To reduce harmful algal blooms and dead zones, the US needs a national strategy for regulating farm pollution

Satellite photo of an algal bloom in western Lake Erie, July 28, 2015. NASA Earth Observatory

by Donald Boesch, University of Maryland Center for Environmental Science and Donald Scavia, University of Michigan

Midsummer is the time for forecasts of the size of this year’s “dead zones” and algal blooms in major lakes and bays. Will the Gulf of Mexico dead zone be the size of New Jersey, or only as big as Connecticut? Will Lake Erie’s bloom blossom to a human health crisis, or just devastate the coastal economy?

We are scientists who each have spent almost 50 years figuring out what causes dead zones and what it will take to resuscitate them and reduce risks of toxic blooms of algae. Researchers can forecast these phenomena quite well and have calculated the nitrogen and phosphorus pollution cuts needed to reduce them.

These targets are now written into formal government commitments to clean up Lake Erie, the Gulf and the Chesapeake Bay. Farmers and land owners nationwide received US$30 billion to support conservation, including practices designed to reduce water pollution, from 2005 to 2015, and are scheduled to receive $60 billion more between 2019 and 2028.

But these efforts have fallen short, mainly because controls on nutrient pollution from agriculture are weak and ineffective. In our view, there is no shortage of solutions to this problem. What’s needed is technological innovation and stronger political will.

Map showing a zone with low oxygen values along the Louisiana coast.
The Gulf of Mexico hypoxic (dead) zone in 2021, which measured 6,334 square miles (16,400 square kilometers). Lower values represent less dissolved oxygen in the water. Louisiana Universities Marine Consortium, CC BY-ND

Problems return to Lake Erie

State and federal agencies have known since the 1970s that overloading lakes and bays with nutrients generates huge blooms of algae. When the algae die and decompose, they deplete oxygen in the water, creating dead zones that can’t support aquatic life. But in each of these “big three” water bodies, efforts to curb nutrient pollution have been slow and halting.

The U.S., Canada and cities around Lake Erie started working to reduce phosphorus pollution in the lake from domestic and industrial wastes in 1972. Water quality quickly improved, dead zones shrank and harmful algal blooms became less frequent.

But the scourges of low-oxygen waters and sometimes-toxic algae reappeared in the mid-1990s. This time, the source was mostly runoff from farm soils saturated with phosphorus from repeated applications of fertilizer and manure. Climate change made matters worse: Warmer waters hold less oxygen and cause faster growth of algae.

Bar chart showing phosphorus entering Lake Erie 1967-2001.
Phosphorus loads to Lake Erie, 1967-2001. Nonpoint sources are wide areas without a distinct discharge point, such as farm fields. Scavia et al., 2014, CC BY-ND

Slow progress in the Chesapeake Bay

Nitrogen and phosphorus reach the Chesapeake Bay from sources including wastewater treatment plants; air pollution emitters, such as factories and cars; and runoff from urban, suburban and agricultural lands. In 1987 the federal government and states around the bay agreed to reduce these flows by 40% by the year 2000 to restore water quality. But this effort relied on voluntary action and failed to make much progress.

In 2010 the states and the U.S. Environmental Protection Agency entered a legally binding commitment, to reduce pollutant loads below prescribed maximum levels needed to restore water quality. If the states make inadequate progress, the EPA can limit or rescind their permitting authority, and the states may lose federal funding.

Nitrogen and phosphorus pollution has been reduced primarily by tightening permit requirements and upgrading wastewater treatment plants. Air pollution controls for power plants and vehicles have also reduced nitrogen reaching the bay. Water quality has improved, and the yearly dead zone has shrunk modestly.

But with the commitment’s 2025 deadline nearing, nitrogen loads have been reduced by less then 50% of the targeted amounts, phosphorus by less then 64%. Most of the remaining pollution comes from farm runoff and urban stormwater. Intensifying agriculture in rural areas and sprawl in urban areas are counteracting other cleanup efforts.

Cleaning up water bodies with large watersheds, like the Chesapeake Bay (64,000 square miles/165,000 square kilometers, involves many states and thousands of pollution sources.

Failure in the Gulf of Mexico

The Gulf of Mexico dead zone forms every year during the summer, fueled by nutrients washing down the Mississippi River from Midwest farms. It typically covers at least 6,000 square miles, sometimes expanding up to 9,000 square miles (23,000 square kilometers), and affects an area very rich in fisheries.

In 2001, the EPA and 12 Mississippi River basin states agreed to take action to reduce the Gulf dead zone by two-thirds by 2015. Researchers estimated that this would require reducing nitrogen loads reaching the Gulf by about 45%, mostly from the Corn Belt.

Now that deadline has been extended to 2035. Nitrogen and phosphorus loadings at the mouth of the Mississippi River haven’t budged in 30 years, so actions taken to date have failed to shrink the Gulf dead zone.

Bar chart showing measurements of the Gulf of Mexico dead zone since 1985.
Since 2017 the Gulf of Mexico dead zone has covered an average of 5,380 square miles (14,000 square kilometers), which is 2.8 times larger than the 2035 target set by a federal task force. LUMCON/NOAA

Overwhelmed by agriculture

In 2020, the EPA and Ohio adopted an agreement similar to that for the Chesapeake to reduce phosphorus pollution below a prescribed maximum load from the Maumee River watershed at the western end of Lake Erie, where algal blooms occur most often. To date, Mississippi River basin states and even the EPA have opposed similarly mandating maximum pollution loads to reduce the Gulf of Mexico dead zone.

Despite substantial government subsidies to implement various agricultural management practices, nitrogen and phosphorus pollution in streams in Iowa and Illinois has actually increased over the 1980-1996 baseline of the Gulf agreement.

Even with increasing crop yields and more efficient use of fertilizer, the expansion and intensification of agriculture in the Midwest has overwhelmed any water quality gains. One driver is ethanol production, which has increased fortyfold since the Gulf action plan was adopted in 2001. Today, over 40% of corn grown in the U.S. is used for ethanol, mostly in the Midwest, while most of the rest is used to feed animals.

In all three regions, the growth of large-scale livestock farms – hogs in the Midwest, poultry around the Chesapeake Bay – is also contributing to nutrient pollution. Improper management of animal waste adds to nitrogen and phosphorus loads in soils and local waters.

Studies show that agriculture contributes 85% of Lake Erie’s Maumee River phosphorus load, 65% of the Chesapeake Bay’s nitrogen load and 73.2% of the nitrogen load and 56% of the phosphorus load to the Gulf of Mexico.

Incentives aren’t working

We believe the evidence is clear that the largely voluntary approaches taken to date, with technical assistance and substantial public financing, are not working.

Economists have called for a fundamental shift in policies controlling agricultural pollution. Instead of offering polluters subsidies to clean up their operations, these experts argue, the strategy should be to pay farmers for performance, based on environmental outcomes that can be measured or predicted at appropriate scales and specific places.

Under this approach, government would set limits on the amount of nutrients that can be lost to the environment, and farmers would choose how to meet them, based on what kinds of action work best for their specific soils and climate. For example, restoring wetlands within the watershed could help to capture nutrients that unavoidably wash off of farmlands.

The ongoing shift to electric vehicles offers an opportunity to grow far less grain for ethanol, which doesn’t even help the climate. And in the long run, developing efficient, plant-based food systems would both reduce nutrient pollution and limit climate change.

In June 2022, the Government Accountability Office concluded that federal agencies charged with preventing and controlling harmful algal blooms and dead zones under a 1998 law have failed to establish a national program to address these issues. Fifty years after the federal Clean Water Act was enacted, we believe such a program is long overdue.

Donald Boesch, Professor of Marine Science, University of Maryland Center for Environmental Science and Donald Scavia, Professor Emeritus of Environment and Sustainability, University of Michigan

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Restoring the Great Lakes: After 50 years of US-Canada joint efforts, some success and lots of unfinished business

Children participate in a water fight in Lake Ontario in Mississauga, Ontario, during a heat wave on June 5, 2021. Zou Zheng/Xinhua via Getty Images

by Daniel Macfarlane, Western Michigan University

The Great Lakes cover nearly 95,000 square miles (250,000 square kilometers) and hold over 20% of Earth’s surface fresh water. More than 30 million people in the U.S. and Canada rely on them for drinking water. The lakes support a multibillion-dollar maritime economy, and the lands around them provided many of the raw materials – timber, coal, iron – that fueled the Midwest’s emergence as an industrial heartland.

Despite their enormous importance, the lakes were degraded for well over a century as industry and development expanded around them. By the 1960s, rivers like the Cuyahoga, Buffalo and Chicago were so polluted that they were catching fire. In 1965, Maclean’s magazine called Lake Erie, the smallest and shallowest Great Lake, “an odorous, slime-covered graveyard” that “may have already passed the point of no return.” Lake Ontario wasn’t far behind.

In 1972, the U.S. and Canada signed the Great Lakes Water Quality Agreement, a landmark pact to clean up the Great Lakes. Now, 50 years later, they have made progress, but there are new challenges and much unfinished business.

I study the environment and have written four books on U.S.-Canadian management of their shared border waters. In my view, the Great Lakes Water Quality Agreement was a watershed moment for environmental protection and an international model for regulating transboundary pollution. But I believe the people of the U.S. and Canada failed the Great Lakes by becoming complacent too soon after the pact’s early success.

Map of the Great Lakes-St. Lawrence Basin
The Great Lakes-St Lawrence River Basin spans nearly half of North America, from northern Minnesota to New England. International Joint Commission

Starting with phosphates

A major step in Canada-U.S. joint management of the Great Lakes came in 1909 when they signed the Boundary Waters Treaty. The Great Lakes Water Quality Agreement built on this foundation by creating a framework to allow the two countries to cooperatively restore and protect these border waters.

However, as an executive agreement, rather than a formal government-to-government treaty, the pact has no legal mechanisms for enforcement. Instead, it relies on the U.S. and Canada to fulfill their commitments. The International Joint Commission, an agency created under the Boundary Waters Treaty, carries out the agreement and tracks progress toward its goals.

The agreement set common targets for controlling a variety of pollutants in Lake Erie, Lake Ontario and the upper St. Lawrence River, which were the most polluted section of the Great Lakes system. One key aim was to reduce nutrient pollution, especially phosphates from detergents and sewage. These chemicals fueled huge blooms of algae that then died and decomposed, depleting oxygen in the water.

Like national water pollution laws enacted at the time, these efforts focused on point sources – pollutants released from discreet, readily identifiable points, such as discharge pipes or wells.

Diagram of the Great Lakes and connecting water bodies in profile.
This profile view of the Great Lakes shows that Lake Erie is much shallower than the other lakes. As a result, its waters warm faster and are more vulnerable to algal blooms. NOAA, CC BY-ND

Early results were encouraging. Both governments invested in new sewage treatment facilities and convinced manufacturers to reduce phosphate loads in detergents and soaps. But as phosphorus levels in the lakes declined, scientists soon detected other problems.

Toxic contaminants

In 1973, scientists reported a perplexing find in fish from Lake Ontario: mirex, a highly toxic organochloride pesticide used mainly to kill ants in the southeast U.S. An investigation revealed that the Hooker Chemical company was discharging mirex from its plant in Niagara Falls, New York. The contamination was so severe that New York State banned eating popular types of fish such as coho salmon and lake trout from Lake Ontario from 1976 to 1978, shutting down commercial and sport fishing in the lake.

In response to this and other findings, the U.S. and Canada updated the Great Lakes Water Quality Agreement in 1978 to cover all five lakes and focus on chemicals and toxic substances. This version formally adopted an ecosystem approach to pollution control that considered interactions between water, air and land – perhaps the first international agreement to do so.

A tour of the Great Lakes and the nature in and around them.

In 1987, the two countries identified the most toxic hot spots around the lakes and adopted action plans to clean them up. However, as scholars of North American environmental regulations acknowledge, both nations too often allowed industries to police themselves.

Since the 1990s, studies have identified toxic pollutants including PCBs, DDT and chlordane in and around the Great Lakes, as well as lead, copper, arsenic and others. Some of these chemicals continued to show up because they were persistent and took a long time to break down. Others were banned but leached from contaminated sites and sediments. Still others came from a range of point and nonpoint sources, including many industrial sites concentrated on shorelines.

Many hazardous sites have been slowly cleaned up. However, toxic pollution in the Great Lakes remains a colossal problem that is largely unappreciated by the public, since these substances don’t always make the water look or smell foul. Numerous fish advisories are still in effect across the region because of chemical contamination. Industries constantly bring new chemicals to market, and regulations lag far behind.

Nonpoint sources

Another major challenge is nonpoint source pollution – discharges that come from many diffuse sources, such as runoff from farm fields.

Nitrogen levels in the lakes have risen significantly because of agriculture. Like phosphorus, nitrogen is a nutrient that causes large blooms of algae in fresh water; it is one of the main ingredients in fertilizer, and is also found in human and animal waste. Sewage overflows from cities and waste and manure runoff from industrial agriculture carry heavy loads of nitrogen into the lakes.

As a result, algal blooms have returned to Lake Erie. In 2014, toxins in one of those blooms forced officials in Toledo, Ohio, to shut off the public water supply for half a million people.

One way to address nonpoint source pollution is to set an overall limit for releases of the problem pollutant into local water bodies and then work to bring discharges down to that level. These measures, known as Total Maximum Daily Loads, have been applied or are in development for parts of the Great Lakes basin, including western Lake Erie.

But this strategy relies on states, along with voluntary steps by farmers, to curb pollution releases. Some Midwesterners would prefer a regional approach like the strategy for Chesapeake Bay, where states asked the U.S. government to write a sweeping federal TMDL for key pollutants for the bay’s entire watershed.

In 2019, Toledo voters adopted a Lake Erie Bill of Rights that would have permitted citizens to sue when Lake Erie was being polluted. Farmers challenged the measure in court, and it was declared unconstitutional.

Warming and flooding

Climate change is now complicating Great Lakes cleanup efforts. Warmer water can affect oxygen concentrations, nutrient cycling and food webs in the lakes, potentially intensifying problems and converting nuisances into major challenges.

Flooding driven by climate change threatens to contaminate public water supplies around the lakes. Record-high water levels are eroding shorelines and wrecking infrastructure. And new problems are emerging, including microplastic pollution and “forever chemicals” such as PFAS and PFOA.

It will be challenging for the U.S. and Canada to make progress on this complex set of problems. Key steps include prioritizing and funding cleanup of toxic zones, finding ways to halt agricultural runoff and building new sewer and stormwater infrastructure. If the two countries can muster the will to aggressively tackle pollution problems, as they did with phosphates in the 1970s, the Great Lakes Water Quality Agreement gives them a framework for action.

Daniel Macfarlane, Associate Professor of Environment and Sustainability, Western Michigan University

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Global Plastic Watch: Satellite eyes pinpoint waste from space to reduce ocean pollution

Read the full story from the Minderoo Foundation.

A cutting-edge new tool developed by Minderoo Foundation has identified thousands of waste sites across 25 countries for the first time using advanced satellite data technology and machine learning to measure piles of plastic waste from space.

Global Plastic Watch is a tool which combines earth observation with artificial intelligence to create the first-ever near-real-time high-resolution map of plastic pollution. This is the largest open-source dataset of plastic waste across dozens of countries. The aim of the tool is to help authorities to better manage plastic leakage into the marine environment.

LSU researcher helps to reduce plastic pollution along Mississippi River

Read the full story at Reveille.

In collaboration with the MRCTI, LSU College of Coast and Environment professor Mark Benfield is researching the flow of plastic waste down the Mississippi River into the Gulf of Mexico using GPS trackers, trash accumulation data, and testing the water for microplastics. 

Latest Toxic 100 and Greenhouse Gas 100 lists name top air and water polluters, climate gas emitters in the U.S.

Read the full story from the University of Massachusetts Amherst.

Researchers at the University of Massachusetts Amherst Political Economy Research Institute (PERI) today published the newest editions of its lists of the top corporate air and water polluters and top greenhouse gas emitters in the United States, based on the most recent data available from the Environmental Protection Agency.

The Toxic 100 Air and Toxic 100 Water Indexes rank U.S. industrial polluters using the EPA Toxics Release Inventory, and the Greenhouse 100 Index ranks U.S. companies by their emissions responsible for global climate change according to the EPA Greenhouse Gas Reporting Program. The PERI Indexes also include environmental justice indicators to assess impacts on low-income people and minorities.

Exposed: Amazon’s enormous and rapidly growing plastic pollution problem

Download the document.

Oceana analyzed e-commerce packaging data and found that Amazon generated 599 million pounds of plastic packaging waste in 2020. This is a 29% increase of Oceana’s 2019 estimate of 465 million pounds. The report also found that Amazon’s estimated plastic packaging waste, in the form of air pillows alone, would circle the Earth more than 600 times.

By combining the e-commerce packaging data with findings from a recent study published in Science, Oceana estimates that up to 23.5 million pounds of Amazon’s plastic packaging waste entered and polluted the world’s waterways and oceans in 2020, the equivalent of dumping a delivery van payload of plastic into the oceans every 67 minutes.

‘A trash heap for our children’: How Norilsk, in the Russian Arctic, became one of the most polluted places on Earth

Read the full story at Inside Climate News.

A smelting company has poisoned rivers, killed off boreal forest and belched out more sulfur dioxide than active volcanoes. Now it wants to produce more metal for the “green economy.”

The cost, complexity and very local scope of Eau Claire’s PFAS response

Read the full story from PBS Wisconsin.

After testing found “forever chemicals” in multiple municipal drinking water wells used by Eau Claire, the city has taken steps to mitigate this contamination, but it’s an expensive and time-consuming problem faced by communities around Wisconsin.

EPA Publishes 2019 Annual Toxics Release Inventory Report and Analysis for the Great Lakes Region

The U.S. Environmental Protection Agency (EPA) has released its 2019 Toxics Release Inventory (TRI) National Analysis, which shows that EPA and companies that manage chemicals continue to make progress in preventing pollution. The report shows that between 2018 and 2019 total releases of TRI chemicals decreased by 9 percent.

For the first time in five years, industrial and federal facilities reported an increased number of new source reduction activities that aim to reduce or eliminate the amount of chemical-containing waste facilities create. Facilities also avoided releasing 89 percent of the chemical-containing waste they created and managed during 2019 into the environment by using preferred practices such as recycling, treatment, and energy recovery.

Chemical releases in Region 5 have decreased by almost 400 million pounds (46 percent) since 2007. Releases from the electric utilities, primary metals and hazardous waste sectors decreased the most, together decreasing their releases by 374 million pounds. During this time, releases of TRI chemicals to air, water, land, and transfers off site for disposal all decreased. Since 2018, releases decreased by 49.2 million pounds (10 percent). For 2019, 7 percent of facilities in Region 5 reported implementing new source reduction activities. Source reduction reporting rates in the region were among the highest in the computers/electronic products manufacturing sector, in which 23 percent of facilities reported source reduction activities.

The 2019 TRI National Analysis released today reflects TRI chemical waste management activities, including releases, that occurred during calendar year 2019 and therefore does not indicate any potential impacts of the COVID-19 public health emergency that began in the United States in early 2020.

A new Spanish TRI website, as well as a Spanish version of the 2019 Analysis, will be available by the end of January. Spanish-speaking communities across the United States will be able to use this resource to learn about TRI chemical releases in their communities—expanding their access to environmental information and making TRI data more easily accessible.


Thanks to the passage of the Emergency Planning and Community Right-to-Know Act of 1986 which helped create EPA’s Toxics Release Inventory program, Americans now have greater awareness of how chemicals are being managed in their communities. Today, nearly 22,000 facilities report annually on the use and quantities of more than 760 chemicals they release to the environment or otherwise manage as waste to the Toxics Release Inventory (TRI) program. EPA, states, and tribes receive TRI data from facilities in industry sectors such as manufacturing, mining, electric utilities, and commercial hazardous waste management. The Pollution Prevention Act also requires facilities to submit information on pollution prevention and other waste management activities of TRI chemicals.

Information on facility efforts to reduce TRI chemical releases is available at

Pandemic waste is adding to wastewater woes and Puget Sound pollution

Read the full story at KUOW.

A complicated series of events has led to where we are now — from the pandemic to pollution.

When the pandemic first hit in early 2020, people stocked up on face masks and gloves. And then people tossed those masks and gloves on the ground. And eventually, it all ended up in our sewage lines.

That also means these discarded masks and gloves are potentially now floating in Lake Washington, Lake Union, or Puget Sound and interacting with wildlife. It also means they are adding to environmental problems down the line.