Parameterization of pharmaceutical emissions and removal rates for use in UK predictive exposure models: steroid estrogens as a case study.

Newly available prescription data has been used along with census data to develop a localised method for predicting pharmaceutical concentrations in sewage influent and effluent for England, and applied to a case study: the steroid estrogens estrone, 17ß-estradiol, and 17α-ethinylestradiol in a selected catchment. The prescription data allows calculation of the mass consumed of synthetic estrogens, while use of highly localised census data improves predictions of naturally excreted estrogens by accounting for regional variations in population demographics. This serves two key purposes; to increase the accuracy of predictions in general, and to call attention to the need for more accurate predictions at a localised and/or catchment level, especially in light of newly proposed regulatory measures which may in the future require removal of steroid estrogens by sewage treatment facilities. In addition, the general lack of measured sewage works data necessitated the development of a novel approach which allowed comparison of localised predictions to average national measurements of influent and effluent. Overall in the case study catchment, estrogen predictions obtained using the model described herein were within 95% confidence intervals of measured values drawn from across the UK, with large improvements to predictions of EE2 being made compared with previous predictive methods.

Novel organoaluminium (and gallium) carboxylate-bridged ring systems.

Treatment of the Schiff-base ligand [3,5-But2-2-(OH)C6H2CHNC6H4-2-(CO2H)] with either Me3Al, Me2AlCl or Me3Ga affords 16-membered macrocyclic tetramers containing both four- and six-coordinate metal centres.

Oligomerisation of ethylene by bis(imino)pyridyliron and -cobalt complexes

A series of bis(imino)pyridyliron and -cobalt complexes [[2,6-(CR=NAr)2C5H3N]MX2] (R=H, Me; M=Fe, Co; X=Cl, Br) 8-16 containing imino-aryl rings (Ar) with at least one small ortho substituent, as well as Ar=biphenyl and Ar=naphthyl, has been synthesised. Crystallographic analyses of complexes 9 (Ar = 2,3-dimethylphenyl), 13 and 14 (Ar= biphenyl; X= Cl or Br, respectively) reveal a distorted trigonal-bipyramidal geometry in the solid state. These complexes, in combination with methyl aluminoxane (MAO), are active catalysts for the oligomerisation of ethylene, yielding >99% linear alpha-olefin mixtures that follow a Schulz-Flory distribution. Iron ketimine (R = Me) precatalysts give the highest activities and a greater alpha-value than their aldimine (R = H) analogues. Cobalt precatalysts follow a similar trend, though their activities are almost two orders of magnitude lower than those of the corresponding iron catalysts. Ethylene pressure studies on cobalt precatalyst 15 reveal a first-order dependence on ethylene for both the rate of propagation and the rate of chain transfer, and a pressure independence of the alpha value.

Aquatic toxicity tests for the control of effluent discharges in the UK - the influence of test precision.

: The initiative by the River Purification Boards (RPBs), National Rivers Authority (NRA) and Her Majesty's Inspectorate of Pollution (HMIP) to control certain complex and toxic effluent discharges by direct toxicity assessment places great emphasis on the use of aquatic toxicity tests. Like all biological and analytical measurements, determinations of toxicity exhibit variability. When setting 'Toxicity-based Consents' (TBCs) and monitoring for compliance with such consents, it is important to understand and if possible control this variability. The implications of toxicity test variability for the way TBCs may be set and monitored are discussed; including a consideration of monitoring consents based on a single exposure concentration (limit) test and procedures involving a range of exposure concentrations (concentration-response test). We also review the precision of data arising from acute aquatic toxicity test methods which may be used for the control and monitoring of complex effluents in the UK. This includes the variability that occurs when repeated tests are carried out on different occasions within the same laboratory (repeatability) and also within different laboratories (reproducibility). Particular attention is given to acute tests using Daphnia magna, the only method for which there is a large amount of published information on the precision of toxicity data.