4-Nonylphenols and 4-tert-octylphenol in water and fish from rivers flowing into Lake Biwa

Surveys of 4-nonylphenols (NOs) and 4-tert-octylphenol (OC) were performed for water and fish samples obtained from eight rivers flowing into Lake Biwa once every two months from April 1998 to March 1999. For water samples, NOs were detected all the year round (0.11-3.08 ng ml(-1)) at high frequency (48/48) in the eight rivers. OC was detected at lower concentrations (ND approximately 0.09 ng ml(-1)) and at lower frequency (23/48). The concentrations of NOs in the river water always showed minimum values at 5-8 degrees C in winter. It was presumed that the formation of NOs by the biotransformation of nonylphenol polyethoxylates decreased much in the sludge treatment of nonionic surfactants at the low temperature (5-8 degrees C) in winter. Average BCF values of NOs and OC in the six kinds of fish were calculated from the field data. The field BCF values of NOs 15-31 in the six kinds of fish were lower than the laboratory BCF values of 167 in Killifish and 282 in Salmon. For OC, the field BCF values 129-297 for the three kinds of fish were nearly equal to the laboratory BCF value, 261, in Killifish.     

Small queens and big-headed workers in a monomorphic ponerine ant

Evolution of caste is a central issue in the biology of social insects. Comparative studies on their morphology so far suggest the following three patterns: (1) a positive correlation between queen–worker size dimorphism and the divergence in reproductive ability between castes, (2) a negative correlation among workers between morphological diversity and reproductive ability, and (3) a positive correlation between queen–worker body shape difference and the diversity in worker morphology. We conducted morphological comparisons between castes in Pachycondyla luteipes, workers of which are monomorphic and lack their reproductive ability. Although the size distribution broadly overlapped, mean head width, head length, and scape length were significantly different between queens and workers. Conversely, in eye length, petiole width, and Weber’s length, the size differences were reversed. The allometries (head length/head width, scape length/head width, and Weber’s length/head width) were also significantly different between queens and workers. Morphological examinations showed that the body shape was different between queens and workers, and the head part of workers was disproportionately larger than that of queens. This pattern of queen–worker dimorphism is novel in ants with monomorphic workers and a clear exception to the last pattern. This study suggests that it is possible that the loss of individual-level selection, the lack of reproductive ability, influences morphological modification in ants.     

Contamination,dynamics, and health risk assessment of pesticides in seawater and marine samples from the Seto Inland Sea,Japan

Environmental Science and Pollution Research - We assessed the contamination, dynamics, and health risks of the pesticides cyanazine, simetryn, fenarimol, isoprothiolane, diazinon, irgarol,...