Interactions between pesticides and microorganisms in freshwater sediments

In aquatic ecosystems sediment microbial communities provide many important functions, such as organic matter decomposition and by constituting a major food source for organisms at higher trophic levels. Sediments are also sites were pesti-cides have been frequently detected. In this thesis, laboratory microcosm experi-ments on the interactions between pesticides and microorganisms in fresh-water sediments were performed. Natural microbial communities were exposed to both environmentally relevant and high concentrations of different pesticides. In short-term exposures, pesticides decreased overall microbial activity at concentrations that are predicted to be environmentally safe. Surprisingly, short-term exposure to the high pesticide concentrations did not always affect the microbial activity. Long-term exposures (one month), were observed to induce different shifts in the microbial community composition, detected by using molecular methods, depending both on the type of pesticide and the concentrations applied. Hence, toxic effects of pesticides in microorganisms are not always straightforward and easy to interpret. The microbial community of an artificial sediment used in toxicity tests was shown to have a low microbial activity, biomass, diversity as well as a different community composition compared to natural sediments. This could have impli-cations for the fate of the test compound and the outcome of the toxicity tests, which may need to be considered when interpreting the toxicity test results. Sediment bacteria and their extracellular polymeric substances (EPS) in biofilms were observed to increase the uptake and bioaccumulation of the hydrophobic pesticide chlorpyrifos to midge larvae, Chironomus riparius. This indicates that microorganisms and EPS may increase the bioavailability and be important vectors for the uptake of sediment-associated contaminants in aquatic food webs. Hence, the quality of the sediment organic carbon may need to be taken in consideration in toxicity tests and risk assessments of these pollutants. This thesis shows that sediment microorganisms can be affected by pesticide exposure and that they can affect pesticide bioavailability. Therefore, the role of microbial processes should be regarded in risk assessments of pesticides

Resthalter av bekämpningsmedel (OP1) som indikator i livsmedel samt uppskattat intag och risk bland svenska konsumenter (inklusive barn)

På uppdrag av Naturvårdsverket har Livsmedelsverket uppskattat exponeringen av bekämpningsmedelsrester från substanser tillhörande gruppen organiska fosforföreningar bland svenska konsumenter, inklusive barn. Intaget delades upp på hur stor del som kommer från svenskproducerade produkter och hur stor del som kommer från importerade produkter från övriga länder, uppdelat på EU och 3:e land. I denna studie har även det sammanlagda intaget av organiska fosforföreningar beräknats. Organiska fosforföreningarna (OP-föreningar) är en grupp bekämpningsmedel vilka tillhör klassen kolinesterashämmare som används för bekämpning av skadeinsekter på grödor. Dessa ämnen påverkar nervsystemet och kan ge såväl akuta som kroniska hälsoeffekter hos människa. På grund av bland annat dessa egenskaper samt ämnenas negativa miljöpåverkan har användningen av organiska fosforföreningar under senare år reglerats allt hårdare inom EU genom att godkännanden upphört, användningen begränsats och gränsvärden sänkts. I Sverige har antalet produkter innehållande OP-föreningar minskat kontinuerligt sedan 90-talet och i dagsläget har användningen upphört helt. Dessa åtgärder borde ha lett till att expone-ringen för svenska konsumenter har minskat under årens lopp, men någon undersökning om så är fallet har inte utförts tidigare. Livsmedelsverket har sammanställt kostdata för barn och vuxna från matvaneunder-sökningarna Riksmaten – barn 2003 och Riksmaten – vuxna 1997-98 och tillsammans med haltdata för OP-föreningar från kontrollprogrammet för bekämpningsmedelsrester uppskattat intaget för den svenska konsumenten, inklusive barn. En bedömning av om denna exponering inneburit en risk för svenska konsumenter har även genomförts. Resultatet av undersökningen visade att exponeringen bland svenska konsumenter för OP-föreningar har minskat under tidsperioden 2005-2011. För varje år var det teoretiska maximala dagliga intaget av enskilda OP-föreningar lägre än det acceptabla dagliga intaget (ADI) för respektive substans, och i de flesta fall var intaget endast runt någon procent av ADI. Det totala kumulativa intaget av OP-föreningar har gradvis sjunkit, från ett intag för barn år 2005-2006 på ca 15-17 % av ADI för referenssubstansen ner till runt 4 % av ADI för både vuxna och barn år 2011. När den exponeringen delades upp i bidrag från produkter producerade i Sverige, inom EU och i tredje land, så var bidraget från svenska produkter försumbart, och förutom två år: 2006 och 2011 då bidraget från EU-grödor var ca 60 % av det totala intaget, så var det varor från tredje land som bidrog mest, med 63-87 %. Den uppskattade kroniska exponeringen av OP-föreningar för svenska konsumenter tyder inte på att det inneburit någon hälsorisk under den undersökta tidsperioden. Uppskattningen av den akuta exponeringen för OP-föreningar, baserad på konservativa antaganden, visade att det inte kan uteslutas att svenska barn vid några tillfällen utsatts för en potentiell hälsorisk. Resthalter i äpple, päron, bordsdruva och persika var i några fall så höga att de kan ha inneburit en risk. Det var fler grödor från tredje land som medförde höga intag, men de flesta fallen inträffade i början av den undersökta perioden, och ingen risk identifierades efter 2009. Livsmedelsverkets slutsats är att det uppskattade kumulativa intaget för OP-föreningar skulle kunna fungera som en indikator för att följa befolkningens exponering för dessa bekämpningsmedel, men att det ur ett hälsoperspektiv vore mer relevant att följa någon annan grupp av bekämpningsmedel som fortfarande används mer allmänt.By request from the Swedish Environmental Protection Agency, the National Food Agency has estimated the exposure of pesticides belonging to the group organophosphates among Swedish consumers, including children. The intake was separated into contribution from commodities produced in Sweden, and the proportion of intake from commodities imported from other countries, divided into EU and third countries. Additionally, in this study an estimation of the cumulative exposure of organophosphates has been performed. Organophosphates (OPs) are pesticides which belong to the group acetylcholinesterase inhibitors and are used to control insect pests on various crops. These substances affect the nervous system and could result in acute and chronic health effects in humans. Because of these properties, as well as negative environmental effects, the use of OPs have become more strictly regulated within EU during the last years, by withdrawal of authorisations, restricting the use, and lowering the EU-MRLs (Maximum Residue Levels). In Sweden the number of pesticide products containing OPs has decreased continuously since the 90’s and nowadays the use has ceased. As a consequence of these actions the exposure of Swedish consumers to OPs should have declined over the last years, but no study has so far confirmed this. The National Food Agency has compiled consumption data for children and adults from the dietary surveys Riksmaten – children 2003 and Riksmaten – adults 1997-98 and together with monitoring data for OPs from the pesticide monitoring program estimated the exposure among the Swedish consumers, including children. An assessment concerning if this exposure has caused any risk to the Swedish consumers has also been performed. The results of this study showed that the exposure among Swedish consumers to OPs has decreased during the time interval 2005-2011. In every year, the theoretical maximum daily intake (TMDI) of individual OPs was below the acceptable daily intake (ADI) for each substance, and in most of the cases only about one per cent of the ADI. The cumulative intake of OPs has decreased, from an intake among children during 2005-2006 of about 15-17 % of ADI for the reference substance to approximately 4 % of ADI for both adults and children in 2011. When the total exposure was divided based on origin of the products, it was evident that the contribution from crops grown in Sweden was negligible, and except for two years: 2006 and 2011, when the contribution from products from EU was about 60 % of the total intake, commodities from third countries contributed the most, with 63-87 %. Thus, the estimated cumulative exposure to OPs among Swedish consumers does not indicate that there has been a chronic health risk. The estimation of the acute exposure to OPs, based on worst-case scenarios, showed that a potential risk for Swedish children cannot be excluded on some occasions, mainly due to residues in apples, pears, table grapes, and peaches. It should be noted that the majority of the crops that lead to high intakes originated from third countries. Most cases occurred in the beginning of the investigated period, and no acute risk was identified after 2009. The National Food Agency concludes that the estimated cumulative intake of OPs may serve as an indicator to monitor the inhabitants’ exposure to these pesticides. However, from a health perspective, it would be more relevant to monitor another group of pesticides, which are still more commonly used

Jämförelse mellan beräknad exponering för resthalter av bekämpningsmedel bland svenska konsumenter – baserat på konsumtionsdata och uppmätta halter i livsmedel eller omräknat från halter av metaboliter i urin

I tidigare Hämi-projekt har Livsmedelsverket på uppdrag från Naturvårdsverket använt haltdata från vår egen kontroll av bekämpningsmedel i livsmedel, och konsumtionsdata från matvaneundersökningar för att uppskatta intaget för konsumenter. Dessa studier har visat på sjunkande exponering och ett lågt intag, i de flesta fall på några få procent av det acceptabla dagliga intaget (ADI) för respektive substans. Slutsatsen har därmed varit att rester av växtskyddsmedel enligt dagens kunskap inte utgör någon risk för konsumenters hälsa. Naturvårdsverket har även finansierat projekt vid AMM Skåne/Lunds universitet, där man analyserat metaboliter av bekämpningsmedel i urin. Resultaten från dessa undersökningar visade att många konsumenter har metaboliter från flera olika bekämpningsmedel i urinproven, och att det därmed sker en kontinuerlig exponering, men det dras inga slutsatser angående om de halter som återfinns skulle kunna orsaka några hälsoeffekter i befolkningen. I detta projekt har Livsmedelsverket, i samarbete med Karolinska institutet, uppskattat exponeringen för bekämpningsmedel bland kvinnor i åldrarna 50-60 år genom två olika metoder. De bekämpningsmedel som omfattades av undersökningen var 2,4-D, klormekvat, mepikvat, klorpyrifos, och grupperna ditiokarbamater och pyretroider som omfattar flera olika substanser. Dels har den mer traditionella exponeringsuppskattningen baserad på haltdata i livsmedel och konsumtionsdata från matvaneundersökningar använts, och dels en metod där metabolithalter man hittar i urin har räknats om till ett uppskattat intag. På så sätt kan man relatera exponeringen till toxikologiska referensvärden som finns för de olika bekämpningsmedlen och få en uppfattning om de mängder som konsumenterna fått i sig skulle kunna orsaka långsiktiga hälsorisker. Ett annat syfte med projektet var att jämföra de exponeringsuppskattningar som Livsmedelsverket och andra riskvärderande myndigheter vanligtvis gör, baserade på haltdata i livsmedel och konsumtionsdata från matvaneundersökningar, med de exponeringsuppskatt-ningar man kan få genom att använda data från biologisk övervakning. Tidigare pilot-beräkningar har visat att den beräknade exponeringen för vissa bekämpningsmedel baserat på metabolithalter i urinen är ca 20 ggr högre än när exponeringen baseras på halt- och konsumtionsdata. Studien ger även möjlighet att jämföra de båda metoderna för exponeringsberäkning och deras för- och nackdelar. Det uppskattade medelintaget av bekämpningsmedlen i denna population överskred inte ADI för någon av substanserna, baserat på resultatet från båda metoderna för beräkning (0,01-18% av ADI). Det visades att för klormekvat och summan av pyretroider var det beräknade intaget i samma storleksordning, oavsett metod. För 2,4-D och ditiokarbamater var det beräknade intaget baserat på haltdata och konsumtionsdata 3-4 gånger högre än baserat på urinmetaboliter, medan det beräknade intaget av mepikvat och klorpyrifos var 2-5 gånger högre med metoden baserat på urinmetaboliter. Det finns flera möjliga förklaringar till dessa skillnader, som till exempel att resthalter finns i skal eller andra oätliga delar av grödor (2,4-D, ditiokarbamater), eller att det finns en exponering av metaboliten i sig från livsmedel (klorpyrifos), alternativt att det finns andra källor till exponeringen, som för mepikvat som bildas vid rostning av kaffebönor. Denna studie visar att båda metoderna kan användas för att beräkna intaget av bekämpningsmedelsrester, och de har sina styrkor och svagheter. De beräknade intagen hos denna grupp i populationen, som har en relativt hög konsumtion av frukt, bär och grönsaker som bidrar mycket till exponeringen av bekämpningsmedel, tyder inte på att det finns en risk för långsiktiga negativa hälsoeffekter.To perform consumer risk assessments of pesticide residues in food, EFSA and other organizations use information on residue levels in food and consumption data from dietary surveys. It can sometimes be questioned if exposure calculated by this method reflects the actual exposure, or if it over- or underestimates the intakes. In this project the National Food Agency, in cooperation with KI, has estimated the exposure of pesticide residues, by using two different methods to be able to compare the results. Firstly, the more traditional exposure assessment based on data of the mean residue levels in foods from the Swedish monitoring program 2008-2012 and mean consumption data for 197 women in the age 50-60 years who participated in the Swedish dietary survey Riksmaten 2010. In the other method, mean levels of metabolites of pesticides in urine from a group of 128 women in the same age range, were used to convert to an estimated intake. The pesticides included in the study were 2,4-D, chlormequat, mepiquat, chlorpyrifos and the groups dithiocarbamates and pyrethroids. None of the estimated intakes exceeded the respective ADI of the substances (0.01-18% of the ADI). It was shown that for chlormequat and the sum of pyrethroids, the estimated mean intakes were similar for both calculation methods. However, for 2,4-D and dithiocarbamates the estimated intakes based on residue levels in food and consumption data were approximately 3-4 times higher than estimates based on urine metabolites, whereas the estimated intakes of mepiquat and chlorpyrifos were higher when based on urine metabolites. Possible explanations for these deviances are that residues are present in the peel or other non-edible parts of fruits (2,4-D and dithiocarbamates) or that there is an exposure of the metabolite directly from the food (chlorpyrifos) or that the exposure comes from other sources, as mepiquat which is formed during the roasting of coffee beans. The study shows that both methods can be used to estimate the intake of pesticide residues, and they have their strengths and weaknesses. Based on the estimated average intakes among this group of the population which has a relatively high consumption of fruits and vegetables that contribute much to the exposure of pesticide residues, there is no concern for negative health effects

Soy intake and possible adverse health effects in Nordic children and pregnant women (unborn children)

Aim: To explore possible adverse health effects of high soy intake among children and pregnant women (unborn children) in the Nordic countries. Methods: A dietary exposure scenario with a high soy content was created based on Danish data on the diet of women (18-45 yrs) and children (4-10 yrs). The literature was searched for relevant studies for a risk assessment of isoflavones. Results: Minor changes in the intake of energy and macronutrients, and no changes to the degree of fulfilling recommended intake levels for most micronutrients were found. Health-based guidance values for genistein intake by pregnant women (unborn children) of 0.09 mg/kg bw/day and for children of 0.07 mg/kg bw/day were established. Conclusion: Estimated exposure to the isoflavone genistein from a diet with high soy content indicated a potential health concern for children and no concern for the unborn child

Associations between dietary pesticide residue mixture exposure and mortality in a population-based prospective cohort of men and women

Background: There is a concern that pesticide residues, regularly detected in foods, might pose a health risk to the consumer, but epidemiological evidence is limited. We assessed the associations between dietary exposure to a mixture of pesticide residues and mortality. Methods: Food consumption was assessed in 68,844 participants from the Swedish Mammography Cohort and the Cohort of Swedish Men, 45–83 years at baseline (1997). Concentrations of pesticide residues detected in foods on the Swedish market (1996–1998), mainly fruits and vegetables, were obtained via monitoring programs. To assess mixture effects, we summed per food item the ratios of each single pesticide mean residue concentration divided by its acceptable daily intake to create for each participant a Dietary Pesticide Hazard Index (adjusted for energy intake and expressed per kilogram of body weight). Multivariable-adjusted Cox proportional hazards models were used to estimate hazard ratios (HR) and 95 % confidence intervals (95 %CI). Results: During 15 years of follow-up (1998–2014), a total of 16,527 deaths occurred, of which 6,238 were caused by cardiovascular disease (CVD) and 5,364 by cancer. Comparing extreme quintiles of Dietary Pesticide Hazard Index, the highest category was inversely associated with CVD mortality HR, 0.82 (95 % CI, 0.75–0.90) and with cancer mortality HR 0.82 (95 % CI 0.75–0.91). In analyses stratified by high/low Dietary Pesticide Hazard Index, similar inverse associations were observed by increasing fruit and vegetable consumption. Conclusions: We observed no indications that dietary exposure to pesticide residue mixtures was associated with increased mortality, nor any clear indications that the benefits of fruit and vegetable consumption on mortality was compromised. Yet, our results need to be interpreted with caution. © 2023 The Author(s)The Swedish Research Council, Formas grant no 2016-00308, and the Swedish Research Council no 2017-00822 and 2017-00644 (SIMPLER) supported the study.</p

Soy intake and possiblie adverse health effects in Nordic children and pregnant women (unborn children)

Aim: To explore possible adverse health effects of high soy intake among children and pregnant women (unborn children) in the Nordic countries. Methods: A dietary exposure scenario with a high soy content was created based on Danish data on the diet of women (18-45 yrs) and children (4-10 yrs). The literature was searched for relevant studies for a risk assessment of isoflavones. Results: Minor changes in the intake of energy and macronutrients, and no changes to the degree of fulfilling recommended intake levels for most micronutrients were found. Health-based guidance values for genistein intake by pregnant women (unborn children) of 0.09 mg/kg bw/day and for children of 0.07 mg/kg bw/day were established. Conclusion: Estimated exposure to the isoflavone genistein from a diet with high soy content indicated a potential health concern for children and no concern for the unborn child

Statement of the Scientific Panel on Plant Protection Products and their Residues (PPR Panel) on the design and conduct of groundwater monitoring studies supporting groundwater exposure assessments of pesticides

Abstract Groundwater monitoring is the highest tier in the leaching assessment of plant protection products in the EU. The European Commission requested EFSA for a review by the PPR Panel of the scientific paper of Gimsing et al. (2019) on the design and conduct of groundwater monitoring studies. The Panel concludes that this paper provides many recommendations; however, specific guidance on how to design, conduct and evaluate groundwater monitoring studies for regulatory purposes is missing. The Panel notes that there is no agreed specific protection goal (SPG) at EU level. Also, the SPG has not yet been operationalised in an agreed exposure assessment goal (ExAG). The ExAG describes which groundwater needs to be protected, where and when. Because the design and interpretation of monitoring studies depends on the ExAG, development of harmonised guidance is not yet possible. The development of an agreed ExAG must therefore be given priority. A central question in the design and interpretation of groundwater monitoring studies is that of groundwater vulnerability. Applicants must demonstrate that the selected monitoring sites represent realistic worst‐case conditions as specified in the ExAG. Guidance and models are needed to support this step. A prerequisite for the regulatory use of monitoring data is the availability of complete data on the use history of the products containing the respective active substances. Applicants must further demonstrate that monitoring wells are hydrologically connected to the fields where the active substance has been applied. Modelling in combination with (pseudo)tracer experiments would be the preferred option. The Panel concludes that well‐conducted monitoring studies provide more realistic exposure assessments and can therefore overrule results from lower tier studies. Groundwater monitoring studies involve a high workload for both regulators and applicants. Standardised procedures and monitoring networks could help to reduce this workload

Statement of the PPR Panel on a framework for conducting the environmental exposure and risk assessment for transition metals when used as active substances in plant protection products (PPP)

Abstract The European Commission asked the European Food Safety Authority (EFSA) to prepare a statement on a framework for the environmental risk assessment (ERA) of transition metals (e.g. iron and copper) used as active substances in plant protection products (PPPs). Non‐degradability, essentiality and specific conditions affecting fate and behaviour as well as their toxicity are distinctive characteristics possibly not covered in current guidance for PPPs. The proposed risk assessment framework starts with a preliminary phase, in which monitoring data on transition metals in relevant environmental compartments are provided. They deliver the metal natural background and anthropogenic residue levels to be considered in the exposure calculations. A first assessment step is then performed assuming fully bioavailable residues. Should the first step fail, refined ERA can, in principle, consider bioavailability issues; however, non‐equilibrium conditions need to be taken into account. Simple models that are fit for purpose should be employed in order to avoid unnecessary complexity. Exposure models and scenarios would need to be adapted to address environmental processes and parameters relevant to the fate and behaviour of transition metals in water, sediment and soils (e.g. speciation). All developments should follow current EFSA guidance documents. If refined approaches have been used in the risk assessment of PPPs containing metals, post‐registration monitoring and controlled long‐term studies should be conducted and assessed. Utilisation of the same transition metal in other PPPs or for other uses will lead to accumulation in environmental compartments acting as sinks. In general, it has to be considered that the prospective risk assessment of metal‐containing PPPs can only cover a defined period as there are limitations in the long‐term hazard assessment due to issues of non‐degradability. It is therefore recommended to consider these aspects in any risk management decisions and to align the ERA with the goals of other overarching legislative frameworks