Lake Pontchartrain

McEall JA, Antoine SR, DeLeon IR. 1985. Organics in the water column of Lake Pontchartrain. 

A maximum trichloroethylene level of 9.9 ppb was found in sediment from Liverpool Bay, England (Pearson and McConnell 1975). Sediment levels from nondetectable to 0.2 ppb (wet weight) trichloroethylene were found in Lake Pontchartrain near New Orleans (Ferrario et al. 1985). An analysis of the EPA STORET Data Base (1980-1982) found that trichloroethylene had been positively detected in sediment samples taken at 6% of 338 observation stations, with median levels of <5 pg/kg (dry weight) (<5 ppb) (Staples et al. 1985). The observation stations included both "ambient" and "pipe" sites. Ambient sites include streams, lakes, and ponds and are intended to be indicative of general U.S. waterway conditions. Pipe sites refer to municipal or industrial influents or effluents. 

Ferrario JB, Lawler GC, DeLeon IR, et al. 1985. Volatile organic pollutants in biota and sediments of Lake Pontchartrain. Bull Environ Contam Toxicol 34 246-255. 

Heptachlor and heptachlor epoxide were detected in water column samples at different depths in Lake Pontchartrain in New Orleans, Louisiana. Heptachlor was detected in the 1.5-meter ebb- and flood- tide samples and in the 10-meter flood-tide samples at concentrations of 0.6, 9.1, and 9.3 ppt, respectively. Heptachlor epoxide was detected in the 1.5-meter ebb- and flood-tide samples and in the 10-meter flood-tide sample at concentrations of 2, 3.9, or 2.5 ppt, respectively (McFall et al. 1985). 

McFall et al. (1985) reported isophorone concentrations in sediments of Lake Pontchartrain, LA, an estuary located in the Mississippi River delta. Sediments containing isophorone were detected in the Inner Harbor Navigation Canal (IHNC), the Rigolets, and the Chef Menteur Pass. Concentrations in the overlying waters were not reported. Therefore, the sorption partition coefficient in these sediments could not be derived from these experimental data. 

McFall et al. (1985) also analyzed oysters from the IHNC and clams from the Rigolets and the Chef Menteur Pass in Lake Pontchartrain for isophorone. Oysters from the IHNC had detectable levels of isophorone (38 ppb dry weight), but clams did not the detection limits were not specified and no BCF can be calculated with the data supplied. These data indicate, however, that isophorone can be found in aquatic organisms at mg/kg levels, although no correlation was found between the concentration of isophorone and lipid content in the organism (Camanzo et al. 1987). 

Isophorone was detected in the Delaware River in the winter only in the summer, biodegradation or other processes (e.g., sorption) may have removed it from the water column. Isophorone has been detected in the sediments of Lake Pontchartrain, which is located in the delta plain of the Mississippi River. Its presence probably is due to the many industries that are situated along the Mississippi River and use the river water as process water. Levels of isophorone in surface waters range from a trace to 100 ppb however, this range represents only a few determinations. 

In a summary of 1975-1979 data on fish tissue from EPA s STORET database, the mean concentration of silver in 221 samples was 0.225 mg/kg (wet weight total fish), with a range of 0.004-1.900 mg/kg (Scowetal. 1981). In Lake Pontchartrain, Louisiana (which is likely to receive substantial inputs of metals from municipal and agricultural activities) silver concentrations in clams and American oyster tissues were 0.4-2.4 mg/kg and 5.5 mg/kg (all dry weight), respectively (Byrne and DeLeon 1986). 

Byrne CJ, DeLeon JR. 1986. Trace metal residues in biota and sediments from Lake Pontchartrain, Louisiana. Bull Environ Contam Toxicol 37 151-158. 

McFall JA, Antoine, SR, DeLeon IR. 1985a. Base-neutral extractable organic pollutants in biota and sediments from Lake Pontchartrain. Chemosphere 14 1561-1569. 

Bianchi (2001) further supported that lignin was not degraded efficiently under low-oxygen conditions in a tidal stream, adjacent to Lake Pontchartrain estuary (USA). 

Argyrou, M.E., Bianchi, T.S., and Lambert, C.D. (1997) Transport and fate of dissolved organic carbon in the Lake Pontchartrain estuary, Louisiana, USA. Biogeochemistry... 

Three channels from Lake Pontchartrain, Louisiana, to the Gulf of Mexico were studied as sample (oysters, clams, and sediments) sources to determine trace element (Ag, As, Be, Cd, Cr, Cu, Hg, Ni, Pb, Se, Tl, and Zn) uptake only T1 was not detected in the tissue and it was minimally present in the three sediments [38]. Oysters in the Inner Harbor Navigation Canal contained high concentrations of Zn, whereas clams from the other two channels (i.e., the Rigolets and the Chef Menteur Pass) contained high levels of Cu. Sediment metal concentrations were reflected in the tissue levels. 

Little information was found on the levels of 1,1-dichloroethane in other media. Ferrario et al. (1985) measured 33 ppb wet weight of 1,1-dichloroethane in oysters from Lake Pontchartrain near New Orleans, Louisiana, however, 1,1-dichloroethane was not detected in types of clams. Kallonen et al. (1985) detected 1,1-dichloroethane in the effluent gases of burning polyester fiber fill. Data on concentrations in human breath are presented in Section 5.5. 

PRINCIPAL OXIDIZED NITROGEN AIRSHEDS FOR NARRAGANSETT BAY, CHESAPEAKE BAY, PAMLICO SOUND, TAMPA BAY, MOBILE BAY, LAKE PONTCHARTRAIN... 

Polynuclear aromatic hydrocarbons from urban runoff were found at elevated levels in nearshore sediment samples from Lake Pontchartrain. Concentrations decreased with distance from the New Orleans shoreline and approached background levels three to six miles offshore. Quantitative profiles for individual PAH isomers differed significantly between nearshore and offshore sediments. Similar trends were observed with chlorocarbons and lead, but concentrations of other heavy metals did not decrease with distance from the shoreline. Salt water Intrusion causes stratification over the southeastern portion of the Lake in the summer. This stratification contributes to and exacerbates bottom anoxic conditions during warm weather months. 

A) determination of the occurrence and distribution of chemicals in Lake Pontchartrain, Louisiana (particularly in the southern portion of the Lake near New Orleans) that resulted from anthropogenic activity and (B) an overall water quality assessment of the Lake to ascertain any phenomena, in particular urban runoff related water pollution, that may be adversely affecting the ecological balance of the Lake. The strategies developed to address these objectives included (1) Collection of biota and sediment samples and their analyses for a broad spectrum of chemical substances which included, but were not limited to, those designated as priority pollutants by the U.S. 

Figure 1. Map of Lake Pontchartrain showing locations of the 148 water quality sampling stations and the locations which were also sampled for sediments.

Figure 2. Top and bottom salinity and dissolved oxygen profiles at two stations in Lake Pontchartrain over a 12 month annual cycle.

Figure 5. Plots showing the sediment concentrations of a) total identifiable compounds and b) parent polynuclear aromatic hydrocarbons with distance from the southern shoreline of Lake Pontchartrain. Sedimnet sample collection dates are April 1982 July 1982 ...

Table I- Specific Compounds Found In Lake Pontchartrain Sediment Samples as well as the Identities of Compounds that Comprise the Various Sub-classes of Pollutants idiose Concentration Trends are Highlighted In this Report.

Figure 8. The quantities (ppb) and distribution of nine polynuclear aromatic hydrocarbons, at three sampling stations, In Lake Pontchartrain sediments.

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