Contamination of Foods from Cameroon with Residues of 20 Halogenated Pesticides, and Health Risk of Adult Human Dietary Exposure.

(1) Background: Halogenated pesticides are abundantly used in Cameroon, but there is no information on the health risk of consumers from exposure to their residues in foods. (2) Methods: Residues of 20 halogenated pesticides were determined in 11 agricultural products collected in the 3 largest cities of Cameroon using QuEChERS extraction and gas chromatography with electron capture detector (GC-ECD), and health risk from dietary exposure was assessed. (3) Results: Organochlorines pesticides aldrin, p,p'-dichlorodiphenyl-trichloroethane (DDT) and ß-hexachlorocyclohexane (ß-HCH) found in 85.0%, 81.9% and 72.5% of samples, respectively, were the most frequently detected. The highest average concentrations of residues were 1.12, 0.74 and 0.39 mg/kg for methoxychlor, alachlor and ß-HCH, respectively, found in chilli pepper. Chili pepper (58.9%), cowpea (56.8%), black beans (56.5%) and kidney beans (54.0%) exhibited the highest residue occurrences. Levels above the European Union maximum residue limits (MRLs) were found for all the 20 pesticides, in 40.1% of the positive analyses, and the food samples contained 14 pesticides banned in Cameroon. Chronic, acute, cumulative and carcinogenic risk assessments revealed that lifetime consumption of maize, black beans, kidney beans, groundnuts and chili pepper contaminated with aldrin, dieldrin, endrin, HCB, heptachlor, o,p'-DDT, p,p'-DDD, p,p'-DDT, p,p'-DDE and ß-HCH, could pose health risks. (4) Conclusion: These results show that there is an urgent need of pesticide usage regulation, effective application of pesticide bans and management of obsolete pesticide stocks in Cameroon.

Pesticides residues in tobacco smoke: risk assessment study.

Pesticides are not only used on food but also on non-food crops, such as tobacco, to control a range of unwanted animal, plant, and microbial, fungal pests. The residue levels in tobacco leaves are expected to decline up to harvest, during drying, and when the leaves are further processed. Additional pesticides may also be applied to the finished product and residue levels may remain present even when the tobacco is burned. Human exposure to pesticide residues on tobacco occurs when residues remaining in cigarette smoke are inhaled. Based on this assumption, the objectives of this research were (i) to determine the level of pesticides residues in harvested tobacco leaves and (ii) to assess the risk of human exposure to these residues in tobacco smoke. Pesticide residues were detected in all analysed tobacco samples. These detected residues represent ten different active ingredients (AI), three of these AIs (thiodicarb, alachlor, and endosulfan) are no longer allowed in Europe. A 54.7% of these residues were quantifiable. Furthermore, it was found that with the use of solid-phase extraction sorbent (SPE) as adsorbent and n-hexane as solvent, higher recoveries of the pesticide residues in the tobacco smoke from the amount spiked can be obtained. It was also found that cigarette filters help to reduce the intake of residues of pesticides that may be present in cigarettes. Finally, the study concluded that both active smoking and passive smoking populations are exposed to pesticide residues in the tobacco smoke.

Comparison of electrospray and UniSpray, a novel atmospheric pressure ionization interface, for LC-MS/MS analysis of 81 pesticide residues in food and water matrices.

In mass spectrometry, the type and design of ionization source play a key role on the performance of a given instrument. Therefore, it is of paramount importance to evaluate newly developed sources for their suitability to analyze food contaminants like pesticide residues. Here, we carried out a head-to-head comparison of key extraction and analytical performance parameters of an electrospray ionization (ESI) source with a new atmospheric pressure ionization source, UniSpray (US). The two interfaces were evaluated in three matrices of different properties (coffee, apple, and water) to determine if multiresidue analysis of 81 pesticides by QuEChERS extraction and LC-MS/MS analysis could be improved. Depending on the matrix and irrespective of the chemical class, US provided a tremendous gain in signal intensity (22- to 32-fold in peak area, 6- to 7-fold in peak height), a threefold to fourfold increase in signal-to-noise ratio, a mild gain in the range of compounds that can be quantified, and up to twofold improvement of recovery. UniSpray offered comparable linearity and precision of the analyses with ESI, and did not affect the ion ratio. A gain in sensitivity of many compounds was observed with US, but in general, the two ionization interfaces did not show significant difference in LOD and LOQ. UniSpray suffered less signal suppression; the matrix effect was in average 3 to 4 times more pronounced, but showed better values than ESI. With no effect on recovery efficiency, US improved the overall process efficiency 3 to 4 times more than ESI. Graphical abstract.

Glyphosate in yam from Ghana.

Glyphosate is used in Ghana on many crops including yam. There is the suspicion that there could be residue problems in the yam crop. Glyphosate as a polar compound is noted for its difficulty to be analysed in biological matrices. In this study, the method for glyphosate analysis based on FMOC-Cl derivatization was modified with a clean-up (CH2Cl2) step and validated to analyse glyphosate in yam by LC-MS/MS. The results showed that the validated method was efficient for the analysis of glyphosate in yam, with recoveries of 34%, linearity of 0.997, RSD of 7%, LOD of 0.04 mg kg-1, and LOQ of 0.12 mg kg-1. Out of 68 samples analysed from a field experiment and from markets, glyphosate was detected in 14 samples, but at levels below the LOQ. It is concluded that the yam contained glyphosate residues at very low levels which may not pose threat to human health.

Cumulative probabilistic risk assessment of triazole pesticides in Belgium from 2011-2014.

Pesticide residues in food can lead to harmful toxic effects when exposed. Some of these compounds have a common Mode of Action and thus elicit a similar biological response. This paper considers the triazoles, a class of widely used fungicides exhibiting the same short-term (acute) and long-term (chronic) response in humans. We examined Belgian pesticide residue data from 2011-2014 and coupled these with the results of the Belgian food consumption survey of 2004. Cumulative probabilistic risk assessment was done using the Monte Carlo Risk Assessment 8.0 web application. The European Food Safety Authority (EFSA) published a guidance document that proposes both optimistic and pessimistic scenarios for dietary exposure assessment. Other than those two, a third, more balanced, scenario was simulated and showed an exposure right in between the EFSA scenarios. In the optimistic scenario, the foods with the highest measured residues in the residue data contributed the most to the total health risk. In the balanced and pessimistic scenarios, the highest contribution to the total health risk was made by active ingredients with a high sampling rate and/or a high consumption rate. No significant trends were observed in the health risk through 2011 to 2014, and the exposure distribution showed no health risks for the extreme consumers, with one exception in 2012.

Pesticides use and exposure among yam farmers in the Nanumba traditional area of Ghana.

Over the years, pesticides have become a dominant feature of Ghana's agriculture. In the past, pesticides usage was restricted to the cocoa, cotton, vegetables, and fruits sectors. Today, there is a widespread use of pesticides in the cultivation of yam. Since the introduction of pesticides into yam production, farmers have expressed satisfaction about the relief it has brought them with regard to labor and productivity. However, there has been public concern about the human and environmental health impacts of pesticides. In this study, 100 farmers were interviewed through a structured questionnaire to determine their knowledge, awareness, and use practices of pesticides and to determine their level of exposure. The study revealed that the common pesticides currently being used for yam production are herbicides. Although the farmers are aware of the risks associated with the use of pesticides, they use more than the recommended doses and do not pay attention to the use of personal protective equipment (PPE) thereby predisposing themselves to the potential health effects of pesticides. A significant percentage (20 to 40%) of the farmers reported to have never used these PPEs and over 44% of them use glyphosate above the recommended dose (between 1.5 and 2 L/ha). This resulted in an average farmer exposure to glyphosate of 4.2 mg/kgBW/day, well above the acute reference dose (ARfD) of 0.5 mg/kgBW/day. The government should develop and implement programs to train pesticides dealers, educate farmers, enforce the laws on pesticides, and support farmers to uphold protective measures.

Distribution of agricultural pesticides in the freshwater environment of the Guayas river basin (Ecuador).

The rapid increase and transition to more intensive agricultural activities in developing nations are often leading to misuse and overuse of pesticides, making their environment vulnerable for pesticide accumulation. In the present study, the Guayas river basin was taken as a representative case study to evaluate pesticide contamination of the Ecuadorean freshwater environment. Pesticide contamination was determined at 181 sampling sites by a multi-residue method using solid phase extraction (SPE) and pesticide residues were linked with agricultural land use activities to identify the main pollution sources. Moreover, the biological water quality status based on macroinvertebrate communities was determined at every location and the relation with the occurrence of pesticide residues was further investigated. Results showed that pesticide contamination of the freshwater environment was widely present in the Guayas river basin with detections at 108 sampling sites (60%). A total of 26 pesticide products were identified. Most frequently detected pesticides included cadusafos (62 locations), butachlor (21 locations) and pendimethalin (21 locations), with concentrations up to 0.081, 2.006 and 0.557 µg·L-1 respectively. Pesticide residues detected in this study did not significantly influence the biological water quality (p = 0.69), but were observed to be positively correlated with ammonium concentrations, supporting the assumed combined application of chemical fertilizers and pesticides in agriculture. These pesticide residues were also associated with one or more agricultural crops, with in particular the banana and rice industries identified as major pollution sources. Both high consumption rates and non-specific application methods, such as aerial spraying of banana plantations and application directly into the water layer of irrigated rice fields, may attribute to pesticide contamination of the freshwater environment of the Guayas river basin. It is therefore suggested that measures, e.g. legal regulations and awareness campaigns, taken to prevent environmental pollution and accumulation of pesticides primarily focus on these industries.

Evaluation of 99 Pesticide Residues in Major Agricultural Products from the Western Highlands Zone of Cameroon Using QuEChERS Method Extraction and LC-MS/MS and GC-ECD Analyses.

There is no information available on pesticide residue levels in major food commodities harvested in Cameroon, especially from the western highlands region, the food basket of the country. Hence, this study evaluated the residues of 99 pesticides in 72 samples of 12 agricultural products collected in the region, using QuEChERS (Quick, Easy, Cheap, Effective, Rugged, and Safe) method extraction, and analyzed by liquid chromatography tandem mass spectrometry (LC-MS/MS) and gas chromatography with electron capture detection (GC-ECD). This method was suitable for detecting the targeted compounds: For 81 pesticides by LC-MS/MS, the limit of quantification (LOQ) was between 0.0004 and 0.0537 mg/kg; and for 18 halogenated pesticides by GC-ECD, it ranged from 0.0012 to 0.2180 mg/kg. The residues of 62 pesticides, including 12 banned compounds, were found in the samples. Insecticides (39.7%) were the most prevalent group, with all the samples containing at least one pesticide. Twenty-one pesticides (34.4%) exceeded their European Union maximum residue limits (MRLs) and 22 pesticides (34.4%) were found in all 6 sampling locations. Malathion and p,p'-DDT were the most distributed pesticides, found in almost all the samples and sampling sites. Food items with the highest rates of positive results were chili pepper (23.2%), white pepper (20.2%), kidney beans (17.3%), and soybeans (17.2%). Samples with residues above their MRLs represented 38% of all the positive analyses; chili pepper (6.4%) and kidney beans (5.5%) were found to have the most residues above their MRLs. The most critical food commodities were kidney beans, soybeans, chili pepper, and maize. This data presents scientific evidence that investigation into continuous monitoring and good regulation of pesticide usage in Cameroon is needed, and paves the way for health risks analysis.

Formulation approaches to reduce post-application pesticide volatilisation from glass surfaces.

Volatilisation is one of the main pathways for pesticide emission to the atmosphere. While formulation strategies and adjuvants are known to affect the fate of active ingredient, no general volatilisation reducing guidelines exist for formulation purposes. Moreover, as limited information on formulation effects is available, current pesticide fate models lack parameters characterising reduction of active ingredient volatilisation. The objective of this study was to investigate the volatilisation reducing potential of formulation types and adjuvants, and to propose an effective vapour pressure for pesticide fate modelling. Several formulations of fenpropimorph, pyrimethanil and tebuconazole were produced and tested in a wind tunnel to evaluate the effect of formulation on active ingredient volatilisation. Produced emulsifiable concentrates with high volatile solvents did not offer any reduction in volatilisation, while the low volatile solvent reduced the volatilisation of pyrimethanil and fenpropimorph with 79.2 and 52.9%, respectively. The microemulsion reduced the volatilisation of fenpropimorph, pyrimethanil and tebuconazole with 57.6, 57.8 and 49.8%, respectively. High surfactant-active ingredient ratios (100:1) reduced the volatilisation of applied amount of pyrimethanil with 50%, on average. The effective vapour pressure of pyrimethanil formulated as a commercial available suspension concentrate was reduced by 33.8%. The commercial available emulsifiable concentrate did not reduce volatilisation of fenpropimorph. Effective vapour pressures of formulated fenpropimorph and pyrimethanil were determined and showed a high correlation with the amount volatilised within 48h. The saturated vapour pressure is useful when comparing the volatility of active ingredients, but effective vapour pressures are more appropriate to be used in pesticide fate models.

Environmental contaminants of honeybee products in Uganda detected using LC-MS/MS and GC-ECD.

Pollinator services and the development of beekeeping as a poverty alleviating tool have gained considerable focus in recent years in sub-Saharan Africa. An improved understanding of the pervasive environmental extent of agro-chemical contaminants is critical to the success of beekeeping development and the production of clean hive products. This study developed and validated a multi-residue method for screening 36 pesticides in honeybees, honey and beeswax using LC-MS/MS and GC-ECD. Of the 36 screened pesticides, 20 were detected. The highest frequencies occurred in beeswax and in samples from apiaries located in the proximity of citrus and tobacco farms. Fungicides were the most prevalent chemical class. Detected insecticides included neonicotinoids, organophosphates, carbamates, organophosphorus, tetrazines and diacylhydrazines. All detected pesticide levels were below maximum residue limits (according to EU regulations) and the lethal doses known for honeybees. However, future risk assessment is needed to determine the health effects on the African genotype of honeybees by these pesticide classes and combinations of these. In conclusion, our data present a significant challenge to the burgeoning organic honey sector in Uganda, but to achieve this, there is an urgent need to regulate the contact routes of pesticides into the beehive products. Interestingly, the "zero" detection rate of pesticides in the Mid-Northern zone is a significant indicator of the large potential to promote Ugandan organic honey for the export market.

Modelling pesticides volatilisation in greenhouses: Sensitivity analysis of a modified PEARL model.

BACKGROUND: The application of the existing PEARL model was extended to include estimations of the concentration of crop protection products in greenhouse (indoor) air due to volatilisation from the plant surface. The model was modified to include the processes of ventilation of the greenhouse air to the outside atmosphere and transformation in the air. RESULTS: A sensitivity analysis of the model was performed by varying selected input parameters on a one-by-one basis and comparing the model outputs with the outputs of the reference scenarios. CONCLUSION: The sensitivity analysis indicates that - in addition to vapour pressure - the model had the highest ratio of variation for the rate ventilation rate and thickness of the boundary layer on the day of application. On the days after application, competing processes, degradation and uptake in the plant, becomes more important.

Multi-residue determination and ecological risk assessment of pesticides in the lakes of Rwanda.

BACKGROUND: To boost agricultural productivity for both domestic and export purposes, agricultural inputs such as pesticides are being promoted in Rwanda. Even though the use of pesticides is important for agriculture, their residues eventually end up in different environmental compartments and may negatively affect the environment. The purpose of this study was to determine the level of knowledge and awareness of the smallholder farmers towards the use of pesticides in Rwanda and to evaluate the ecological risks of pesticides in the surface water and in the vertical profile of Lake Kivu. RESULTS: Based on the collected data, a method to monitor 33 currently used pesticides was developed. No contamination of the lower water layer was found, indicating that the groundwater that flows into Lake Kivu has not been polluted. Of the pesticides in the surface water, malathion exceeded the risk thresholds and posed a risk towards arthropods. CONCLUSION: The results of this study show that there is a lack of farmer's awareness towards the hazards of pesticides when working with these compounds. Farmers in Rwanda are in need of specialised stewardship for pesticide application training and guiding services. Surface water has been contaminated with malathion, metalaxyl and carbendazim which were the most used pesticides by the farmers in the environment.

Pesticide residues in drinking water and associated risk to consumers in Ethiopia.

Access to safe and reliable drinking water is vital for a healthy population. However, surface water may be contaminated with pesticides because of the nearby agricultural areas as well as from household application. Water samples were collected from water sources in Jimma zone and Addis Ababa, Ethiopia. The extraction and clean up of the samples were undertaken using liquid-solid and liquid-liquid methods. Human exposure was assessed by calculating the estimated daily intake (EDI) of pesticides in water and compared with the acceptable daily intake (ADI) and the acute reference dose (ARfD). The mean concentrations of 2,4-D, malathion, diazinon and fenpropimorph were 1.59-13.90 µg/l and 0.11-138 µg/l in Jimma and Addis Ababa water sources, respectively. The residue level of some of the pesticides were above the European drinking water guide line values, which is an indication of an illegal use of pesticides in the study areas. Concerning human health risk estimation, there was no acute risk (EDI < ARfD). However, chronic risks to human health were observed from exposure to diazinon and fenpropimorph (EDI > ADI) for Jimma and Addis Ababa populations, respectively. A comprehensive monitoring is required to reduce the level of pesticide residues in the water and to minimize particularly the long term human health risks.

Pesticide knowledge and practice among horticultural workers in the Lâm Dong region, Vietnam: A case study of chrysanthemum and strawberries.

BACKGROUND: In Vietnam, large amounts of pesticides are being used in agriculture. Next to benefits for agriculture, pesticides impose a huge threat to the environment when they are used in the wrong way. The objective of this work was to determine the level of knowledge and awareness of the smallholder farmers towards the use of pesticides in Vietnam, Dà Lat region. Based on the collected data, an occupational and environmental risk assessment was performed. RESULTS: The results indicate that the majority of the pesticide operators in the strawberry and chrysanthemum crops have a rather high education. Pesticide knowledge, on the other hand, is usually gained through experience with pests and diseases. Only 30% of the farmers consulted a pesticide specialist or government stewardship for information on (new) pesticide products. Pesticide usage is rather high with application frequencies up to once every three days during the wet season. Pesticide packages are stored to be incinerated (51%) or to be thrown away with the garbage/taken to the landfill (37%). Only a small percentage disposes the packages into the local river (2%). The use of personal protection equipment is well established. Occupational risk assessment showed that the re-entry worker is exposed to a high risk. CONCLUSION: While a general awareness of the hazard of pesticides to human health and the environment is present, practical implementation of this awareness, however, is still limited in strawberry and chrysanthemum crop. The environmental risk evaluation indicated plant protection products of which the use should be limited.

Pressure of non-professional use of pesticides on operators, aquatic organisms and bees in Belgium.

Various studies focus on professional pesticide use, whereas pressure of non-professional use on human and the environment is often neglected. In this study, an attempt was made to estimate the pressure of non-professional use of pesticides on operators, aquatic organisms and bees in Belgium based on sales figures and by using three exposure models. A classification in non-professional use was made based on type of pesticide, application method and on intensity of non-professional use. Pressure of non-professional use on operators is highest for intensive operators, caused by the use of insecticides in an aerosol spray can. Pressure of non-professional pesticides on aquatic life is mainly generated by the use of herbicides. The aerosol spray induces the highest pressure whereas the trigger application hardly affects operator and environmental exposure. The ordinary non-professional user generates most pressure on aquatic organisms. Pressure of non-professional pesticides on bees is mainly caused by the use of insecticides, especially the active substance imidacloprid in combination with the aerosol spray can application method applied by an intensive operator. In general, both total usage (kg) and pressure of pesticides decreased for the period 2005 to 2012 due to efforts made by the government and industry. The results of this study suggest to pay special attention to aerosol spray applications and the non-professional use of insecticides.

Pesticide contamination of Tenebrio molitor (Coleoptera: Tenebrionidae) for human consumption.

The use of pesticides contributes to the productivity and the quality of the cultivated crop. A large portion of the agricultural produce is not consumed as it is not an edible part or the quality of the product is too low. This waste of agricultural produce can be valorised as a substrate for the production of certain insects for human consumption. However, pesticides applied on the plants might accumulate during the life cycle of the insects fed on the waste materials and may cause a health risk to humans consuming the insects. Pesticide residues in larvae of the yellow mealworm, Tenebrio molitor, were investigated. We monitored the accumulation of pesticides in the larvae upon consumption of contaminated fresh produce. An increased uptake rate by the insects was found for pesticides with higher Kow-values. Excretion of pesticides by the insect was inversely related to the log(Kow) values of the pesticides.

Volatilisation of pesticides under field conditions: inverse modelling and pesticide fate models.

BACKGROUND: A substantial fraction of the applied crop protection products on crops is lost to the atmosphere. Models describing the prediction of volatility and potential fate of these substances in the environment have become an important tool in the pesticide authorisation procedure at the EU level. The main topic of this research is to assess the rate and extent of volatilisation of ten pesticides after application on field crops. RESULTS: For eight of the ten pesticides, the volatilisation rates modelled with PEARL (Pesticide Emission Assessment at Regional and Local scales) corresponded well to the calculated rates modelled with ADMS (Atmospheric Dispersion Modelling System). For the other pesticides, large differences were found between the models. Formulation might affect the volatilisation potential of pesticides. Increased leaf wetness increased the volatilisation of propyzamide and trifloxystrobin at the end of the field trial. The reliability of pesticide input parameters, in particular the vapour pressure, is discussed. CONCLUSION: Volatilisation of propyzamide, pyrimethanil, chlorothalonil, diflufenican, tolylfluanid, cyprodinil and E- and Z-dimethomorph from crops under realistic environmental conditions can be modelled with the PEARL model, as corroborated against field observations. Suggested improvements to the volatilisation component in PEARL should include formulation attributes and leaf wetness at the time of pesticide application. © 2015 Society of Chemical Industry.

Influence of adjuvants on the dissipation of fenpropimorph, pyrimethanil, chlorpyrifos and lindane on the solid/gas interface.

The use of pesticides is an integral part of modern agriculture and contributes to the productivity and the quality of the cultivated crop. However, use of pesticides imposes a huge burden on the environment. Volatilisation of pesticides contaminates the environment, affects nearby crops, bystanders and residents but research to mitigate this environmental contamination remains scarce. In this study, the use of adjuvants to reduce the volatilisation and mitigate the environmental contamination was investigated. Dissipation of fenpropimorph, pyrimethanil, chlorpyrifos-ethyl and lindane as pure active ingredient, formulated by different adjuvants and in a commercial formulation were studied. An empirical model assuming exponential decay of the volatilisation rate was used to calculate the volatilisation. In 48 h, up to 90% of the pure fenpropimorph and lindane volatilised. Addition of adjuvants was shown to reduce the volatilisation of pesticides by up to 80%. Commercial formulation was able to reduce the volatilisation of pyrimethanil but the formulation of fenpropimorph had no effect on its volatilisation.

Risk of DDT residue in maize consumed by infants as complementary diet in southwest Ethiopia.

Infants in Ethiopia are consuming food items such as maize as a complementary diet. However, this may expose infants to toxic contaminants like DDT. Maize samples were collected from the households visited during a consumption survey and from markets in Jimma zone, southwestern Ethiopia. The residues of total DDT and its metabolites were analyzed using the Quick, Easy, Cheap, Effective, Rugged and Safe (QuEChERS) method combined with dispersive solid phase extraction cleanup (d-SPE). Deterministic and probabilistic methods of analysis were applied to determine the consumer exposure of infants to total DDT. The results from the exposure assessment were compared with the health based guidance value in this case the provisional tolerable daily intake (PTDI). All maize samples (n=127) were contaminated by DDT, with a mean concentration of 1.770 mg/kg, which was far above the maximum residue limit (MRL). The mean and 97.5 percentile (P 97.5) estimated daily intake of total DDT for consumers were respectively 0.011 and 0.309 mg/kg bw/day for deterministic and 0.011 and 0.083 mg/kg bw/day for probabilistic exposure assessment. For total infant population (consumers and non-consumers), the 97.5 percentile estimated daily intake were 0.265 and 0.032 mg/kg bw/day from the deterministic and probabilistic exposure assessments, respectively. Health risk estimation revealed that, the mean and 97.5 percentile for consumers, and 97.5 percentile estimated daily intake of total DDT for total population were above the PTDI. Therefore, in Ethiopia, the use of maize as complementary food for infants may pose a health risk due to DDT residue.

Volatilisation of pesticides after application in vegetable greenhouses.

BACKGROUND: Volatilisation of pesticides after application to the soil or the crop is an important source of emission into the atmosphere. As a result, workers, residents and bystanders are potentially at risk when exposed to these volatilised substances. Nonetheless, data on measured concentrations are quite scarce, especially in greenhouses. The objective of this work is to present the results of volatilisation experiments performed in greenhouses. RESULTS: The results indicate that the concentrations are highest in the hours after application and rapidly decline during the days following application. CONCLUSION: Greenhouse temperature, ventilation rate, the substance vapour pressure and the rate of competing processes were identified as important factors influencing volatilisation in greenhouses. The results from this study contribute to a better understanding of volatilisation in greenhouses and may help to improve the recent PEARL model for volatilisation in greenhouses.