water toxicants Flashcards
What are the main uses of water in relation to food? (6)
ingredient food processing irrigation livestock drinking water aquaculture post harvest activities
Water may lead to what types of contaminants?
organic (pesticides, PAHs, Volatile organic compounds)
inorganic (trace metals, nitrates, radioactive compounds)
biological hazards (pathogens, toxins)
common trace metals found in ground and surface water: (7)
Pb, Cu, Cr, As, Hg, Cd, Zn
What are VOCs? Where are they commonly found in water?
volatile organic compounds
in ground/surface water in urban area
PAHs are: _____. How are they produced?
polyaromatic hydrocarbons
incomplete combustion of organic material
examples of radioactive elements contaminating water:
Iodine 131, Cesium 137, Barium 140
Rice has been noted to have high levels of _____, due to _____.
arsenic
contaminated irrigation water
How does contaminated water affect agriculture in the food supply chain?
irrigation: may introduce chemical contaminants and pathogens from wastewater
animals: contaminants may accumulate; be present in meat and other products
aquaculture: accumulate in fish
What is the source of many inorganic contaminants? (6)
natural deposits discharge from metal refineries wastewater from factories/plants mining pipe corrosion fertilizer runoff
What is a common source of nitrates in water?
fertilizer runoff, septic leaching
Do contaminant levels stay constant in water? Why or why not?
no, varies with time
depends on rainfall, season, changes in land, human activity, etc
What could cause an increase in PAHs in seafood?
pollution; oil spill
True/False: a larger fish will have lower concentration of contaminants in its meat, because it is evenly distributed throughout
FALSE: higher concentration due to BIOACCUMULATION
consumption of _____ fish should be limited, especially for ____. Why?
large, carnivorous
pregnant women, children
higher levels of toxicants such as mercury, PAHs, etc
The levels of contaminants present in the fish will depend on:
location it was grown/caught
species
size
Why would wastewater be commonly used as an irrigation source despite risks? (2)
Used in rural areas; other sources are not available (poorer areas, developing countries)
wastes in water can be fertilizer, has nutrients
How can wastewater be safely reused? How can this be done? (3)
INDIRECT reuse; need intermediate step
(some disinfection, filtration, treatment)
use as water for growing feed (pasture, aquatic plants)
refill aquifers (groundwater supply)
use for irrigation, but not in contact with edible portions
*keep away from potable water supplies
Where can water be sourced from? (4)
private supply (rainwater, groundwater, surface water) public supply
Should the use of wastewater in agriculture be banned?
No; impact livelihood of many farmers with no other choice; wasting nutrients in wastewater1
In what ways does water quality influence food, in addition to safety?
affect food processing
affect sensory qualities
____ water is safe, drinkable water.
potable
food production/processing must use ____ water.
potable
The CFIA guidelines for food industries: (3)
- meet water safety req for handling, production, processing of food (*and have action plan if water become unsafe - boil water alert)
- establish communication with municipal/provincial authorities to stay informed about safety status of water
- the industry is responsible for producing safe food! CFIA will inspect and enforce
What criteria need to be checked to see if the water is suitable to use? (4)
- Does it contain biological or chemical hazards in significant amounts?
- is it to be consumed, or contact consumables?
- Is it going to be treated to eliminate hazards before contact/consumption?
- is the final product going to be treated to eliminate hazards before consumption?
