Eric A. Crecelius

Effect of hepatic methyl donor status on urinary excretion and DNA damage in B6C3F1 mice treated with sodium arsenite

This study evaluated the effect of hepatic methyl donor status on the ability of sodium arsenite (2.5, 5.0 and 10.0 mg/kg) administered by gavage once or on four consecutive days to induce DNA damage in male B6C3F1 mice. Maintenance on a choline-deficient (CD) diet prior to treatment resulted in mice with hepatic methyl donor deficiency (HMDD) and altered arsenical metabolism, as demonstrated by a decreased total urinary excretion of inorganic and organic arsenicals. The alkaline (pH > 13) Single Cell Gel (SCG) assay was used to evaluate for the induction of DNA damage (single strand breaks, alkali labile sites, DNA crosslinking) in blood leukocytes, liver parenchymal cells, and cells sampled from bladder, lung, and skin, while the bone marrow erythrocyte micronucleus (MN) assay was used to assess for the induction of chromosomal damage in bone marrow cells. Treatment with sodium arsenite once or four times induced a significant decrease in DNA migration (indicative of DNA crosslinking) in bladder and liver parenchymal cells of hepatic methyl donor sufficient (HMDS) mice, but in skin cells of HMDD mice. Both HMDD and HMDS mice exhibited a significant increase in the frequency of micronucleated polychromatic erythrocytes (MN-PCE) in bone marrow following four, but not following one, treatments. However, the positive response occurred at a lower dose for HMDS mice and, in these mice, bone marrow toxicity, as demonstrated by a significant reduction in the percentage of PCE, was present also. These results indicate that hepatic methyl donors deficiency significantly decreases the total urinary excretion of orally administered sodium arsenite and markedly modulates target organ arsenic-induced DNA damage, with an apparent shift from liver and bladder to skin.

Elevated arsenic concentrations in bivalves from the southeast coasts of the USA.

Abstract Since 1986, the National Oceanic and Atmospheric Administration (NOAA) National Status and Trends (NS&T) Program, Mussel Watch Project (MWP) has been analyzing contaminants in bivalves (oysters and mussels) collected along the coastal USA. Compared to the rest of the USA, the oysters collected from sites located along the southeastern coasts, from North Carolina to the Florida panhandle, display high concentrations of arsenic (As) in their soft tissues. In this area, As concentrations can be elevated in sediments and in bivalves, although exact spatial correspondence between the two is infrequent. As concentrations in waters and food (plankton and suspended particles) directly surrounding the mollusks collected in winter are not unusually high. Phosphate deposits and soil pesticide residues are the hypothesized main sources of this As, and the enrichment mechanism appears to result from a mixture of processes including atmospheric deposition, river and aquifer inputs, and ocean up-welling. In the southeast oysters, the large bio-accumulation of As may also be affected by the seasonal cycle of adsorption/solubilization of As observed in several estuarine and coastal areas, by local physico-chemical parameters such as temperature, salinity, and the nature of sediments (e.g. high contents in iron, calcium, phosphate, and organic material). Even at these very high concentrations, the As present in the southeastern oysters does not appear to present a health threat to humans or to marine life.

Sea-surface microlayer metals enrichments in an urban and rural bay☆

The sea-surface microlayer is an important interface between the atmosphere and ocean and a collection point for many anthropogenic materials including potentially toxic metals. We developed a glass plate sampler to collect the upper 30 to 55 micrometers of the sea surface. Samples of the microlayer and subsurface bulk water from an urban and rural bay were analysed for concentrations of Pb, Zn, Cu, Cd and Fe. Metal concentrations in both the microlayer and bulk water were generally 2 to 15 times greater in the urban than in the rural bay. Concentrations of metals in the microlayer of both bays averaged 6 to 65 times greater than those in the bulk water. In the urban bay, microlayer concentrations of Pb, Zn and Cu from 10 to > 100 μg 1−1 were common. Measured microlayer metals concentrations agree well with those predicted from atmospheric deposition rates using a previously derived empirical model developed from laboratory microcosm studies. Further work will be required to determine whether or not these high microlayer metal concentrations contain significant biologically available fractions which could impact fisheries recruitment of larval icthyoneuston.

Contaminant concentrations and toxicity of sea-surface microlayer near Los Angeles, California

Abstract Sea-surface microlayer samples were collected from six nearshore areas receiving different amounts of anthropogenic inputs. The samples were analyzed for selected trace metals, chlorinated hydrocarbons, and polycyclic aromatic hydrocarbons. The relative toxicities of the samples were determined with fish embryo bioassays. Contaminant concentrations generally increased from offshore to the inshore stations. Contaminant concentrations were several orders of magnitude higher in microlayer samples from the highly industrialized Los Angeles and Long Beach harbors compared to samples from a site 15km offshore. Microlayer samples from the inshore stations were significantly more toxic, and induced significantly more developmental abnormalities and chromosome aberrations, than samples from the offshore stations.

Particulate lead contamination recorded in sedimentary cores from Lake Washington, Seattle.

downtown locations.) During the mid 1950’s, stringent emission controls were applied to stationary sources in Los Angeles. Since the Sawicki study, carried out in 1958 and 1959, the stationary source control program has seen fewer changes as compared t o the earlier t ime period. T h e effect of the motor vehicle emissions control program on organic particulate mat te r is difficult to assess. Air sampling is now under way a t other sites in the Los Angeles basin.

Aquatic surface microlayer contamination in chesapeake bay

Abstract The aquatic surface microlayer (SMIC), ∼50 μm thick, serves as a concentration point for metal and organic contaminants that have low water solubility or are associated with floatable particles. Also, the eggs and larvae of many fish and shellfish species float on, or come in contact with, the water surface throughout their early development. The objectives of this study were (1) to determine the present degree of aquatic surface microlayer pollution at selected sites in Chesapeake Bay, and (2) to provide a preliminary evaluation of sources contributing to any observed contamination. Twelve stations located in urban bays, major rivers, and the north central bay were sampled three times, each at ∼5-day intervals during May 1986. Samples of 1.4–4.1 each were collected from the upper 30–60-μm water surface (surface microlayer, SMIC) using a Teflon-coated rotating drum microlayer sampler. One sample of subsurface water was collected in the central bay. At all stations, concentrations of metals, alkanes, and aromatic hydrocarbons in the SMIC were high compared with one bulk-water sample and with typical concentrations in water of Chesapeake Bay and elsewhere. SMIC contamination varied greatly among the three sampling times, but high mean contaminant levels (total polycyclic aromatic hydrocarbons, 1.9–6.2 μg 1 −1 ; Pb, 4.9–24 μg 1 −1 ; Cu, 4–16 μg 1 −1 ; and Zn, 34–59 μg 1 −1 ) were found at the upper Potomac and northern bay sites. Three separate areas were identified on the basis of relative concentrations of different aromatic hydrocarbons in SMIC samples - the northern bay, the Potomac River, and the cleaner southern and eastern portions of the sampling area. Suspected sources of surface contamination include gasoline and diesel fuel combustion, coal combustion, and petroleum product releases. Concentrations of metals and hydrocarbons, at approximately half the stations sampled, are sufficient to pose a threat to the reproductive stages of some fish and shellfish. Sampling and analysis of the surface microlayer provides a sensitive tool for source identification and monitoring of potentially harmful aquatic pollution.

The sea-surface microlayer of puget sound: Part II. Concentrations of contaminants and relation to toxicity

Abstract Many aquatic contaminants, because of low water solubility (hydrophobicity) or association with floatable particles, concentrate at the sea surface. Thirty-six samples of the sea-surface microlayer (SMIC), the upper 50 μm, were collected from sites in Puget Sound, Washington State. Sites included three urban bays, central Puget Sound, and a rural reference site. Exposure of floating fish eggs to approximately half of these samples resulted in sublethal and lethal toxic effects (Hardy et al., 1987c). Chemical analyses revealed high concentrations of contaminants in many of the samples. Major temporal and spatial differences in sea-surface chemistry occurred, but maximum (for all) and mean (for 1985) concentrations were aromatic hydrocarbons, 8030 (mean 132) μg liter−1: saturate hydrocarbons, 2060 μg liter−1: pesticides, 43·8 (mean 0·46) ng liter−1; PCBs, 3890 (mean 631) ng liter−1; and total metals, 4750 (mean 626) μg liter−1. Stepwise multivariate regression indicated that the percentage of fish eggs developing to normal live larvae decreased with increasing concentrations of a complex mixture of contaminants. Principal component analysis demonstrated that the major types of contaminants did not differ greatly in their statistical contribution to the toxicity, i.e. no single chemical was responsible for the observed toxicity. The chemical composition of the SMIC samples suggested that contamination originated from a variety of sources including atmospheric deposition, terrestrial runoff of fossil fuel combustion products, and sewage disposal.

Inorganic contaminants in Arctic Alaskan ecosystems: long-range atmospheric transport or local point sources?

The moss monitoring technique (Hylocomium splendens) for tracking environmental concentrations of atmospheric contaminants is applied to arctic Alaska. Median 1990–1992 concentrations of Pb, Cd, Cu, V, and Zn are ≤ median 1990 concentrations in northernmost parts of the Nordic/European monitoring network. Extremely low Pb concentrations (median, 0.6 μg/g) indicate that long-range atmospheric transport (LRTAP) of Pb to arctic Alaskan ecosystems is neglible. However, samples taken adjacent to a local source point (the Dalton Highway) have elevated Pb, V, and Cu. Site-specific watershed studies indicate that natural within- and between-site variability does not affect the interpretation of our Alaskan data relative to the Nordic/European network for Pb, V and Cu. Variability is greater relative to regional data for Cd and Zn, but neither LRTAP nor the Dalton Highway appear to be significant contributors to local concentrations of Cd and Zn. Pilot studies of blueberries and other selected wildlife forage foods indicate that concentrations inH. splendens are generally comparable to those in a common carbou forage lichen, but thatH. splendens may underestimate Cu and overestimate Pb, Hg, and in some cases Cd, relative to selected forage fruits. More studies of contaminants in arctic Alaskan forage foods are needed to characterize potential exposure of human and wildlife populations to airborne contaminants in this region.

Is atmospheric particulate matter inhibiting marine primary productivity

Present deposition rates of atmospheric particulate matter do not appear great enough to inhibit marine primary productivity except, perhaps, at the sea-surface microlayer. Milligram/liter quantities of air particulate matter added to seawater result in an exponential reduction in photosynthetic /sup 14/C assimilation of natural marine phytoplankton populations. Urban particles are 6 times more toxic than rural particles. The ratios of soluble trace elements from equal amounts of urban (Seattle) to rural (Quillayute) atmospheric particles are as follows: As, 112; Br, 6.4; Cr, 3.4; Cu, 3.7; Ni, 3.0; Pb, 36; V, 2.7; and Zn, 2.2.

The impact of scavenging on trace metal budgets in Puget Sound

Abstract The distributions of dissolved and particulate Mn, Pb, Cu and Zn in Puget Sound, its tributaries, and its sediments were determined to illustrate the impact of scavenging reactions on trace metal budgets of a large fjordlike estuary. About 75% of the dissolved Pb discharged into the main basin of Puget Sound was scavenged from the dissolved phase. The high particulate Pb concentrations in regions of high particulate Mn concentrations and the significant correlations between Pb and Mn concentrations on suspended particles demonstrate the importance of hydrous manganese oxide phases in scavenging dissolved Pb. Since particles are effectively retained within the main basin, scavenging results in the sedimentation of about 70% of the total Pb added to the main basin. Only isolated instances of scavenging of dissolved Cu and Zn were observed and the discharge rates of dissolved Cu and Zn from known sources were equal to their rates of advective removal within the errors of the budget. The remineralization of organically-bound particulate Cu is partly responsible for its quasi-conservative behavior within the main basin of Puget Sound. The fates of Cu and Zn are controlled mainly by physical processes such as advection and settling of particles. Advection removes about 60% of the total Cu and Zn added to the main basin while 40% is deposited in the sediments of Puget Sound.