Emerging challenges of the impacts of pharmaceuticals on aquatic ecosystems: A diatom perspective

Pharmaceuticals are a ubiquitous group of emerging pollutants of considerable importance due to their biological potency and potential to elicit effects in wildlife and humans. Pharmaceuticals have been quantified in terrestrial, marine, fresh, and transitional waters, as well as the fauna and macro-flora that inhabit them. Pharmaceuticals can enter water ways through different human and veterinary pathways with traditional wastewater treatment, unable to completely remove pharmaceuticals, discharging often unknown quantities to aquatic ecosystems. However, there is a paucity of available information regarding the effects of pharmaceuticals on species at the base of aquatic food webs, especially on phytoplankton, with research typically focussing on fish and aquatic invertebrates. Diatoms are one of the main classes of phytoplankton and are some of the most abundant and important organisms in aquatic systems. As primary producers, diatoms generate ∼40 % of the world's oxygen and are a vital food source for primary consumers. Diatoms can also be used for bioremediation of polluted water bodies but perhaps are best known as bio-indicators for water quality studies. However, this keystone, non-target group is often ignored during ecotoxicological studies to assess the effects of pollutants of concern. Observed effects of pharmaceuticals on diatoms have the potential to be used as an indicator of pharmaceutical-induced impacts on higher trophic level organisms and wider ecosystem effects. The aim of this review is to present a synthesis of research on pharmaceutical exposure to diatoms, considering ecotoxicity, bioremediation and the role of diatoms as bio-indicators. We highlight significant omissions and knowledge gaps which need addressing to realise the potential role of diatoms in future risk assessment approaches and help evaluate the impacts of pharmaceuticals in the aquatic environment at local and global scales.

Dade county: the politics of managing urban growth

This is one of several articles specially prepared for this issue of Science in recognition of Habitat: The United Nations Conference on Human Settlements now taking place in Vancouver.

The Adolescent Sexual Activity Index (ASAI): a standardized strategy for measuring interpersonal heterosexual behaviors among youth

This study reports on the properties of a standardized measure that is used to index the spectrum of sexual behaviors typical of adolescents. Prior work has shown sexual behaviors to be ordered and progressive. Using pre-coitus sexual behaviors that did not refer to sex organs and self-reports of sexual intercourse, a 13-item index was developed. The index was standardized with values ranging from 0.0 to 10.0. Measures were administered to 1493 female and 1073 male black and white adolescents aged 12-19 years in community settings. Analyses reveal the index to have high internal consistency and to perform as a psychometrically sound dependent variable. Because the index uses conservative language, its use may avoid the controversy common to much of the research on adolescent sexuality. The Adolescent Sexual Activity Index will provide researchers and practitioners with an interpretable tool for examining developmental patterns that precede sexual intercourse.

The effects of tumor promoters on HTLV-1 expression in a low-virus producer and a non-virus producer cell line

Chemical agents including 5-iodo-2'-deoxyuridine (IUdR), 4-O-methyl 12-O-tetradecanoyl phorbol-13-acetate (TPA), phorbol, and the tumor promoters teleocidin and TPA were tested for their ability to induce Human T-cell leukemia-lymphoma virus Type I (HTLV-I) expression in the low-virus producer MT-1 cell line and in the non-virus producer C63/CRII-2 cell line, which contains at least one integrated HTLV-I genome equivalent per cell [26]. Viral antigen expression increased from 0.3% to 8.7% in the MT-1 cell line after treatment with IUdR, while TPA and teleocidin were marginally or non-effective as inducers. Chemicals did not induce HTLV-I antigen expression in the C63/CI(II-2) cell line. No enhancement of reverse transcriptase activity or alteration of proviral organization was observed after chemical treatment of MT-1 cells.

Intrauterine fetal tachypnea

In a previous case report, intrauterine fetal tachypnea was associated with sudden fetal death. The authors have observed a similar case of fetal tachypnea. Early intervention occurred and a normal fetus was delivered. Pathophysiologic mechanisms for the phenomenon are discussed.