CB_method: Conservative Balance (CB) Method for Isotopic Tracer Analysis

In fingerPro: A Comprehensive Package for Sediment Source Unmixing

Conservative Balance (CB) Method for Isotopic Tracer Analysis

Description

This function transforms isotopic ratio and content data of individual tracers in a dataset into virtual elemental tracers, which can then be combined with classical tracers and analyzed with standard unmixing models.

Usage

CB_method(data)

Arguments

data

A data frame containing the isotopic tracer characteristics of sediment sources and mixtures. The data should be correctly formatted for isotopic analysis, including both isotopic ratio and isotopic content. Users should ensure their data is in a valid format by using the check_database() function before running the CB method.

Details

The Conservative Balance (CB) method provides a novel, physically-based framework for analyzing isotopic tracers in sediment fingerprinting.

The core of the method is an exact transformation that combines the isotopic ratio and isotopic content into a virtual elemental tracer. This approach has two key advantages: it allows isotopic tracers to be analyzed using classical unmixing models, and it enables their combined use with elemental tracers to potentially increase the discriminant capacity of the fingerprinting analysis.

This function implements the simplified approximation of the CB transformation, assuming that the isotopic ratio is much smaller than 1. The calculation is performed for both averaged and non-averaged datasets.

A key feature of this transformation is that the tracer values for the mixture are set to zero. This is a direct consequence of the method, as the isotopic ratio of each source is subtracted from the mixture's isotopic ratio, meaning the mixture's own value minus itself results in zero.

Value

A data frame where isotopic tracers have been converted into scalar virtual tracers for further analysis. After the transformation, the mixture's row will have tracer values of zero.

References

Lizaga, I., Latorre, B., Gaspar, L., & Navas, A. (2022). Combined use of fingerprinting and tracing. Science of The Total Environment, 832, 154834.

fingerPro documentation built on Aug. 27, 2025, 5:11 p.m.