Scientists Use Honey and Wild Salmon to Trace Industrial Metals in the Enviroment

ScienceMag August 21, 2019

Credit: Dominique Weis

Credit: Dominique Weis

Scientists have combined analyses from honey and salmon to show how lead from natural and industrial sources gets distributed throughout the environment. By analysing the relative presence of differing lead isotopes in honey and Pacific salmon, Vancouver-based scientists have been able to trace the sources of lead (and other metals) throughout the region. Scientists in France, Belgium and Italy are now looking to apply the same approach to measure pollutants in honey in major European cities. The research* is being presented at the Goldschmidt conference in Barcelona.

Scientists have long known that honey bees pick up small amounts of metal elements (i.e., iron, zinc, and pollutants such as lead, and cadmium) when they alight on flowers and leaves. They carry these metals back to the hive where tiny amounts are incorporated into the honey. However, this is the first time researchers have been able to establish clearly the sources of the metals carried by the bees and their products, making them reliable biomarkers for environmental pollution.

“We’ve found that we can let the bees do the hard the work for us: they go to thousands of sites where metal-containing dust particulates might land, then bring samples back to a central hive. From there we can take the honey to have it analysed and begin to identify the source of pollutants like lead” said Ph.D. candidate Kate Smith, part of a team working at the Pacific Centre for Isotopic and Geochemical Research (University of British Columbia).

Once they have sampled the honey gathered by the bees, it is taken to a specialised geochemistry lab to be analysed using a high-resolution ICP-MS (Inductively coupled plasma mass spectrometry) instrument. This allows scientists to distinguish between different types (isotopes) of certain metal pollutants, like lead.

Smith continued, “Looking at the lead isotopic composition of the honey samples, we can tell the difference between honey gathered in the city centre of Vancouver and honey gathered in rural areas. We see that the trace amounts of lead in urban honey samples contain higher 208Pb/206Pb ratios that have no local natural equivalent, indicating that they come from man-made sources like aging city infrastructure and fuel combustion (e.g. cars and ships). Lead ratios measured in rural honey, on the other hand, reflect those of natural sources, like the local geology or particulates from nearby forest fires.”

Presenting the work on salmon, postdoctoral researcher Dr. Miling Li added “This work with honeybees is mirrored in initial findings from shellfish and salmon. Juvenile salmon breed and live in remote freshwater ecosystems in British Columbia, and their lead composition reflects that found in nature, e.g. the nearby Garibaldi volcano range. Adult salmon that forage in the open ocean off the BC coast reveal isotopic compositions consistent with downtown Vancouver honeys. This indicates that Pacific salmons were exposed to lead during their sea life mostly from anthropogenic sources in the Northeast Pacific Ocean.”

Although we can identify the sources of lead, the lead concentrations in both the honey and salmon from Vancouver and the surrounding areas are extremely low and well below the reported world-wide average of lead in honey.

Following the proof of concept work in Metro Vancouver (and similar work in Australia, in Sydney and the site of the vast Broken Hill lead mines, the main source of lead added to gasoline in Europe, Asia and many other places in the world), the UBC team has now developed standardised protocols for measurement of lead isotopes in honey to apply the technique to other cities. Experiments are now being set up in Paris, Brussels, and Piacenza, with interest also coming from the U.S. Simultaneously, the UBC team is confirming the efficacy of the Vancouver honey data by monitoring topsoil and air quality near the hives.

Kate Smith said, “Honey is particularly useful because honeybees can be found pretty well everywhere, so we believe that using honey as a proxy measurement for lead pollution may become an important urban geochemistry and environmental tool. This means we need to make sure that we have a framework that gives results of consistent quality from year to year and city to city. This is what we are now testing.”

Research team leader Professor Dominique Weis said “Urban geochemistry has become an important discipline in understanding the spread of heavy metal pollutants in cities, as long as the natural background is well characterized. Lead isotopic analysis is a standard geochemical method that for decades provided a signal dominated by lead that was used as an additive in gasoline. Honey is an effective biomonitor, and allows us to identify the source of some pollutants even at very low levels; we think that this method could become an internationally accepted way of assessing metal sources and distribution in urban environments”.

Airborne lead pollution varies significantly from area to area. It is found naturally at low levels. Major sources of pollution are metal processing, incinerators, and other industrial processes. Lead in gasoline was banned in the 1990s in North America, which caused a significant decrease in airborne lead levels (98% in the USA). Depending on the level of exposure, lead can have significant health effects**.

Commenting, Professor Mark P Taylor***, Macquarie University, Australia, leader of the Australian group working on honey said,

“This research is emblematic of contemporary science because it touches on two emerging key public interests in an increasingly urbanised world: it examines environmental quality by way of assessing anthropogenic changes to trace element sources in the wider environment and it engages citizens directly through the collection and sharing of honey for geochemical analysis. Nothing could be sweeter for science.”

This is an independent comment; Professor Taylor was not involved in this work.

https://scienmag.com/scientists-use-honey-and-wild-salmon-to-trace-industrial-metals-in-the-environment/?fbclid=IwAR0zbMwynvYS6sGZdYdGS8ZQtkleI8Jw19Ub64BrYyprWC063kdDM_DcUYo

The Laborious Honey Bee

BugSquad By Kathy Keatley Garvey September 9, 2019

Today is Labor Day 2019, a federal holiday celebrated the first Monday of September.

However, "the girls" are working, as they do every day of the year, weather permitting.

"The girls" are the worker honey bees.

Unless you keep bees or have access to a hive, you mostly see them foraging. But inside the hive, they are also nurse maids, nannies, royal attendants, builders, architects, dancers, honey tenders, pollen packers, propolis or "glue" specialists, air conditioning and heating technicians, guards, and undertakers.

They ensure the survival of the hive, but their life span is short.

"Worker bees live for approximately five to six weeks in the spring and summer," writes author and retired bee scientist and bee wrangler Norman Gary, emeritus professor of entomology at the University of California, Davis, in his book, Honey Bee Hobbyist: The Care and Keeping of Bees."Those reared in the fall live for several months--long enough for the colony to survive the winter--and are replaced by young bees in late winter or early spring."

In peak season, a honey bee queen can lay 1500 to 2000 eggs a day, and most of them will be worker bees, the most needed of the three castes (queen, drone and worker) in the hive.  Although the smallest, but they do most of the work.  The queen is the egg layer. The drone's role is strictly reproduction.

Worker bees forage within four to five miles of their hive. If you provide no nectar or pollen sources in your yard, they'll go elsewhere.

Theirs is a dangerous occupation. No thanks to predators (such as birds, praying mantids and spiders) and pesticides, many do not return home at night.

Like to photograph them? Try the "magic hour," which occurs about an hour before the sun sets. We love photographing them on Mexican sunflowers (Tithonia). The light is soft, warm and welcoming.

(Editor's Note: Interested in becoming a beekeeper or learning more about beekeeping? Be sure to check out the UC Davis-based California Master Beekeeper Program, directed by Extension apiculturist Elina Lastro Niño of the UC Davis Department of Entomology and Nematology. The next course is on managing varroa mites, a major pest.)

Worker honey bee forages on a Mexican sunflower (Tithonia) in the magic hour, the hour before sunset. (Photo by Kathy Keatley Garvey)

Worker honey bee forages on a Mexican sunflower (Tithonia) in the magic hour, the hour before sunset. (Photo by Kathy Keatley Garvey)

Illuminated by the late afternoon sun, the worker bee prepares to fly to another Tithonia blossom. (Photo by Kathy Keatley Garvey)

Illuminated by the late afternoon sun, the worker bee prepares to fly to another Tithonia blossom. (Photo by Kathy Keatley Garvey)

A worker bee takes flight, lifting over a Mexican sunflower. (Photo by Kathy Keatley Garvey)

A worker bee takes flight, lifting over a Mexican sunflower. (Photo by Kathy Keatley Garvey)

Honey Bees Can Help Monitor Pollution in Cities

Honey from urban bees can tell us how clean a city is and help pinpoint the sources of environmental pollutants such as lead, new University of British Columbia research has found.

In a study published today in Nature Sustainability, scientists from UBC’s Pacific Centre for Isotopic and Geochemical Research (PCIGR) analyzed honey from urban beehives in six Metro Vancouver neighbourhoods. They tested for minuscule levels of lead, zinc, copper and other elements and carried out lead isotope analyses – akin to fingerprinting – to identify where the lead came from.

“The good news is that the chemical composition of honey in Vancouver reflects its environment and is extremely clean,” said Kate E. Smith, lead author of the study and PhD candidate at PCIGR. “We also found that the concentration of elements increased the closer you got to downtown Vancouver, and by fingerprinting the lead we can tell it largely comes from manmade sources.”

Tiny elements, tiny measurements

Metro Vancouver honey is well below the worldwide average for heavy metals like lead, and an adult would have to consume more than 600 grams, or two cups, of honey every day to exceed tolerable levels.

“The instruments at PCIGR are very sensitive and measure these elements in parts per billion, or the equivalent of one drop of water in an Olympic-sized swimming pool,” said Dominique Weis, senior author and director of the institute.

The researchers found the concentration of elements increased closer to areas with heavy traffic, higher urban density and industrial activity such as shipping ports. Places like the city of Delta showed elevated levels of manganese, which could be a result of agricultural activity and pesticide use in the area.

Map of Metro Vancouver, featuring locations of the sampled for this study and possible sources of manmade trace elements.

Map of Metro Vancouver, featuring locations of the sampled for this study and possible sources of manmade trace elements.

Lead fingerprints point to manmade culprits

In the first study of its kind in North America, the researchers also compared the lead fingerprints of the honey to those from other local environmental samples like lichen from around British Columbia, rock from the Garibaldi volcanic belt, sediment from the Fraser River and trees in Stanley Park.

They discovered that the lead fingerprints of the honey did not match any local, naturally-occurring lead. However, the trees in Stanley Park and the honeys from downtown displayed some striking similarities that pointed to potential manmade sources of lead.

“We found they both had fingerprints similar to aerosols, ores and coals from large Asian cities,” said Weis. “Given that more than 70 per cent of cargo ships entering the Port of Vancouver originate from Asian ports, it’s possible they are one source contributing to elevated lead levels in downtown Vancouver.”

Honey is able to provide such localized “snapshots” of the environment because honey bees typically forage for pollen and nectar within a two- to three-kilometre radius of their hives.

“We now have four years of consistent data from Metro Vancouver, which provides a present-day baseline that will allow us to monitor even tiny changes in our environment very efficiently,” said Weis.

Citizen science for communities

The research was carried out in partnership with Hives for Humanity, a local non-profit that creates opportunities for people in Vancouver's Downtown Eastside to engage in urban beekeeping.

"One of the exciting parts of this study is that it bridges science with community interests," said Smith. "Honey sampling can easily be performed by citizen scientists in other urban centres, even if they lack other environmental monitoring capabilities."

The team will continue to study how honey analysis might complement traditional air and soil monitoring techniques and test the efficiency of honey as an environmental monitor in other cities.

Find other stories about: Dominique WeisHoneybeesKate E. SmithPacific Centre for Isotopic and Geochemical Research (PCIGR)

https://news.ubc.ca/2019/03/11/honey-bees-can-help-monitor-pollution-in-cities/