EROD activity and biliary fluorescence in Schroederichthys chilensis (Guichenot 1848): biomarkers of PAH exposure in coastal environments of the South Pacific Ocean

Schroederichthys chilensis is a common shark that lives in Chilean coastal environments. In this work, the relationship between liver 7-ethoxyresorufin-O-deethylase dealkylation (EROD) activity and Fluorescent Aromatic Compounds (FAC) in bile of S. chilensis sampled in three bays with different degrees of pollution were performed including a reference area. Sixty individuals were collected, 20 for each site; (10 males and 10 females per site) livers and bile samples were obtained and immediately frozen. EROD activity and FAC were measured according to three standard methods. EROD activity and FAC were higher in polluted areas than in the reference area. Synchronous Fluorescence Spectra of the bile from the fish collected at the most polluted area showed a peak at 347nm representing a metabolite corresponding to 1-hydroxypyrene. The low EROD activity in the reference area is likely related to the low level of PAH in sediments. We propose that this species is a good indicator of exposure to FACs, since it presents a series of characteristics that make it suitable for monitoring PAH exposure in coastal zones.     

Distribution of lead in urban roadway grit and its association with elevated steel structures

In an effort to determine the source of exterior lead contamination, we investigated the concentration of lead in roadway grit along major thoroughfares in New York City and in certain areas under elevated steel structures supporting elevated rails. Such structures represent only one source of lead in roadway grit. While data revealed that the median lead concentration in roadway grit did not exceed the standard for a lead hazard in bare residential soil in any borough, the limit of 400 microg/g was exceeded 22%, 18%, 10.5%, and 7.7% of the time in Manhattan, Brooklyn, The Bronx, and Queens, respectively. The second part of the study revealed the presence of high concentrations of lead in roadway grit directly under elevated steel structures. The differences in the concentration of lead in roadway grit under steel structures in comparison to areas in NYC not near elevated rails was statistically significant. Of the eight sites studied from 225 total samples, the median roadway grit lead level was 340 ppm, while the level under steel structures was 1480 ppm. Preliminary efforts to determine particle size distribution revealed that 84% of the particles were in the range of 125-500 microm, but the highest concentration of lead was in the smallest fraction analyzed (<63 microm). Lead contamination of roadway grit from restoration of elevated painted steel structures is a public health problem as these lead particulates get re-suspended in the ambient environment and are wafted and tracked into residences.     

Maternal nest defense reduces egg cannibalism by conspecific females in the maritime earwig <Emphasis Type="Italic">Anisolabis maritima</Emphasis>

Nest predation imposes a major cost to reproductive females, who should therefore take measures to avoid encounters with predators. However, when predators are conspecifics, avoidance can be more difficult and may be a consequence of social or aggregative behaviors. In this study, we measured the consequences of conspecific egg cannibalism on hatching success in the maritime earwig (Anisolabis maritima), which occasionally form aggregations. We hypothesized that conspecific egg cannibalism is a byproduct of aggregation, and that cannibalism rates would increase with aggregation density; however, our results do not support this. We combined field data with a lab experiment to test the effectiveness of maternal nest defense in protecting nests from a conspecific. Nests with a guard had higher hatching success and lower rates of cannibalism than unattended nests in the presence of a conspecific. We also measured body and forcep size to see whether the outcome of contests was determined by relative size. Female guards who were larger relative to the invading conspecific maintained their nest and had higher hatching success than females who were relatively smaller, suggesting that the maritime earwig is under directional selection for larger body and/or forcep size.     

Decomposition of 4-bromobiphenyl in soil mediated by microwave energy

It is shown the 4-bromobiphenyl in soil can be decomposed quickly and almost quantitatively to organic fragments free of bromine, in a specially designed bomb in the presence of a reagent such as cuprous oxide and aqueous alkali, by using microwave energy.     

Contrasting nitrate adsorption in Andisols of two coffee plantations in Costa Rica

Fertilizer use in coffee plantations is a suspected cause of rising ground water nitrate concentrations in the ground water-dependent Central Valley of Costa Rica. Nitrate adsorption was evaluated beneath two coffee (Coffea arabica L.) plantations in the Central Valley. Previous work at one site had identified unsaturated zone nitrate retardation relative to a tritium tracer. Differences in nitrate adsorption were assessed in cores to 4 m depth in Andisols at this and one other plantation using differences in KCl- and water-extractable nitrate as an index. Significant adsorption was confirmed at the site of the previous tracer test, but not at the second site. Anion exchange capacity, X-ray diffraction data, extractable Al and Si, and soil pH in NaF corroborated that differences in adsorption characteristics were related to subtle differences in clay mineralogy. Soils at the site with significant nitrate adsorption showed an Al-rich allophane clay content compared with a more weathered, Si-rich allophane and halloysite clay mineral content at the site with negligible adsorption. At the site with significant nitrate adsorption, nitrate occupied less than 10% of the total anion adsorption capacity, suggesting that adsorption may provide long-term potential for mitigation or delay of nitrate leaching. Evaluation of nitrate sorption potential of soil at local and landscape scales would be useful in development of nitrogen management practices to reduce nitrate leaching to ground water.     

Evaluation of a System to Automatically Sample Zooplankton From the Discharge of Dams1

ABSTRACT: Automatic plankton samplers installed at two dams on the Connecticut River Continuously monitored crustacean zooplankton from October 1977 through 1979 and allowed a significant reduction in man-hours involved in an extensive sampling program. Automatic samplers efficiently sampled most species and size classes of crustacean zooplankton in a similar, but not consistently identical manner as a commonly used towed-net plankton sampler. The smallest sized zooplankton were captured more efficiently than the largest. Mesh selection and sampler avoidance exerted different influences on automatic samplers and towed nets. Future use of the samplers and direct comparison of results to results obtained by other methods was supported.