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Water content in the tissues, tissue proportions, and content and concentrations of copper, zinc, iron, cadmium, manganese, and cobalt were determined in male shore crabs Carcinus maenas of different sizes. Average wet to dry weight ratios in midgut gland, gills, muscle, exoskeleton, stomach, heart, testes, hypodermis, and haemolymph were 5.3, 9.5, 4.1, 1.5, 4.8, 6.1, 3.8, 4.7, and 13, respectively. The water content in the soft tissues generally increased with increasing size of the crabs (except in testes). Dry midgut gland, gills, muscle, exoskeleton, stomach, heart, testes, hypodermis, and haemolymph constituted 4, 0.9, 20, 68, 0.5, 0.12, 0.5, 0.7 and 5.3%, respectively, of the body dry weight. Dry midgut gland, gills, stomach, hypodermis, and haemolymph constituted a larger proportion of the body weight in small than in large crabs, whereas the opposite was the case for exoskeleton. Protein concentrations in the haemolymph decreased with size whereas haemolymph volume increased. Seventy percent of the copper body burden was located in the haemolymph. The majority of zinc (61%) occurred in muscle, whereas the midgut gland was the major site of cadmium storage (89%). The exoskeleton contained the major part of the body burden of iron (71%) and manganese (95%). Most of the cobalt body burden was located in the exoskeleton (45%) and haemolymph (44%). As tissue hydration and tissue proportions changed with size, tissue metal concentrations did not necessarily vary identically with size when expressed on a dry weight compared to a wet weight basis. Tissue potassium concentrations were negatively correlated with tissue water contents, indicating that water in tissues with a high wet to dry weight ratio was of extracellular origin. However, comparison of tissue and haemolymph copper levels showed that this extracellular water could not be pure haemolymph as tissue copper concentrations would have been higher than the values actually found.

Valve and cardiac activity were simultaneously measured in the blue mussel (Mytilus edulis) in response to 10 d copper exposure. Valve movements, heart rates and heart-rate variability were obtained non-invasively using a Musselmonitor[R] (valve activity) and a modified version of the Computer-Aided Physiological Monitoring system (CAPMON; cardiac activity). After 2 d exposure of mussels (4 individuals per treatment group) to a range of dissolved copper concentrations (0 to 12.5 [micro] M as [CuCl.sub.2]) median valve positions (% open) and median heart rates (beats per minute) declined as a function of copper concentration. Heart-rate variability (coefficient of variation for interpulse durations) rose in a concentration-dependent manner. The 48 h [EC.sub.50] values (concentrations of copper causing 50% change) for valve positions, heart rates and heart-rate variability were 2.1, 0.8, and 0.06 [micro] M, respectively. Valve activity was weakly correlated with both heart rate (r = 0.48 [+ or -] 0.02) and heart-rate variability (r = 0.32 [+ or -] 0.06) for control individuals (0 [micro] M [Cu.sup.2+]). This resulted from a number of short enclosure events that did not coincide with a change in cardiac activity. Exposure of mussels to increasing copper concentrations ([is greater than or equal to] 0.8 [micro] M) progressively reduced the correlation between valve activity and heart rates (r = 0 for individuals dosed with [is greater than or equal to] 6.3 [micro] M [Cu.sup.2+]), while correlations between valve activity and heart-rate variability were unaffected. The poor correlations resulted from periods of valve flapping that were not mimicked by similar fluctuations in heart rate or heart-rate variability. The data suggest that the copper-induced bradycardia observed in mussels is not a consequence of prolonged valve closure.

The effect of various copper concentrations on the gill ultrastructure of Carcinus maenas was investigated. This was done by exposing shore crabs to sublethal concentrations in a static laboratory system. Gills five and eight were then removed and damage to the ultrastructure examined by transmission microscopy. Results showed that damage was first observed at 100 ug Cu(-1) in the respiratory gill in areas close to the marginal canal. At 200 to 500 ug Cu(-1), structural damage spread progressively throughout the lamellae of the respiratory gill.

A study was conducted to examine the effectiveness of the automated interpulse duration assessment (AIDA) in measuring heart beat regularity of shore crabs as a biomaker of contaminant exposure to copper. Cardiac activities in shore and nocturnal crabs were influenced by the factors such as temperature and body size. Results revealed the incidence of cardiac activity variability of shore crabs exposed to copper. AIDA proved to be an effective method in measuring both heart rate and beat regularity in reaction to copper exposure. It was a suggested tool for toxicity testing.

The biomarker approach has been much used by ecotoxicologists to detect exposure to and effects of environmental contamination. They can provide an early warning of pollutant or UV-B-induced reversible departures from homeostasis. A study has been undertaken to assess the suitability of chlorophyll fluorescence, changes to in vivo pigment absorption and ion leakage, as biomarkers for UV-B explosure in marine macroalgae.

Shore crabs (Carcinus maenas) were studied to determine whether varying degrees of contamination affected physiological responses, such as heart-rate and osmoregulatory ability. The results showed that osmoregulatory ability changes were sensitive to differences in environmental contamination.

The Automated Interpulse Duration Assessment system (AIDA) helps in the diagnosis of disturbances in cardiac rhythms in macroinvertebrates by regularly monitoring the interpulse intervals. AIDA studies show that starvation in the mussel Mytilus edulis and the crab Carcinus maenas increases disturbances in cardiac rhythms and a fall in the heart rate. The system has the potential to measure locomotor activity, nutritional state and thermal and salinity stress.

Analysis of the effects of salinity and calcium ion concentrations on cadmium accumulation in Littorina littorea, Mytilus edulis and Carcinus maenas reveals that cadmium accumulation in soft sites of L. littorea, soft areas and shells of M. edulis and the entire body and exoskeleton of C. maenas vary inversely with salinity. A significant amount of inter-species alterations in cadmium accumulation in the three species depend on wet to dry weight tissue ratios and organism size.

The analysis of the influence of nutritional state and sex on accumulation of arsenic in shore crab reveals the concentration of arsenic in the gills and mid gut gland. Arsenic pollution affects arsenic concentration and distribution in tissues, and crabs from polluted site have more arsenic concentration. Nutritional state of the crab and sex difference also influence arsenic concentration.

While the ability of xeno-oestrogens, like 4-n-nonylphenol (4-NP), to disrupt the natural hormonal systems of aquatic vertebrates is well known, evidence for comparable endocrine disrupting effects in decapod crustaceans, particularly during their larval development, remains scarce. In this investigation, a polyclonal antiserum raised against an apolipovitellin purified from the mature ovaries of the intertidal prawn, Palaemon elegans, was found to be immunoreactive with a 86 kDa polypeptide (IRP) present in all the larval and early post-larval stages. An indirect ELISA technique, developed to quantify the levels of the immunoreactive proteins present in the soluble protein fraction of homogenates of P. elegans larvae, found the quantity of the IRP varied between 0.47-0.67 ng [micro] depending on stage. Exposure of P. elegans larvae to 4-NP at the environmentally realistic concentrations of 0.2-20 [micro]g [L.sup.-1], resulted in a significant, concentration independent, increase in IRP levels of 13-18%. Conversely, exposure to comparable concentrations of the natural oestrogen, 17a-oestradiol ([E.sub.=2]), significantly reduced IRP levels by up to 11% in a similar concentration independent manner. Significant fluctuations in IRP levels were correlated with exposure to 4-NP and [E.sub.2]. However, with the exception of a slight reduction in the survival of larvae exposed to 4-NP at 2 [micro]g [L.sup.-1], neither 4-NP nor [E.sub.2] had any significant effect on the development, growth or survival of P. elegans larvae.