Copper accumulation in the crayfish (Orconectes rusticus)

Use of crayfish in biomonitoring studies of environmental pollution of the river Meuse

The river Meuse, located in western Europe, is contaminated by different pollutants, of both organic and inorganic nature. The predominant sources of Meuse contamination in The Netherlands are agricultural activities and pollution derived from urban areas. Crayfish, water, and sediment samples were collected at four different locations of the river Meuse, in order to cover a large part of the catchment area of this river in The Netherlands. Crayfish may be very useful in biomonitoring studies, since they can integrate body load by pollutants over time in an area-bound manner. In these crayfish, levels of aromatic DNA adducts, heavy metal residues, polychlorinated biphenyls (PCBs), and organochlorine pesticides were determined in hepatopancreatic tissue. Also analyzed were water and sediment samples derived from the same locations, for polycyclic aromatic hydrocarbons (PAHs), heavy metals, and organochlorine compounds. In sediments from the four different sampling sites, no clear differences were observed in PCB levels. Organochlorine pesticide concentrations were highest at location A, the most upstream sampling site, whereas a general decrease was observed following the river Meuse downstream. A similar pattern was observed for the metal compounds. For PAH sediment levels no consistent tendency could be observed. Highest values were detected at site B, followed by, respectively, locations A, D, and C. In water samples, a different pattern was observed. The highest metal concentration was observed at location D, whereas the total organochlorine level was higher at sites B and D, compared to the two other sampling sites. Differences in pollution levels in crayfish between sampling sites were evident. Site D, the most downstream-situated site examined, appeared to be the most polluted site with respect to PCBs, DDT, DDE, and Cu in crayfish. Moreover, DNA adduct levels, which may serve as a dosimeter for the internal dose of aromatic compounds such as PAHs and PCBs, were also significantly higher in hepatopancreatic tissue of crayfish captured at site D, compared to the three other sampling sites. Moreover, significant correlations were observed between DNA adduct levels and the lower chlorinated PCB congeners (PCB 28-PCB 101). By correlating the different pollutants in water and/or sediment with xenobiotic levels in crayfish, no consistency could be observed, indicating that monitoring aquatic species may provide specific information on the presence of surface water pollutants. These results indicate that crayfish can be used as biological indicators of exposure to both organic and inorganic pollution in aquatic systems.

Comparative body measurements, fecundity, oxygen uptake, and ammonia excretion in Cambarus robustus (Astacidae, Crustacea) from an acidic and a neutral site in northeastern Ontario, Canada

Cambarus robustus (Astacidae, Crustacea) females from acidic, metal-contaminated Wavy Lake and circumneutral, uncontaminated, fast-flowing Pike Creek showed significant allometric differences (relationships between total body length and wet mass, total body length and chela length, and carapace length and carapace width), as well as differences in their fecundity (relationships between total body length and numbers of eggs per ovary and numbers of eggs per ovary and diameter of eggs). Whereas crayfish from Pike Creek showed linear relationships between total body length, wet mass, and chela length (= isometry), decapods from Wavy Lake showed isometry only between total body length and chela length. Females from Pike Creek produced significantly more but smaller ovarian eggs than did those from Wavy Lake. Oxygen consumption was significantly lower and ammonia excretion significantly higher in crayfish from Wavy Lake than in those from Pike Creek.

Physiological effects of metal toxicity on the tropical freshwater shrimp Microbrachium carcinus (Linneo, 1758)

Pilot tests were performed to determine the level at which Zn(++) and Cu(++) ceased to be acutely toxic in Macrobrachium carcinus. The data indicated that the static 96h-LC(50) values for Zn(++) and Cu(++) were 0.2 and 0.1 mg litre(-1) respectively. A differential reduction in respiration and ammonia excretion rates was noted with increasing concentrations of these metals in the water. These levels may in a toxic body burden and a progressive deterioration of gill efficiency. A decrease in respiration and ammonia excretion rates resulted in a decrease in O:N ratios, upon exposure to Zn(++) and Cu(++) concentrations. The ratios obtained indicate that these metals, also increased dependence on carbohydrate or lipid reserves.