Pesticides are developed to control pests including weeds and are being extensively used in India. Pesticide includes any substance, or mixture of substances of chemical or biological ingredients intended for repelling, destroying or controlling any pest, or regulating plant growth.
According to statistical database of Directorate of Plant Protection, Quarantine & Storage, India, in 2017-18, 62247 “000’ hectare area under cultivation is under pesticide usage. It indicated that 71.54 % of area under cultivation in India is under pesticide usage.
Environment protection act 1986 and Hazardous wastes Management rules, 2016 recognizes date expired and off specification pesticides as hazardous wastes under schedule 1. At various stages from production to usage pesticide becomes obsolete. India is a country with diverse geography and rich biodiversity.
Highly hazardous obsolete pesticides stockpiled may pose risk to human and environment. The Vulnerability is high for pesticide related hazards in the country.
It is the social responsibility of people using pesticides in farming and public health applications to prevent accumulation of obsolete pesticides that have adverse human health and environment implications.
In this article issues on obsolete pesticides, prevention of their accumulation and their safe disposal as per the Food and Agriculture Organizations’ International Code of Conduct on Pesticide Management is discussed.
What are obsolete pesticides?
Obsolete pesticides are outdated and deteriorated stocks of pesticides that can no longer be used as prescribed on the label. According to FAO estimates about 400 000-500 000 tonnes of obsolete pesticides is stockpiled in developing countries.
How obsolete pesticides get stockpiled?
Stockpiles of obsolete pesticides occur on different scales. Large quantities of obsolete pesticides are generated in trade operations - Wastes from production or formulation of pesticides - Wastes from accidents and deteriorated products as a result of different circumstances. Bad storage conditions that changed their physicochemical properties and therefore they can no longer be applied.
Stock piling of obsolete pesticides occurs on large scale in producing companies and is dependent on several factors including market. Disposal of accumulated pesticides need adequate facilities to dispose of such stocks in a safe and environmentally sound manner.
In many cases, these are managed by shipment of the pesticides to a country that has special hazardous waste incineration facilities. Pesticide companies can reduce obsolete stocks lies by preventive measures like improved stock management and reduction of stocks.
According to FAO the six key factors that lead to the accumulation of obsolete pesticides in developing countries are product bans; inadequate storage and poor stock management; unsuitable products or packaging; donation or purchase in excess of requirements; lack of coordination between donor agencies; commercial interests of private sector and hidden factors.
Small quantities of obsolete pesticides are generated by producers, experimental stations or research institutes and by users. The generation of obsolete pesticides on a small scale in research centres and farmer fields can be prevented by following ways.
The Preparation of Inventories of Pesticides and Contaminated Materials
A farm inventory/ record has to be maintained by each farmer listing the pesticide purchased, its expiry date and quantity available in the farm. This helps the farmer to prevent stockpiling of obsolete pesticides. If not used within expiry date, it can be given for usage in other farms.
Purchase of pesticides in small packages
Pesticides are marketed in different packages. If a farmer needs one litre of insecticide for his crop. Instead of purchasing 1 litre pack, he should purchase 10 units of 100 ml or 4 units of 250 ml. This reduces left over pesticide problem.
Avoiding pesticide dependence
Several institutes have developed location specific area wide integrated pest management schedules and programmes. Farmers can adopt these schedules which automatically reduces pesticide dependence by more than 75%.
This not only reduces pesticide dependence but also ensures safe environment and residue free food availability. Usage of resistant varieties, cultural, biological interventions and pesticides with green chemistry should be given priority.
Inappropriate disposal practices
The burial of pesticide-related waste in soil
It is not an appropriate practice. Buried pesticides can leak from their containers into the surrounding soil and spread to contaminate large areas. Leaking pesticides can leach into water to contaminate underground aquifers, rivers, lakes and even the sea.
Pesticides in water can damage or destroy aquatic life and affect people and livestock if the water is used for drinking, irrigation or washing. When pesticides and their containers are continually buried on the same site, the area can become severely contaminated and unusable.
Conversely, if pesticide-related wastes are buried in several different sites, a far larger land area could eventually become contaminated.
The burning of waste pesticides, empty containers and contaminated materials
Though it’s also an inappropriate practice, but still it is been followed for disposal of left over pesticides and empty containers at present Burning in open fields emits toxic fumes and leaves toxic hazards as a result of incomplete combustion. The fumes pose immediate serious health hazard to humans and animals. So farmers should avoid burning pesticide containers and left over pesticides.
Disposing pesticides into rivers, streams, lakes, drainage channels or any other water body.
Pesticides are toxic to fish and other aquatic organisms even in small quantities. In addition, disposing pesticide in water contaminates drinking and irrigation water. Once water gets contaminated it is expensive and complex task to purify it. Obsolete pesticides should never be disposed in water bodies.
Re use of empty pesticide containers
It is a usual practice followed by farmers. Empty pesticide containers are washed with water and reused to store seeds, feeds and other materials. Pesticide containers should never be used for any other purposes. It should be tampered immediately after pesticide usage to prevent its usage in farm house.
Re use of Expired pesticides
Expired pesticides have reduced bio-efficacy against target pest. Usage of expired pesticides with sub lethal dose may lead to resistance development and resurgence of pests.
Appropriate disposal methods of obsolete pesticides
Pesticides, their containers and contaminated materials need to be treated as toxic waste. Always segregate hazardous pesticides waste at source from non hazardous one. Do not burry and burn in landfills. They can be disposed of by following ways
- The best way to dispose of any currently labeled pesticide is to apply it according to the label. If that is not possible because of a label change, contact your local County Agricultural Commissioner – in many instances, you will be directed to use the remainder of the product per label instructions. For any currently labeled pesticide, the best alternative would be to find another person or area with the same pest problem, so that the pesticide gets used up legally and effectively.
- Pesticide can be disposed locally by containing in closed container or structure with absorbent materials like soil, sand or sawdust. This should be located under rain shelter to avoid pesticide leaching by rainwater and escape in to the surrounding environment. Microbial communities in the soil degrade organic contaminants over time.
- High temperature incineration. Expired Pesticides and pesticides containers should be collected and handed over to nearest municipality. It should be disposed of by local administration by handing over to authorized hazardous waste treatment incineration plants.
- Always dispose of pesticide containers in a manner specified on the label. Pesticide container disposal can be a significant problem, particularly if you have a large number of contain Many pesticide containers can be recycled, either as a part of a regular recycling program, if approved on the label, or by returning to the chemical supplier. Many chemical companies now re-cycle their pesticide containers.
Sandeep Kumar G.M. and Prasannakumar N.R.