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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.

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.

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 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.