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Recycling of home garden pesticide containers - PS2808

Description
Home and garden pesticides are available either as products that are ready-to-use (RTU), or concentrated products that require diluting. RTU sprayers are designed to be user-friendly and to reduce pesticide exposure to both the user and the environment, primarily by removing the need to handle concentrated product (thus preventing accidental spills), and also by ensuring that the solution is at the correct concentration. RTUs are therefore very popular with home and garden users accounting for 50-70% of the market, and this figure is likely to increase in the future. Current government advice for the disposal of empty home and garden pesticide containers is based on the historic use of concentrated products and therefore recommends rinsing the containers and disposing of them in the dustbin - recycling of these containers is discouraged. However, we are being increasingly encouraged to recycle plastics.

Residues of concentrated products could expose refuse collectors and workers in recycling centres to unacceptable levels of pesticides, whilst rinsing the containers could potentially impact on the environment. RTUs contain much lower levels of pesticide, but the number of actual containers to be disposed of will be greater than for concentrated. Any environmental or occupational human exposure to pesticide residues from RTUs will therefore be at a lower level, but occur more frequently. The common use of RTUs and recycling means that government advice regarding the disposal of used home and garden pesticide containers may no longer be appropriate and there is a need to assess the risk to humans and the environment from the disposal of empty pesticide containers whether it be via landfill or recycling.

The aim of this study is to provide a robust, quantitative assessment of the risks posed by the recycling of empty home and garden pesticide containers and to compare these risks with those posed by disposal through the household waste stream into landfill.
The objectives are to:
1. Identify a range of active ingredients that are representative of the home and garden pesticide market.
2. Quantify residual pesticide quantities in different container types.
3. Quantify the potential for dilution of pesticide containers by other plastics in the waste stream.
4. Identify the routes of exposure to humans and the environment associated with a. Recycling, b. Disposal to landfill, and c. Inappropriate disposal of the washings.
5. Quantify the levels of exposure at the different steps.
6. Create a simple model to assess the risk.
7. Perform sensitivity analysis on the exposure model and its inputs.
8. Compare risks of different product types and disposal routes.

The researchers involved in the study have in-depth knowledge of how pesticides react in the environment and the factors that influence this; they are also experienced in human exposure and have knowledge of the waste stream. This knowledge will be applied to the scenario of the disposal of an ‘empty’ container via landfill and recycling. Existing literature and knowledge will be used to provide relevant quantitative data for objectives 1 – 5. For example, physico-chemical properties of the compound; initial concentration of the active ingredient in the product; container type/shape/volume/plastic; usage; residues remaining when unwashed, and rinsed; % of washings going to sewage treatment; % of washings going to drain (and hence stream); % of containers going to landfill/recycling; plastic available for dilution; residues remaining after washing at reprocessing plant; washing water available for dilution; duration and frequency of human exposure; size and turnover of water body in the environment; degradation in landfill.

The relationship between these different factors will be described simply in an excel spreadsheet to quantify an overall amount of pesticide that workers may be exposed to and that could enter water and air (and soil if applicable). This value will then be compared to existing threshold values such as operator exposure levels and no effect concentrations. If the predicted total mass is greater than the threshold value then there is a potential risk. The values of the model inputs in the real can be variable and changes in any one of these inputs, or groups of inputs, can result in large or small changes in the output. It is important to show that if an input is not precisely known, changes in that input to other plausible values does not lead to important differences in the risk estimates and this sensitivity analysis will be undertaken.

This simple model will enable regulators to assess whether RTUs or containers from concentrated pesticides pose a greater risk to humans and/or the environment, and similarly to compare the risks associated with disposal to landfill or recycling. This will then enable appropriate advice to be given regarding their disposal.
Objective
The objectives are to:
1. Identify active ingredients with a range of environmental and human toxicities that are representative of the home and garden pesticide market.
2. Quantify residual pesticide quantities in different container types.
3. Quantify the potential for plastic dilution.
4. Identify the routes of exposure to humans and the environment associated with:
a. Recycling
b. Disposal to landfill
c. Inappropriate disposal of the washings.
5. Quantify the levels of exposure at the different steps.
6. Create a simple model to produce an outcome for each disposal route.
7. Perform sensitivity analysis on the exposure model and its inputs.
8. Compare risks of different product types and disposal routes
9. Prepare a report to include guidance on use of the model for future scenarios, identification of any significant data gaps and hence any limitations in the model.
Project Documents
• EVID4 - Final project report : PS2808 evid4   (471k)
• ANX - Annex : PS2808 GLOSSARY   (34k)
• ANX - Annex : PS2808 Incineration   (251k)
• ANX - Annex : PS2808 Landfill   (125k)
• ANX - Annex : PS2808 Sensitivity analysis   (61k)
• ANX - Annex : PS2808 Waste streams   (141k)
Time-Scale and Cost
From: 2011

To: 2012

Cost: £74,712
Contractor / Funded Organisations
F E R A (FERA)
Keywords
Analytical Chemistry              
Environment              
Pesticide Residues              
Plastics              
Water              
Fields of Study
Pesticide Safety