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George Robertson - One of the best experts on this subject based on the ideXlab platform.
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rapid nitrification of wastewater ammonium near coastal Ocean Outfalls southern california usa
Estuarine Coastal and Shelf Science, 2017Co-Authors: Karen Mclaughlin, Nikolay P Nezlin, Meredith D A Howard, Carly D A Beck, Raphael M Kudela, Michael J Mengel, George RobertsonAbstract:Abstract In the southern California Bight (SCB), there has been a longstanding hypothesis that anthropogenic nutrient loading is insignificant compared to the nutrient loading from upwelling. However, recent studies have demonstrated that, in the nearshore environment, nitrogen (N) flux from wastewater effluent is equivalent to the N flux from upwelling. The composition of the N pool and N:P ratios of wastewater and upwelled water are very different and the environmental effects of wastewater discharges on coastal systems are not well characterized. Capitalizing on routine maintenance of the Orange County Sanitation District’s Ocean Outfall, wherein a wastewater point source was “turned off” in one area and “turned on” in another for 23 days, we were able to document changes in coastal N cycling, specifically nitrification, related to wastewater effluent. A “hotspot” of ammonium (NH4+) and nitrite (NO2−) occurred over the Ocean Outfall under normal operations and nitrification rates were significantly higher offshore when the deeper Outfall pipe was operating. These rates were sufficiently high to transform all effluent NH4+ to nitrate (NO3−). The dual isotopic composition of dissolved NO3− (δ15NNO3 and δ18ONO3) indicated that N-assimilation and denitrification were low relative to nitrification, consistent with the relatively low chlorophyll and high dissolved oxygen levels in the region during the study. The isotopic composition of suspended particulate organic matter (POM) recorded low δ15NPN and δ13CPN values around the Outfall under normal operations suggesting the incorporation of “nitrified” NO3− and wastewater dissolved organic carbon into POM. Our results demonstrate the critical role of nitrification in nitrogen cycling in the nearshore environment of urban Oceans.
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liver lesions in demersal fishes near a large Ocean Outfall on the san pedro shelf california
Environmental Monitoring and Assessment, 2008Co-Authors: Edward Basmadjian, Michael J Mengel, Edwin M Perkins, Charles R Phillips, Daniel J Heilprin, Susan D Watts, Douglas R Diener, Mark S Myers, Kelly A Koerner, George RobertsonAbstract:The prevalence of toxicopathic liver lesions in demersal fish on the San Pedro Shelf, California was determined for a 15-year period (1988–2003). Fish livers were sampled at fixed locations as part of the Orange County Sanitation Districts (OCSD) Ocean monitoring program. Histopathological examination of selected fish liver tissues was studied to determine whether the wastewater discharge had affected fish health. The prevalence of toxicopathic lesion classes neoplasms (NEO), preneoplastic foci of cellular alteration (FCA), and hydropic vacuolation (HYDVAC) varied among species and locations. For all species sampled, severe lesions occurred in 6.2% of the fish examined (n = 7,694). HYDVAC (4.1%) was the most common toxicopathic lesion type followed by FCA (1.4%) and NEO (0.7%). HYDVAC occurred only in white croaker (Genyonemus lineatus), accounting for 84.8% of the toxicopathic lesions for this species. Prevalence of HYDVAC, NEO, and FCA in white croaker was 15.2, 2.0, and 0.7%, respectively. The prevalence of HYDVAC and NEO in white croaker increased with age and size but there was no sexual difference. A linear regression model was used for hypothesis testing to account for significant differences in fish size (and age for croakers) at the different sampling locations. This analysis showed that for HYDVAC there was no spatial or location effect for lesion rate or size/age of onset. For NEO, the model predicted that white croaker near the wastewater Outfall may acquire these lesions at a smaller size/younger age, and at a higher rate, than at other sites. However, this result may be biased due to the unequal size frequency distributions and the low prevalence of NEO in white croaker at the different sampling sites. Bigmouth sole (Hippoglossina stomata) had a prevalence of FCA and NEO of 1.3 and 0.35%, respectively, but the prevalence and distribution of lesions was too few for statistical testing. There was no sexual difference for lesion prevalence in hornyhead turbot (Pleuronichthys verticalis) and the prevalence of FCA and NEO was 3.4 and 0.37%, respectively. FCA prevalence increased with size in hornyhead turbot and there were no significant spatial differences for lesion rates and fish size at lesion onset. Overall, consistent spatial differences for lesion prevalence were not demonstrated and highlight the analytical difficulties of detecting a possible point source impact when the effect is rare, correlated with the size/age structure of the population, and may be caused by exposure to unknown multiple sources. Thus, the usefulness of liver histopathology as a point-source monitoring tool is best applied to where the spatial scale of impact generally exceeds the home range of the target species.
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spatial and temporal patterns of the infaunal community near a major Ocean Outfall in southern california
Marine Pollution Bulletin, 1995Co-Authors: D R Diener, S C Fuller, A Lissner, C I Haydock, Don Maurer, George Robertson, Tom GerlingerAbstract:Effects of waste water discharge from a major Ocean Outfall in Southern California to the benthic infaunal community were examined during a 5-year monitoring programme. Natural features, primarily water depth, accounted for 82% of the variability in the infaunal community, while discharge-related effects represented less than 8% of the variability. The area immediately adjacent to the diffuser had the strongest Outfall effects. Infaunal abundance showed a pattern of enhancement centred at the Outfall. Diversity was also high, indicating that the area was not characterized by a degraded community.
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long term temporal and spatial fluctuations of soft bottom infaunal invertebrates associated with an Ocean Outfall from the san pedro shelf california
International Review of Hydrobiology, 1993Co-Authors: Don Maurer, George Robertson, Tom GerlingerAbstract:Temporal (annual) and spatial fluctuations of soft-bottom invertebrates from 1977 to 1988 were reviewed and analyzed from an Ocean Outfall area on the San Pedro Shelf, California. Several dominant species which occurred throughout the monitoring period provide continuity between early sampling efforts and recent ones. Annual fluctuations in the mean number of species, abundance, diversity and biomass were generally conservative compared to spatial fluctuations. Temporal changes of note include a marked reduction in abundance and biomass between 1981 and 1984 and another decline in biomass in 1988. The former was associated with conditions of the 1982–1983 El Nino, and the latter with a shift in population dominance from a bivalve to a polychaete. Mean abundance and biomass were enhanced by the Outfall without a significant reduction in number of species. The response of the biota to the Outfall extended further upcoast (northwest) than downcoast. Several hypotheses were posed and briefly examined. These include the effects of total suspended solids generated from the Outfall, and the role of the “Three Little Pigs” (bivalve-Parvilucina tenuisculpta CARPENTER, ostracod-Euphilomedes carcharodonta (SMITH), polychaete-Capitella capitata (FABRICIUS)) in influencing benthic community structure. Finally, measures of infauna from the San Pedro Shelf were, except for abundance, very similar to those reported from other California shelf areas. Through time and space the Outfall has had limited negative effect on infaunal community structure.
Sergio A Netto - One of the best experts on this subject based on the ideXlab platform.
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multiple benthic indicators suggest low sewage impact from an Ocean Outfall in a high energy sandy shore south brazil
Ecological Indicators, 2020Co-Authors: Thabata Fernandes Cândido, Sergio A NettoAbstract:A urbanizacao de areas costeiras nao tem sido acompanhada de tratamento adequado de esgoto, e a sobrecarga de materia orgânica compromete importantes valores economicos, ecologicos e sociais suportados por esses ecossistemas. Os emissarios oceânicos podem ser uma alternativa eficaz para o destino final das aguas residuarias nas regioes costeiras, desde que devidamente instalados e monitorados. Neste estudo nos investigamos os efeitos de um pequeno emissario em uma costa arenosa e de alta energia, utilizando como indicadores esteroides sedimentares, composicao bioquimica e qualidade nutricional da materia orgânica e biodiversidade da meiofauna. Os resultados mostraram que perturbacoes fisicas predominaram nas areas proximas ao emissario, afetando as densidades da fauna e a concentracao de fitopigmentos. As maiores concentracoes de esterois sedimentares, detectados a 1000 m a NE do emissario, indicaram a influencia da hidrodinâmica local no processo de transporte e dispersao do esgoto. Nesta area, a contaminacao do esgoto alterou o estado trofico bentico e levou a uma forte diminuicao na diversidade trofica e aumento de formas oportunistas. No geral, os resultados mostraram um impacto espacial relativamente baixo e espacialmente limitado do emissario. O uso combinado de esterois fecais, estado trofico bentico e biodiversidade da meiofauna foram muito eficazes na deteccao da contaminacao de esgoto por um pequeno emissario de aguas residuarias em uma costa arenosa e de alta energia.
Thabata Fernandes Cândido - One of the best experts on this subject based on the ideXlab platform.
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multiple benthic indicators suggest low sewage impact from an Ocean Outfall in a high energy sandy shore south brazil
Ecological Indicators, 2020Co-Authors: Thabata Fernandes Cândido, Sergio A NettoAbstract:A urbanizacao de areas costeiras nao tem sido acompanhada de tratamento adequado de esgoto, e a sobrecarga de materia orgânica compromete importantes valores economicos, ecologicos e sociais suportados por esses ecossistemas. Os emissarios oceânicos podem ser uma alternativa eficaz para o destino final das aguas residuarias nas regioes costeiras, desde que devidamente instalados e monitorados. Neste estudo nos investigamos os efeitos de um pequeno emissario em uma costa arenosa e de alta energia, utilizando como indicadores esteroides sedimentares, composicao bioquimica e qualidade nutricional da materia orgânica e biodiversidade da meiofauna. Os resultados mostraram que perturbacoes fisicas predominaram nas areas proximas ao emissario, afetando as densidades da fauna e a concentracao de fitopigmentos. As maiores concentracoes de esterois sedimentares, detectados a 1000 m a NE do emissario, indicaram a influencia da hidrodinâmica local no processo de transporte e dispersao do esgoto. Nesta area, a contaminacao do esgoto alterou o estado trofico bentico e levou a uma forte diminuicao na diversidade trofica e aumento de formas oportunistas. No geral, os resultados mostraram um impacto espacial relativamente baixo e espacialmente limitado do emissario. O uso combinado de esterois fecais, estado trofico bentico e biodiversidade da meiofauna foram muito eficazes na deteccao da contaminacao de esgoto por um pequeno emissario de aguas residuarias em uma costa arenosa e de alta energia.
Charles R Phillips - One of the best experts on this subject based on the ideXlab platform.
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liver lesions in demersal fishes near a large Ocean Outfall on the san pedro shelf california
Environmental Monitoring and Assessment, 2008Co-Authors: Edward Basmadjian, Michael J Mengel, Edwin M Perkins, Charles R Phillips, Daniel J Heilprin, Susan D Watts, Douglas R Diener, Mark S Myers, Kelly A Koerner, George RobertsonAbstract:The prevalence of toxicopathic liver lesions in demersal fish on the San Pedro Shelf, California was determined for a 15-year period (1988–2003). Fish livers were sampled at fixed locations as part of the Orange County Sanitation Districts (OCSD) Ocean monitoring program. Histopathological examination of selected fish liver tissues was studied to determine whether the wastewater discharge had affected fish health. The prevalence of toxicopathic lesion classes neoplasms (NEO), preneoplastic foci of cellular alteration (FCA), and hydropic vacuolation (HYDVAC) varied among species and locations. For all species sampled, severe lesions occurred in 6.2% of the fish examined (n = 7,694). HYDVAC (4.1%) was the most common toxicopathic lesion type followed by FCA (1.4%) and NEO (0.7%). HYDVAC occurred only in white croaker (Genyonemus lineatus), accounting for 84.8% of the toxicopathic lesions for this species. Prevalence of HYDVAC, NEO, and FCA in white croaker was 15.2, 2.0, and 0.7%, respectively. The prevalence of HYDVAC and NEO in white croaker increased with age and size but there was no sexual difference. A linear regression model was used for hypothesis testing to account for significant differences in fish size (and age for croakers) at the different sampling locations. This analysis showed that for HYDVAC there was no spatial or location effect for lesion rate or size/age of onset. For NEO, the model predicted that white croaker near the wastewater Outfall may acquire these lesions at a smaller size/younger age, and at a higher rate, than at other sites. However, this result may be biased due to the unequal size frequency distributions and the low prevalence of NEO in white croaker at the different sampling sites. Bigmouth sole (Hippoglossina stomata) had a prevalence of FCA and NEO of 1.3 and 0.35%, respectively, but the prevalence and distribution of lesions was too few for statistical testing. There was no sexual difference for lesion prevalence in hornyhead turbot (Pleuronichthys verticalis) and the prevalence of FCA and NEO was 3.4 and 0.37%, respectively. FCA prevalence increased with size in hornyhead turbot and there were no significant spatial differences for lesion rates and fish size at lesion onset. Overall, consistent spatial differences for lesion prevalence were not demonstrated and highlight the analytical difficulties of detecting a possible point source impact when the effect is rare, correlated with the size/age structure of the population, and may be caused by exposure to unknown multiple sources. Thus, the usefulness of liver histopathology as a point-source monitoring tool is best applied to where the spatial scale of impact generally exceeds the home range of the target species.
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linear alkylbenzenes in muscle tissues of white croaker near a large Ocean Outfall in southern california usa
Environmental Toxicology and Chemistry, 2001Co-Authors: Charles R Phillips, Indira M Venkatesan, Timothy LinAbstract:Muscle tissues of a bottom-dwelling marine fish, white croaker (Genyonemus lineatus), collected near a large wastewater Outfall in southern California, USA, were analyzed for long-chain linear alkylbenzenes (LABs). Total LABs (summed concentrations of C11 through C14 isomers) were highest (166-748 ng g-1 wet wt) in individuals collected in the immediate vicinity of the Orange County Sanitation District (OCSD; Fountain Valley, CA, USA) Outfall diffuser, whereas relatively lower concentrations occurred in fish from mid-shelf and inshore locations at distances of 2.5 and 5 km, respectively, from the Outfall. Fish tissue LAB concentrations were roughly proportional to sediment LAB concentrations at the respective collection sites. The extent of LAB degradation, as determined by ratios of internal to external C12 isomers, did not appear to relate to LAB concentrations or sampling location. Tissue DDT and PCB concentrations were not significantly correlated with LABs and, thus, did not appear to relate to recent exposures to sewage residues from the OCSD discharge. Measurements of LAB concentrations in fish tissues may be widely applicable as a monitoring tool for interpreting exposures to sewage discharges.
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distribution of trialkylamines and coprostanol in san pedro shelf sediments adjacent to a sewage Outfall
Marine Pollution Bulletin, 2000Co-Authors: Cristina Maldonado, Charles R Phillips, Indira M Venkatesan, Josep M BayonaAbstract:Abstract The fate of sewage from the Orange County Sanitation District (OCSD) Ocean Outfall was assessed by measurements of trialkylamines (TAMs) and coprostanol (COP) in bottom sediments from the San Pedro Shelf (southern California). The wastewater discharge is an important source for steroidal sewage markers, as deduced from ratios of COP to other sterols (COP/epicoprostanol, COP/dinosterol and COP/total sterols) and from the very high concentrations of TAMs (35 μ g g−1) and COP (8.3 μ g g−1) in sediments in the immediate vicinity of the Outfall. Decreasing concentrations of both molecular markers with increased distance from the Outfall were observed, except in the north-west, which corresponds with the predominant bottom current direction in the region. The offshore portions of Newport and San Gabriel submarine canyons act as efficient traps for fine-grained sediments containing high concentrations of TAMs, which have a high clay affinity characteristic of their amphiphilic chemical properties. The TAM/COP ratio in sediments (0.3–11.2) was larger than in the effluent (0.07), indicating a relatively higher stability of TAMs than COP in sediments under prevailing oxic conditions. Because the two markers exhibit different distributions and fates, an integrated use of both markers provides an effective tool to assess the effects of wastewater discharges to the marine environment.
Tom Gerlinger - One of the best experts on this subject based on the ideXlab platform.
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effect of marine sediments associated with the orange county california Ocean Outfall on the survival and growth of juvenile neanthes arenaceodentata annelida polychaeta
Water Environment Research, 1999Co-Authors: Donald J Reish, Tom Gerlinger, Martina Fanizza, Karl Soong, Jeffrey L ArmstrongAbstract:Sediments taken from the Ocean Outfall of the County Sanitation Districts of Orange County, California, were tested for toxicity using Neanthes arenaceodentata survival and growth as the criteria to measure toxic effects. Eight experiments were conducted in which juveniles taken from a laboratory-inbred population were exposed to sediments from varying distances from the discharge. Sediment geochemical parameters measured included organic carbon, grain size, and concentrations of metals, dichlorodiphenyl trichloromethane, and polychlorinated biphenyl 1254. Controls consisted of seawater. seawater with inert silica, and sediment from control sites. Stations were grouped by their relative distance from the discharge point. Organic carbon and certain metal concentrations were greater at the discharge but not significantly different from other sites. Survival was approximately 90% in almost all test exposures. Worm growth rate. expressed as milligrams growth (dry weight) per day, was greater in animals exposed to field sediments compared to controls. This difference was attributed to the presence of organic matter in the field sediment. Results indicate that sediments from the Districts' Outfall are not toxic to this species.
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spatial and temporal patterns of the infaunal community near a major Ocean Outfall in southern california
Marine Pollution Bulletin, 1995Co-Authors: D R Diener, S C Fuller, A Lissner, C I Haydock, Don Maurer, George Robertson, Tom GerlingerAbstract:Effects of waste water discharge from a major Ocean Outfall in Southern California to the benthic infaunal community were examined during a 5-year monitoring programme. Natural features, primarily water depth, accounted for 82% of the variability in the infaunal community, while discharge-related effects represented less than 8% of the variability. The area immediately adjacent to the diffuser had the strongest Outfall effects. Infaunal abundance showed a pattern of enhancement centred at the Outfall. Diversity was also high, indicating that the area was not characterized by a degraded community.
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long term temporal and spatial fluctuations of soft bottom infaunal invertebrates associated with an Ocean Outfall from the san pedro shelf california
International Review of Hydrobiology, 1993Co-Authors: Don Maurer, George Robertson, Tom GerlingerAbstract:Temporal (annual) and spatial fluctuations of soft-bottom invertebrates from 1977 to 1988 were reviewed and analyzed from an Ocean Outfall area on the San Pedro Shelf, California. Several dominant species which occurred throughout the monitoring period provide continuity between early sampling efforts and recent ones. Annual fluctuations in the mean number of species, abundance, diversity and biomass were generally conservative compared to spatial fluctuations. Temporal changes of note include a marked reduction in abundance and biomass between 1981 and 1984 and another decline in biomass in 1988. The former was associated with conditions of the 1982–1983 El Nino, and the latter with a shift in population dominance from a bivalve to a polychaete. Mean abundance and biomass were enhanced by the Outfall without a significant reduction in number of species. The response of the biota to the Outfall extended further upcoast (northwest) than downcoast. Several hypotheses were posed and briefly examined. These include the effects of total suspended solids generated from the Outfall, and the role of the “Three Little Pigs” (bivalve-Parvilucina tenuisculpta CARPENTER, ostracod-Euphilomedes carcharodonta (SMITH), polychaete-Capitella capitata (FABRICIUS)) in influencing benthic community structure. Finally, measures of infauna from the San Pedro Shelf were, except for abundance, very similar to those reported from other California shelf areas. Through time and space the Outfall has had limited negative effect on infaunal community structure.