RIVER PHOSPHORUS DYNAMICS AND RESERVOIR EUTROPHICATION POTENTIAL1

ABSTRACT: Sediments from the Pompton and Passaic Rivers at Two Bridges were analyzed for potentially available phosphorus fractions and total phosphorus (TP). Water samples from the same sites were analyzed for dissolved phosphorus, TP, suspended solids (SS), and volatile SS. Significant negative correlations between river TP concentrations and flow were observed. However, storm flows resulted in increases in TP and SS concentrations and flux (loadings). Most of the increase in river P loading at high flow was in the dissolved fraction, suggesting that the sediments may be a large source of dissolved P. Concentrations of potentially available P in the sediments ranged from 140 to 1310 times the TP concentration in the overlying water. According to a modified Vollenweider model, current P concentrations in the Pompton and Passaic Rivers will result in excessive P loading in the Wanaque Reservoir if even small volumes of river water are pumped to the reservoir through the recently completed Wanaque South pipeline. Reductions in sewage treatment plant effluent P concentrations alone will not produce sufficient decreases in river phosphorus concentrations to avoid this predicted overloading and eutrophication.     

Preconception and preimplantation diagnosis for cystic fibrosis

Preimplantation diagnosis provides couples at high genetic risk the possibility of avoiding genetic disease without the need for prenatal diagnosis and selective abortion of the affected pregnancy. Following extensive background work on the reliability of genetic diagnosis in a single cell, we offered on a research basis preimplantation diagnosis to five couples at risk for offspring with the delta-F508 mutation (the major mutation causing cystic fibrosis). There was no detrimental effect from polar body removal on either fertilization or preimplantation development. Genetic analysis, undertaken in 22 polar bodies and 15 corresponding blastomeres, identified 21 embryos of which ten were transferred.     

Phytoplankton blooms are strongly impacted by microzooplankton grazing in coastal North Pacific waters

Phytoplankton growth and microzooplankton grazing were measured in two productive coastal regions of the North Pacific: northern Puget Sound and the coastal Gulf of Alaska. Rates of phytoplankton growth (range: 0.09–2.69 day⁻¹) and microzooplankton grazing (range: 0.00–2.10 day⁻¹) varied seasonally, with lowest values in late fall and winter, and highest values in spring and summer. Chlorophyll concentrations also varied widely (0.19–13.65 μg l⁻¹). Large (>8 μm) phytoplankton cells consistently dominated phytoplankton communities under bloom conditions, contributing on average 65% of total chlorophyll biomass when chlorophyll exceeded 2 μg l⁻¹. Microzooplankton grazing was an important loss process affecting phytoplankton, with grazing rates equivalent to nearly two-thirds (64%) of growth rates on average. Both small and large phytoplankton cells were consumed, with the ratio of grazing to growth (g:μ) for the two size classes averaging 0.80 and 0.42, respectively. Perhaps surprisingly, the coupling between microzooplankton grazing and phytoplankton growth was tighter during phytoplankton blooms than during low biomass periods, with g:μ averaging 0.78 during blooms and 0.49 at other times. This tight coupling may be a result of the high potential growth and ingestion rates of protist grazers, some of which feed on bloom-forming diatoms and other large phytoplankton. Large ciliates and Gyrodinium-like dinoflagellates contributed substantially to microzooplankton biomass at diatom bloom stations in the Gulf of Alaska, and microzooplankton biomass overall was strongly correlated with >8 μm chlorophyll concentrations. Because grazing tended to be proportionally greater when phytoplankton biomass was high, the absolute amount of chlorophyll consumed by microzooplankton was often substantial. In nearly two-thirds of the experiments (14/23), more chlorophyll was ingested by microzooplankton than was available for all other biological and physical loss processes combined. Microzooplankton were important intermediaries in the transfer of primary production to higher trophic levels in these coastal marine food webs. Received: 12 November 1999 / Accepted: 4 October 2000     

Biological removal of gaseous ammonia in biofilters: space travel and earth-based applications

Gaseous NH3 removal was studied in laboratory-scale biofilters (14-L reactor volume) containing perlite inoculated with a nitrifying enrichment culture. These biofilters received 6 L/min of airflow with inlet NH3 concentrations of 20 or 50 ppm, and removed more than 99.99% of the NH3 for the period of operation (101, 102 days). Comparison between an active reactor and an autoclaved control indicated that NH3 removal resulted from nitrification directly, as well as from enhanced absorption resulting from acidity produced by nitrification. Spatial distribution studies (20 ppm only) after 8 days of operation showed that nearly 95% of the NH3 could be accounted for in the lower 25% of the biofilter matrix, proximate to the port of entry. Periodic analysis of the biofilter material (20 and 50 ppm) showed accumulation of the nitrification product NO3- early in the operation, but later both NO2- and NO3- accumulated. Additionally, the N-mass balance accountability dropped from near 100% early in the experiments to approximately 95 and 75% for the 20- and 50-ppm biofilters, respectively. A partial contributing factor to this drop in mass balance accountability was the production of NO and N2O, which were detected in the biofilter exhaust.     

Oxidation of acid-volatile sulfide in surface sediments increases the release and toxicity of copper to the benthic amphipod Melita plumulosa

Acid-volatile sulfides (AVS) are an important metal-binding phase in sediments. For sediments that contain an excess of AVS over simultaneously extracted metal (SEM) concentrations, acute or chronic effects should not result from the metals Cd, Cu, Ni, Pb and Zn. While AVS phases may exist in surface sediments, the exposure to dissolved oxygen may oxidize the AVS and release metals to more bioavailable forms. We investigated the role of oxidation of AVS, and specifically copper sulfide phases, in surface sediments, in the toxicity to juveniles of the epibenthic amphipod, Melita plumulosa. Sediments containing known amounts of copper sulfide were prepared either in situ by reacting dissolved copper with AVS that had formed in field sediments or created in sediments within the laboratory, or by addition of synthesised CuS to sediments. Regardless of the form of the copper sulfide, considerable oxidation of AVS occurred during the 10-d tests. Sediments that had a molar excess of AVS compared to SEM at the start of the tests, did not always have an excess at the end of the tests. Consistent with the AVS-SEM model, no toxicity was observed for sediments with an excess of AVS throughout the tests. However, the study highlights the need to carefully consider the changes in AVS concentrations during tests, and that measurements of AVS and SEM concentrations should carefully target the materials to which the organisms are being exposed throughout tests, which in the case of juvenile M. plumulosa is the top few mm of the sediments.     

Elevated radioxenon detected remotely following the Fukushima nuclear accident

We report on the first measurements of short-lived gaseous fission products detected outside of Japan following the Fukushima nuclear releases, which occurred after a 9.0 magnitude earthquake and tsunami on March 11, 2011. The measurements were conducted at the Pacific Northwest National Laboratory (PNNL), (46°16′47″N, 119°16′53″W) located more than 7000 km from the emission point in Fukushima Japan (37°25′17″N, 141°1′57″E). First detections of ¹³³Xe were made starting early March 16, only four days following the earthquake. Maximum concentrations of ¹³³Xe were in excess of 40 Bq/m³, which is more than ×40,000 the average concentration of this isotope is this part of the United States.     

Lymphatic transport of inhaled diesel particles in the lungs of rats and guinea pigs exposed to diluted diesel exhaust

Factors influencing the disposition of the inhaled diesel particles were studied by analyzing the deposition of radioactively labelled diesel particles in the respiratory system, by determining the specific function of alveolar cellular mechanisms in the primary defense against inhaled particles and by identifying the important role of the lymphatic system in the lung clearance of experimental animals exposed to diluted emissions from a diesel engine. Radioactive ¹³¹Barium was used as a tracer of diesel particles and the deposition efficiency was determined to be 15%±6% of the inhaled dose in the Fischer 344 rat strain. The number of cells obtained by bronchial lavage increased significantly after a prolonged exposure to a concentration of 1500 μg/m³ of diesel particles. The increased cell number was more than twofold, contained two distinct cell populations (alveolar macrophages and neutrophils) and represented a reactive mobilization of the defense mechanisms in the organism. Light microscopy studies investigated the role of lymphatic transport of the particulate matter and revealed that the peribrochial and perivascular aggregates of lymphoid tissue contained diesel particles even after short exposure periods at low dose levels. With the increasing burden of particles in the respiratory system, the coloration of hilar and mediastinal lymph nodes continuously changed to gray and finally to dark black, depending upon the dose level and exposure. However, at all exposure levels, most of the diesel particles in the alveoli were phagocytized by an increased alveolar cellular defence and particle-containing macrophages were actively moving towards the mucociliary escalator or towards lymphatic channels leading to peribronchial lymphoid aggregates and bronchial or mediastinal lymph nodes. In the lymph nodes, alveolar macrophages containing diesel particles were found mostly in the afferent subcapsular lymphatic vessels and marginal sinuses. In the later stages, cellular structure disintegrated and large aggregates of particulate matter were dispersed throughout the medullary cords with increasing accumulation towards the hilus. It is concluded that the lymphoid aggregates and lymphatic nodes play an important role in sequestering diesel particles or particle-containing phagocytizing cells and provide a pathway, in addition to the mocociliary clearance for particulate removal from the deep pulmonary region.