisions, truck serious collisions, and off-road left (ORL) combined with head-on (HO) serious collisions. For RCB sections, statistically significant reductions of 74.7, 100, and 100% were found in all serious collisions, truck serious collisions, and off-road right (ORR) serious collisions, respectively. The impact of the after period on the evaluation results was explored. It was found that the changes in safety become more stable using an after period of 2–5 years.

Conclusions: Cable barriers were successful in reducing the frequency of serious collisions on provincial highways in British Columbia.     

Metal associations in soils before and after EDTA extractive decontamination: implications for the effectiveness of further clean-up procedures

The distribution of Pb, Ni and Zn in two contaminated soils was determined before and after treating the soils with an EDTA solution. After the EDTA extraction, the proportion of Pb accumulated in the acid-extractable fraction considerably increased, which was related to the greater degree of metal extraction from the other fractions. EDTA was also able to extract certain amounts of Pb, Zn and Ni from the silicate matrix, which implied that these extractable amounts were not so strongly fixed to the residual fraction as previously supposed. As a consequence, after EDTA application, metal content (especially Pb) remained more weakly adsorbed to soil components (more easily leachable), potentially favouring the application of phytoremediation technologies. The extraction recoveries (for only one application) were generally low for the three metals (33-37% for Pb, 5-11% for Ni and 14-19% for Zn), although this fact is an advantage as plants would not be able to assimilate very high mobilised contents of metals.     

Homogeneous degradation of 1,2,9,10-tetrachlorodecane in aqueous solutions using hydrogen peroxide, iron and UV light

The homogeneous degradation of the polychlorinated n-alkane, 1,2,9,10-tetrachlorodecane (T4C10), was studied in aqueous solutions of hydrogen peroxide, including Fenton and photo-Fenton reaction conditions. All solutions were adjusted to a pH of 2.8 and an ionic strength of 0.1 M NaClO4 prior to photolysis. T4C10 (2 x 10(-6) M) was substantially degraded by the H2O2/UV system (1.0 x 10(-2) M H2O2), with 60% disappearance in 20 min of irradiation in a photoreactor equipped with 300 nm lamps of light intensity 3.6 x 10(-5) Ein L(-1) min(-1) (established by ferrioxalate actinometry). The reaction produced stoichiometric amounts of chloride ion indicating complete dechlorination of the chlorinated n-alkane. T4C10 degraded very slowly under Fenton (Fe2+/H2O2/dark) and Fenton-like (Fe3+/H2O2/dark) conditions. However, when the same solutions were irradiated, T4C10 degraded more rapidly than in the H2O2/UV system, with 61% disappearance in 10 min of exposure. The rapid degradation is related to the enhanced degradation of hydrogen peroxide to oxidizing *OH radicals under photo-Fenton conditions. Degradation was inhibited in both the H2O2/UV and photo-Fenton systems by the addition of KI and tert-butyl alcohol due to *OH scavenging.     

Behavior of 1,3-dichloropropene and methyl isothiocyanate in undisturbed soil columns

To develop alternatives to methyl bromide (MeBr) for soil disinfection under environmental Moroccan conditions, distribution and persistence of 1,3-dichloropropene (1,3-D) and methyl isothiocyanate (MITC) were tested in undisturbed soil columns (12 cm internal diameter, 1 m length). 1,3-D was injected at a 15 cm depth and directly followed by metam-sodium (a precursor of MITC), which was applied at the soil surface of the same column using a peristaltic pump. Concerning the distribution of these fumigants in the soil profiles, our results showed that 24 h after treatment, 1,3-D and MITC were concentrated at the 0-40 cm soil layers, and reached the deeper layers 48 h later. MITC and 1,3-D dissipation was studied and the half-life (DT50) measured were 6.5 and 8 days, respectively. Total volatilization losses reached 9% for MITC and 28% for 1,3-D. MITC and 1,3-D volatilization was found to be influence by soil water contents.The results show that by reducing volatilization, photodegradation and leaching of these fumigants a suitable alternative to MeBr use is offered.     

Degradation of diuron by the electro-Fenton process

The degradation of the herbicide diuron has been undertaken by electrochemical advanced oxidation in aqueous solution. This process generates catalytically hydroxyl radicals that are strong oxidizing reagents for the oxidation of organic substances. Hydroxyl radicals degrade diuron in less than 10 min. Kinetic results evidence a pseudo-first-order degradation, with a rate constant of reaction between diuron and hydroxyl radicals of 4.8x10⁹ M^–1 s^–1. Several degradation products were identified by chromatography-mass spectrometry (LC-MS). The mineralization degree of a 1.7x10^–4 M diuron solution reached 93% at 1,000 coulombs.     

Behavior of methyl isothiocyanate in soils under field conditions in Morocco

The behavior of methyl isothiocyanate (MITC), active metabolite of metam-sodium (MS), was studied under field conditions in Morocco. MS was applied through drip irrigation in: (i) uncovered soil, (ii) soil covered with transparent polyethylene, and (iii) soil covered with virtual impermeable film. Concentrations of MITC were determined at different soil depths to determine the distribution of MITC and the concentration-time product (CTP). Six hours after MS application, in a sandy soil, MITC reaches the 20-30 cm soil layer, but remains highly concentrated in the upper 10-20 cm soil layer. In a silty clay soil, MITC was concentrated in the upper 0-10 cm soil layer. The dissipation of MITC under different conditions of application was fast and complete after seven days. However, MITC dissipation time (DT(50)) was <24 h in sandy soil treated, but 63 h in silty clay soil. Under these application conditions of MS, the plastic film reduced MITC loss to the atmosphere but the plastic film quality did not affect the behavior of MITC. The use of plastic film maintained high MITC concentrations and appropriate CTP at different soil depths.     

Determination of Hydrocarbons in Mussels from the Egyptian Red Sea Coast

Mussels (Brachidontes Sp.) collected in April 2000 from the Red Sea coastal of Egypt in order to determine the contamination by hydrocarbons. The study included 11 sampling stations covering about 450 Km of the Egyptian Red Sea coast for the first time. Total concentrations of 20 aliphatics (average 0.105 ng g(-1) of wet weight) and sixteen polycyclic aromatic hydrocarbons (PAHs) (average 5452 ng g(-1) of wet weight) were generally lower in comparison with those reported for some of the published surveillance and monitoring studies of coastal areas from various regions. These results suggest that the coastal area in the Red Sea of Egypt might be considered as a relatively unpolluted.