Related Experiment Video
Updated: Jun 10, 2026

A Protocol for Conducting Rainfall Simulation to Study Soil Runoff
Published on: April 3, 2014
Elemental composition at different points of the rainwater harvesting system
A C Morrow1, R H Dunstan, P J Coombes
1School of Environmental and Life Sciences, The University of Newcastle, University Drive, Callaghan, NSW 2300, Australia. abigail.morrow@newcastle.edu.au
Abstract:
Entry of contaminants, such as metals and non-metals, into rainwater harvesting systems can occur directly from rainfall with contributions from collection surfaces, accumulated debris and leachate from storage systems, pipes and taps. Ten rainwater harvesting systems on the east coast of Australia were selected for sampling of roof runoff, storage systems and tap outlets to investigate the variations in rainwater composition as it moved throughout the system, and to identify potential points of contribution to elemental loads. A total of 26 elements were screened at each site. Iron was the only element which was present in significantly higher concentrations in roof runoff samples compared with tank tap samples (P<0.05). At one case study site, results suggested that piping and tap material can contribute to contaminant loads of harvested rainwater. Increased loads of copper were observed in hot tap samples supplied by the rainwater harvesting system via copper piping and a storage hot water system (P<0.05). Similarly, zinc, lead, arsenic, strontium and molybdenum were significantly elevated in samples collected from a polyvinyl chloride pipe sampling point that does not supply household uses, compared with corresponding roof runoff samples (P<0.05). Elemental composition was also found to vary significantly between the tank tap and an internal cold tap at one of the sites investigated, with several elements fluctuating significantly between the two outlets of interest at this site, including potassium, zinc, manganese, barium, copper, vanadium, chromium and arsenic. These results highlighted the variability in the elemental composition of collected rainwater between different study sites and between different sampling points. Atmospheric deposition was not a major contributor to the rainwater contaminant load at the sites tested. Piping materials, however, were shown to contribute significantly to the total elemental load at some locations.
Related Concept Videos
Precipitation and Co-precipitation
Precipitation Titration: Overview
A precipitation titration curve demonstrates the change in concentration of the titrant or analyte upon adding the...
Precipitation of Ions
The equation that describes the equilibrium between solid calcium carbonate and its solvated ions is:
Precipitation Titration: Endpoint Detection Methods
In the Volhard method, a standard excess of AgNO3 is first added to the...
Classifying Matter by Composition
According to its composition, the matter can be classified into two broad categories — pure substances and mixtures.
A pure substance is a form of matter that has a constant composition throughout with uniform properties. For example, any sample of sucrose has the same composition and same physical properties, such as melting point, color, and sweetness, regardless of the source from which it is isolated.
A mixture is composed of two or more types of...
Precipitation Titration Curve: Analysis

