topic d6 Flashcards
Define high-level waste
waste that gives off large amounts of ionising
radiation for a long time.
how is high-level waste produced and what does it contain?
Produced in nuclear reactors and contains a mixture of nuclear fission products with unused nuclear fuel
Radionuclides with long half-lives or high activity for shorter.
how is HLW disposed of?
Waste is vitrified or immobilised, then encased in steel cylinders, covered with concrete and buried deep underground in geologically stable locations.
Define low-level waste
waste that gives off small amounts of ionising
radiation for a short time.
explain how LLW is disposed of
- has limited environmental impact and is usually suitable for shallow land burial or incineration
Some types (i.e. large quantities/high concentrations of radionuclides) must be stored for days/weeks in shielded containers until most of the isotopes have decayed and the radiation level has dropped below a safe limit.
give examples of LLW
Radionuclides with low activity/short half life
Eg contaminated syringes, swabs, protective clothing, etc
describe how nuclear waste is produced
Many medical procedures involve the use of radionuclides (unstable isotopes that undergo spontaneous radioactive decay)
Administered as water-soluble salts/radiopharmaceutical drugs
Used in medical equipment as sources of ionising radiation
During these medical procedures radionuclides + ionising radiation come into contact with various materials, which subsequently become radioactive.
These materials, along with leftover radionuclides, produce nuclear waste.
what is the issue with the treatment, transportation and disposal of nuclear waste
present serious risks due to possible release of radionuclides to the environment.
what does ionising radiation cause in living organisms?
Cellular and genetic damage, mutations, increased probability of developing diseases such as cancer, birth defects and reproductive disorders. Also weakens the immune system.
environmental issues related to left-over organic solvents
Organic solvents used in the pharmaceutical industry constitute a significant proportion of chemical waste:
- most are toxic to living organisms, affecting
Nervous/respiratory systems, liver, kidneys, reproductive organs
- benzene (C6H6) and chloroform (CHCl3) increase risk of cancer
- many solvents are highly flammable while their vapours contribute to the greenhouse effect
environmental issues associate with chlorinated solvents
- due to low bond enthalpy of C-Cl bonds, they act as ozone-depleting agents and contribute to the formation of photochemical smog in large cities.
- some have low biodegradability and may accumulate in groundwater, causing damage to ecosystems
issues with the disposal of organic/chlorinated solvents
- expensive + complex
- cannot be incinerated with common organic waste as their incomplete combustion could produce highly toxic phosgene (COCl2) and dioxins.
- must be oxidised separately at high temperatures/recycled by distillation.
Explain the dangers of antibiotic waste from hospitals and the pharmaceutical industry
Hospitals and the pharmaceutical industry release antibacterial waste
Exposure to low levels of antibiotics allows some bacteria to survive and mutate
when does antibiotic resistance occur?
when microorganisms become resistant to antibacterials.
Explain the dangers of antibiotic waste from the agricultural industry
They are never completely metabolised in animal organisms, so a % of each drug is excreted, therefore released into the groundwater and absorbed by other organisms. Some are also consumed by humans through animal food.
