Chemical waste

Chemical waste is waste that is made from harmful chemicals (mostly produced by large factories). Chemical waste can damage the environment and cause health problems and as such may fall under regulations such as COSHH in the United Kingdom, or the Clean Water Act and Resource Conservation and Recovery Act in the United States. In the U.S., the Environmental Protection Agency (EPA) and the Occupational Safety and Health Administration (OSHA), as well as state and local regulations also regulate chemical use and disposal.[1] The disposal and handling of radioactive waste is a particular focus for regulatory bodies due to the environmental and health risks of radiation and the challenges of safe disposal. [2]

Chemical Waste Bin (Chemobox)
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Chemical waste may or may not be classed as hazardous waste. A chemical hazardous waste is a solid, liquid, or gaseous material that displays either a "Hazardous Characteristic" or is specifically "listed" by name as a hazardous waste. There are four characteristics chemical wastes may have to be considered as hazardous. These are ignitability, corrosivity, reactivity, and toxicity. This type of hazardous waste must be categorized as to its identity, constituents, and hazards so that it may be safely handled and managed.[3] Chemical waste is a broad term and encompasses many types of materials. The Material Safety Data Sheet (MSDS), Product data sheet or Label can provide a list of constituents. These sources should state whether this chemical waste is a waste that needs special disposal.[4]

Guidance for disposal of laboratory chemical wastes
Chemical waste category that should be followed for proper packaging, labeling, and disposal of chemical waste

In laboratories, chemical waste is usually segregated on-site into appropriate waste carboys, and disposed by a specialist contractor in order to meet safety, health, and legislative requirements.

Innocuous aqueous waste (such as solutions of sodium chloride) may be poured down the sink. Some chemicals are washed down with excess water.[4] This includes concentrated and dilute acids and alkalis, harmless soluble inorganic salts (all drying agents), alcohols containing salts, hypochlorite solutions, fine (tlc grade) silica and alumina. Aqueous waste containing toxic compounds are collected separately.

Waste elemental mercury, spent acids and bases may be collected separately for recycling.

Waste organic solvents are separated into chlorinated and non-chlorinated solvent waste. Chlorinated solvent waste is usually incinerated at high temperature to minimize the formation of dioxins.[5][6] Non-chlorinated solvent waste can be burned for energy recovery.

In contrast to this, chemical materials on the "Red List" should never be washed down a drain. This list includes:[4] compounds with transitional metals, biocides, cyanides, mineral oils and hydrocarbons, poisonous organosilicon compounds, metal phosphides, phosphorus element, and fluorides and nitrites.

Moreover, the U.S. Environmental Protection Agency (EPA) prohibits disposing certain materials down any drain.[7] Including flammable liquids, liquids capable of causing damage to wastewater facilities (this can be determined by the pH), highly viscous materials capable of causing an obstruction in the wastewater system, radioactive materials, materials that have or create a strong odor, wastewater capable of significantly raising the temperature of the system, and pharmaceuticals or endocrine disruptors.

Broken glassware are usually collected in plastic-lined cardboard boxes for landfills. Due to contamination, they are usually not suitable for recycling. Similarly, used hypodermic needles are collected as sharps and are incinerated as medical waste.

Chemical compatibility guideline

Many chemicals may react adversely when combined. It is recommended that incompatible chemicals be stored in separate areas of the lab.[8]

Acids should be separated from alkalis, metals, cyanides, sulfides, azides, phosphides, and oxidizers. The reason being, when acids combine with these type of compounds, violent exothermic reaction can occur possibly causing flammable gas, and in some cases explosions.

Oxidizers should be separated from acids, organic materials, metals, reducing agents, and ammonia. This is because when oxidizers combine with these type of compounds, inflammable, and sometimes toxic compounds can occur.

Container compatibility

When disposing hazardous laboratory chemical waste, chemical compatibility must be considered. For safe disposal, the container must be chemically compatible with the material it will hold. Chemicals must not react with, weaken, or dissolve the container or lid. Acids or bases should not be stored in metal. Hydrofluoric acid should not be stored in glass. Gasoline (solvents) should not be stored or transported in lightweight polyethylene containers such as milk jugs. Moreover, the Chemical Compatibility Guidelines should be considered for more detailed information.[9]

Laboratory waste containers
Laboratory waste containers

Packaging, labeling, and storage are the three requirements for disposing chemical waste.

Packaging

For packaging, chemical liquid waste containers should only be filled up to 75% capacity to allow for vapor expansion and to reduce potential spills which could occur from moving overfilled containers. Container material must be compatible with the stored hazardous waste. Finally, wastes must not be packaged in containers that improperly identify other non-existing hazards.

In addition to the general packaging requirements mentioned above, incompatible materials should never be mixed together in a single container. Wastes must be stored in containers compatible with the chemicals stored as mentioned in the container compatibility section. Solvent safety cans should be used to collect and temporarily store large volumes (10–20 liters) of flammable organic waste solvents, precipitates, solids or other non-fluid wastes should not be mixed into safety cans.[10]

Labeling

All containers should be labeled with the group name from the chemical waste category and an itemized list of the contents. All chemicals or anything contaminated with chemicals posing a significant hazard. All waste must be appropriately packaged.[11]

Storage

When storing chemical wastes, the containers must be in good condition and should remain closed unless waste is being added. Hazardous waste must be stored safely prior to removal from the laboratory and should not be allowed to accumulate.[10] The container should be sturdy and leak-proof, and must be labeled.[12] All liquid waste must be stored in leak-proof containers with a screw-top or other secure lid. Snap caps, mid-sized caps, parafilm and other loose fitting lids are not acceptable. If necessary, transfer waste material to a container that can be securely closed. Waste containers should be kept closed except when adding waste. Secondary containment should be in place to capture spills and leaks from the primary container, segregate incompatible hazardous wastes, such as acids and bases.[13]

Chemical waste in Canadian aquaculture

Chemical waste in oceans is becoming a major issue for marine life. There have been many studies conducted to try and prove the effects of chemicals in our oceans. In Canada, many of the studies concentrated on the Atlantic provinces, where fishing and aquaculture are an important part of the economy. In New Brunswick, a study was done on the sea urchin in an attempt to identify the effects of toxic and chemical waste on life beneath the ocean, specifically the waste from salmon farms. Sea urchins were used to check the levels of metals in the environment. It is advantageous to use green sea urchins because they are widely distributed, abundant in many locations, and easily accessible. By investigating the concentrations of metals in the green sea urchins, the impacts of chemicals from salmon aquaculture activity could be assessed and detected. Samples were taken at 25-metre intervals along a transect in the direction of the main tidal flow. The study found that there was impacts to at least 75 meters based on the intestine metal concentrations.

See also

References
  1. Hallam, Bill (April–May 2010). "Techniques for Efficient Hazardous Chemicals Handling and Disposal". Pollution Equipment News. p. 13. Archived from the original on 8 May 2013. Retrieved 10 March 2016.
  2. "Chemical Waste−an overview". Science Direct. Elsevier. Retrieved 2021-07-06.
  3. "Laboratory Chemical Waste Management Guidelines" (PDF). Environmental Health and Radiation Safety, University of Pennsylvania. Archived from the original (PDF) on 24 August 2015. Retrieved 10 March 2016.
  4. "Waste−Disposal of Laboratory Wastes (Guidance)". Health and safety. St Andrews, Scotland, UK: University of St Andrews. Retrieved 2016-02-04.
  5. Shibamoto, T; Yasuhara, A; Katami, T (2007). "Dioxin formation from waste incineration". Reviews of Environmental Contamination and Toxicology. 190: 1–41. doi:10.1007/978-0-387-36903-7_1. ISBN 978-0-387-36900-6. PMID 17432330.
  6. "Waste incineration". Summaries of EU Legislation. Luxembourg: European Union. Retrieved 10 March 2016.
  7. "Chemical Waste Management". Safety in Laboratories. Burlington, VT: University of Vermont. Archived from the original on 2016-01-31. Retrieved 2016-02-04.
  8. "Chemical Compatibility and Segregation Guides". Waste Disposal. National Institutes of Health (US). Retrieved 2016-02-12.
  9. "How to Store and Dispose of Hazardous Chemical Waste". Research Safety. University of California at San Diego. Retrieved 2016-02-12.
  10. "General Requirements". Environmental Health and Safety. University of Toronto. Retrieved 2016-02-19.
  11. "8. Management of Waste". Prudent Practices in the Laboratory: Handling and Management of Chemical Hazards: Updated Version. Washington, D.C.: National Research Council (US). 2011. ISBN 978-0-309-21158-1.
  12. "Laboratory Waste Disposal" (PDF). University of Wisconsin. 2007.
  13. "Procedures for Laboratory Chemical Waste Disposal" (PDF). St. John's, NL: Memorial University of Newfoundland. Retrieved 10 March 2016.

Further reading
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