Municipal Outfalls Research Articles

PBDE and PCB accumulation in benthos near marine wastewater outfalls: The role of sediment organic carbon

Polybrominated diphenyl ethers (PBDEs) and polychlorinated biphenyls (PCBs) were measured in sediments and benthic invertebrates near submarine municipal outfalls in Victoria and Vancouver, B.C., Canada, two areas with contrasting receiving environments. PBDE concentrations in wastewater exceeded those of the legacy PCBs by eight times at Vancouver and 35 times at Victoria. Total PBDE concentrations in benthic invertebrates were higher near Vancouver than Victoria, despite lower concentrations in sediments, and correlated with organic carbon-normalized concentrations in sediment. Principal Components Analysis indicated uptake of individual PBDE congeners was determined by sediment properties (organic carbon, grain size), while PCB congener uptake was governed by physico-chemical properties (octanol-water partitioning coefficient). Results suggest the utility of sediment quality guidelines for PBDEs and likely PCBs benefit if based on organic carbon-normalized concentrations. Also, where enhanced wastewater treatment increases the PBDEs to particulate organic carbon ratio in effluent, nearfield benthic invertebrates may face increased PBDE accumulation.

Responses of infaunal composition, biomass and production to discharges from a marine outfall over the past decade

The largest municipal outfall on the west coast of Canada discharges into the southeastern Strait of Georgia, where high sedimentation from the Fraser River has maintained stable sediment geochemical and contaminant conditions from 2001 to 2011. Outfall exposure has not affected trophic structure or diversity (H′), but has significantly affected faunal composition and species richness, resulting in loss of crustaceans and echinoderms near-field. Organic biomass and production have mostly remained within expected background ranges for the Strait, due to recent increases in a low oxygen tolerant polychaete in the high deposition zone.A significant regional shift in faunal composition occurred after 2003, followed by gradual declines in richness, abundance, calcareous organisms and production. This cannot be attributed to changes in outfall exposure, but is exaggerated by it. We hypothesize that changing river flow, extreme events and shifts in offshore upwelling water temperature, oxygen and pH may be increasing geochemical stress in benthos.

Effect of receiving environment on the transport and fate of polybrominated diphenyl ethers near two submarine municipal outfalls

The fate of contaminants entering the marine environment through wastewater outfalls depends on the contaminant's persistence and affinity for particles. However, the physical characteristics of the receiving environment, for example, current velocity and sedimentary processes, may be even more important. Because of the complexity of natural settings and the lack of appropriate comparative settings, this is not frequently evaluated quantitatively. The authors investigated the near-field accumulation of particle-reactive polybrominated diphenyl ethers (PBDEs) entering coastal waters by way of two municipal outfalls: one discharging into a high-energy, low-sedimentation environment near Victoria, BC, Canada; the other into a low-energy, high-sedimentation environment, near Vancouver, BC. The authors used ²¹⁰Pb profiles in box cores together with an advection-diffusion model to determine surface mixing and sedimentation rates, and to model the depositional history of PBDEs at these sites. Surprisingly, 88 to 99% of PBDEs were dispersed beyond the near-field at both sites, but a greater proportion of PBDEs was captured in the sediment near the Vancouver outfall where rapid burial was facilitated by inorganic sediment supplied from the nearby Fraser River. Although the discharge of PBDEs was much lower from the Victoria outfall than from Vancouver, some sediment PBDE concentrations were higher near Victoria.

Anthropogenic nexus on organochlorine pesticide pollution: a case study with Tamiraparani river basin, South India

The levels of 17 organochlorine pesticides residues (OCPs) in surface water and sediments from Tamiraparani river basin, South India were investigated to evaluate their potential pollution and risk impacts. A total of 96 surface water and sediment samples at 12 sampling stations were collected along the river in four seasons during 2008-2009. The ΣOCP concentrations in surface water and sediments were in the range of 0.1 to 79.9 ng l(-1) and 0.12 to 3,938.7 ng g(-1) dry weight (dw), respectively. Among the OCPs, the levels of dichlorodiphenyltrichloroethanes (DDTs), aldrin, dieldrin, cis-chlordane, trans-chlordane, and mirex were dominant in the sediments. The dominant OCPs in water samples are heptachlor, o,p'-DDE, dieldrin, o,p'-DDD, and mirex, which show different source of contamination pattern among sampling seasons. The distribution pattern of DDTs, hexachlorocyclohexane, and other OCPs in the present study shows heterogenic nature of nonpoint source of pollution. Notable contamination of water and sediment sample that was observed in upstream (S2) 58 ng l(-1) and downstream (S11) 1,693 ng g(-1) dw explains agricultural and municipal outfalls, whereas frequent damming effect reduces the concentration level in the midstream. The overall spatial-temporal distribution pattern of ΣOCP residues are illustrated by GIS package.

Relationship between mRNA biomarker candidates and location near a marine municipal wastewater outfall in the benthic indicator species Modiolus modiolus (L.)

The deep-sea horse mussel Modiolus modiolus (L.) is a sentinel bivalve species used for the assessment of potential biological exposure to anthropogenic contaminants in benthic environments. Using a combination of endpoints that included gross biological metrics, reproductive status, tissue contaminant load, and mRNA abundance profiles, we characterized variation in the local M. modiolus population situated in different spatial zones relative to a municipal wastewater outfall. Significant differences were observed in reproductive indicators, growth parameters, and abundance of four specific mRNA transcripts representative of stress response or membrane transport ( CAT, NET/SCF6, ABCA4 and HSP70) in adductor muscle tissue of animals adjacent to the wastewater outfall. Concentrations of metals and organic chemicals in M. modiolus tissue were generally highest directly at the outfall site with much lower levels at 100–800 m from the outfall. This general pattern did not match the mRNA profiles. HSP70 and ABCA4 mRNA showed increased abundance in all regions adjacent to the municipal outfall compared to the reference site. One site group located within 100–200 m south/south-easterly of the outfall had increased levels of all four transcripts. Some mRNAs showed significant correlations with nickel, arsenic, lead, selenium, copper, and one of thirteen polycyclic aromatic hydrocarbons measured (dibenzo(a,h)-anthracene). Three mRNAs ( CAT, NET/SCF6, and ABCA4) were negatively correlated with bis(2-ethylhexyl)phthalate. The data suggest that these benthic organisms are exhibiting biological responses to the outfall and support an alternate interpretation regarding dispersal of contaminants. The potential effects of emerging chemicals of concern entering the receiving environment merits further assessment.

Predictive modeling of selenium accumulation in brine shrimp in saline environments

Great Salt Lake, Utah, is a large, terminal, hypersaline lake consisting of a northern more saline arm and a southern arm that is less saline. The southern arm supports a seasonally abundant fauna of low diversity consisting of brine shrimp (Artemia franciscana), 7 species of brine flies, and multiple species of algae. Although fish cannot survive in the main body of the lake, the lake is highly productive, and brine shrimp and brine fly populations support large numbers of migratory waterfowl and shorebirds, as well as resident waterfowl, shorebirds, and gulls. Selenium and other trace elements, metals, and nutrients are contaminants of concern for the lake because of their concentrations in municipal and industrial outfalls and runoff from local agriculture and the large urban area of Salt Lake City. As a consequence, the State of Utah recently recommended water quality standards for Se for the southern arm of Great Salt Lake based on exposure and risk to birds. The tissue-based recommendations (as measured in bird eggs) were based on the understanding that Se toxicity is predominately expressed through dietary exposure, and that the breeding shorebirds, waterfowl, and gulls of the lake are the receptors of most concern. The bird egg-based recommended standards for Se require a model to link bird egg Se concentrations to their dietary concentrations and water column values. This study analyzes available brine shrimp tissue Se data from a variety of sources, along with waterborne and water particulate (potential brine shrimp diet) Se concentrations, in an attempt to develop a model to predict brine shrimp Se concentrations from the Se concentrations in surrounding water. The model can serve as a tool for linking the tissue-based water quality standards of a key dietary item to waterborne concentrations. The results were compared to other laboratory and field-based models to predict brine shrimp tissue Se concentrations from ambient water and their diet. No significant relationships were found between brine shrimp and their dietary Se, as measured by seston concentrations. The final linear and piecewise regression models showed significant positive relationships between waterborne and brine shrimp tissue Se concentrations but with a very weak predictive ability for waterborne concentrations<10 µg/L.

Environmental fractionation of PCBs and PBDEs during particle transport as recorded by sediments in coastal waters

The Strait of Georgia (British Columbia, Canada) is a hydrologically complex inland sea with a rich abundance and diversity of species of aquatic life. Marine sediments, as both a sink for hydrophobic contaminants and a potential source for aquatic food webs, were collected from 41 sites throughout the 6,900-km(2) Strait of Georgia. The congener-specific concentrations of polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs), including BDE-209, were measured. Urban harbors represented hotspots for both PCBs and PBDEs, whereas PBDEs were also found at high concentrations near municipal outfalls. Patterns of PCB distribution were consistent with historical point source emissions in urban areas and environmental distillation toward lighter profiles in remote sites over time. The single congener BDE-209 dominated the PBDEs, accounting for 52% of the average total concentration. However, nonurban deep-water sediment PBDE profiles were both heavier and had higher concentration-weighted average log K(OW) (octanol-water partition coefficient) values compared to shallow samples (percent BDE-209 of total PBDE, 66 versus 32%; log K(OW) , 9.5 versus 8.2, respectively). Collectively, our results suggest that although source signals largely explain PCB and PBDE hotspots in the Strait of Georgia, the combination of physicochemical properties and environmental processes drive divergent compositional fates for the PCBs and the heavier PBDEs in the sediments of the Strait of Georgia.

A Preliminary Canadian Environmental Emissions Inventory for Endogenous and Retail Pharmaceutical Estrogens

ABSTRACT Pharmaceuticals and personal care products (PPCPs), including estrogen pharmaceuticals, have been an environmental concern for well more than a decade, but no environmental emissions inventory for Canada has yet been published. Endogenous estrogens cannot be distinguished from the equivalent pharmaceutical estrogens in the environment. Therefore, data were compiled to estimate total environmental emissions of endogenous and retail pharmaceutical estrogens by the Canadian population for year 2007. Approximately 1,700 kg of pharmaceutical estrogens were dispensed through retail pharmacies in Canada in 2007. Of this amount, total environmental emissions were estimated to be approximately 730 kg, half to surface water via municipal sewage outfalls (> 90% via sewage treatment plants providing primary, secondary, or tertiary treatment), and half to the soil vadose zone and (potentially) groundwater via in situ sewage treatment systems. Approximately 960 kg of endogenous estrogens were excreted by the Canadian population, with about 420 kg reaching the environment, again approximately half to each of surface water and soil/groundwater. In situ sewage treatment may deliver an equivalent load of estrogens to the environment as do sewage treatment plants, despite servicing only 22% of the Canadian population.

Patterns of Bioaccumulation of Polybrominated Diphenyl Ether and Polychlorinated Biphenyl Congeners in Marine Mussels

Marine mussels (Modiolus modiolus) and sediment from 14 stations near a municipal outfall and three reference locations were analyzed for polybrominated diphenyl ethers (PBDEs) and polychlorinated biphenyls (PCBs) to evaluate and compare patterns of bioaccumulation of individual congeners between these two groups of chemicals. Of the 47 PBDEs and 209 PCBs analyzed, 34 PBDE and 153 PCB congeners or coeluting groups of congeners were detected in one or more matrices. The predominant PBDE congeners were BDEs 47, 99, 100, and 209, accounting for 80-90% of the total PBDEs in all matrices. PCBs and PBDEs exhibited a parabolic relationship of the biota-sediment accumulation factor (BSAF) versus the log octanol-water partition coefficient(Kow). Below Kow 10(5.5), BSAFs ranged between 1 and 3, reflecting approximate equilibrium between mussels and sedimentforthese relatively water soluble congeners. BSAFs increased with increasing Kow to maximum values of approximately 30-100 for congeners with Kow approximately 10(7) and then declined at higher Kow to a value of approximately 1 for BDE 209. BSAFs for PBDEs were generally 2- to 3-fold higher than those for PCBs of a similar Kow. The calculated BSAFs for PBDE congeners indicate that PBDEs have a pattern of bioaccumulative behavior in mussels similar to that of the PCBs, and that some PBDE congeners may be more bioaccumulative in mussels than PCBs.

Estrogenic activity and reproductive effects of the UV-filter oxybenzone (2-hydroxy-4-methoxyphenyl-methanone) in fish

Previous studies in extracts of sediments surrounding municipal outfalls off the coast of California, USA and effluents of New York City, NY, USA indicated the UV-filtering agent, oxybenzone (CAS# 131-57-7; benzophenone-3) as a potential estrogen. The effects of oxybenzone on estrogenic activity and reproduction were evaluated using a 14-day juvenile rainbow trout assay for plasma vitellogenin and a subsequent 21-day Japanese medaka reproduction assay. Significant induction of vitellogenin was observed in the rainbow trout at the 1000 μg/L nominal concentration (749 μg/L median measured value) of oxybenzone which was approximately 75 times greater than the concentrations observed in previous wastewater effluent. Vitellogenin induction was also observed in the 1000 μg/L nominal concentration (620 μg/L median measured) of oxybenzone in male Japanese medaka ( Oryzias latipes) after 21 days of exposure. The number of eggs produced per female per day exposed to the same concentration (620 μg/L) were significantly lower after 7 days, but returned to control values after 21 days. Fertilized eggs were then monitored for 20 days to assess hatching success. The overall percentage of fertilized eggs collected during the 21-day exposure that hatched was significantly lower in the 620 μg/L oxybenzone concentration. There was also a temporal effect at this concentration as egg viability (percentage of fertilized eggs that hatched) was diminished 13–15 days after eggs were collected. All three oxybenzone concentrations (16, 132, and 620 μg/L) and the 50 ng/L estradiol positive control showed reduced hatching of eggs at day 15, and the 132 and 620 μg/L oxybenzone concentrations diminished the percentage of eggs that hatched on days 13–15. These data indicate that the UV-filter oxybenzone alters endocrine or reproduction endpoints in two fish species, but at concentrations significantly higher than those measured in the environment.

Sediment redox tracers in Strait of Georgia sediments – Can they inform us of the loadings of organic carbon from municipal wastewater?

Organic carbon composition and redox element (Mn, Cd, U, Re, Mo, ΣS, AVS) distributions are examined in seven 210Pb-dated box cores collected from the Strait of Georgia, British Columbia to evaluate the potential for redox elements to reveal impacts of anthropogenic loadings of labile organic carbon to sediments. In particular, the cores have been collected widely including regions far from local anthropogenic inputs and from locations within the zone of influence of two municipal outfalls where sediments are exposed to enhanced organic loadings from outfalls. We find a wide natural range in organic carbon forcing within the basin sediments generally reflected as Mn enrichments near the surface in cores exhibiting slow organic oxidation and sulphide, Cd, Mo, U and Re enrichments in cores exhibiting higher organic oxidation rates. Concentration profiles for redox elements or organic carbon are misleading by themselves, as they are influenced strongly by sediment porosity and sedimentation rate, and the organic matter remaining in sediment cores is predominantly recalcitrant. Fluxes of redox elements together with rates of organic metabolism estimated from sedimentation rates provide a better picture of the organic forcing. One core, GVRD-3, collected within the zone of influence of the Iona municipal outfall (0.5 km away), exhibits the highest organic carbon oxidation rates, enhanced Ag fluxes in the sediment surface mixed layer and altered δ 15N composition, all of which implicate outfall particulates. Cd is also elevated in the GVRD-3 surface sediments, but evidence points to contamination and not redox forcing supporting this observation. Uranium also shows enrichment at sites near the outfalls, possibly in response to enhanced microbial metabolism. Predominantly these cores exhibit a wide natural range of organic carbon fluxes and organic carbon oxidation rates, supported by fluxes of marine and terrigenous organic carbon, within which it is difficult to identify any significant impact from municipal outfall organic carbon.

Axinopsida serricata shell encrustation: A potential indicator of organic enrichment conditions in sediments in the southern Strait of Georgia, British Columbia, Canada

We evaluate the potential of the geographic and within-sediment distribution patterns of rust-coloured shell encrustations on an abundant subtidal bivalve, Axinopsida serricata (Carpenter, 1864) as geochemical indicators of organic enrichment from marine municipal outfalls. The progressive development of shell encrustation over the life of the animals is suggested by heavier encrustations on large shells compared to smaller shells regardless of the geochemical conditions of the habitat. Heavy encrustations decline in an exponential manner at sediment acid volatile sulphide (AVS) levels >7 μmol/g. Analyses show that the reddish shell encrustations are from an amorphous iron oxide or hydroxy-oxide likely micro-biologically mediated; the oxides appear to be embedded within the inner matrix of an organic layer, with a chemically distinct outer layer. A schematic model is proposed which shows how enrichment of labile organic carbon around outfalls affects the availability of dissolved iron in sediments and leads to less extensive encrustations on bivalve shells. Predominantly sandy sediments with low organic loading have much less potential for iron oxide deposition than silty sediments due to greater oxygen penetration into the surface sediment. Shell encrustation appears to be relatively persistent and indicative of long-term conditions, regardless of spatial and temporal fluctuations in sediment geochemistry. With more research on development over the life-cycle of the animal, the pattern of A. serricata shell encrustation has the potential to rapidly provide a map of cumulative labile organic loading and oxygen penetration of sediments around municipal outfalls on the west coast of North America where this species is common. However, caution must be used in interpreting results, since background sediment characteristics (substrate type, bottom currents and sediment transport) can affect encrustation patterns.

Biogeochemical cycling in the Strait of Georgia

The papers in this special issue present the results of a five-year project to study sedimentary biogeochemical processes in the Strait of Georgia, with special emphasis on the near-field of a large municipal outfall. Included in this special issue are overviews of the sedimentology, benthic biology, status of siliceous sponge reefs and distribution of organic carbon in the water column. Other papers address the cycling of contaminants (PCBs, PBDEs) and redox metals in the sediment, a method to map the extent of the influence of municipal effluent from staining on benthic bivalves, and the relationships among geochemical conditions and benthic abundance and diversity. The latter set of papers addresses the role of municipal effluent as a pathway of organic carbon and other contaminants into the Strait of Georgia and the effect of the effluent on benthic geochemistry and biology.

Energetics of the Beamed Zombie Turbulence Maser Action Mechanism for Remote Detection of Submerged Oceanic Turbulence

Sea surface brightness spectral anomalies from a Honolulu municipal outfall have been detected from space satellites in 200 km areas extending 20 km from the wastewater diffuser (Leung and Gibson 2004, Bondur 2005, Keeler et al. 2005, Gibson et al. 2006). Dropsonde and towed body microstructure measurements show greatly enhanced viscous and temperature dissipation rates above the outfall trapping-layer. Fossil-turbulencewaves (FTWs) and secondary zombie-turbulence-waves (ZTWs) break as they propagate near-vertically and then break again near the surface to produce wind-ripple smoothing with narrow-wavelength λ patterns from the soliton-like internal waves that supply turbulence energy to advected outfall fossils and to the ZTWs they radiate. The λ = 30-250 m solitons reflect an efficient maser-action conversion of horizontal tidal and current kinetic energy by bottom boundary layer turbulence events to near-vertical FTWs with λ the Ozmidov scale of the events at fossilization. Secondary (zombie) turbulence amplifies, channels in chimneys, and near-vertically beams ambient internal wave energy at scales λ just as energized metastable molecules amplify and beam quantum wavelengths in astrophysical lasers and masers around stars. Kilowatts of buoyancy power from the treatment plant produce fossil turbulence patches trapped below the thermocline. Beamed zombie turbulence maser action (BZTMA) in mixing chimneys amplifies these kilowatts into the megawatts of surface turbulence dissipation required to affect brightness on wide sea surface areas. The BZTMA vertical mixing mechanism appears critical to vertical oceanic transport of information, heat, mass and momentum, and to the conversion of barotropic tides to baroclinic tides.

Autonomous Environmental Water Quality Monitoring—The Future of Continuous Flow Analysis

Biochemist and hospital laboratory supervisor Leonard Skeggs’ burst of insight in the early 1950s that ‘. . .[manually intensive clinical] analyses could be done in a continuously flowing stream’[1] launched, and to a large extent defined, the field of automated clinical diagnostic testing for the quarter century that followed. Segmented analytical streams, in which air bubbles enhance within-segment mixing and minimize between-segment mixing, are the hallmark of Skeggs’ continuous flow (CF) analysis concept.[2] In 1975, Jaromir Ruzicka and Elo Hansen demonstrated the feasibility of performing CF analysis in non-air-segmented analytical streams.[3] This new approach to CF analysis, which they named flow injection analysis (FIA), launched a new wave of research and development directed primarily at bench-top analysis and environmental, industrial and pharmaceutical process monitoring applications. As described in this Research Front, CF analysis technology that has accrued over the past half century is well poised to meet global water quality monitoring needs in the present century. Terrestrial, estuarine and coastal waters are adversely impacted by substantial anthropogenic nutrient loads they receive from fertilized cropland runoff, confined animal feeding operation discharges, and municipal sewage outfalls. Globally burgeoning nutrient loads promote unsightly eutrophication and occasional ‘fish kills’ in freshwater regimes, and their entry into estuaries and gulfs at the terminus of major river systems drives a reduced dissolved oxygen condition known as hypoxia,[4] which threatens shallowwater fisheries in coastal areas. Excessive nutrient inputs into coastal waters can also trigger blooms of harmful algal species whose toxins are concentrated in fish and shellfish consumed by marine mammals and humans. In the United States, for example, the Chesapeake Bay Foundation identified nitrogen and phosphorus as ‘the Bay’s two primary pollutants’ in its 2004 State of the Bay report.[5] In light of the global proliferation of nutrients-as-contaminants, articles included in this Research Front, including a review of nutrient monitoring by CF analysis techniques,[6] and papers

Alteration of the biochemical properties of female gonads and vitellins in the clam Mya arenaria at contaminated sites in the Saguenay Fjord

Vitellins (Vn) are the major egg yolk proteins that constitute an important energy reserve for mollusc embryos. The purpose of the present study was to examine whether the relative levels of sugars, lipids, phosphates, and labile IIb metals and calcium normally associated with Vn would differ in clam populations living at contaminated sites. Softshell clams ( Mya arenaria) were collected at three sites in the area of the Saguenay Fjord: a marina, a municipal sewer outfall zone, and a reference site. The condition factor (weight:length ratio), metallothionein-like proteins, cytochrome P450 1A1 activity and DNA damage were all determined in the clam's digestive gland. Levels of total sugars, lipids, alkali-labile phosphates, proteins, and labile zinc and calcium were determined in female gonad homogenates and in purified Vn. The results show that clam gonads at the contaminated site by a marina displayed a lower index of gonad activity than the reference site. In addition, the condition factor was significantly lower at the marina site as compared to the reference site, with a concomitant increase in DNA damage and metallothionein (MT) induction. In fact, the condition factor was significantly correlated with DNA damage ( R=−0.413, P=0.045) and MT levels ( R=−0.622, P=0.03). Homogenates of female gonads were found to contain higher levels of labile IIb metals and calcium, with lower lipid content at the marina site compared to the reference site, and much higher levels of alkali-labile phosphates (ALP) and calcium at the municipal outfall site. Vn from the marina site were significantly higher in labile IIb metals but lipid content appeared to be somewhat lower than at the reference site. Vn from the municipal site were found to be highly phosphorylated, with higher levels of lipids and calcium. These results suggest that the chemical composition of the gonads and Vn are altered in contaminated sites.

Occurrence of compounds estrogenic to freshwater mussels in surface waters in an urban area.

Estrogens play a major role in the sexual differentiation, gonad development, and oocyte growth of most oviparous organisms. They also stimulate vitellogenesis, the formation of high-density glycolipophosphoprotein that serves as an energy source for the developing embryo. Surface waters from the St. Lawrence River, obtained in the vicinity of an urban area (Montreal, Quebec, Canada), were studied with respect to their estrogenic potential to the freshwater mussel Elliptio complanata. Estrogenicity was measured in water extracts by means of a competitive assay of estradiol binding to cytosolic proteins and by the vitellin-inducing ability of mussel hemolymph following direct extract injection. Surface-water samples drawn downstream of a municipal outfall plume and in a river draining a large farming and agricultural area had high levels of total and fecal coliform bacteria. High levels of estrogen competitors were also found and were able to induce vitellins in injected mussels. Moreover, the estrogen-competing potential of the extracts was found to be significantly correlated with total and fecal coliform bacteria (R = 0.9, p < 0.01) and with the levels of vitellins in the hemolymph (R = 0.62, p = 0.03). The results indicate that water samples drawn from within the municipal effluent plume and from a river draining an agricultural area are estrogenic to freshwater mussels. Thus, the environmental inputs of estrogens are likely to be associated with human sewage and pesticide products.

Evaluation of Contaminated Sediments by Toxicity Characteristic Leaching Procedure Extraction Techniques

The metals Cr, Cu, Hg, Pb, and Zn were measured by using the Total Characteristic Leaching Procedure (TCLP) extracts from sediment samples taken from Bayou d'Inde, southwestern Louisiana. Bayou d'Inde has been severely contaminated by numerous industrial and municipal outfalls along its length. Fishing advisories have been posted to prevent excessive consumption of fish caught within the bayou. Sediment samples were crushed and allowed to pass through a 20-mesh sieve (<0.85 mm), well below the maximum particle size of 9.5 mm mandated by the TCLP extraction procedure. Despite the small particle size used in this study and the extraction of heavy metals from contaminated sediments, none of the studied metals in the extracts exceeded the U.S. Environmental Protection Agency limits of 100 times the maximum contaminant levels given in the primary and secondary drinking water standards.

Persistence of Nonylphenol Ethoxylate Surfactants and Their Primary Degradation Products in Sediments from near a Municipal Outfall in the Strait of Georgia, British Columbia, Canada

Marine sediment cores and surface grabs were collected from the Strait of Georgia, British Columbia, Canada, near the Iona municipal outfall and were analyzed for nonylphenol (NP) and its ethoxylate compounds (NPnEOs). We used normal-phase liquid chromatography with electrospray mass spectrometric detection to determine concentrations of ethoxylates from n = 1 to n = 19. Over half the NPnEO inventory in marine sediments resides in ethoxylates of chain length greater than n = 2, suggesting that analyses limited to short-chain ethoxylates (n = 2) are under-reporting total NPnEO by a factor of 2. The NPnEO vertical profiles and oligomer distributions in dated sediment cores suggest that little degradation occurs once these compounds enter the sediments: the half-life for these compounds is estimated to be greater than 60 yr. The lack of change in NPnEO oligomer distribution with age suggests that degradation by chain shortening does not occur significantly. A rough inventory shows that over 30 t of NPnEO re...

Distribution of BOD and bacteria along the coast of the Us-Mexico border

Biochemical oxygen demand (BOD) and total coliform bacteria (TCB) from the Tijuana municipal outfall were analyzed from six surface samplings (5-7 February and 30 June to 2 July 1987), conducted along the coast between the US-Mexico border and north of Rosarito, Baja California. This study was carried out under two oceanographic conditions: with a littoral transport towards the South (February) and north (July). Results indicate that BOD and TCB surface distribution patterns remained relatively constant during the sampling periods, indicating a short-term (three-day) stationary plume. However, spatial distribution showed seasonal differences, with the highest concentrations of BOD (55 mg 1–1) and TCB (1,350,000 MPN 100 ml–1) occurring in summer. The surface distribution of the variables identifies a long- and offshore dispersion of matter, predominantly towards the South-southeast, indicating that the outfall is the principal source of BOD and TCB. Based on the physicochemical factors associated with the dispersion and degradation of the organic-bacteriological matter, it is unlikely that the surface outfall of the effluent from the San Antonio de los Buenos treatment plant, 9 km South of the border, affects the coasts of San Diego, California. The relatively high concentrations of BOD (2.0 mg 1–1) and TCB (1,000 MPN 100 ml–1) at the US border are due to sources from the north and non-point outfalls along the coast of Playas de Tijuana.