environment

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Hazardous waste

Introduction

A hazardous waste is waste that presents potential threats to public health or the environment. Hazardous waste is defined in The Hazardous Waste (Regulation of Exports and Imports) Act 1989 as:

  • Waste with characteristics mentioned in Annex III to the Basel Convention. These characteristics include: Explosives, Flammable Liquids/Solids, Poisonous, Toxic, Ecotoxic and Infectious Substances.
  • Wastes contained in Annex I to the Basel Convention, unless they do not possess any of the hazardous characteristics contained in Annex III. Including : Clinical wastes, Waste oils/water, hydrocarbons/water mixtures, emulsions, Wastes from resins, latex, plasticizers, glues or adhesives, Wastes resulting from of metals and plastics, Residues from industrial waste disposal operations and Wastes containing compounds such as: copper, zinc, cadmium, mercury, lead and asbestos.
  • Household waste
  • Residues arising from the incineration of household waste. (1)

The Basel Convention on the Control of Trans-boundary Movements of Hazardous Wastes and their Disposal is a 1992 global agreement of 172 parties aiming to 'protect human health and the environment against the adverse effects resulting from the generation, management, trans-boundary movements and disposal of hazardous and other wastes.' (3)

They are generally deemed hazardous because of the 'chemical reactivities, fire hazards, toxicities and other properties.' (2)

Hazardous waste differs from everyday household waste as it cannot be disposed of by ordinary methods. Depending on the type or physical state, brings in different methods for disposal or containment.

Pesticides

A pesticide is a chemical (or mixture of chemicals) intended to be used for the selective control of pests. It can be classed as an animal, plant or microbes. These are often poisonous to humans, animals and other plants that are not the intended. (4)

There are numerous forms of pesticide for various purposes:

Pesticide

For the Control of

Algaecides

Algae

Avicides

Birds

Bactericides

Bacteria

Fungicides

Fungi

Herbicides

Weeds

Insecticides

Insects

ovicides

Insect Eggs

larvicides

Insect Larvae

adulticides

Insect Adults

Miticides

Mites

Molluscicides

Slugs & Snails

Nematicides

Nematodes

Virucides

Viruses

Rodenticides

Rodents

(5)

Pesticides are also classified as Persistent organic pollutants, POPs. They are compounds that do not easily break down and can remain in the environment for many years. Some pesticides including aldrin, chlordane, DDT, dieldrin and toxaphene are considered POPs. The chemicals also have the ability to bioaccumulate and biomagnify, and can increase their concentration up to 70,000 times their original concentrations. A POPs may continue to spread amongst its surrounding areas and increase risks among other plants, animals or humans. (11)

Air Pollution is caused by pesticide drift. It is the process by which suspended pesticides are carried by wind to other areas potentially contaminating them. Over 98% of sprayed insecticides and 95% of herbicides reach a destination other than their target species, including non target species, air, water, bottom sediments, and food. (6) It is thought that pesticides contribute as much as 6% to total ozone production. (7)

Pesticides are found in water through 4 main ways. It may be carried through pesticide drift, it may be carried to the water as runoff, it may filter through the soil or it ma be spilled accidently. (8) Maximum limits for pesticide concentration in water are set by the government. The presence of pesticides in water also affects aquatic life. It can cause fish to die when rotting plants use up the waters oxygen. Some herbicides that are applied to water to kill plants are also toxic to fish. (10)

Soil is also affected by the pesticides. Not only due to the leaching through the soil. Soil conservation is negatively affected because pesticides are soil contaminants. Not using the chemicals results in a higher soil quality, and increases the biodiversity in the soil. This also affects the plants within the area. Nitrogen fixation, which is required for the growth of plants, is hindered by pesticides in soil. (9)

The measures that can be in place to minimise the unwanted spread of pesticides are set in the Occupational Health and Safety Regulations 2000.

The include:

  • Ensuring the pesticide container is labelled
  • Disclosure of chemical name to registered medical practitioner
  • An employer or a self-employed person must ensure that any hazardous substance is not used at the employer's workplace for any purpose specified in those schedules (National Model Regulations for the Control of Workplace Hazardous Substances) or that determination in respect of that substance. (12)

Other measures that can be used to minimise the adverse affects of using pesticides include:

  • Look for alternatives to pesticides; Farmers may adopt whole farm systems, which use cultural, mechanical, and biological methods before targeted pesticide use. Integrated Pest Management (IPM) are other alternatives. (8)
  • Ensure Pesticide retailers are meeting storage requirements. Also vehicles assessed for suitability and driven by trained drivers carrying spillage equipment.

(8)

  • Use pesticide only if necessary and in quantities that will be effective in controlling pests and where possible, select pesticides that are less toxic and less persistent or less likely to leach. Some carbamate pesticides are more likely to leach and cause groundwater contamination than other pesticides. (8)(13)
  • Identify the vulnerability of the soil. Sandy soils and well drained soils have a higher potential for ground water contamination. Pesticide container labels often have instructions or precautions to help minimise contamination. (13)
  • Keep pesticides away from surface water sources to prevent pesticide drift contamination. (13)
  • Apply correct timing to coincide with pest life cycle. Also applying prior to rain should be avoided to minimise run-off. (13)
  • Maintain and calibrate equipment to ensure correct quantities are applied, there are no leaks or that they are being applied correctly. (8)(13)
  • Avoid spills or reverse flow through the hoses (13)
  • Carefully direct spraying to target sites and use buffers to leave out sensitive areas or non target areas. (13)
  • Correct Disposal involves multiple rinses of equipment and containers. Following instructions on the label can be critical. (13)
  • Storage must be in their original containers in a cool, well-ventilated, protected location away from pumps and water sources. (13)
  • Training to enforce the need to exercise care, especially around water sources, labelling systems, preventing and minimising spillages and waste disposal. (8)

These measures are not so much a means for treating the hazardous waste, but a means for preventing a situation where you may need to. Following a best practice guide for the use of pesticides should minimise the need to treat this hazardous waste.

References:

(1) Hazardous Waste - Department of the Environment, Water, Heritage and the Arts

http://www.environment.gov.au/settlements/chemicals/hazardous-waste/index.html

Accessed 13-08-09

(2) ENVI 1038 Hazardous Waste and Contaminated Sites

Resource Material

Pg 1-18

(3) Basel Convention on the Control of Transboundary Movements of Hazardous Wastes and their Disposal

http://www.basel.int/

Accessed 13-08-09

(4) Household Hazardous Waste - PESTICIDES

http://www.esc.nsw.gov.au/site/Waste/pesticid.pdf

Accessed 13-08-09

(5) A to Z of Pesticides - Pesticides Residues Committee

www.pesticides.gov.uk/prc.asp?id=2678

Accessed 13-08-09

(6) Sustaining the Earth, 6th edition. Miller GT, (2004)

Chapter 9, Pages 211-216.

(7) What's up, Doc? Maybe less air pollution 2006

http://www.ipm.ucdavis.edu/NEWS/carrot-news.html

Accessed 13-08-09

(8) States of Jersey (2007), Environmental protection and pesticide use

http://www.gov.je/PlanningEnvironment/Environment/Environmental+Protection/EnvironmentalProtectionandPesticideUse.htm

Accessed 13-08-09

(9) Down on the Farm? Yields, Nutrients and Soil Quality - Rusty Rockets

http://www.scienceagogo.com/news/farming.shtml

Accessed 14-08-09

(10) Pesticides and Aquatic Animals: A Guide to Reducing Impacts on Aquatic Systems - Aquatic Toxicology

http://www.pubs.ext.vt.edu/420/420-013/420-013.html#L4

Accessed 10-08-09

(11) Persistent Organic Pollutants, L. Ritter, K.R. Solomon, J. Forget

http://www.chem.unep.ch/pops/ritter/en/ritteren.pdf

Accessed 14-08-09

(12) Occupational Health and Safety Regulations

Part 4.1-Hazardous Substances

(13) Pesticides and Groundwater Contamination - Preventative Measures

http://www.cartage.org.lb/en/themes/sciences/earthscience/geology/WaterCycles/WaterPollution/PesticidesGroundwater/PreventiveMeasures/PreventiveMeasures.htm

Accessed 14-08-09