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Dave Black    2,998

A couple of days ago the results of a global survey began to hit the headlines; A worldwide survey of neonicotinoids in honey, Mitchell et al., Science 358, 109–111 (2017) 6 October 2017.

 

The study was based on a collection of samples from 'local producers' all around the world donated by colleagues, friends, and relatives connected the the University and Botanic Gardens of Neuchtel in Switzerland. Of the 300 received, gathered from apiaries, markets, and commercial sources, 198 were selected, in theory representing a broad range of environments but also avoiding an over-representation of European-sourced samples. Most but not all the EU samples were collected before the 'ban' on neonicotinoid use on bee-visited crops. Only 7% had the name of the beekeeper provided.


The researchers point out this 'citizen science' aspect meant they had only a hazy (or no idea) about the honey samples and their provenance, whether they were blended, what nectar sources might be present, or the time period involved. Nor did they have any idea of the potential pesticides the sample was exposed to, or how the sample was stored prior to them receiving it. They are limited in what they can conclude about the potential environmental contamination by their ignorance about the behavioural and ecological aspects that many have affected the sample.


There are four New Zealand samples in the data. One from near Marsden Point for thiamethoxam. Two from near the Korowai-Torlesse Tusockland Park outside Springfield for imidacloprid. One between the Tekapo military camp and Mt Cook, positive for imidacloprid, thiamethoxam, thiacloprid, and acetamiprid. I've had a look and acetamiprid is not in the current ACVM list as registered for use in New Zealand. Imidacloprid has bee registered since 1992, thiamethoxam and thiacloprid since 2000, and clothianidin from 2003.


The seven Australian samples presented a simpler picture, one with no detection, four for imidacloprid (one including thiacloprid), one with only thiacloprid, and one with only thiamethoxam.
 

Of the 198 samples tested, 149 had a measurable amount of at least one compound - 75%. Several compounds were found in 60% of samples. It's curious that three tests, for Italy, Portugal, and Spain, list thiamethoxam as 'Not detected' (ND, rather than >LOD - Limit of Detection). In the other 987 tests results are reported as an amount or as below the limit of quantification (<LOQ). If the distinction is correctly made, in 990 tests 987 must positive (but not quantifiable), or 99.7% This is not the claim being made. They do say that 48% of their samples exceeded a 'biologically relevant dose. The biologically relevant dose they chose has been derived mainly from a study on bumble bee brains reporting harm to neurons after several days exposure. I'm not really able to say if their choice was a valid one, the evaluation of the scientific literature on this is very difficult. My only observation would be that there are good reasons to think, behaviourally and ecologically, bumble bees, honey bees, and other pollinators are not the same, and neither are the five neonicotinoids. In the New Zealand results, most are very low and seemingly not significant. The two thiamethoxam results are relatively high, but it's difficult to draw the conclusion they are significant from the table of concentrations given in the Supplementary Data.


Overall I'd say this is an interesting attempt at answering some important questions about the use of these pesticides. That they have become so ubiquitous in (for NZ) the last 25 years is startling, and from samples in, to me, pretty unlikely places. The claim neonicotinoids have been found in 75% of their samples isn't helpful, in that newspapers and consumers just hear "contaminated honey". Science magazine reported the study with the headline "Nerve agents in honey". Whether or not we can say it is harming pollinating insects (it isn't harming people!), it is actually an indictment of the way in which we are managing our landscapes, and the fact that so many samples had two or more of the compounds says something about the persistent and pervasive nature of these pesticides. There is a case to be made for a well designed long term monitoring programme, even in New Zealand.

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Alastair    4,329

Thanks Dave.

 

What I wondered, is that testing of just about anything we consume, will find tiny levels of pesticides. The world is drenched in it. 

 

So to me anyway, it would be more of a surprise if they had not found tiny levels in at least most of the honey samples.

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Dave Black    2,998
22 minutes ago, Alastair said:

So to me anyway, it would be more of a surprise if they had not found tiny levels in at least most of the honey samples.

A common sentiment I'm sure @Alastairbut no less depressing. I don't think its the sensitivity of the testing. Perhaps it surprises me because I suspect it's nectar that is not from food crops, so the contamination is indirect. I have in mind NZ honey crops, kamahi and so on. We are not treating manuka seed are we?

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Alastair    4,329

Well, you got to wonder about the tests when they find a poison that is not even used in NZ. While it might be possible someone smuggled some in, why would anyone try that, when other poisons that can do the job are legally available here. And even on the off chance someone did go to the trouble of smuggling it in, seems a heckuva coincidence it happened to be used right where this particular sample came from.

 

All the same, in my view, just about any honey is likely to have some contamination. Maybe it's kamahi, but where else have those hives been, or what else went through the extracting plant. Some of the levels they detected were very small, equal to 1.8 grams per 1,000 tons of honey. So how much is in a pot, not much.

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Jas    252

A couple of factors come to mind with regards to time lines for chemicals being withdrawn from use . With honey sometimes being stored for extended periods of time before being packed for sale , there is potential for honey in the market place to show traces of chemical that is no longer in use . I personally think that if you tested everything we stick in our mouth , you would be sure to find something in almost everything . 

 

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Dave Black    2,998

All fair points. We have of course no idea if the samples went through an extraction plant - that's one of the problems with the study! 

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Josh    111

Eels in our rivers. Bees in or fields. Canaries in the mine. 

 

When they’re gone, watch out, you’re next

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Dave Black    2,998

Here’s some context for the numbers in the study.

 

The measurements are listed in nanograms per gram (ng/g), the equivalent of parts per billion (ppb). Their average value, across all five compounds, ranged from around 0.3 to 2ppb; the range in all the tests was between 0.07ppm and 46.8ppb. The Limits of Quantification (LOQ) were in hundredths, or thousandths of 1ppb (0.002 – 0.03ppb). The New Zealand values ranged from 0.018 – 0.337ppb. All but two were less than 0.07ppb.

 

In a US study of residues in wax and pollen samples collected in 2007 and 2008 they published values for 121 pesticides and their metabolites found. These included (in wax) fluvalinate (2.0 - 204,000.0ppb; median 3595.0), amitraz (9.2 – 43,000ppb; median 228.0), thiacloprid (1.9 – 7.8ppb; median 5.9), imidacloprid (2.4 - 13.6ppb; median 8.0), and acetamiprid (14 – 134ppb; median 57.0).

 

In Spain a study looking at Bayvarol residues in honey (2009) had a detection limit of around 7.9ppb – 11.5ppb and couldn’t find anything. An earlier Swiss study (1998) had a detection limit for flumethrin (Bayvarol) of 25ppb in wax and couldn’t detect any. The detection limit for flumethrin in honey was 3ppm and there wasn’t any. In this study the Limit of Detection was between 0.001 and 0.01ppb. The Swiss MRL (1999) was 50ppb for fluvalinate and 5ppb for flumethrin. Germany was finding fluvalinate at 2 – 7ppb (7% of samples).

 

It not clear what kind of levels have effects on honey bees. It depends on the active ingredient, the length and route of exposure, and on any synergy with other immunological challenges. Some chronic effects on neurology and behaviour have been reported at 1 or 2ppb, occasionally at a fraction of 1ppb. Effects on reproduction are being reported at 5ppb, and increased mortality by exposure to 50ppb or more. The New Zealand values in the new study are mostly hundreds or thousands times lower.

 

The study authors have this to say; “… to some extent, our results illustrate that the ever-increasing analytical sensitivity allows detecting traces of pesticides where they previously were not detectable. But given the increasing use of neonicotinoid pesticides in the different regions of the world, despite partial bans such as the one implemented in the EU, it is also reasonable to expect contamination to have increased over time.” A little ironic maybe, given they use the increased sensitivity to demonstrate the increased use, but if the compounds weren’t there, they couldn’t be detected, whatever the sensitivity. It’s plainly pollution.

 

Mullin CA, Frazier M, Frazier JL, Ashcraft S, Simonds R, et al. (2010) High Levels of Miticides and Agrochemicals in North American Apiaries: Implications for Honey Bee Health. PLoS ONE 5(3): e9754. doi:10.1371/journal.pone.0009754

 

Bogdanov, S., Kilchenmann, V.,  Imdorf, A. (1998) Acaricide residues in some bee products.  Journal of Apicultural Research 37(2): 57–67

 

Wallner, Klaus. Varroacides and their residues in bee products. Apidologie, Springer Verlag, 1999, 30 (2-3), pp.235-248.

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tom sayn    1,106
23 hours ago, Dave Black said:

We are not treating manuka seed are we?

soil drenching might be the cause. some plants receive a huge load of nics into their plant hole. even if those plants don't produce nectar they might produce honey dew or fruit that is taken up by bees or weeds that grow around these plants will be contaminated. the soil contamination is very persistent over time. i think grape plantings for wine for example are treated that way.

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