toxic

Controlling Malaria Without Chemicals

August 28, 2019 By EarthWise Leave a Comment

Nearly half of the world’s population lives in areas vulnerable to malaria. The disease kills roughly 450,000 people each year, most of them children and pregnant women. Malaria is spread by Anopheles mosquitoes and, over time, the mosquitoes have been developing resistance to the chemical insecticides that are used to control them. In addition, there is great concern about the toxic side effects of the chemicals used on the mosquitoes.

About 30 years ago, scientists identified a type of bacteria that kills Anopheles, but the mechanism was not understood. As a result, the bacteria could not be replicated or used as an alternative to chemical insecticides.

But now, an international research team, headed by researchers at UC Riverside, has identified the neurotoxin produced by the bacteria and has determined how it kills Anopheles. The work is described in a paper published in Nature Communications.

It took the team 10 years to achieve a breakthrough in understanding the bacteria. Modern gene sequencing techniques were the key.

While many neurotoxins target vertebrates and are highly toxic to humans, the neurotoxin that kills Anopheles mosquitoes does not affect humans, vertebrates, fish, or even other insects. Known as PMP1, the substance is not even toxic to mice when given by direct injection.

The team has applied for a patent on this discovery and hopes to find partners to help them develop the bacteria-based insecticide.

There is a high likelihood that PMP1 actually evolved to kill the Anopheles mosquito. This finding opens the door to new avenues of research into other environmentally friendly insecticides that would be targeted at other disease-spreading pests.

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Controlling deadly malaria without chemicals

Photo, posted June 9, 2018, courtesy of Mario Yardanov via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Concerns About Dam Safety

August 22, 2019 By EarthWise Leave a Comment

The United States has a total of 91,000 dams of various sizes and types. Many of them are aging and sorely in need of repairs. All that maintenance would add up to tens of billions of dollars. Experts are increasingly worried that as extreme precipitation events become increasingly common, dams are increasingly at risk of failure, threatening lives and posing environmental risks.

In 2017, Oroville Dam in California – the tallest dam in the country – nearly collapsed. That incident forced the evacuation of 190,000 people and cost the state of California $1.1 billion in repairs. California is considered one of the nation’s leading states in dam safety management and yet the partial disintegration of Oroville’s two spillways during a heavy rainstorm was not anticipated.

So far, federal and state dam safety officials have not been able to get disinterested state legislatures and the U.S. Congress to fork up the money needed for repairs to the nation’s aging dam infrastructure.

Th American Society of Civil Engineers gave the nation’s dams a D grade on the latest infrastructure report card. They estimate that the cost of rehabilitating dams whose failure would threaten human life at nearly $45 billion, and the cost of fixing all dams in need of repair at more than $64 billion.

Scientists say the likelihood of dam failures – which not only threaten lives but also release toxic sediments trapped in reservoirs behind many dams – will increase as extreme precipitation events become more frequent in a warming world. Apart from about 1,500 dams owned by federal agencies, regulating dam safety is primarily the responsibility of the states. So far, states have not applied remotely sufficient resources to a growing problem.

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In an Era of Extreme Weather, Concerns Grow Over Dam Safety

Photo, posted August 20, 2014, courtesy of Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

High-Tide Flooding And Pollution

April 30, 2019 By EarthWise Leave a Comment

Global sea levels are steadily rising. They are up 8 inches in the past century and now increasing at an average of 1.3 inches per decade. As a result, the incidence of high-tide “sunny day” flooding is on the rise, especially along the U.S. East Coast.

Norfolk Virginia experienced fewer than 2 days of high-tide flooding a year in the 1960s; it had 14 in 2017. Up and down the East Coast, flood days have increased by factors of 5 and more.

This has led to a form of pollution that hasn’t gathered much attention in the past: when these floodwaters recede, they can carry debris, toxic pollutants and excess nutrients into rivers, bays, and oceans.

In the aftermath of high-tide flooding in Norfolk, Chesapeake Bay was littered with tipped-over garbage cans, tossed-away hamburgers, oil, dirty diapers, pet waste and all manner of other things. Water that comes up on the landscape takes everything back into the river or ocean with it.

Analysis of tidal flooding along the Lafayette River in Norfolk indicated that just one morning of tidal flooding poured nearly the entire EPA annual allocation of nitrogen runoff for the river – nearly 2,000 pounds – into Chesapeake Bay. The effects of excess nitrogen in the water are well-known and responsible for the toxic algal blooms that endanger aquatic life as well as human health.

According to the National Oceanic and Atmospheric Administration, high-tide flooding frequency along the southeastern coast of the U.S. rose 160% since 2000. With the expected continuing rises in sea level, NOAA projects that as many as 85 days of high-tide flooding will occur along the coast by the year 2050. It’s a big problem.

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As High-Tide Flooding Worsens, More Pollution Is Washing to the Sea

Photo, posted September 20, 2018, courtesy of SC National Guard via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Protection From Toxic Algae

March 28, 2019 By EarthWise Leave a Comment

Toxic algal blooms have been a growing problem in recent years associated with warming waters and nutrient-rich agricultural runoff in lakes, rivers, and oceans. In 2014, an algal bloom in Lake Erie left half a million residents of Toledo, Ohio without safe drinking water for three days.

The most common toxic substance released by algal blooms in the lake is called microcystin, which is closely linked to liver cancer and other diseases. Toxicologists measure microcystin and other contaminants using the metric of parts per billion. The EPA recommends that young children not drink water containing more than 0.3 parts per billion and adults no more than 1.6 parts per billion of microcystin.

Scientists at the University of Toledo have been working on developing a biofilter that uses naturally occurring Lake Erie bacteria to remove microcystin released by algal blooms and thereby reduce or eliminate the use of chlorine and other chemicals.

They have successfully isolated a number of types of bacteria that degrade microcystin toxin at a daily rate of up to 19 parts per billion. To their knowledge, such bacteria have not been previously used to fight algal blooms in other parts of the world. Based on the recorded toxin levels in Lake Erie in recent years, the bacteria would be able to effectively remove microcystin from water supplies. None of the 13 bacterial isolates they found have any association with human disease so their use in future water-purifying biofilters should not pose a public health concern.

The researchers are now developing and testing biofilters, which are water filters containing the specialized bacteria that will degrade the toxins from lake water as it flows through the filter.

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Scientists advance new technology to protect drinking water from Lake Erie algal toxins

Photo, posted April 30, 2014, courtesy of NOAA via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Hacking Photosynthesis

February 25, 2019 By EarthWise Leave a Comment

There is an enzyme known as RuBisCo that is involved in carbon fixation, the process plants use to convert carbon dioxide into sugar molecules. The RuBisCo molecule is inside the leaves of most plants and is probably the most abundant protein in the world.

RuBisCo picks up carbon dioxide from the air and uses energy from the sun to turn the carbon into sugar molecules. This process of photosynthesis is pretty much the foundation of life on Earth.

Wonderful as it is, the process is not perfect. RuBisCo is not very selective in grabbing molecules from the air. It picks up oxygen as well as CO₂ and it produces a toxic compound when it does that.

Plants operate a whole other complicated chemical process to deal with this toxic byproduct and uses up a lot of energy along the way, leaving less energy for making leaves or food that we can eat.

A research program at the University of Illinois called Realizing Increased Photosynthetic Efficiency (or RIPE) has been trying to correct this problem; they have been trying to hack photosynthesis. And they may well have succeeded.

Using genetic modification on tobacco plants, they have shut down the existing detoxification process and set up a much more efficient new one. The result is super plants that grow faster and up to 40% bigger.

The next step is to get it to work on plants that people actually rely upon for food, like tomatoes, soybeans and black-eyed peas (which are a staple food crop in sub-Saharan Africa where food is scarce.)

It will be years before we know if the process can really produce more food and be safe, but it may end up leading to a major increase in crop productivity.

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Scientists Have ‘Hacked Photosynthesis’ In Search Of More Productive Crops

Photo, posted June 10, 2013, courtesy of Boon Hong Seto via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Fumes From Gas Stations

November 15, 2018 By EarthWise Leave a Comment

A study by environmental health scientists at Columbia University examined the release of vapors from gas station vent pipes and found that emissions were 10 times higher than the estimates used to establish setback regulations that determine how close schools, playgrounds, and parks can be to the facilities.

Clean Water In The Corn Belt

October 26, 2018 By EarthWise Leave a Comment

Iowa is grappling with a growing battle over the integrity of its water. Nitrogen and phosphates have been flowing in ever-increasing quantities into Iowa’s public water supplies and dealing with the problem has become a major political issue in the state.

Hippo Waste And Fish

September 10, 2018 By EarthWise Leave a Comment

Agricultural and sewage pollution can cause low-oxygen conditions and fish kills in rivers. A new study published in Nature Communications reports that hippo waste can have a similar effect in Africa’s Mara River, which passes through the world renowned Maasai Mara National Reserve of Kenya and is home to more than 4,000 hippos.

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Infinitely Recyclable Plastic

June 8, 2018 By EarthWise Leave a Comment

Less than 10% of discarded plastic is recycled. This is one of the major reasons that plastic waste is such a threat to the environment. There are many challenges to recycling plastics. For one thing, there are many different types of plastic and if they are melted together, they tend to phase-separate like oil and water and the resultant substance is structurally weak. Sorting plastics by type is not a simple task. More generally, it is very difficult to produce plastic with its original properties from recycled feedstock. So recycled plastics generally end up being useful in only more limited applications.

Is It Time to Ban Neonics?

May 10, 2018 By EarthWise Leave a Comment

Neonicotinoids (or ‘neonics’ for short) are a class of insecticides chemically related to nicotine. In fact, the name ‘neonicotinoid’ literally means “new nicotine-like insecticide.” And like nicotine, neonics act on certain kinds of receptors in the nerve synapse. Most corn, soy, and wheat seeds planted today are coated with neonics, which is reportedly 5,000 to 10,000 times more toxic than DDT.

The Chinese War On Pollution

April 10, 2018 By EarthWise Leave a Comment

For years, China has been struggling with some of the worst air pollution in the world. According to the European Union, only 1% of the country’s half a billion city dwellers were considered safe because almost all of its major cities were covered with what was described as a toxic grey cloud.

Nitrogen Pollution

March 30, 2018 By EarthWise Leave a Comment

Earth system scientists say that there are four major human-caused forces that threaten to cause irreversible and abrupt environmental upheaval: climate change, deforestation, biodiversity loss, and excess nitrogen.

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Turning Biofuel Waste Into Valuable Chemicals

December 20, 2017 By EarthWise Leave a Comment

When biofuels are made, tough plant material is left over as waste. The material is lignin, which is a main component of plant cell walls that gives plants their structural integrity. Lignin is made up of many valuable compounds, but taking it apart to extract them is very difficult.

Is A Real Christmas Tree Or A Fake One Better for the Planet?

December 7, 2017 By EarthWise 2 Comments

For many, the Christmas tree is a quintessential part of the holiday season. According to the American Christmas Tree Association, 81% of Christmas trees Americans decorated in 2016 were artificial. But are artificial trees really the better option for the environment?

Global Warming And The Nitrogen Problem

September 13, 2017 By EarthWise

Excess nitrogen in the environment is a big problem. The most visible aspect of the problem is the spread of toxic algae blooms in oceans, lakes and other bodies of water. But there are other effects as well such as unwanted alterations to ecosystems.

Coal Plants And Fish

March 20, 2017 By EarthWise

High levels of an element found in coal ash have been detected in fish in two lakes where Duke Energy coal-fired power plants are located, according to a peer-reviewed study at Duke University. The element, selenium, occurs naturally but is concentrated in coal ash.

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