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What are the environmental impacts of the offshore exploration drilling in KZN expected to be?

Oil spill_30 April 2012_MozApart from an accident occurring during the exploration for oil and gas off the KZN coastline, the actual operation itself will have various impacts on the area. These include Physical Impacts, such as destroying the seabed; Biological Impacts, such as changing the natural behaviour of animals; and Pollution Impacts, such as chemicals and noise. All these will occur even if a spill does not occur.

Below is a summary of the different environmental impacts which are expected to occur during oil and gas operations:

  1. Physical disturbance – will cause a disturbance to the seabed habitat and the animals (benthic fauna) which live on and in the sea bed:
    • By the Remote Operated Vehicle (ROV) which is used to undertake visual surveys of the area. The area in which the drilling occurs is too deep to send divers to so all surveys are under taken with an ROV;
    • Residual cement will be discharged to the surrounding seabed;
    • The installation of the well valves will disturb the sea bed;
    • Equipment could be lost, become irretrievable and left on the sea bed.
  1. Accumulation of excess cement (used to reinforce the drill hole walls) and disposed drill cuttings on the seabed, will cause:
    • Smothering of seabed habitat and associated benthic animals;
    • Toxicity and bioaccumulation effects on marine animals;
    • Reduced physiological functioning of marine organisms due to the biochemical effects on the water column and seabed sediments;
  1. Discharge of drilling fluids and product water will cause:
    • An increase in water turbidity and reduced light penetration;
    • Reduced physiological functioning of marine animals due to the biochemical effects on the water column and on the seabed sediments.
  1. The seabed habitat will be altered through the physical presence of man-made structures, solidified excess cement and possible loss of equipment. This will cause a  change in the benthic (on or in sea bed) and demersal (just above or on sea bed) biodiversity and biomass.
  2. Introduction of invasive alien species in the ballast water of the drilling units causing threats to South Africa’s ecosystem biodiversity.
  3. Increase in underwater and atmospheric noise levels by drilling unit, support vessels and helicopters, which will cause a disturbance and/or behavioural changes by:
    • Impacting coastal and marine animals;
    • Animals may avoid their key feeding areas;
    • The key breeding areas of coastal birds and cetaceans could result I additional noise;
    • Some animals may abandonment their nests (birds) and young (birds and seals).
  1. Discharge of waste to sea from the drill ship, its support vessels and the drilling equipment, wastes such as deck and machinery drainage, sewage and galley wastes, which will cause a reduction in water quality and cause the following:
    • Reduced physiological functioning of marine animals from the biochemical effects on the water column and seabed sediments;
    • Increased food source for marine fauna;
    • Fish aggregation and increased predator-prey interactions.
  1. Increase in ambient lighting from drilling unit, including flaring and support vessels may cause the following:
    • Disorientation and mortality of marine birds;
    • Physiological and behavioural effects on marine animals;
    • Fish aggregation and increased predator-prey interactions.
  1. Reduction in water quality due to accidental release of fuel into the sea, discharge of fuel during bunkering and discharge of hydraulic fluid due to pipe ruptures, causing toxic effects on marine biota and reduced health on marine animals.
  1. Accidental uncontrolled release of oil/gas from the well, could cause the following devastating impacts:
    • Toxic effects on marine animals and reduced animal health;
    • Pollution and smothering of coastal habitats.

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