No abstract

In recent years there has been considerable concern over the ability of substances discharged into the environment to disrupt the normal endocrine function of wildlife. In particular, the apparent widespread feminization of male fish in rivers has received significant attention from regulators in the United Kingdom, the United States, Europe, and Japan. The U.K. and European epidemiological data sets have demonstrated that the occurrence of feminized fish is associated with effluent discharges and that the incidence and severity is positively correlated with the proportion of treated sewage effluent in receiving waters. Although weakly estrogenic substances may contribute to the overall effect, studies have concluded that steroid estrogens are the principal and most potent estrogenic components of domestic sewage. Extensive laboratory data sets confirm that steroid estrogens are capable of eliciting the effects observed in wild fish at concentrations that have been measured in effluents and in the environment. Based on evaluation of the available information, the Environment Agency (England and Wales) has concluded that the weight of evidence for endocrine disruption in fish is sufficient to develop a risk management strategy for estrogenically active effluents that discharge to the aquatic environment.

No abstract

Microorganisms are a ubiquitous feature of most hard substrata on Earth and their role in the geomorphological alteration of rock and stone is widely recognized. The role of microorganisms in the modification of engineering materials introduced into the intertidal zone through the construction of hard coastal defences is less well understood. Here we use scanning electron microscopy (SEM) to examine microbial colonization and micro-scale geomorphological features on experimental blocks of limestone, granite and marine concrete after eight months' exposure in the intertidal zone in Cornwall, UK.Significant differences in the occurrence of microbial growth features, and micro-scale weathering and erosion features were observed between material types (ANOVA p < 0·000). Exposed limestone blocks were characterized by euendolithic borehole erosion (99% occurrence) within the upper 34·0 Ϯ 12·3 mm of the surface. Beneath the zone of boring, inorganic weathering (chemical dissolution and salt action) had occurred to a depth of 125·0 Ϯ 39·0 mm. Boring at the surface of concrete was less common (27% occurrence), while bio-chemical crusting was abundant (94% occurrence, mean thickness 45·1 Ϯ 27·7 mm). Crusts consisted of biological cells, salts and other chemical precipitates. Evidence of cryptoendolithic growth was also observed in limestone and concrete, beneath the upper zone of weathering. On granite, biological activity was restricted to thin epilithic films (<10 mm thickness) with some limited evidence of mechanical breakdown.Results presented here demonstrate the influence of substratum lithology, hardness and texture on the nature of early micro-scale colonization, and the susceptibility of different engineering materials to organic weathering and erosion processes in the intertidal zone. The implications of differences in initial biogeomorphic responses of materials for long-term rock weathering, ecology and engineering durability are discussed.