A mathematical model has been simulated to describe natural in situ bioremediation of contaminated soil. The model equations consist of a system of three non-linear partial differential equations. Sensitivity analysis conducted by numerically solving them, has demonstrated the effect of initial contaminant concentration on the time and mechanism of remediation. The result of simulation indicate...

Pentachlorophenol (PCP) is a persistent and ubiquitous environmental contaminant. No published data exist on the temporal variability or important predictors of urinary PCP concentrations in young children. In this further analysis of study data, we have examined the associations between selected sociodemographic or lifestyle factors and urinary PCP concentrations in 115 preschool children over...

We study the kinetics of infiltration in which contaminant particles, which are suspended in a flowing carrier fluid, penetrate a porous medium. The progress of the "invader" particles is impeded by their trapping on active "defender" sites which are on the surfaces of the medium. As the defenders are used up, the invader penetrates further and ultimately breaks through. We study this process i...

How chronic exposure to aquatic pollution affects reproductive traits was assessed in nesting wild-caught plainfin midshipman Porichthys notatus in areas with low and high contaminant exposure on Vancouver Island, British Columbia. Males in high-exposure areas had a greater degree of testicular asymmetry, sperm with shorter heads and fewer live eggs in their nests. The results of this study pro...

The effect of argon and oxygen sputtering on carbon contaminant buildup on ZnO during XPS (X-ray photoelectron spectroscopy) analysis has been examined. Argon and oxygen sputtering cause a rapid decline in hydroxyl oxygen and contaminant carbon content at the surface. Reduc­ tion to metallic zinc is not observed. In a carefully baked instrument after sputtering a stable clean surface could be m...

This paper summarizes three mathematical models used to describe how contaminant concentration profiles in soil may be inferred from the intensities of neutron-induced capture-gamma photon intensities measured at the soil surface. In particular, the linear regularization, linear regularization with an iterative positivity constraint, and the Backus-Gilbert methods are applied to the soil contam...

In the recently published results of the 1977 College of American Pathologists Enzymology Survey, Some anomalous results were obtained in measuring the creatine kinase (EC 2.7.3.2) activity of the samples. The cause of these anomalies was discovered to be an arginine kinase (EC 2.7.3.3) contaminant in one of the enzyme pools used to make the samples. The contaminant shows cross reactivity with ...

• Including biofilm processes in the organic contaminant fate model in rivers is very important, especially in shallow rivers. • The nutrient load dynamics can affect the fate of organic contaminants, and thus including nutrients in the organic contaminant fate modelling is necessary. • The sensitivity of LAS degradation to the ammonia nitrogen is an interesting finding and can induce further r...

1527 *Fa {Fa The reliable assessment of hazards or risks arising from groundwater contamination problems and the design of ecient and e€ective techniques to mitigate these problems require the capability to predict the behavior of chemical contaminants in ̄owing water. Most attempts at quantifying contaminant transport have relied on a solution of some form of a well-known governing equation re...