AP Environmental Science

## Learning Outcomes

- Define **ocean dumping** and distinguish it from broader marine debris pollution
- Explain how ocean dumping harms marine organisms through ingestion, entanglement, and oxygen stress
- Identify how dumped materials damage coastal and benthic habitats
- Understand how sewage sludge and dredged material cause different environmental impacts
- Describe how persistent pollutants can enter marine food webs through bioaccumulation and biomagnification
- Connect ocean dumping to human impacts such as fisheries losses, beach contamination, and seafood safety concerns
- Recall key U.S. laws and international rules that regulate or restrict ocean dumping

## AP Environmental Science Syllabus

For the AP Environmental Science, you are expected to understand ocean dumping consequences, with a focus on the following syllabus points:

- Know that **ocean dumping** is the deliberate disposal of waste at sea and is different from general land-based marine litter
- Identify major ecological consequences, including wildlife injury or death, habitat degradation, and water-quality decline
- Explain how plastics cause **ingestion**, **entanglement**, and the formation of **microplastics**
- Understand how nutrient-rich waste can increase **biological oxygen demand (BOD)**, lower dissolved oxygen, and contribute to **eutrophication**
- Distinguish the impacts of **sewage sludge dumping** from **dredged material dumping**
- Explain how toxic substances can enter marine food webs through **bioaccumulation** and **biomagnification**
- Know that U.S. ocean dumping is regulated by the **Marine Protection, Research, and Sanctuaries Act (1972)** and that sewage sludge and industrial waste dumping were banned after **1991**
- Use a historical example such as the **New York Bight** to show why regulation became stricter

## Test Your Knowledge

_Attempt these questions before reading this article. If you find some difficult or cannot remember the answers, look more closely at that area during your revision._

1. What is the difference between ocean dumping and marine debris more generally?
2. How can dumped waste lower dissolved oxygen in seawater?
3. Name two ways plastics harm marine animals.
4. Why is dredged material especially dangerous for benthic organisms?
5. Which U.S. law regulates intentional ocean dumping?

## Introduction

Ocean dumping may seem like an easy disposal method because the ocean is large, moving, and out of sight for most people. For AP Environmental Science, though, the key idea is that dumping waste into the ocean does not remove the problem. It transfers the problem into marine marine environmentss, where pollutants can spread, persist, and harm organisms, habitats, and human economic activities.

This topic sits at the intersection of solid waste disposal, aquatic pollution, food webs, and environmental policy. Exam questions often ask you not just to name a consequence, but to explain the mechanism: how dumped waste causes injury, oxygen depletion, habitat burial, or contaminant transfer through the food chain.

> **Key Term: ocean dumping**
> The deliberate disposal of municipal, industrial, sewage, dredged, or hazardous waste materials into ocean waters.

### Why ocean dumping is harmful even when the ocean seems “big enough”

A common mistake is to assume that dilution solves pollution. The ocean is huge, but that does not mean wastes disappear. Many materials float, sink, fragment, accumulate in currents, or persist in sediments for years to centuries. This is why the exam often rewards answers that explain what happens after disposal, not just where waste goes.

There are two broad reasons ocean dumping is dangerous:

- some wastes cause **physical damage**
- some wastes cause **chemical and biological damage**

Physical damage includes burial of organisms, entanglement in plastics or fishing gear, and abrasion or crushing of habitats. Chemical and biological damage includes nutrient enrichment, oxygen depletion, pathogen contamination, and toxic pollutant transfer.

> **Key Term: marine debris**
> Persistent human-made material in the ocean, including plastics, nets, and other discarded waste.

Ocean dumping is only one source of marine debris. Much marine litter comes from land through rivers, runoff, and wind. That distinction matters on the AP exam: ocean dumping is intentional disposal at sea, while marine debris can come from many pathways.

> **Key Term: microplastics**
> Plastic particles smaller than 5 mm, formed by the breakdown of larger plastics or released directly into the environment.

Microplastics are especially important because they show why “breaking down” is not the same as becoming harmless. A plastic bottle may fragment into smaller and smaller pieces, but those pieces remain plastic. They can be eaten by plankton, small fish, and seabirds, then move through the food web.

A strong cause-and-effect chain looks like this:

- larger plastic enters the ocean
- sunlight and wave action break it into smaller pieces
- organisms ingest the fragments
- digestion cannot remove them easily
- feeding, growth, or survival is reduced
  > **Test Tip:** If a question says “explain,” use arrows or a chain in your mind: dumped waste → environmental change → effect on organism or people. One named consequence alone is usually too thin for full credit.

### Harm to marine organisms: ingestion, entanglement, and oxygen stress

One of the safest and most exam-ready consequences to use is direct harm to marine organisms. Plastics, discarded fishing gear, and other floating debris can injure animals in two major ways: **ingestion** and **entanglement**.

> **Key Term: ingestion**
> The uptake of waste material by an organism through eating or swallowing it.

When seabirds, sea turtles, fish, or marine mammals mistake plastic for food, they may swallow it. This can block the digestive tract, reduce feeding, or create a false sense of fullness. A turtle that eats plastic bags may stop eating real prey and slowly starve even though its stomach seems full.

> **Key Term: entanglement**
> The trapping or wrapping of animals in waste such as plastic bands, ropes, or fishing nets.

Entanglement causes a different kind of harm. Nets and lines can trap animals so they cannot swim, surface, feed, or escape predators. Wounds may become infected, and some animals drown. Abandoned fishing gear can continue catching animals long after it is discarded, a process sometimes called ghost fishing.

NOAA notes that marine debris affects hundreds of wildlife species. That matters because exam questions often ask for biodiversity impacts. If many species are harmed across multiple trophic levels, food-web stability can also be affected.

Ocean dumping can also harm organisms indirectly through oxygen depletion. Sewage sludge and other organic wastes provide food for decomposer bacteria. As bacterial populations increase, they use more oxygen during respiration.

> **Key Term: biological oxygen demand (BOD)**
> The amount of oxygen required by microorganisms to break down organic matter in water.

When BOD rises, dissolved oxygen tends to fall. Fish, invertebrates, and many aerobic organisms then experience stress or die. This is not just a sewage issue on land; it can happen in marine disposal areas too.

The reasoning chain is:

- sewage sludge adds organic matter
- decomposers break it down
- decomposers use oxygen
- BOD rises
- dissolved oxygen drops
- hypoxia or fish kills may follow

This is why APES often links ocean dumping to concepts from water pollution, not just solid waste.

### Habitat damage: from benthic burial to turbidity and smothering

Ocean dumping does not just affect individual animals. It can also damage whole habitats, especially on the seafloor and in shallow coastal environmentss.

> **Key Term: benthic habitat**
> The ecological zone at the bottom of a body of water, including the sediments and organisms living on or in them.

Benthic habitats are highly vulnerable because dumped materials often sink. If dredged material or heavy waste is released over the seafloor, it can bury organisms that cannot move away quickly. Worms, shellfish, and other bottom-dwellers may be smothered.

> **Key Term: smothering**
> The covering of organisms or habitats by deposited material, reducing oxygen exchange, light, or access to food.

This matters because many benthic organisms support larger food webs. If bottom communities are buried, fish that feed on them may decline too. That gives you a good analysis chain in FRQs: habitat burial can scale up to population and community effects.

Dredged material is especially associated with physical habitat damage. Dredging removes sediments from harbors, channels, or waterways, and the material may then be disposed of offshore. The problems include:

- burial of benthic organisms
- increased suspended sediment
- reduced water clarity
- possible release of contaminants trapped in sediments

Reduced water clarity means less light penetration. Seagrasses and algae in shallow zones may then photosynthesize less effectively.

> **Key Term: turbidity**
> The cloudiness of water caused by suspended particles such as silt or organic material.

Higher turbidity also affects animals that rely on sight to feed. So dredged material dumping is not just about “putting mud somewhere else.” It can physically alter habitat structure and water quality at the disposal site.

Coastal and shallow habitats such as mangroves, salt marshes, coral reefs, sandy beaches, seagrass beds, oyster reefs, and benthic sediments can all be harmed by debris that scrapes, crushes, buries, or blocks light. Plastic and other litter can also provide hard surfaces that help invasive species travel and colonize new regions.

> **Test Tip:** Compare waste types when possible. Sewage sludge is most strongly linked to nutrients, pathogens, and BOD. Dredged material is most strongly linked to burial, turbidity, and sediment contamination.

### Water quality, food webs, and human consequences

Some of the worst consequences of ocean dumping are less visible than floating trash. Sewage sludge, industrial waste, and certain persistent chemicals can alter water chemistry and contaminate marine food webs.

> **Key Term: eutrophication**
> Nutrient enrichment of water that stimulates excessive plant or algal growth, often followed by oxygen depletion.

If dumped material contains high levels of nitrogen and phosphorus, algal blooms may increase. When algae die, decomposition increases BOD and lowers dissolved oxygen. In severe cases, this can produce hypoxic zones where many organisms cannot survive.

Sewage sludge can also introduce pathogens, heavy metals, and toxic organic chemicals. Even after dilution, these pollutants may remain biologically significant if they persist in sediments or are taken up by organisms.

Persistent toxins are especially dangerous when they move through food chains.

> **Key Term: bioaccumulation**
> The buildup of a substance in an individual organism over time.
>
> **Key Term: biomagnification**
> The increase in concentration of a substance at successively higher trophic levels in a food web.

These two terms are often confused. Bioaccumulation happens within one organism. Biomagnification happens across the food chain. For example:

- polluted particles or dissolved toxins enter seawater
- plankton or small organisms take them up
- small fish eat many plankton
- larger fish eat many small fish
- top predators and humans eating seafood receive the highest concentrations

That is why dumped pollutants such as mercury, PCBs, dioxins, and some pesticides can become a seafood safety issue. APES expects you to link ecological harm to human systems, and this is a strong way to do it.

Human and economic consequences include:

- contamination concerns in seafood
- fishery losses if fish populations decline or become unsafe
- beach closures and public health fears
- reduced tourism if visible debris washes ashore
- hazards to navigation or coastal recreation

The historical example of the **New York Bight** is useful here. It became strongly associated with sewage sludge dumping, contaminated sediments, beach debris, public health concern, and losses to tourism and fisheries. That case helps explain why U.S. policy became stricter.

### Why regulation became stricter: U.S. and international rules

For APES, you do not need every legal detail, but you should know the main distinction: intentional dumping at sea is regulated differently from general ship pollution.

> **Key Term: Marine Protection, Research, and Sanctuaries Act (MPRSA)**
> The **1972** U.S. law, also called the Ocean Dumping Act, that regulates intentional disposal of materials into ocean waters.

Under this law, dumping is not simply allowed because it is convenient. Permits, site selection, waste characterization, and monitoring are used to prevent unreasonable harm to human health, marine marine lifes, and economic uses of the ocean.

The U.S. also later tightened restrictions further. The **Ocean Dumping Ban Act of 1988** banned ocean dumping of municipal sewage sludge and industrial waste after **December 31, 1991**. So a strong exam answer should avoid saying “all ocean dumping is legal with a permit” or “all ocean dumping is banned everywhere.” Neither is accurate.

A key distinction:

- **MPRSA** regulates intentional ocean dumping
- **MARPOL** and related ship-pollution rules regulate garbage and pollution from ships

Internationally, the **1996 London Protocol** generally prohibits dumping unless the material falls on a limited approved list and passes environmental review. That is sometimes called a reverse-list approach.

The exam takeaway is simple: ocean dumping is not a harmless disposal shortcut. Modern law treats it as a serious pollution risk because it can damage marine habitatss, food webs, and human economic activity.

## Key Point Checklist

_This article has covered the following key knowledge points:_

- Ocean dumping is the deliberate disposal of waste into ocean waters
- Ocean dumping is different from general marine debris because dumping is intentional disposal at sea
- Plastics harm marine life through ingestion and entanglement
- Microplastics do not disappear; they fragment and can enter marine food webs
- Sewage sludge can increase BOD, lower dissolved oxygen, and contribute to eutrophication
- Dredged material can bury benthic organisms and increase turbidity
- Habitat damage can occur in coral reefs, seagrass beds, mangroves, beaches, oyster reefs, and benthic sediments
- Toxic pollutants from dumped waste can bioaccumulate in organisms and biomagnify up food chains
- Human consequences include seafood contamination concerns, fishery losses, beach pollution, tourism decline, and navigation hazards
- The **Marine Protection, Research, and Sanctuaries Act (1972)** regulates U.S. intentional ocean dumping
- The **Ocean Dumping Ban Act of 1988** ended U.S. sewage sludge and industrial waste dumping after **1991**
- The ocean does not solve pollution by simple dilution; wastes can persist, spread, or fragment

## Key Terms and Concepts

- ocean dumping
- marine debris
- microplastics
- ingestion
- entanglement
- biological oxygen demand (BOD)
- benthic habitat
- smothering
- turbidity
- eutrophication
- bioaccumulation
- biomagnification
- Marine Protection, Research, and Sanctuaries Act (MPRSA)


Solid Waste Disposal - Ocean dumping consequences