Domestic Outfalls Research Articles

Natural and anthropogenic sterols inputs in surface sediments of Patos Lagoon, Brazil

The Patos Lagoon, the largest coastal lagoon in the world, has long been receiving considerable anthropogenic input resulting from urban, rural and industrial activities. Thus, sewage contamination possibly originating from the more than 2 million inhabitants living within its drainage basin is examined in this study. Sediment samples collected from various points along the Lagoon were extracted, purified and analysed by GC-MS. Ten different sterols and ketones, including coprostanol and epicoprostanol, were identified and quantified. The highest coprostanol concentration was found near Porto Alegre City (1,423 ng g-1 dry wt.), whilst most sediment levels ranged between < DOL and 91.78 ng g-1. The highest concentrations were found at those three sites located closest to domestic outfalls though levels tended to decrease with distance from the sources. The 5beta/(5beta+5alpha) isomeric ratios indicated sewage-contaminated sediments near Porto Alegre City, while the epicoprostanol/coprostanol ratio showed values characteristic of untreated sewage input.

Impact of storm‐water outfalls on sediment quallity in corpus Christi Bay, Texas, USA

AbstractTo determine the quality of sediments and extent of contaminant impacts, a Sediment Quality Triad (SQT) study was conducted at 36 sites in the Corpus Christi Bay, Texas, USA, system. Fifteen of the 36 sites were located near storm‐water outfalls, but 13 other sites (i.e., industrial and domestic outfalls, oil field–produced water discharges, and dredging activity) and eight reference sites were also evaluated. Sediment samples were collected and analyzed for physical–chemical characteristics, contaminant concentrations (metals, polycyclic aromatic hydrocarbons [PAHs], polychlorinated biphenyls [PCBs], and pesticides), toxicity (amphipod and mysid solid phase and sea urchin pore‐water fertilization and embryological development tests), and a benthic index of biotic integrity (BIBI) composed of 10 independent metrics calculated for each site. This large data matrix was reduced using multivariate analysis to create new variables for each component representing overall means and containing most of the variance in the larger data set. The new variables were used to conduct the correlation analysis. Toxicity was significantly correlated with both chemistry and ecological responses, whereas no correlations between the benthic metrics and sediment chemistry were observed. Using the combined information from the SQT, four of the five most degraded sites were storm‐water outfall sites. Although estuaries are naturally stressful environments because of salinity and temperature fluctuations, this ecosystem appears to have been compromised by anthropogenic influences similar to what has been observed for other heavily urbanized bay systems along the Texas and Gulf coast.

Spatial and temporal distributions of aromatic petroleum hydrocarbons in the coastal waters of Bahrain

A comprehensive field study of the levels of aromatic petroleum hydrocarbons in water was conducted throughout the coastal areas of Bahrain in the Arabian Gulf. Fifty monitoring stations were established, and each station was visited twice during the investigation. Monitoring stations included industrial, ports, marinas and mooring stations, public beaches and residential stations, domestic outfall stations, and remote ‘background’ stations. The results of the survey revealed marked temporal and spatial variations in petroleum hydrocarbons concentrations in the sea water analyzed. The highest overall mean value was 88.5 μg/L measured in industrial areas and the lowest was 16.1 μg/L chrysene equivalent at remote stations. Generally, levels of petroleum hydrocarbons were high in all stations compared to other coastal areas in the Gulf, indicating a chronic oil pollution problem. The results revealed significant temporal variations, however, no specific patterns could be identified.

Some comparative marine chemistries of rhenium, gold, silver and molybdenum

Four metals, Re, Au, Ag and Mo, whose dissolved forms in seawater can potentially be reduced to insoluble states, have been measured in a variety of solids depositing under anoxic conditions: hydrothermal sulfides; coastal sediments; and phosphorites. For comparative purposes these elements have also been determined in ferromanganese minerals and pelagic sediments which have accumulated under oxidizing conditions. Rhenium appears to be a unique sentinel for identifying reducing depositional environments, where enrichments of greater than three orders of magnitude above crustal concentrations are found. Molybdenum follows Re in these sediments but Mo is enriched also in those that accumulate under oxidizing conditions. The reported Mo crustal concentrations appear low in comparison to our measured sedimentary values. Gold and Ag are concentrated in hydrothermal deposits and sulfides appear to be involved in the precipitation of these elements. Coastal sediments adjacent to a domestic outfall of Los Angeles, California contain extraordinary high accumulations of anthropogenic Au, Ag and Pt. The study seeks an understanding of the mobilities and sinks of these metals in the marine environment during the major weathering cycle. Further, anthropogenic contributions to their sedimentary concentrations are identified.

The effects of varying concentrations of nutrients, chlorinity, and dissolved oxygen on polychaetous annelids

The effects of varying concentrations of known environmental variables around marine domestic outfall sewers were studied on four species of polychaetous annelids which have been employed as indicators of varying degrees of marine pollution. The variables included increased concentrations of phosphates, nitrates, and silicates and decreased concentrations of chlorinity and dissolved oxygen. These factors were measured individually, the 3 nutrients together, and all 5 variables together. Data were expressed in the form of 28 day tl m values. Nereis grúbei, the healthy zone indicator, was most sensitive species studied. In general, the tolerances of the two semi healthy zone indicators and polluted zone indicator were similar. Comparisons of the 28 day tl m values with the concentrations of these factors present at the bubble of the Orange County, California, outfall sewer showed that these four species would be unaffected directly by the altered conditions in the waste discharge.

An ecological study of the algae of the Saline River, Michigan

1. The algal vegetation of the Saline River, Michigan, U.S.A. was studied throughout a period of eighteen months in 1951–1953, with exact qualitative and quantitative records maintained throughout a fourteen-month period. Determinations were made at regular intervals of a variety of environmental physico-chemical variables which may be supposed to influence algal growth. 2. The upper course of the Saline River is unpolluted and mildly alkaline, has a high bicarbonate content, usually abundant nutrients, and has an algal vegetation which includes Cladophora glomerata in spring, Diatoma vulgare and Gomphonema olivaceum in winter, and a calcified Phormidium-Schizothrix community which is present throughout the year. 3. The lower course of the river was influenced by industrial wastes and sewage entering the river principally at Saline and Milan. Below the industrial outfall at Saline the water contained chromium, and other toxic ions, and the flora of the upper course had disappeared almost entirely, being replaced by a luxuriant flora of Stigeoclonium tenue and other species. Below the domestic outfall at Saline, the summer riffle vegetation was dominated by the bacterium Sphaerotilus and the diatom Nitzschia palea; at other seasons Stigeoclonium tenue, Tetraspora, and Navicula atomus were present on riffles whereas the pools were dominated by Spirogyra spp. 4. No marked change was observed in the flora of the middle course of the stream between Saline Mills and Milan. Below Milan, Cladophora returned to the stream flora within a single riffle. A massive accession of sewage at Milan polluted the stream again at this riffle, and the stream remained polluted for the remainder of its course. 5. The periodicity of the principal algae is described and is summarized in figures 8–13. 6. The following organisms are markedly resistant to the presence of chromium and other polluting ions; possibly also they profit from the presence of one or more of these pollutants: Stigeoclonium tenue, Tetraspora sp., Closterium acerosum, Nitzschia palea, N. linearis, Navicula atomus, Navicula cuspidata, Euglena sociabilis, E. viridis, E. acus, E. oxyuris, E. stellata.