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ENVS232 Marine Pollution > heavy metal pollution > Flashcards

heavy metal pollution Flashcards

1
Q

what are heavy metals?

A

any metallic chemical element that has a relatively
high density.

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2
Q

What are trace metals?

A

present at very low (‘trace’) concentrations in the
environment (most trace metals are heavy metals).

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3
Q

What is bioaccumulation?

A

Bioaccumulation means an increase in the concentration of a chemical within an organism over time, compared to the chemical’s concentration in the environment.

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4
Q

What is biomagnification?

A

Biomagnification means the element concentrates up the food chain, with organisms at higher trophic levels most affected.

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5
Q

Why are heavy metals dangerous?

A

Heavy metals can be dangerous because they can bioaccumulate or biomagnify.

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6
Q

What happens when compounds are taken up and stored faster than they are broken down or excreted in living things?

A

They accumulate in living things.

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7
Q

Which process describes the increase in chemical concentration within an organism over time?

A

Bioaccumulation.

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8
Q

Which process describes the concentration of elements up the food chain?

A

Biomagnification.

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9
Q

Can many metals exist dissolved in water and be toxic?

A

Yes, many metals can exist dissolved in water and be toxic or poisonous even at low concentrations.

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10
Q

Are any metals essential to life?

A

Yes, some metals are essential elements to life but can be toxic at certain concentrations or in certain forms (chemical species).

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11
Q

Under what conditions can essential metals become toxic?

A

Essential metals can become toxic at certain concentrations or in certain chemical forms.

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12
Q

What determines the toxicity of metals that are essential to life?

A

The concentration and the chemical form (species) of the metals determine their toxicity.

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13
Q

Why does speciation matter for arsenic (As)?

A

Because As(III) is much more toxic than As(V).

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14
Q

Why does speciation matter for chromium (Cr)?

A

Because Cr(III) is a required nutrient, whereas Cr(VI) is deadly.

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15
Q

How does the toxicity of lead (Pb) vary?

A

Inorganic lead compounds are less toxic than organic lead compounds.

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16
Q

Why does speciation matter for mercury (Hg)?

A

Hg(0) has low risk, while Hg(II) and organic mercury compounds are deadly.

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17
Q

What factor determines the toxicity of these metals?

A

The dosage or concentration determines the toxicity.

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18
Q

What is the saying about pollution and dilution?

A

“The solution to pollution is dilution,” unless you are a homeopath.

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19
Q

List the elements As, Cr, Hg, Pb in terms of toxicity variation based on speciation.

A

Arsenic (As), Chromium (Cr), Mercury (Hg), Lead (Pb).

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20
Q

What is speciation in the context of elements like arsenic or mercury?

A

Speciation refers to the chemical distribution of an element in its environment.

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21
Q

What is speciation analysis?

A

Speciation analysis is the analytical activity of identifying and/or measuring the quantities of one or more individual chemical species in a sample.

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22
Q

How are chemical species defined in speciation analysis?

A

Chemical species are specific forms of an element defined by isotopic composition, electronic or oxidation state, and/or complex or molecular structure.

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23
Q

Why is speciation important?

A

Because each chemical species behaves differently in terms of mobility, bioavailability, and toxicity.

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24
Q

What factors can define a chemical species in speciation analysis?

A

Isotopic composition, electronic or oxidation state, and complex or molecular structure.

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25
Q

How do different chemical species impact environmental behavior?

A

They impact mobility, bioavailability, and toxicity differently.

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26
Q

What does “bioessential” mean?

A

Bioessential refers to something that is essential for life, particularly metals that are crucial for biological processes that maintain life.

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27
Q

Where are bioessential metals often found in the body?

A

Bioessential metals are often found in enzymes, other proteins, and in our red blood cells.

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28
Q

Give examples of bioessential metals.

A

Examples of bioessential metals include Fe (Iron), Zn (Zinc), Co (Cobalt), Mn (Manganese), and Ni (Nickel).

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29
Q

What does “toxic” mean in the context of metals?

A

Toxic refers to something that can cause death or illness in an organism. Some metals are always considered toxic, while others are toxic at high concentrations.

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30
Q

Give examples of metals that are considered toxic.

A

Examples of toxic metals include Pb (Lead), As (Arsenic), Hg (Mercury), and Sn (Tin).

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31
Q

Can bioessential elements become toxic?

A

Yes, the concentration at which an element goes from being bioessential to toxic varies for different elements.

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32
Q

What roles do metals play in proteins and enzymes?

A

Metals are key components in proteins and enzymes, being crucial for various biological activities

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33
Q

List some biologically active trace metals.

A

Biologically active trace metals include Fe, Zn, V, Cr, Ni, Co, Cu, Mo, and Se.

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34
Q

Which metals are influenced by biological activity?

A

Metals influenced by biological activity include Cd, Pb, Hg, Au, Sb, and As.

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35
Q

What processes involve Fe-containing molecules?

A

Fe-containing molecules are involved in photosynthetic and respiratory processes, denitrification, and N2 fixation.

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36
Q

What is the role of Ni in biological processes?

A

Ni is a co-factor in the enzyme urease, which is required for the assimilation of urea as a nitrogen source.

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37
Q

What enzyme requires Zn, and what happens when Zn is deficient?

A

The enzyme carbonic anhydrase requires Zn. When Zn is deficient, it can be replaced by Cd or Co.

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38
Q

What is carbon fixation?

A

Carbon fixation is the conversion of inorganic carbon into organic carbon by living organisms, occurring through processes like photosynthesis and chemosynthesis.

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39
Q

What is remineralisation?

A

Remineralisation is the conversion of organic forms into inorganic elemental forms.

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40
Q

What is N2 fixation?

A

N2 fixation is the process of converting unreactive dinitrogen (N2) from the atmosphere into biologically available nitrogen forms such as ammonium, nitrate, or nitrite.

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41
Q

What is nitrification?

A

Nitrification is the process of nitrogen compound oxidation

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42
Q

Is denitrification the reverse of nitrification?

A

No, denitrification is not the reverse of nitrification. It is the removal of nitrate by its reduction to nitrogen gas.

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43
Q

What are photopigments?

A

Photopigments are photosynthetic pigments, such as chlorophyll and carotenoids, that transform light into biochemical energy.

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44
Q

What are some anthropogenic sources of metals entering the environment?

A

Mining, smelting, fossil fuel combustion (e.g., coal burning), the automotive industry, industrial effluents (e.g., tanning, chlorine production), and sewage.

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45
Q

What are some natural sources of metals entering the environment?

A

Weathering/erosion, dust particles (wind-blown, forest fires), volcanoes, and hydrothermal vents.

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46
Q

How do metals enter the marine system through atmospheric deposition?

A

Metals enter the marine system through atmospheric deposition in both coastal and open oceans.

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47
Q

How do rivers contribute to metal inputs in the marine environment?

A

Rivers contribute to metal inputs through river inputs and runoff waters into coastal areas.

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48
Q

What is Submarine Groundwater Discharge (SGD)?

A

Submarine Groundwater Discharge (SGD) is a process through which metals enter the marine system.

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49
Q

How does sediment release contribute to metal inputs in the marine environment?

A

Sediment release from the continental shelf contributes to metal inputs in the marine environment.

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50
Q

How do antifouling paints from ships impact the marine environment?

A

Antifouling paints from ships introduce metals into the marine environment, predominantly in coastal waters and harbors/marinas.

51
Q

What role do hydrothermal inputs play in metal deposition in the marine system?

A

Hydrothermal inputs contribute to metal deposition in the marine system.

52
Q

Are only bio-essential metals bio-accumulated?

A

No, not only bio-essential metals are bio-accumulated but also other metals like Pb.

53
Q

At what concentrations are trace metals present in plankton biomass?

A

Trace metals are present in plankton biomass at concentrations ranging from about 50 mmol/mol C (~1000 μM) for Fe down to approximately 2 mmol/mol C (~30 μM) for Co.

54
Q

How do these toxic effects of trace metals impact algae?

A

These effects may strongly inhibit primary production in algae.

55
Q

What does biological uptake refer to?

A

Biological uptake refers to the process where organisms absorb metals from their environment, including both bio-essential and other metals like Pb.

56
Q

What are some toxic effects of trace metals on algae?

A

Reduction of photosynthetic carbon fixation, inhibition of oxygen consumption, disruption of nutrient uptake processes, inhibition of enzyme reactions or protein synthesis, production of abnormal morphological development (e.g., impairment of motility with loss of flagella), and degradation of photosynthetic pigments.

57
Q

How do metals accumulate in sediments?

A

Metals accumulate in sediments by being adsorbed onto inorganic or organic surfaces or by forming complexes with sulphide, followed by precipitation of these metal-sulphide complexes.

58
Q

How can metals be released back into the water column from sediments?

A

Metals can be released back into the water column through various processes, including re-suspension processes (e.g., storms, dredging, trawling), dissolution of iron oxides due to reductive conditions, and oxidation of metal-sulphide complexes.

59
Q

What happens to iron oxides in estuaries as ionic strength increases?

A

As ionic strength increases in an estuary, it leads to the formation of iron oxides.

60
Q

How do iron oxides contribute to the removal of trace metals in estuaries?

A

Iron oxides are strong adsorbents for trace metals, and along salinity gradients, they sink to the sediment, taking with them adsorbed metals and effectively removing them from the water column.

61
Q

What determines the extent of metal removal in estuarine systems?

A

The extent of metal removal in estuarine systems is dependent on the water’s physico-chemical properties

62
Q

What role do sediments play in estuarine systems regarding metal accumulation?

A

Sediments in estuarine systems accumulate large amounts of metals and limit the amount of metals that reach marine waters.

63
Q

What happens to metals released from hydrothermal vents?

A

Most of the metals released from hydrothermal vents precipitate with sulfur immediately in the vicinity of the vent.

64
Q

What is the purpose of antifouling agents in marine infrastructure?

A

Antifouling agents prevent or slow the growth of organisms that attach to marine infrastructure, improving its performance and durability.

65
Q

What are some benefits of using antifouling paint?

A

Some benefits include substantial fuel savings, reduced emissions of greenhouse gases, less maintenance, and equipment working more efficiently for longer periods.

66
Q

What is Tributyl Tin (TBT)?

A

Tributyl Tin (TBT) is a class of organotin compounds that contain the (C4H9)3Sn group, such as tributyltin hydride or tributyltin oxide.

67
Q

When were the antifouling properties of TBT discovered, and how has it been used?

A

The antifouling properties of TBT were discovered in the 1950s, and it has been used as a biocide in antifouling paint on boat hulls and other marine structures for around 40 years

68
Q

What is the concern regarding TBT use in antifouling paint?

A

Although effective, TBT-derived leachates are highly toxic to other marine organisms, even at low concentrations.

69
Q

When were the first issues regarding Tributyl Tin (TBT) documented?

A

The first issues were documented in the late 1970s in the Bay of Biscay, showing a severe decrease in Pacific oyster production

70
Q

Which organisms are particularly affected by TBT toxicity?

A

TBT is particularly toxic to sea snails, mussels, clams, oysters, crustaceans (lobsters, crayfish, crabs), zebrafish, and even rats.

71
Q

What is significant about TBT’s impact on marine organisms?

A

TBT was the first documented endocrine disruptor in the marine environment.

72
Q

What condition affects female dog whelk snails due to TBT exposure?

A

Female dog whelk snails develop a condition called imposex, where they become sterile and grow male sex organs.

73
Q

What are some effects of TBT exposure on marine organisms?

A

TBT exposure can induce structural changes such as thick shells, changes in overall shape, growth retardation, and death.

74
Q

Why is imposex particularly dangerous?

A

Imposing is particularly dangerous because it impacts development, which has led to the collapse of whole populations of organisms.

75
Q

What is the effect of TBT bioaccumulation?

A

TBT bioaccumulates up the food chain.

76
Q

What is the half-life of TBT?

A

TBT has a long half-life of 2 years.

77
Q

How long can TBT remain in sediments and continue to be released?

A

TBT can remain in sediments and continue to be released for up to 30 years.

78
Q

When were restrictions brought in for TBT, and when was it fully banned?

A

Restrictions were brought in during the 1980s, and TBT was fully banned in 2008. However, it is still used in under-regulated countries and in some antibacterial products.

79
Q

How long has copper been used as an antifouling agent?

A

Copper has been used as a major ingredient in antifouling agents for many years, dating back to the early Phoenicians and Carthaginians around 2000 years ago.

80
Q

Is copper naturally occurring?

A

Yes, copper is naturally occurring.

81
Q

Why is copper considered an essential element?

A

Copper is considered an essential element required for normal growth by both plants and animals, but only at low concentrations.

82
Q

What compounds are commonly approved and used in antifouling paints for underwater hull protection?

A

Copper compounds are commonly approved and used in antifouling paints for underwater hull protection.

83
Q

Which form of copper is generally considered most responsible for copper toxicity?

A

The cupric ion (Cu2+) is generally considered most responsible for copper toxicity.

84
Q

What is Coppercoat™?

A

Coppercoat™ is the combination of a specially developed solvent-free epoxy resin and high purity (99%) copper.

85
Q

How is Coppercoat™ formulated to maximize its effectiveness?

A

Each liter of resin in Coppercoat™ is impregnated with 2 kilos of ultra-fine spherical copper powder, the maximum allowed by law, making it the strongest copper-based antifouling available.

86
Q

How is copper utilized as an anti-fouling agent on boats?

A

Copper is widely used as an anti-fouling agent on boats due to its strong efficiency as an insecticide, algicide, or molluscicide.

87
Q

What is the toxicity of copper for phytoplankton?

A

Copper is extremely toxic for phytoplankton. Even low concentrations of free copper in the picomolar (pM) range have been found sufficient to limit the biological activity of many species.

88
Q

What concerns have some EU authorities raised regarding copper compounds in antifouling paints?

A

Some EU authorities have raised concerns over copper compounds used in antifouling paints on pleasure craft, leading to restrictions and/or bans of copper-based anti-fouling paints in countries like Sweden and the Netherlands.

89
Q

What specific regulations regarding copper-based antifouling paints exist in Denmark?

A

In Denmark, the import, marketing, and use of biocidal antifouling paint are banned if the release of copper exceeds 200μg Cu/cm2 after the first 14 days and 350μg copper/cm2 after the first 30 days. This ban applies to pleasure crafts of 200 kg and above, mainly used in saltwater.

90
Q

What factors have led to bans or restrictions on copper-based antifouling paints in certain regions?

A

Bans or restrictions have been implemented due to perceived risks to unique environmentally sensitive local environments.

91
Q

What is the status of copper use in antifouling paints in the USA?

A

In the USA, the use of copper is currently under review by the EPA (Environmental Protection Agency).

92
Q

What concern exists regarding copper in waters of Californian harbors and marinas?

A

There is concern over the amount of copper in the waters of Californian harbors and marinas. Antifouling paints have been identified as a major source of copper in these areas.

93
Q

How has copper historically been regulated?

A

Historically, copper has been regulated based on total concentration.

94
Q

Why is there increasing recognition that regulating copper based solely on total concentration is oversimplistic?

A

There is increasing recognition that regulating copper based solely on total concentration is oversimplistic because any assessment of copper impacts should include bioavailability.

95
Q

What controls copper speciation, and why is this important in assessing its toxicity?

A

Water characteristics control copper speciation, and speciation controls toxicity.

96
Q

How does copper behave in terms of toxicity and micronutrient status?

A

Copper can be both toxic and a micronutrient, depending on the species and the concentration (or bioavailability).

97
Q

What is complexation in the context of trace metals in seawater?

A

Complexation refers to the formation of complexes when free metal ions bind with ligands present in seawater.

98
Q

How do complexes formed through complexation affect trace metal bioavailability?

A

Complexes formed through complexation affect trace metal bioavailability based on the type of ligand and the strength of the complex.

99
Q

What is a ligand in the context of complexation?

A

A ligand is an ion or molecule that is attached to a metal ion by coordinate bonding.

100
Q

What are siderophores and how do they affect iron complexation?

A

Siderophores are strong Fe complexing agents released by certain bacteria to mop up weakly bound Fe, enhancing iron complexation.

101
Q

What are thiols and how do they affect copper complexation?

A

Thiols form strong complexes with Cu and are released during Cu stress, reducing Cu bioavailability and thereby reducing Cu toxicity.

102
Q

What are exopolysaccharides and how do they affect iron complexation?

A

Exopolysaccharides form complexes with Fe and are highly bioavailable. They can increase the residence time of bioavailable Fe in the euphotic zone.

103
Q

How does a natural wetland play a role in mitigating metal pollution in the Afon Goch?

A

A natural wetland now acts as a reed-bed, naturally removing excess metals from the water.

103
Q

What is the Afon Goch known for?

A

The Afon Goch, meaning ‘Red River’ in Welsh, was one of the largest sources of copper pollution to the Irish Sea due to discharge of highly acidic polluted water from the Parys mine in North Wales.

104
Q

What role do organic ligands produced by fauna within the wetland play in metal removal?

A

Organic ligands produced by fauna within the wetland absorb and bind free metals, concentrating them in the sedimentary deposits, effectively removing them from the water and incorporating them into the geological cycle.

105
Q

What happened on April 21, 1956, in Minamata Bay, Japan?

A

On April 21, 1956, a 5-year-old girl presented unusual symptoms including difficulty walking and speaking, as well as convulsions.

106
Q

What occurred on April 23, 1956, related to the symptoms observed in Minamata Bay?

A

On April 23, 1956, the same symptoms were observed in the girl’s sister, prompting a screening test of the area.

107
Q

What was discovered on May 1, 1956, in Minamata Bay?

A

On May 1, 1956, the discovery of an “epidemic of unknown disease of the central nervous system” was made in Minamata Bay.

108
Q

What was the situation by October 1956 in Minamata Bay?

A

By October 1956, 40 patients were identified, 14 of whom had died from the mysterious disease.

109
Q

Who were the victims of the epidemic in Minamata Bay?

A

The victims were all from fishing hamlets along the shore of Minamata Bay, where food was mostly based on a diet of fish and shellfish.

110
Q

What did a British neurologist identify in relation to the symptoms observed in Minamata Bay?

A

A British neurologist identified the symptoms as being related to organic mercury poisoning.

111
Q

What was Chisso’s company using mercury chloride (HgCl2) for?

A

Chisso’s company was using mercury chloride (HgCl2) as a catalyst for the production of chlorine.

112
Q

How was inorganic mercury released, and what was its biological transformation?

A

Inorganic mercury released by Chisso’s company was biologically transformed into methyl mercury (CH3Hg) by bacteria in the sediments, or methyl mercury was directly released from the plant.

113
Q

What controls were in place regarding the release of methyl mercury during that time?

A

There were no controls in place regarding the release of methyl mercury during that time.

114
Q

What is a highly volatile element used in many different applications such as light bulbs, thermometers, batteries, and dental fillings?

A

Mercury (Hg)

115
Q

What common items contain mercury?

A

Light bulbs (especially fluorescent), thermometers, some types of batteries, and dental fillings (amalgam)

116
Q

How is mercury released into the environment?

A

Mercury is released through waste incineration and fuel combustion

117
Q

How have concentrations of mercury in surface waters changed since pre-industrial times?

A

Concentrations of mercury in surface waters have tripled since pre-industrial times (Lamborg et al., 2014, Nature).

118
Q

What environmental impact does mercury have on the food chain?

A

Mercury is biomagnified along the food chain, leading to higher concentrations in organisms at higher trophic levels

119
Q

Why are there consumption restrictions on fish at higher trophic levels?

A

Due to the biomagnification of mercury, which poses health risks when consuming fish with high mercury concentrations

120
Q

Why are pregnant women recommended to lower their consumption of fish?

A

Due to mercury contamination in fish, which can harm developing foetuses and infants

121
Q

What are the effects of mercury exposure on foetuses and infants?

A

Mental retardation
Cerebral palsy
Blindness and deafness
Speech disturbances
Muscle rigidity

122
Q

How many newborns in the US are estimated to be at risk each year due to contaminated seafood?

A

Approximately 300,000 newborns per year (Mahaffey, 2004).

123
Q
A

ENVS232 Marine Pollution (24 decks)

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