A national risk assessment for intersex in fish arising from steroid estrogens

Abstract

The occurrence of intersex fish is widespread in the rivers of England and Wales. The extent of intersex in fish populations is believed to be strongly linked to their exposure to steroid estrogens. The present study presents, to our knowledge, the first national, catchment-based risk assessment for steroid estrogens in the world. A graphical information system-based model predicted the concentrations of estradiol (E2), estrone, and ethinylestradiol, which were combined and compared with known biological effect levels to predict the risk of endocrine disruption for 10,313 individual river reaches (21,452 km) receiving effluent from more than 2000 sewage treatment plants serving more than 29 million people. The large scale of this assessment underlines the usefulness of computer-based risk assessment methods. Overall, 61% [corrected] of the modeled reaches (all percentages are in terms of the total river length modeled) in England and Wales were predicted to be not at risk from endocrine disruption (mean concentrations, <1 ng/L E2 equivalents). A large range existed in the percentage of river reaches at risk in the various regions, from 5% in Wales to 67% in the Thames catchment. Important factors influencing this proportion are the population density, particularly their location, and the available dilution. A very small proportion of reaches (approximately 1-3%) were predicted to be at high risk (>10 ng/L E2 equivalents). Many of these high-risk reaches, however, were ditches, which were composed almost entirely of sewage effluent. The model could be applied equally well to any other chemical of concern emanating from the human population that would be impractical to assess by measurement.

Large microplastic particles in sediments of tributaries of the River Thames, UK – Abundance, sources and methods for effective quantification

“…Sampling sites within the Thames river basin were selected based on two variables; average % effluent present in the river as estimated using the Low Flows 2000 (LF2000) WQX (Water Quality eXtension) model (Williams et al, 2009) and population equivalent density as calculated using population within the catchment area (of known area) served by the upstream sewage treatment 6 works (Pottinger et al, 2013;Williams et al, 2009). Selected sites comprised three tributaries of the Thames: the River Leach, the River Lambourn and The Cut (two sites).…”

Disruption of the stress response in wastewater treatment works effluent-exposed three-spined sticklebacks persists after translocation to an unpolluted environment

“…The distances between the WWTW discharge and the sample site varied between 100 m (Woolton, Huyton) and 2500 m (Blackburn). The effluent concentrations at each sample site were estimated using the Low Flows 2000 Water Quality eXtension model (LF2000-WQX) which combines hydrological models with water-quality models to make predictions on the concentration of a given chemical originating from a point source (Williams et al 2009). The percentage effluent was estimated as the concentration modelled for a conservative chemical discharged from all WWTWs in the river system at a fixed concentration of 100 ng/l (Pottinger et al, 2013).…”

The distribution of Polychlorinated Biphenyls (PCBs) in the River Thames Catchment under the scenarios of climate change

“…However, it includes the most heavily urbanised area which houses nearly a quarter of the population of England and Wales (supporting about 14 million people) . There are 352 sewage treatment plants in the Thames Region which discharge into the River Thames and its tributaries (Williams et al, 2009). The bedrock of the Thames is mainly high permeable chalk, although there are also some reaches of low permeability clays .…”