Sewage Treatment Plant Discharges Research Articles

Chromosome aberrations in cultured central mudminnow heart cells and chinese hamster ovary cells exposed to polycyclic aromatic hydrocarbons and sediment extracts

1. Genotoxicity experiments were conducted with cultured fish cells to determine if the high frequency of epidermal papillomas observed in lemon sole from Sturgeon Bank, where a sewage treatment plant discharges, could be correlated with contamination of the sediments with chemicals such as 3,4-benzopyrene. 2. The frequency of chromosome aberrations was measured in cultured Umbra limi heart (U1-H) and Chinese hamster ovary (CHO) cells following exposure to the polycyclic aromatic hydrocarbons (PAH) 3,4-benzopyrene (BP), 1,2,5,6-dibenzanthracene (DBA), 1,2-benzanthracene (BA), and pyrene (PY), activated using S9 prepared from rainbow trout liver. 3. An increase in the chromosome aberration frequency was only observed following exposure to fish S9-activated BP in both cell lines. 4. Following exposure of the cells to both Sturgeon Bank and Spanish Bank sediment extracts, it was determined that a higher level of toxic and genotoxic activity was associated with the Sturgeon Bank sediments. 5. Since the detection of PAH genotoxicity requires the presence of S9, and since a higher level of genotoxic activity was noted following sediment extract exposures with no S9 present, this suggests that the extracts contain a complex mix of chemicals, some of which express genotoxic activity. 6. An assessment using the micronucleus test failed to indicate in vivo genotoxicity in fish collected from Sturgeon and Spanish Banks. 7. It was, therefore, difficult to associate the observed sediment genotoxicity with the previously noted high incidence of epidermal papillomas in lemon sole from this area.

An evaluation of benthic macroinvertebrate biomass methodology

This study shows that biological assessments of water quality status using biomass estimates of wet, dry, and ash-free dry weights and counts of individual organisms from a small, headwater stream in southwestern Ohio provide essentially similar results concerning the impact of a sewage treatment plant discharge. Of the indices of biotic status for the stream segment employed for data evaluation; Diversity Index (D), Community Diversity Index (d), Trophic Condition Index (TCI), and Empirical Biotic Index (EBI), the latter two provided evaluations most consistent with benchmark water chemistry and physics information concerning the trophic status of the stream. In addition, the percent composition of macro-invertebrate taxa by pollutional category; 'clean water', 'facultative', and 'pollution tolerant', as ascribed using TCI and EBI ranges for individual taxa collected in combination of Ekman grab, rock-filled basket sampler and drift net samples, proves adequate for interpretation of biotic status.

Projected Cladophora Growth in Southern Georgian Bay in Response to Proposed Municipal Sewage Treatment Plant Discharges to the Mary Ward Shoals

The impact of proposed municipal sewage treatment plant discharge to the Mary Ward Shoals has been assessed in terms of projected areal distribution, seasonal production, and linear shoreline accumulation of Cladophora. It is expected that extensive proliferation of Cladophora will occur with discharge 800 m and 1,750 m offshore from Long Point and to a lesser extent with discharge to the deeper waters 650 m off Delphi Point. These conclusions form the basis for Ontario Ministry of the Environment Southwestern Region's decision to advise against the discharge of treated sewage to the shallow waters of the Mary Ward Shoals.

Wastewater Risk Assessment

Risk assessment takes place in three broad and overlapping steps: hazard identification, risk estimation, and social evaluation. Human pathogens are of primary concern in wastewater although focus has recently shifted to chemical hazards. The relation of dose-response between hazardous substances and exposed populations can be coupled with predictions of likely dosages resulting from human exposure to polluted water to give estimates of maximal risk. This methodology was used to show that less than 0.1 cases of hepatitis A per 100,000 persons per year can reasonably be attributed to drinking treated surface water or to swimming downstream from an unchlorinated sewage treatment plant discharge.

Some chemical and physical relationships on lake ontario

Submersible recording water chemistry and current instruments were concurrently operated on a submerged tower located approximately 2.5 km offshore on Lake Ontario. This area is influenced by several large sewage treatment plant discharges with the closest discharge 1.6 km away. The instruments were 3.0 m off the bottom in 9.6 m of water and operated primarily during the months of June and November, 1970. One-thousand fivehundred and seventy-four hourly measurements were made of currents, temperature, dissolved oxygen, conductivity, pH and turbidity. The measurements were validated with field measurements by other methods. Time series analyses of the collected data showed that time variations of water chemistry for 8–15 h cannot be explained by water movements for distances of 2 km from a major waste discharge. A measure of the biological activity as well as other chemical and physical processes is required to determine concentrations of the measured chemical parameters. Current magnitudes with a mean value of 3.5–6.0 cm s −1 are not the primary mechanism responsible for the distribution of water chemistry in this location for the 8–15 h period. The need for the evolution of reliable recording chemistry instruments which can be used in the offshore regions of the lakes is clearly indicated to effect a better understanding of the near shore chemistry at distances of 2 km from known waste discharges. Long-term period (greater than 15 h) temporal variations of the measured water chemistry are related to water movement patterns.