Investigation into the impacts of contaminants in mineral fertilisers, fertiliser ingredients and industrial residues and the derivation of guidelines for contaminants

The application of mineral fertilisers is vital to the ongoing success of Australian agriculture. Yet, fertilisers contain contaminants and thus there is the potential for harmful effects to occur to agricultural production systems, the environment and human health. There are government policies to reduce and re-use industrial residues and one re-use option is their application to agricultural land. They can also contain contaminants and thus potentially cause harmful effects. In 2002, a heavily contaminated industrial waste was imported into
Australia and used as a fertiliser. This incident highlighted gaps in the regulatory framework that required addressing.
The aims of this project were to derive guidelines for contaminants that would provide protection from adverse effects associated with their application for a period of 100 years and then to assess the risk posed by contaminants in current Australian mineral fertilisers and selected industrial residues when applied to agricultural land. Adverse effects were to be prevented in agricultural soil, surface water, ground water, sediments, plants, seafood, fish, humans (from eating contaminated food) and livestock. A total of 132 fertiliser ingredients and industrial residues were assessed based on information provided by companies that manufacture and import mineral fertilisers and generate industrial residues.
This report focuses on the toxic effects of contaminants, which includes nutrients present at excessive concentrations. The contaminants assessed were those inorganic chemicals known to occur and those organic chemicals most likely to occur in Australian mineral fertilisers and industrial residues. The report is divided into two parts. Part A presents and discusses the results. Part B
describes the methodology used to calculate guidelines for the contaminants and to assess the risk posed by contaminants in fertilisers and industrial residues, as well as indicating how future assessments may be conducted and the information required to do so.
The project was a desktop study and derived guidelines for all the identified contaminants for which there were appropriate data and environmental benchmarks (e.g. food standards, water quality guidelines). However, the risk posed by the contaminants could only be assessed for those mineral fertiliser ingredients and industrial residues for which chemical composition data were available. Thus, any limitations in the data as well as in the assessment methods could have implications for the project results. Such limitations are discussed in detail in Part A. The deliverables for this project were:
• guideline values for contaminants in fertilisers and an assessment of the
environmental suitability of mineral fertilisers and their ingredients, and industrial residues;
• lists of substances, including industrial residues, that:
- should not be permitted as ingredients in mineral fertilisers;
- should be permitted in mineral fertilisers;
- could not have their suitability for inclusion in mineral fertilisers currently
assessed;
• lists of contaminants:
- that pose minimal risk and do not require further assessment;
- that pose a potential risk and therefore require further assessment to
determine guideline values for them;
- for which insufficient data are available to make a reliable assessment of risk;
a description of data requirements and guidance on how future assessments
should be conducted.
All of the above deliverables are presented in this report. The project established two sets of guideline values i.e., Fertiliser Contaminant Guideline Values (FCGVs) and Fertiliser Contaminant Trigger Values (FCTVs).
The FCGV is the highest concentration of a contaminant in any mineral fertiliser ingredient used in Australia and assessed in the current project that will not increase the lowest ambient background concentration of that contaminant in any Australian agricultural soil after 100 years application at the maximum recommended rate. The FCGV values are based on the “as little as reasonably achievable” (ALARA) principle, and thus can change over time as “what is reasonably achievable” changes. All the inorganic contaminants examined had the potential to increase the background soil concentration and thus FCGVs could not be derived. FCGVs could not be derived for organic chemicals as data on their concentration in Australian mineral fertiliser ingredients and industrial residues were not available. The FCTVs are the highest concentration of contaminants in mineral fertiliser ingredients and industrial residues used in Australia that will not, after 100 years of application to agricultural soil, lead to exceedances of the benchmarks in any of the assessed environmental compartments. The FCTVs can never be smaller than the FCGVs. A total of 52 FCTVs were derived, 21 for inorganic contaminants and 31 for organic contaminants. A list of not permitted ingredients in fertilisers would only cover the listed contaminants. A more comprehensive approach is to ban all chemicals which are not on the permitted list. This latter approach was therefore adopted in this project. However, the Federal, State and Territory organisations responsible for regulating fertilisers may add particular substances to the not permitted ingredients list, should they desire. The permitted ingredients list consists of 71 ingredients. The risk posed by contaminants present in Australian mineral fertilisers and industrial residues was assessed. For each feriliser type (e.g. nitrogen, phosphorus, potassium and micronutrient fertilisers) or industrial residue, if the highest concentration of a contaminant is less than the appropriate FCTV, then that combination of contaminant and fertiliser type/industrial residue poses a minimal risk to environmental, livestock and human health. For each feriliser type or industrial residue, if the highest concentration of a contaminant is higher than the appropriate FCTV, then that combination of contaminant and fertiliser type/industrial residue poses a potential risk. The inorganic contaminants in fertilisers that pose a minimal risk are antimony, beryllium, cobalt, nickel, selenium, silver and tin. The contaminants that pose a potential risk in at least one fertiliser type or industrial residue are arsenic, barium, cadmium, chromium, copper, fluorine, lead, mercury, molybdenum, vanadium and zinc. Due to the conservative nature of the methodology used and the assumptions made in the current project, it is recommended that further detailed assessment be conducted for those contaminants that pose a potential risk. The risk posed by lanthanum, tin, thorium and uranium in mineral fertilisers could not be assessed despite having FCTVs, as they lacked sufficient chemical concentration data. The risk posed by silver, beryllium, fluorine, lanthanum, magnesium, antimony, tin, thorium and
uranium in the selected industrial residues could not be assessed despite having FCTVs as they also lacked concentration data. The risk posed by all 31 organic contaminants included in the project also could not be assessed for the same reason.
The report also provides guidance and a methodology on how future assessments of fertiliser ingredients and contaminants in mineral fertilisers and industrial residues should be conducted. The outcomes of this project are expected to provide a scientific basis for Federal, State and Territory policy responses on how to address the issue of potentially adverse impacts of contaminants in mineral fertilisers and industrial residues on agricultural production systems and the environment.