Exposure to toxic waste containing high concentrations of hydrogen sulphide illegally dumped in Abidjan, C?te d’Ivoire

Introduction

On August 2006, a cargo ship illegally dumped 500?t of toxic waste containing high concentrations of hydrogen sulphide in numerous sites across Abidjan. Thousands of people became ill. Seventeen deaths were associated with toxic waste exposure.

Materials and methods

This study reports on environmental and health problems associated with the incident. A cross-sectional transect study was conducted in five waste dumping site areas.

Results

Of the households, 62.1% (n?=?502) were exposed to the effects of the pollutants and 51.1% of the interviewed people (n?=?2,368) in these households showed signs of poisoning. Most important symptoms were cough (37.1%), asthenia (33.1%), pruritus (29.9%) and nausea (29.1%).

Discussion

The health effects showed different frequencies in the five waste impact sites. Among the poisoned persons, 21.1% (n?=?532) presented symptoms on the survey day (i.e., 4?months after incident). Transect sampling allowed to determine a radius of vulnerability to exposure of up to 3?km from the point of toxic waste disposal.

Conclusion

The area of higher vulnerability is influenced by various environmental factors, such as size and severity of pollution site, duration of toxic waste pollution on the impact site and locally climatic conditions. The surveillance of effects on environment and human health is warranted to monitor the development.     

A simple random path method for the analysis of flow networks

The path of a particle through an ecosystem is modelled as a Markov chain. For a given flow network, powers of the transition matrix are used to calculate the distribution of the particles over the network after each transition. The method may be applied for the definition and calculation of trophic levels in food webs. The algorithm yields the trophic level distribution of species, the species composition of trophic levels, and the path length distribution of output flows. In addition, the network can be described as a linear chain, with the throughflows at each step identified. Data from several ecosystems are analyzed by the method, showing that surprising insights may result.     

Hidden ancient diversification in the circumtropical lancelet Asymmetron lucayanum complex

The tropical lancelet Asymmetron lucayanum (= Epigonichthys lucayanus) is distributed from the western Indian Ocean to the central Pacific Ocean, and the western Atlantic Ocean. Molecular phylogenetic analysis of mitochondrial cytochrome c oxidase subunit I (COI) sequences (1,035 bp) of A. lucayanum (80 specimens from seven localities) showed clearly that this species is genetically distinguished into three major groups of geographical populations based on neighbor-joining tree using maximum likelihood distance (HKY model with invariable sites and gamma correction), suggesting the existence of three cryptic species. Our genetic data show that (1) inter-oceanic divergence time between Clade B (the West-Central Pacific) and Clade C (the Atlantic) (d = 6.6%, ca. 12 million years ago) was smaller than intra-oceanic divergence time between Clade A (the Indo-West Pacific) and Clade B (d=39.5%, ca. 100 million years ago); (2) there are two cryptic species in the West Pacific in sympatry; and (3) high gene flow is implied between the Maldives and the Ryukyus in Clade A (10,000 km distance), the Philippines and Hawaii in Clade B (8,500 km distance), and Barbados and Bermuda in Clade C (2,200 km distance).     

Prenatal sonographic signs of possible fetal genital anomalies

The sonographic markers of female and male external genitalia have been documented in early and late gestation. The aim of the present study was to report our experience of possible sonographic markers of fetal genital anomalies. Sonography was performed with a vaginal probe in early gestation and an abdominal sector scanner in advanced gestation. The following genital anomalies were observed: hypospadias, epispadias, ambiguous genitalia, and testicular feminization or Smith-Lemli-Opitz syndrome. It is therefore concluded that prenatal diagnosis of some genital anomalies is now possible.     

Oligohydramnios with amnio-chorionic separation at 15–16 weeks' gestation

Nine patients with oligohydramnios and amnio-chorionic separation were identified out of 7000 women who underwent a vaginal ultrasound examination at 15–16 weeks' gestation. Oligohydramnios was defined as a reduced amount of amniotic fluid, a distance of more than 1 cm between the chorion and amnion, and a good turgor of the amnion without floating membranes or intrauterine sheets. Fetal malformations were observed in all nine cases. In four of six fetuses where chromosomal analysis was available, an abnormal karyotype was found. It is concluded that oligohydramnios in the early second trimester is associated with fetal abnormality.