Urban total phosphorus loads to the St. Clair-Detroit River System

Recently, the Asian rivers have faced the strong reduction of riverine total suspended solids (TSS) flux due to numerous dam/reservoir impoundment. The Red river system is a typical example of the Southeast Asian rivers that has been strongly impacted by reservoir impoundment in both China and Vietnam, especially in the recent period. It is known that the reduction in total suspended solids may lead to the decrease of some associated elements, including nutrients (N, P, Si) which may affect coastal ecosystems. In this paper, we establish the empirical relationship between total suspended solids and total phosphorus concentrations in water environment of the Red river in its downstream section from Hanoi city to the Ba Lat estuary based on the sampling campaigns conducted in the dry and wet seasons in 2017, 2018 and 2019. The results show a clear relationship with significant coefficient between total suspended solids and total phosphorus in the downstream Red river. It is expressed by a simple equation y = 0.0226x0.3867 where x and y stand for total suspended solids and total phosphorus concentrations (mg/l) respectively with the r2 value of 0.757. This equation enables a reasonable prediction of total phosphorus concentrations of the downstream Red river when the observed data of total suspended solids concentrations are available. Thus, this work opens up the way for further studies on the calculation of the total phosphorus over longer timescales using daily available total suspended solids values.

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Modelling the Pathways of Toxic Contaminants in the St. Clair-Detroit River System Using the Toxfate Model: The Fate of Perchloroethylene

Water Quality Research Journal ◽

10.2166/wqrj.1986.036 ◽

1986 ◽

Vol 21 (3) ◽

pp. 411-421 ◽

Cited By ~ 1

Author(s):

Efraim Halfon

Keyword(s):

Half Life ◽

Lake Erie ◽

River System ◽

High Water ◽

Water Levels ◽

Water Soluble ◽

Detroit River ◽

Wind Speeds ◽

High Volatility ◽

Local Water

Abstract Perchloroethylene (PERC) is a heavier-than-water, soluble and volatile solvent used primarily in the dry cleaning business. Black puddles (popularly known the the “blob”), containing several contaminants inducing PERC, were reported in the St. Clair River bottom sediments downstream from Sarnia in 1984 and in 1985. The TOXFATE model is used to predict the fate of PERC and the relative importance of volatilization in relation to water transport. Simulations show that in the St. Clair-Detroit River system about 82% (78-87%). under a variety of temperature and wind conditions) of the PERC loading is volatilized, about 17% (12-21%) of loading enters Lake Erie (more in winter, less in summer) and only about 1% remains in the system. The residence half life of PERC being transported in the water from Sarnia to Lake Erie is 350-400 hours and the half life of PERC being volatilized is 80-85 hours. A sensitivity analysis shows the importance of knowing the daily loadings to compute, in real time, local water concentrations following a PERC spill. The high water levels in the St. Clair River system do not influence the fate of PERC. Given the high volatility of PERC low temperatures and wind speeds do not reduce significantly the rate of removal of PERC from the system through volatilize nation.

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