Pollutants that Persist

Question 1

What are some features of conservative pollutants?

Answer 1

• Persist – are resistant to breakdown
• Act like conservative properties of water: ‘tracers’
• Substances falling into this group are
  
  • heavy metals, Hg, Pb, Zn, Cu, Cd, …
  • complex halogenated hydrocarbons, PCBs. pesticides etc
  • radioactive discharges
  • plastics

Question 2

What forms does mercury come in?

Answer 2

• Dissolved
• Adsorbed onto particulate matter
• Methyl mercury = organic form – linked to human deaths.

Question 3

How has mercury been used in the past?

Answer 3

• Historic use: pesticides, in drugs, lumber industries
• Industrial processes employing mercury electrodes in electrolytic processes
• Burning of fossil fuels
• Artisanal gold mining
• Batteries
• Sewage

Question 4

what is an effectr of mercury poisoning?

Answer 4

Ò

Òmethyl mercury is a cumulative toxin with very severe effects, e.g. Minimata disease

Question 5

when did mercury production peak?

Answer 5

Òconsiderable international effort to reduce the release of mercury to the environment

Épeak production methyl mercury >10,000 t in 1970s globally

Question 6

WIDER READING - mercury levels

Answer 6

Mercury Levels
‘Mercury and selenium status of bottlenose dolphins (Tursiops truncatus): A study in stranded animals on the Canary Islands’

García-Alvarez et al, (2015) (Science of the Total Enviroment)

ÒThis study reports Mercury (Hg) and selenium (Se) status, and the first Se/Hg molar ratio assessment in bottlenose dolphins (Tursiops truncatus) inhabiting the waters of the Canary Islands.

ÒTotal Hg and Se concentrations were determined in the blubber and liver collected from 30 specimens stranded along the coasts of the archipelago from 1997 to 2013.

ÒThe relationship between Hg and Se is studied because they form compounds which can be sequested from the body, (HgSe) forming the last step in mercury detoxification. A 1:1 molar ratio may protect against the toxic effects of these toxins. Conversely selenium is an essential element, therefore high levels of mercury, in turn causing selenium to be sequested could cause a selenium deficiency.

ÒA newborn and calf were among the animals studied with the lowest Hg content. Additionally, they were deficient in Se which could lead to Hg toxicity.

ÒNewborn and calf specimens of this research accumulated greater levels of Hg in the blubber than the liver.

Ò10 of 29 livers of stranded individuals (34.5%) exceeded the minimum Hg tolerance level.

ÒThe results indicate that the youngest and oldest bottlenose dolphins may be of greater toxicological concern.

ÒThe bottlenose dolphin population from the Canary Islands is not especially threatened by Hg or Se. However, concentrations of the elements were highly variable between specimens; some fall into the Hg threshold established for hepatic damage, and others are Se deficient.

Question 7

what is cadium?

Answer 7

• use in
  
  • solders, batteries, as a stabiliser in plastics
  • electroplating
  • a bi-product of zinc production
• ~ 1/2 the annual input to the marine environment is due to anthropogenic effects
• It is a ‘black list substance’
• Hard to prove directly related impacts

Question 8

What is copper

Answer 8

ÒCopper is a necessary micro-nutrient.

Ò

ÒCopper rates as third most toxic, after mercury and silver, metal for many marine organisms.

Question 9

Where has high copper levels?

Answer 9

ÒThe Fal estuary in Cornwall naturally has high levels of copper from weathering ores, and a long history of copper discharges from mineral workings.

Ò

ÐYet, the fauna is fairly typical.

Ð

ÐNotable faunal absences are molluscs.

Ð

ÐTolerant strains

Question 10

Why is lead a problem?

Answer 10

• Metallic lead tends to be re-cycled, but most of the lead compounds produced each year eventually reach the marine environment.
• 10% of all lead used annually is in the form of petrol additives, from where they enter the atmosphere and are available for deposition to the ocean.
• Highly poisonous to humans, affecting the nervous system
• ead is not particularly toxic to marine organisms, but can be bioaccumulated.

Question 11

Why is tin a problem?

Answer 11

The toxicity of organo-tin compounds to the biota is reflected in its (earlier) widespread use in anti-fouling paints e.g. TBT. – points to a whole range of marine fauna.

Question 12

Whta are organochlorines?

Answer 12

ÒOrganochlorines are organic molecules with at least one covalently bonded chlorine atom

ÒOccur naturally

ÒManmade OGCs are persistent, fat soluble and bio-accumulate

ÉVinyl chloride production, pesticides, insulators

É

É1950’s onwards release of organichemicals

Question 13

wHAT IS ddt?

Answer 13

ÒDDT (dichloro-diphenyl-trichloroethane) came into widespread use in 1939.

ÒHighly toxic to insects, but having a low toxicity to other groups,

Écheap and easy to handle

Ésingle application remains effective for a long time

Éhighly bioaccumulating.

Question 14

Why is DDT a problem?

Answer 14

Òbreaks down to DEE (dichloro-diphenyl-ethane) - by the loss of one chlorine atom.

Òmost of the chlorinated hydrocarbons in the sea are DDE, and 80% of those in marine organisms are DDE, mostly derived from DDT.

ÒEggs breaking in nets before they hatch.

Question 15

what are drins?

Answer 15

• pesticides
• fat soluble - organochlorines
• toxic breakdown

Question 16

What does DDT do in seabirds?

Answer 16

ÒDDT

ÉInterferes with calcium causing convulsions and paralysis in birds

ÉInterferes with calcium anhydrase: egg thinning

Question 17

Whta are chlorinated hydrocarbons soluble in?

Answer 17

ÒChlorinated hydrocarbons are not very soluble in seawater, but are highly soluble in fats.

Question 18

Whataffects the concentration of pollutants in blibber?

Answer 18

ÒVariation with age and gender

ÒReproductive status

ÒTopography of blubber sample

ÒTime since death/stranding

ÒGeographic location and diet

Ò

ÒImmunosuppression, fertility impacts, carcinogenic

Question 19

How are inert solids a pollutant?

Answer 19

• ÒInert solids are those that remain in particulate form. Not a pollutant untill it is interacted with.
• ÒTheir effects:
• Émainly physical:
• Ðimmediate burial and smothering
• Ðsediment stability
• Ðparticle size
• Ðturbidity
• É if contaminated with e.g. heavy metals, include a toxic element

Question 20

give some sources of inert solids

Answer 20

ÒMine waste

Échina clay – created unique assemblages of tolerant organisms.

Écoal

ÒPower station ash – fly ash – very fine and coaggulates forming a concrete like substace with little or no intertishal space.

ÒDredge spoil

ÒLitter

ÉAre plastics truly inert?

Question 21

WIDER READING fly ash

Answer 21

• ‘The Cessation of Long-term Fly-ash Dumping: Effects on Macrobenthos and Sediments.’
• Herrando-Perez & Frid 1998 (Marine Pollution Bullitin) – Publsihed - Dove Marine Lab
• ÒFour decades of continual fly-ash disposal off Northumberland, U.K., ended in December 1992. Nearly 14 × 106 tonnes of an alien material, fly ash was introduced to the inshore region of the Northumberland coast over a period of 36 years.

ÒQuantitative sampling of the sediment and the macrobenthos was undertaken in the Summer 1993 over the seabed covering the Blyth Fly-ash Dumpsite and the surrounding area

ÒContinuous dumping caused suffocation of the macrofauna which was originally a Echinocardium-filiformis community.

ÒThe seabed within the designated dumpsite was still composed of pure fly ash, resulting in macrobenthic densities and species richness markedly lower than control areas.

ÒThe quantities of dredgings and coal-ash wastes disposed of went through large fluctuations over the years, so that the seabed was subjected to a variable cocktail of pollutants.

ÒFly-ash dumping made a major contribution to the siltation of the sediments.

ÒThe sampled cobbly pozzolans were actually forming an extensive and persistent artificial reef at the seabed.

Ò(Pozzolans are a broad class of siliceous or siliceous and aluminous materials which, in themselves, possess little or no cementitious value but which will, in finely divided form and in the presence of water, react chemically with calcium hydroxide at ordinary temperature to form compounds possessing cementitious properties.)

Ò

Question 22

What are the different type of dredging?

Answer 22

]

A)Grab dredging

•e.g. Tin ore extraction

●

B)Static suction or anchor dredging

●

C)Trailer suction dredging (smaller area of impact.

D)Agitation dredging

Shakes area, lets current remove material.

Question 23

What are the impacts of dredging?

Answer 23

Impacts at dredge site

Éhabitat loss

Éin the water column: turbidity, oxygen

Érelease of contaminants CDMS

methane, hydrogen

Impacts at deposition site:

Ésmothering, alter particle size

Éfine seds: anoxic, defaunation

Éloss of spawning grounds

É

Beneficial Use

Ée.g. Wallasea Island, Essex

ÐDefra 2006

Ð550,000m3

Question 24

WIDER READING dredgoing

Answer 24

Dredging
‘Preliminary observations of the effects of dredging intensity on the re-colonisation of dredged sediments off the southeast coast of England’
Boyd et al 2003 (Estuarine, Coastal and Shelf Science)

ÒThe re-colonisation of a site used for the extraction of sand and gravel for ca. 25 years off the southeast coast of the UK was examined 4 years after the cessation of dredging.

ÒPreliminary observations indicated that the fauna remained in a perturbed state some 4 years after cessation of dredging. Therefore, relatively rapid ‘recovery’ rates, commonly cited as 2-3 years for European coastal gravelly areas, should not be assumed to be universally applicable.

ÒThe area that was previously dredged at a high intensity had a reduced complement of species and, substantially, lower densities of individual macrofaunal organisms than other sampled sediments.

Question 25

Threats to marine life from macro-litter

Answer 25

• Choking / clogging
• ‘Ghost fishing’
• Entanglement
• Drowning
• Starvation
• Rafting: spread of non-natives

Question 26

WIDER READING; accumulation of plastic debris

Answer 26

• ‘Accumulation and fragmentation of plastic debris in global environments’
  Barnes et al, (2009) (Philosophical transactions of the Royal Society B) (think it’s a review)
• • While plastics typically constitute approximately 10 per cent of discarded waste, they represent a much greater proportion of the debris accumulating on the shorelines.
• The longevity of plastic is estimated to be hundreds to thousands of years, but is likely to be far longer in deep sea and non-surface polar environments.
• Plastic debris poses considerable threat by choking and starving wildlife, distributing non-native and potentially harmful organisms, absorbing toxic chemicals and degrading to micro-plastics that may subsequently be ingested.
• There were dramatic increases in quantities of mega- and macro-plastic debris in the northern hemisphere up to the 1990s. Quantities of debris in the oceans appear to have stabilized over the last decade but have increased on shorelines.
• Fouled by organisms and sediment, plastics can sink and form an even higher proportion of human waste reaching the seabed, and quantities in excess of tens of thousands of items square kilometer’s been reported.
• Contamination of the environment by micro-plastic pieces seems set to increase.
• Haline environment’s, the cooling effect of the ocean and fouling by organisms protect plastic from degradation from UV in the ocean.
• In Europe plastics are estimated to comprise of 7 % (UK 8-10%) of waste mass as generated.
• Plastics comprise of approximately 10 per cent of municipal waste mass around the world. In contrast, plastics comprise 50-80% of the waste stranded on beaches, floating on the ocean surface and on the Seabed.

Question 27

What are microplastics?

Answer 27

• Plastics < 5mm
• Fragmentation of macro-litter
• Nurdles
• Cleaning products
• Exfoliants in facial cleansers

Question 28

How do microsplatics have an toxic affect?

Answer 28

Micro-plastics can adsorb toxins onto their surface and provide a dose mechanism of poison to marine animals that ingest them

Nurdles are used in packaging and as plastic stock.

Question 29

What toxins are associated with plastic?

Answer 29

• Additives (plastics have toxins put in)
• Small molecular size, usually not bound to polymer
• Lipophilic
• E.g. flame retardants
• Phthalates and bisphenol A (BPA)
• Chemicals adsorp to surface
• Nurdles pick up and condense any chemical compounds in the water column.

Question 30

WIDER READING: plastics and persistan pollutants.

Answer 30

Plastics & Persistant Pollutants
‘Polychlorinated biphenyls and organochlorine pesticides in plastics ingested by seabirds’

• Colabuono et al, (2010) (Marine Pollution Bullutin)
• Procellariiformes is an order of seabirds that comprises four families: the albatrosses, petrels and shearwaters, and 2 families of storm petrels.
• The occurrence of plastic objects in the digestive tract was assessed in eight species of Procellariiformes collected in southern Brazil. Within the pellets the occurrence of polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs) were evaluated (which are both persistent organic pollutants).
• Among the OCPs, p,p′-DDE had the highest concentrations
• The occurrence of organic pollutants in post-consumer plastics supports the fact that plastics are an important source carrying persistent organic pollutants in the marine environment (plastic debris accumulates contaminants due to its hydrophobic nature)
• Although transfer through the food chain may be the main source of exposure to POPs to seabirds, plastics could be an additional source for the organisms which ingest them, like Procellariiformes which are the seabirds most affected by plastic pollution.
• Plastic objects were found in 28% of the birds
• All plastics ingested by the birds in the present study, with the exception of one nylon line piece were less dense than sea water and were therefore able to float on the ocean surface. Consequently, these plastics could float long distances and take on contaminants from sea water before being ingested by the birds.
• The profiles of organochlorine compounds found in the plastics analyzed in the present study are similar to those seen in these seabirds. Although transfer through the food chain may be the main source of exposure of POPs to seabirds.

Question 31

How can microplastics affect biota?

Answer 31

ÒBioavailable to smaller organisms

Épermeate foodwebs

ÒGreater surface area

Émore adsorption power for toxins

ÒReduction of feeding (Besseling et al., 2013)

ÒReduction of reproductive success (Lee et al., 2013)

ÒReduced energy production (Oliveira et al., 2013)

ÒNo effects (Van Cauwenberghe et al., 2013)

ÒSee Bottrell et al 2019 review on impacts on plankton – mixed results from studies

Question 32

WIDER READSING: plastic contamination in decapod crustaceans

Answer 32

‘Plastic contamination in the decapod crustacean Nephrops norvegicus (Linnaeus, 1758)’
Murray & Cowie (2011) (Marine pollution bulletin)

ÒPlastic contamination was found to be high in Nephrops, 83% of the animals sampled contained plastics (predominately filaments) in their stomachs.

ÒTightly tangled balls of plastic strands were found in 62% of the animals studied but were least prevalent in animals which had recently molted.

ÒSome of the plastics found in the Nephrops were positively identified as being used in the fishing industry for rope and nets, and potentially also by the recreational yachting industry.

ÉSome vessels in the Clyde deliberately use bundles of hard rope as “chafers” which protect expensive nets by fraying along the seabed. Fisheries restrictions do not focus on the chafers being a pollutant.

ÒThere is a potential for mobilised chemicals to occur in Nephrops tail flesh, which is eaten, and is a potential health concern.

ÒThe results of this study clearly show that Nephrops in the Clyde are consuming plastics and that one of the sources of this plastic is the rope used by the Nephrops fishery itself.