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Contaminated Sites

Contaminated vs. Polluted Land

Land is defined as contaminated when the concentration of an element or compound in the soil is above the defined background or natural level.  It is important to realise that contamination does not necessarily mean pollution.  There are many examples of ‘naturally’ contaminated sites around the world.  Here, geological processes have increased the concentration of certain trace elements in soil.  The ecosystem in such places will evolve to respond and manage such contaminants.

Where contamination does affect the growth of microorganisms, plants and animals, then contamination becomes pollution and can present unacceptable risk to the healthy functioning of the environment.  The use of pesticides and the discharge of industrial waste to the environment are two common mechanisms by which the environment can become polluted.  Contamination in ecosystems that are inhabited by people is often anthropogenic (manmade).


What CPL can offer...

Where pollution is expected, or where concern over contamination is raised, Croesus can assist with diagnosing environmental risk. Croesus can then assist with the planning, implementing and managing of remediation solutions. Risk exposure pathways are an important part of this work. Risk vectors may include eating plants grown on contaminated soil, eating plants irrigated with contaminated water, the dispersion of contaminants via wind erosion, or the leaching of contaminants into drinking water. If soil contaminants are not actually interacting with the environment and therefore do not actually present a risk, then expensive remediation or management procedures are often not justifiable. In contrast, accurate and precise risk assessment can identify low levels of contamination that may need urgent remediation to address unacceptable risk.

Environmental Impact and Risk Assessment

Croesus is active with environmental impact and risk assessment of artisanal and small scale mining in Indonesia and China.  This work is assessing the risk that mercury, arsenic, cyanide and other trace elements discharged to the environment may be having on people living in mining areas. 


Croesus has completed several environmental impact assessments for the Crown Forestry Rental Trust in New Zealand to understand the impact of European activities on the environment since colonisation of New Zealand in the 1800s. Environmental impacts include land-use change, deforestation, intensification of agricultural activities, and the introduction of contaminants into the environment. These reports have helped define compensation that can be sought from the New Zealand Government through Treaty of Waitangi settlements.  


Chris Anderson is supervising the PhD research of a student at Massey University who is assessing the extent of human risk associated with the ingestion of vegetables irrigated with arsenic-contaminated water.  This research has shown that flood irrigation of spinach with water containing as little as 1 ppm arsenic (1 mg of As per L of water) can lead to unacceptable carcinogenic and non-carcinogenic risk to humans when this spinach is eaten.  Flood irrigation with arsenic-contaminated water is a common practice in south Asia, and this work is formulating crop and irrigation management guidelines that could be implemented in Pakistan to protect human health.




Environmental Science: Processes & Impacts, DOI: 10.1039/C3EM00218G

Bhatti S.M., Anderson, C.W.N., Stewart, R.B. and Robinson, B.H. (2013)

Risk assessment of vegetables irrigated with arsenic-contaminated water.

A base-metal refinery in Africa.  Heavy metal contamination is a common theme for inefficient or historic facilities, especially in developing countries.

The aim of contaminated site management is to mitigate risk and to restore a working and healthy ecosystem

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