Okra, Fenugreek Extracts Remove Most Microplastics from Water
The substances behind the slimy strings from okra and the gel from fenugreek seeds could trap microplastics better than a commonly used synthetic polymer. Previously, researchers proposed using these sticky natural polymers to clean up water. Now, they report in ACS Omega that okra and/or fenugreek extracts attracted and removed up to 90 percent of microplastics in ocean water, freshwater and groundwater.
To extract the sticky plant polymers, the research team soaked sliced okra pods and blended fenugreek seeds in separate containers of water overnight. They then removed the dissolved extracts from each solution and dried them into powders. Analyses showed that the powdered extracts contained polysaccharides, which are natural polymers. Initial tests in pure water spiked with microplastics showed that:
- One gram of either powder in a quart of water trapped microplastics the most effectively.
- Dried okra and fenugreek extracts removed 67 and 93 percent, respectively, of the plastic in an hour.
- A mixture of equal parts okra and fenugreek powder reached maximum removal efficiency (70 percent) within 30 minutes.
- The natural polymers performed significantly better than the synthetic, commercially available polyacrylamide polymer used in wastewater treatment.
The researchers then tested the plant extracts on real microplastic-polluted water. They collected samples from waterbodies around Texas and brought them to the lab. The plant extract removal efficiency changed depending on the original water source: okra worked best in ocean water (80 percent), fenugreek in groundwater (80-90 percent), and the 1:1 combination of okra and fenugreek in freshwater (77 percent). The researchers hypothesize that the natural polymers had different efficiencies because each water sample had different types, sizes and shapes of microplastics.
Inhaled agricultural dust disrupts gut health
Inhaling agricultural dust may pose significant risks to gut health for workers in animal agriculture, a University of California, Riverside, study has found. The study expands on prior findings that hog farm dust causes airway inflammation. The researchers now report in the Journal of Applied Toxicology that inhaling this dust also alters the gut microbiome and impairs intestinal function, including increased “leaky gut” or intestinal permeability. Leaky gut is associated with a range of chronic diseases, including inflammatory bowel disease, celiac disease and type-1 diabetes.
“Exposure to swine farm dust, which contains high levels of bacteria and endotoxins, caused both airway inflammation and increased passage of gut bacterial products into the bloodstream in our mouse models,” said researcher Meli’sa Crawford. “But what’s especially striking is the impact we observed on the gut microbiome and metabolism.”
The researchers exposed mice intranasally to hog dust extract for three weeks. The mice showed a significant drop in beneficial bacterial species, including Akkermansia muciniphila, Clostridium sp. ASF356, and Lachnospiraceae bacterium.
The research team also found decreased levels of critical compounds in the gut of the mice, such as riboflavin, nicotinic acid, inosine and leucine — key players in energy metabolism, immune regulation and gut barrier maintenance.
The study builds on growing evidence that pollution from concentrated animal feeding operations can impact multiple organ systems.
Dirty Water and Warm Trucks: Why Romaine Keeps Making Us Sick
E. coli outbreaks in romaine lettuce have long been a public health concern, and now a new Cornell University paper suggests that a combination of efforts in the field, and even postharvest techniques, can minimize risk to human health.
The study results suggested that much contamination originates from irrigation with untreated surface water applied through overhead spray irrigation systems. The researchers found that risk from irrigation was reduced either through water treatments or by switching to furrow or drip irrigation.
They also explored the importance of maintaining proper cold storage temperatures along the entire supply chain to romaine’s final destination. The “perfect storm” occurs if contamination happens at the farm or processing level and then improper transportation temperatures allow bacteria to grow.
“The big message is the American food supply chain is extremely safe compared to other countries,” co-author Renata Ivanek said. “We’re exploring how can we make it even safer and where we should put additional effort.”
Ozonated Water Hack Keeps Mangoes Fresh for 28 Days
In good news for mango lovers, new research has identified a way to extend the storage life of the popular tropical fruit.
The study found that dipping mangoes in ozonated water (aqueous ozonation) for 10 minutes before cold storage extended the cold storage life by up to two weeks, with significantly lowered occurrence of chilling injury.
With a global rise in the consumption of fruit and vegetables in recent years, there has been a subsequent increase in the production of mangoes. However, a significant proportion is lost along the supply chain due to rapid ripening and excessive perishability. For example, about 20 percent of Australian mangos are lost in transport, and fresh produce causes about 50 percent of total food waste in Australia.
Mangoes are typically picked at the mature green stage and stored at 55 degrees F for up to 14 days. However, this is not cold enough for extended storage, and being tropical fruits, mangoes cannot successfully be stored under this temperature.
The study — carried out on Australia’s most widely produced variety of mango, Kensington Pride — tested aqueous ozonation technology to improve chilling tolerance during cold storage. By dipping the mango in the ozonated water for 10 minutes prior to cold storage at 41 degrees F, researchers found that they could keep the mangoes for longer with much less chilling injury — up to 28 days, with 40 percent less chilling injury than untreated mangoes.
Ozonation can be controlled on-site, is cost-effective, and is considered safe for workers at a threshold level due to its fast break down into oxygen.
“Aqueous ozonation is bubbling ozone into water through an ozone generator,” said researcher Mekhala Vithana. “Ozone is a compound widely used to sanitize fruits and vegetables on a commercial scale. The ozonation can be combined with the hydrocooling step after quarantine heat treatment in export mangoes or separately as a sanitization step just after harvesting, depending upon the convenience of the grower, but this needs further optimization under commercial settings.”
Researchers are hoping to do further research on other varieties of mangoes to test their responsiveness and to achieve further reduction in chilling injury for extended cold storage.
Bigger Crops, Fewer Nutrients as a Result of Climate Change
New preliminary research suggests that a combination of higher atmospheric CO2 and hotter temperatures contribute to a reduction in nutritional quality in food crops, with serious implications for human health and wellbeing.
Most research into the impact of climate change on food production has focused on crop yield, but the size of the harvest means little if the nutritional value is poor. Researcher Jiata Ugwah Ekele’s research is focused on popular leafy vegetables, including kale, rocket and spinach. She grew these crops in environment-controlled growth chambers, with the CO2 and temperature levels changed to simulate predicted future climate scenarios. Photosynthetic markers such as chlorophyll fluorescence and quantum yield were assessed as the crops grew, and yield and biomass were recorded at harvest. Their nutritional quality was analyzed using high-performance liquid chromatography (HPLC) and x-ray fluorescence profiling to measure the concentrations of sugar, protein, phenolics, flavonoids, vitamins and antioxidants.
Preliminary results suggest that elevated levels of atmospheric CO2 can help crops grow faster and bigger, but certainly not healthier. “After some time, the crops showed a reduction in key minerals like calcium and certain antioxidant compounds,” said Ekele. These changes were only exacerbated by increases in temperature. Different crops responded differently to these climate change stressors, with some species reacting more intensely than others.
Whatever nutritional changes are caused by climate change are only in addition to the large decreases since the advent of agricultural practices that are reliant on synthetic chemical inputs.
Arbuscular Mycorrhizal Fungal Inoculation Increases Nutrients in Wheat
New research in the journal Plants, People, Planet indicates that wheat’s micronutrient content can be increased by cultivating it with a specific type of fungus.
When investigators grew different types of wheat with and without the arbuscular mycorrhizal fungus Rhizophagus irregularis, they observed that crops grown with fungi developed larger grains with greater amounts of phosphorus and zinc. The higher amount of phosphorus in the grain did not result in an increase in phytate (a compound that can hinder digestion of zinc and iron). As a result, bread wheat grown with fungi had higher bioavailability of zinc and iron overall compared with bread wheat grown in the absence of fungi.
“Beneficial soil fungi could be used as a sustainable option to exploit soil-derived plant nutrients. In this case, we found potential to biofortify wheat with important human micronutrients by inoculating the plants with mycorrhizal fungi,” said corresponding author Stephanie J. Watts-Williams.
Agricultural Liming in the US Is a Large CO2 Sink
Adding lime to agricultural soils can remove CO2 from the atmosphere. The findings, based on over 100 years of data from the Mississippi River basin and detailed computer modelling, run counter to international guidelines on reducing agricultural emissions. The research was presented at this year’s Goldschmidt Conference in Prague.
The team from Yale University showed that the addition of acidity, in the form of atmospheric pollution and fertilizers, is the main driver for CO2 emissions from soils. By calculating emissions based on acid inputs, they showed how emissions may be underestimated in some cases and argued that the potential for lime to reduce emissions is being overlooked.
The Intergovernmental Panel on Climate Change (IPCC) calculates that all the carbon in lime, when added to agricultural soils to reduce acidity, is emitted as CO2. When lime is added to soil, it does react with carbonic acid to create bicarbonate, calcium and magnesium. If there are strong acids present in the soil, such as nitric or sulfuric acid, these will react with the bicarbonate to create carbonic acid and release CO2.
Yet, as lead author Tim Jesper Suhrhoff said, “It is the reaction of acidity with the carbonate that creates CO2 emissions, not the addition of the lime itself. In the absence of the strong acids, the liming would not lead to any emissions and would actually remove CO2 from the atmosphere through the formation of bicarbonate.
“Current guidelines that penalize liming assume that if we didn’t lime, there would be no emissions, but that’s not the case. If we continue to add acidity to the soil, it will react with remaining natural pools of alkalinity to create emissions. By penalizing liming, rather than the addition of acids, we are targeting the wrong driver and potentially losing the other benefits that liming can bring, in terms of increased yields and lower nitrous oxide emissions.”
The researchers showed that the combination of industrial pollution from fossil fuel burning and increasing use of nitrogen fertilizers since the 1930s has created high levels of acidity in the soil that have not been counterbalanced by liming. Since the 1930s, when limestone application to croplands substantially increased, both the efficacy and efficiency of carbon dioxide removal has also increased, as indicated by river records and model results. The researchers estimated that removal today is occurring at approximately 75 percent of the theoretical maximum rate.
The researchers call for a reconsideration of policy on agricultural emissions, with emissions being linked to addition of acid fertilizers rather than lime. “We have known for a long time that liming is great for farmers and global food security,” said Suhrhoff. “What we show here is that over longer timescales, it is also an efficient way to remove CO2 from the atmosphere. Adding a large amount of silicate rock to neutralize the acidity, before moving to liming, may be the best strategy to limit emissions and gain the additional benefits that liming can bring.”
Environmental Impact of Common Pesticides Seriously Underestimated
The environmental impact of nine pesticides commonly used in grape cultivation and other crops may have been significantly underestimated, suggesting current pesticide risk assessment criteria need updating. The research was presented at this year’s Goldschmidt Conference in Prague.
In laboratory experiments, the nine pesticides far exceeded the two-day threshold set by the Stockholm Convention for the half-life of chemicals in the atmosphere. The researchers also identified several unknown molecules when they looked at how the pesticides break down and degrade in the atmosphere.
Global use of pesticides has doubled since 1990, according to the UN Food and Agriculture Organization, raising concerns about the potential impact on health and the environment.
Pesticides enter the atmosphere in particular when sprayed onto crops, leading to air pollution. As semi-volatile compounds, their molecules can be present in the atmosphere in several forms — either as a gas or vapor (gas phase), or as particles (particulate phase). In the particulate phase, they are adsorbed onto the surface of airborne particles, like dust or organic matter suspended in the air. This adsorption can lead to longer half-lives, meaning they take longer to break down and can travel further.
European regulations currently only consider the atmospheric lifetimes of pesticides based on their gas phase. If a pesticide is shown to have an atmospheric half-life of more than two days, it is considered prone to long-range atmospheric transport, which is a key factor in classifying it as a persistent organic pollutant.
Researchers at Aix-Marseille University and CNRS, France, investigated the atmospheric half-lives of nine pesticides commonly used in viticulture. They adsorbed the pesticides onto atmospheric particles and exposed them to ozone and hydroxyl radicals to simulate how they would behave in the earth’s lower atmosphere or troposphere.
They discovered that none of the compounds has a half-life within the two-day limit set by Stockholm convention: instead, they ranged from three days (Cyprodinil) to over a month (Folpet). This suggests all nine compounds could be reclassified as persistent organic pollutants — far more harmful and persistent than previously thought.
In a second experiment, the team studied the degradation mechanisms of their pesticides, observing several toxic and non-commercially available molecules. This suggests further study is needed to appropriately assess the toxicity of these pesticides.
Finally, they looked at how temperature and relative humidity affect the partitioning of the pesticide molecules between gas and the particle phase, finding discrepancies compared with current models of their behavior.
