David Sheahan

• Principal Chemical Risk Assessor at Centre for Environment, Fisheries and Aquaculture Science

The Severn Estuary is a large macrotidal estuary which includes an extensive mudflat with microphytobenthos (MPB) playing a key role in the ecosystem. This study evaluated the impact of chlorination at two different dosing levels (0.05 and 0.5 mg/l as total residual oxidants, TRO, representative of potential concentrations in the mixing zone and wi...

Action Levels (ALs) are thresholds which are used to determine whether dredged material is suitable for disposal at sea by providing a proxy risk assessment for potential impacts to biological features such as fish and benthos. This project tested proposed scenarios for changes to the UK Action Levels to determine the likely implications for naviga...

Seawater chlorination is widely used for coastal, marine industries for the prevention of fouling. Using a choice chamber system, we investigated the influence of chlorinated seawater at typical concentrations occurring near chlorinated cooling water discharges, on the behaviour of juvenile seabass (Dicentrachus labrax). These studies showed that t...

The development of desalination has been essential to the rapid economic development of the countries bordering the Arabian Gulf. The current production capacity of sea water desalination plants drawing water from Gulf is over 20 million m 3 day − 1 , which may rise to 80 million m 3 day − 1 by 2050. Whilst supporting aspects of sustainable develop...

Chlorination is a widely used method to prevent biofouling in power station cooling water systems in coastal and estuarine environments. This study evaluated the impact of chlorination together with temperature increase to simulate primary entrainment of a phytoplankton community. Biomass, diversity, and photosynthetic activity were monitored over...

This study provides toxicity values for early life stages (ELS) of two phylogenetically distinct marine animal taxa, the sea urchin (Paracentrotus lividus), a deutero-stome invertebrate, and the turbot (Scophthalmus maximus), a vertebrate (teleost), when challenged by six hazardous and noxious substances (HNS): aniline, butyl acrylate, m-cresol, cy...

An inhomogeneous continuous‐time Markov chain model is proposed to quantify animal preference and avoidance behaviour in a choice experiment. We develop and apply our model to a choice flume experiment designed to assess the preference or avoidance responses of sea bass (Dicentrarchus labrax) exposed to chlorinated seawater. Due to observed fluctua...

The development of desalination has been essential to the rapid economic development of the countries bordering the Arabian Gulf. The current production capacity of sea water desalination plants drawing water from Gulf is over 20 million m 3 day − 1 , which may rise to 80 million m 3 day − 1 by 2050. Whilst supporting aspects of sustainable develop...

Fish acute toxicity tests are conducted as part of regulatory hazard identification and risk assessment packages for industrial chemicals and plant protection products. The aim of these tests is to determine an LC50 endpoint – that is, the concentration which would be lethal to 50% of the animals treated. These tests are therefore associated with s...

Chlorination is a widely used antifouling method for freshwater and marine applications. Chlorine added to seawater reacts to form oxidants that are toxic to biofouling organisms. Further, the oxidants that result are short-lived, but may nevertheless affect non-target species in waterbodies receiving the antifouling effluent. This study evaluated...

2017-262 Over recent decades there has been an increase in the shipping of chemicals at sea with a subsequent increase in the risk of incidents involving hazardous and noxious substances (HNS). Typically, during HNS spills and during scenario planning the impact upon marine organisms is estimated using spill model predictions of time-weighted avera...

Arsenic (As), a toxic metalloid, is finding its route to human through intake of As-contaminated water and consumption of food grown on contaminated soil. Rice is the most As-affected crop. Present study is aimed to assess the impact of stabilized orthosilicic acid (a proprietary formulation for plant-available silicon (Si) and earlier used as fert...

Emergent aquatic insects can represent an important subsidy to terrestrial ecosystems but may also transport accumulated contaminants across ecosystem boundaries when larvae develop in contaminated sediments. We sampled tetragnathid spiders (terrestrial predators), larval chironomids (spider prey of aquatic origin) and terrestrial insects (terrestr...

The ecotoxicity testing of chemicals for prospective environmental safety assessment is an area in which a high number of vertebrates are used across a variety of industry sectors. Refining, reducing, and replacing the use of animals such as fish, birds, and amphibians for this purpose addresses the ethical concerns and the increasing legislative r...

ITOPF's shipowners and their Protection and Indemnity (P&I) insurers have established the annual 'ITOPF R&D Award' to encourage organisations worldwide to inspire innovative thinking and to present ideas that could provide solutions to some of the challenges faced in spill response and environmental monitoring. Each year £50,000 is made available t...

The offshore oil and gas industry will use and discharge large quantities of chemicals into the marine environment during operational activities, with some of those chemicals considered hazardous. Chemical substitution, as part of the environmental regulatory regime, has been advocated as a simple and effective tool to reduce inputs of hazardous su...

We have become progressively more concerned about the quality of some published ecotoxicology research. Others have also expressed concern. It is not uncommon for basic, but extremely important, factors to apparently be ignored. For example, exposure concentrations in laboratory experiments are sometimes not measured, and hence there is no evidence...

EXECUTIVE SUMMARY Climate change may alter physical and chemical processes increasing pollution of transitional and coastal waters. Drought conditions, particularly in the southeast of the UK will reduce surface runoff but also dilution of continuous discharges. Drier summers, but more extreme rainfall events, will exacerbate microbial delivery fro...

Climate change may alter physical and chemical processes increasing pollution of transitional and coastal waters. Drought conditions, particularly in the south-east of the UK will reduce surface runoff but also dilution of continuous discharges. Drier summers, but more extreme rainfall events, will exacerbate microbial delivery from livestock farmi...

Ocean acidification (OA) may alter the behaviour of sediment-bound metals, modifying their bioavailability and thus toxicity. We provide the first experimental test of this hypothesis with the amphipod Corophium volutator. Amphipods were exposed to two test sediments, one with relatively high metals concentrations (Σmetals 239 mg kg−1) and a refere...

Effects of nanoparticles on aquatic organisms have been little studied to date and toxicological data are urgently needed for development of regulatory frameworks for these substances. Here, we report the findings of a study exposing sticklebacks to cadmium sulfide (CdS) as bulk material and quantum dots. Fish were exposed for 21 d in a flow throug...

Data are presented on four pesticides applied to agricultural land at the Agricultural Development Advisory Service, Rosemaund, in the west of England. The farm covers a well-defined and isolated water basin of cracking heavy clay loam soils drained by a single stream. Levels of the relatively particle-bound pesticides trifluralin, deltamethrin, ch...

The Toxicity Identification and Evaluation (TIE) approach was applied to the final effluents of sewage treatment works that treat industrial effluents including textile wastewater. Wastewater samples from sites up and downstream of the effluent discharges to the River Aire and Calder system in West Yorkshire, UK were also tested for toxicity. The m...

This study investigated the response of biomarker measurements and histopathological indicators of polycyclic aromatic hydrocarbon (PAH) exposure in the flounder (Platichthys flesus L.). Flounder were fed food spiked with a mixture of four PAHs at an environmentally relevant range of concentrations for either one or six months. Ethoxyresorufin-O-de...

Twenty-six pesticidal compounds and samples of stormwater from two different agricultural catchments were screened for oestrogenic activity using an in vitro recombinant yeast-based assay. Only six fungicides showed an oestrogenic response with low comparative biological activity of 5000 to 2.5 million times less potent than 17beta-estradiol (E2),...

Chemical analyses were combined with a biological assay to investigate the main estrogenic chemicals as they passed through a sewage treatment works (STW) and entered a river. The STW studied was unusual in that it received wastewater from the textile trade. This wastewater was shown to contain high concentrations of alkylphenol polyethoxylates and...

As a result of the introduction of tighter discharge limits and effluent treatment processes at source, the concentration of alkylphenol ethoxylates and nonylphenol present in the final effluent discharge from a sewage treatment works that treats trade effluent from the textiles industry was reduced. The estrogenic effects of the final effluent dis...

The transient movement of pesticides at biologically active concentrations during storm events is considered to be a cause of biological impoverishment in some headwater streams. The programme of work described sought to identify compounds that are the cause of toxic effects during such events. Along with targeted pesticide analysis, toxicity ident...

Sewage effluent discharged to surface water has been shown to contain human hormones, particularly oestrogens, and synthetic chemicals which may be able to disrupt the endocrine system. Since many surface waters which receive sewage effluent are subsequently used as drinking water sources, it is important to demonstrate that treated drinking water...

Insecticides must be tested to determine their nontarget toxicity when released into the environment. Currently, new insecticides registered in Europe are likely to be tested, at the highest tier, in microcosms or mesocosms, although the costeffectiveness of these systems has yet to be established. This study investigated the effects of the organop...

The occurrence of certain natural and synthetic steroidal estrogens in the final effluent from STW has been demonstrated. 17β-Estradiol and estrone were present at concentrations in the tens of nanograms per liter range, and the synthetic estrogen 17α-ethynylestradiol was also identified, albeit in the low nanogram per liter range. The findings fro...

This paper describes an evaluation of the toxicity of contaminated sediments obtained in June 1992 from six intertidal stations on a 25 km stretch of the industrialised River Tyne Estuary in northeast England. The bioassays for toxicity included the amphipod Corophium spp. and the polychaete Arenicola marina whole sediment tests, as well as tests o...

It was recently demonstrated that most, if not all, effluents of sewage-treatment works (STWs) in the United Kingdom are estrogenic to fish. As many STWs discharge into rivers, it is possible that some stretches of rivers downstream of where the effluent enters might also be estrogenic. To assess this possibility, the induction of vitellogenin synt...

Vitellogenin, a yolk-precursor protein normally found only in the blood plasma of sexually mature female teleosts and other egg-laying vertebrates, was used as an indicator of exposure of male rainbow trout (Oncorhynchus mykiss) to exogenous estrogens. Vitellogenin concentrations were measured using a specific radioimmunoassay for trout. Cages cont...

It is becoming evident that an increasing number of widely used industrial and agricultural chemicals are estrogenic. The biodegradation products of a major group of nonionic surfactants, the alkylphenol polyethoxylates, are one such group. Some of these chemicals are widespread aquatic pollutants, and bioconcentrate in aquatic biota. Exposure of m...

There is now much information on the presence of pesticides in surface waters, but very little about their actual effects on aquatic life. This paper reports on the transient concentrations of a carbamate insecticide carbofuran, which were observed in a head-water stream draining treated farmland, and describes the resulting effects on a bioassay o...

The work reported here follows on from an earlier DoE-funded study which had shown that treated sewage effluent discharges were oestrogenic to fish. The report describes research conducted in 1992-1995 to assess whether oestrogenic effects could be detected in male fish held in cages at selected sites in rivers below sewage treatment works, and at...

Tecnazene, 2,3,5,6-tetrachloronitrobenzene, a sprouting inhibitor and fungicide used on stored potatoes, has been found to enter the freshwater environment at specific sites in the United Kingdom due to the practice of bulk washing potatoes for supermarket presentation. Because of the paucity of toxicity data for aquatic organisms, the acute toxici...

The joint toxicity to rainbow trout fingerlings (Salmo gairdneri Richardson) of eleven tank-mixes composed of pairs of six fungicides and herbicides (prochloraz, fenpropimorph, diclofop-methyl, tridemorph, benzoylprop-ethyl and propiconazole) was measured using 96 h LC50 tests. The toxicity of the mixtures ranged from being half of that expected on...