Bioaerosols in the Earth system: Climate, health, and ecosystem interactions

SARS-CoV-2 in wastewater: State of the knowledge and research needs.

Airborne particulate matter from livestock production systems: a review of an air pollution problem.

Background
Ambient particulate matter (PM) exposure is associated with respiratory and cardiovascular morbidity and mortality. To what extent such effects are different for PM obtained from different sources or locations is still unclear. This study investigated the in vitro toxicity of ambient PM collected at different sites in the Netherlands in relation to PM composition and oxidative potential.

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In vitro toxicity of particulate matter (PM) collected at different sites in the Netherlands is associated with PM composition, size fraction and oxidative potential - the RAPTES project

This review summarises existing evidence on the impact of organic food on human health. It compares organic vs. conventional food production with respect to parameters important to human health and discusses the potential impact of organic management practices with an emphasis on EU conditions. Organic food consumption may reduce the risk of allergic disease and of overweight and obesity, but the evidence is not conclusive due to likely residual confounding, as consumers of organic food tend to have healthier lifestyles overall. However, animal experiments suggest that identically composed feed from organic or conventional production impacts in different ways on growth and development. In organic agriculture, the use of pesticides is restricted, while residues in conventional fruits and vegetables constitute the main source of human pesticide exposures. Epidemiological studies have reported adverse effects of certain pesticides on children’s cognitive development at current levels of exposure, but these data have so far not been applied in formal risk assessments of individual pesticides. Differences in the composition between organic and conventional crops are limited, such as a modestly higher content of phenolic compounds in organic fruit and vegetables, and likely also a lower content of cadmium in organic cereal crops. Organic dairy products, and perhaps also meats, have a higher content of omega-3 fatty acids compared to conventional products. However, these differences are likely of marginal nutritional significance. Of greater concern is the prevalent use of antibiotics in conventional animal production as a key driver of antibiotic resistance in society; antibiotic use is less intensive in organic production. Overall, this review emphasises several documented and likely human health benefits associated with organic food production, and application of such production methods is likely to be beneficial within conventional agriculture, e.g., in integrated pest management.

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Human health implications of organic food and organic agriculture: a comprehensive review

Endotoxin is a well-known bacterial toxin that causes several health effects. Animal faeces and plant materials contaminated with bacteria have been identified as important determinants of organic dust related endotoxin exposure. Although high exposure to organic dust and endotoxins has been described regularly in agricultural industries, a detailed overview of levels of airborne exposure to endotoxins in the agricultural industry, as well as a systematic comparison between several specific branches using the same exposure assessment protocols are lacking. In this study, personal endotoxin exposure in a broad spectrum of agricultural industries was investigated and possible determinants of exposure were explored. 601 personal inhalable dust samples were taken in 46 companies of three agricultural industrial sectors: grains, seeds and legumes sector (GSL), horticulture sector (HC) and animal production sector (AP), with 350 participating employees. Dust and endotoxin levels were determined gravimetrically and by using the Limulus Amoebocyte Lysate (LAL) assay, respectively. Basic descriptive analysis and elaborate analysis of variance were performed. Mean exposure levels were high, with large differences between sectors and between companies within the sectors. Highest dust and endotoxin exposures were found in companies of the GSL sector. In all three sectors exposure was higher in the primary production part compared to the (industrial) products processing part of the sector. The Dutch proposed health based occupational exposure limit (50 EU m−3) and temporary legal limit (200 EU m−3) for endotoxin were often exceeded. Differences in exposure between workers were larger than the day-to-day variability. Identified determinants increasing exposure levels were company, dustiness of the product and contact with animals/faeces. ‘Wet’ processes resulted in less dusty working environments and thus lowered endotoxin exposure. Overall, exposure to endotoxins over the whole range of agricultural industries is high. A 10–1000 fold reduction in exposure is needed to reduce endotoxin related health risks.

Exposure to inhalable dust and endotoxins in agricultural industries

Introduction:Inthepastdecade,westudiedoccupationalbioaerosolexposuresinvarioussitesof the waste management chain. In this paper we present an overview of exposure levels of inhalable dust, endotoxin, b(1!3)-glucan (known or probable inducers of airways inflammation), and extracellular polysaccharide antigens of Aspergillus and Penicillium species (EPS-Pen/Asp; a common and probably more specific marker of fungal exposure). Methods: Over450personalbioaerosolsamplesweretaken.Mixedregressionanalyseswereperformedto estimate exposure determinants, between- and within-worker variance of exposure, and determinants of these variances. Furthermore, we explored whether the type of waste affected the bioaerosol composition of the dust. Results: Endotoxin and glucan exposure levels were relatively low and comparable for waste collection and transferral, green waste composting and use of biomass in power plants. Exposure levels were 5–20 times higher in domestic waste transferral withsorting,andcomposting ofbothdomesticanddomestic andgreenwaste (� 300– 1000 EU m � 3 for endotoxin, and 5–10 m gm � 3 for glucan). Observed exposure exceeded Dutch occupational exposure limits at all sites. EPS-Pen/Asp exposure was detected in 20% of waste collectors and 49% of compost workers. Exposure variability within tasks was large (geometric standard deviation > 2), with smaller between-worker than within-worker variance. Type of company and waste largely explained between-worker variance (40–90%), although within companies no major task-related determinants could be established. Markers of exposure correlated moderately to strongly. Relative endotoxin and glucan content in the dust was only weakly associated with handled waste. Conclusions: Occupational bioaerosol exposure in the waste management chain is lowest for outdoor handling of waste and highest when waste is handled indoors. However, exposure variability is large, with greater within-worker than between-worker variance. Occupational exposure limits for organic dust and endotoxins are frequently exceeded, suggesting workers are at risk of developing adverse health effects.

Overview of Personal Occupational Exposure Levels to Inhalable Dust, Endotoxin, β(1→3)-Glucan and Fungal Extracellular Polysaccharides in the Waste Management Chain

Background

Wastewater treatment workers can be exposed to biological and chemical agents resulting in work-related health effects. The aim of this study was to investigate work-related symptoms in these workers.



Methods

Questionnaire data of 468 employees from 67 sewage treatment plants is evaluated. Personal endotoxin exposure (8 hr measurements; n = 460) was measured in a sample of workers in three different periods over 1 year.



Results

Endotoxin exposure ranged from 0.6 to 2093 endotoxin units (EU)/m3, the geometric mean exposure was low (27 EU/m3). Factor analysis yielded three clusters of correlated symptoms: “lower respiratory and skin symptoms,” “flu-like and systemic symptoms,” and “upper respiratory symptoms.” Symptoms appeared to be more prevalent in workers exposed to endotoxin levels higher than 50 EU/m3. A significant dose-response relationship was found for “lower respiratory and skin symptoms” and “flu-like and systemic symptoms” (P < 0.05).



Conclusions

Wastewater treatment workers reported a wide range of symptoms that may be work-related. Microbial exposures such as endotoxin seem to play a causal role. Am. J. Ind. Med. 48:30–39, 2005. © 2005 Wiley-Liss, Inc.

https://courses.washington.edu/eh451/articles/EndotoxinWastewater.pdf

Endotoxin exposure and symptoms in wastewater treatment workers

Endotoxin exposure occurs in homes and occupational environments and is known to cause adverse health effects. In order to compare results from different studies and establish standards, airborne endotoxin exposures should be assessed using standardized methods. Although the European Committee for Standardization (CEN) developed guidelines for endotoxin exposure assessment, these leave room for individual interpretation. The influence of methods of sampling, extraction, and analysis has never been investigated in a full experimental design. Thus, we sought to fully elucidate the importance of all facets of endotoxin assessment. Inhalable dust samples collected simultaneously were used to investigate the effects on and interactions with airborne endotoxin concentration in two working environments of filter type (glass fiber or Teflon), transport conditions (with/without desiccant), sample storage (-20 or 4°C), extraction solution (pyrogen-free water [PFW] or PFW plus 0.05% Tween 20), extract storage (-20 or 4°C), and assay solution (PFW or PFW plus 0.05% Tween 20). Four hundred samples were collected and randomly distributed over the 20 combinations of treatments. There were no differences found for transport conditions and storage temperature of extracts. Also, no interactions between study variables existed. Sampling on glass-fiber filters, storage of samples in the freezer, and extraction in PFW plus 0.05% Tween 20 resulted in 1.3-, 1.1-, and 2.1-fold-higher estimated endotoxin concentrations, respectively. Use of PFW plus 0.05% Tween 20 in the assay solution had an additive effect. Thus, this study investigated gaps in the CEN protocol and provides data with which to fully specify a protocol for standardization of endotoxin exposure assessment. Copyright © 2007, American Society for Microbiology. All Rights Reserved.

Optimization of airborne endotoxin exposure assessment: effects of filter type, transport conditions, extraction solutions, and storage of samples and extracts.

The measurement of airborne endotoxins is thus far not standardized. Earlier studies reported higher endotoxin yields when Tween 20 was added to the media used for filter extraction and in the Limulus amebocyte lysate (LAL) assay. This study compared four common media and assessed the effects of Tween during extraction and analysis separately. Parallel airborne dust samples from five work environments (n = 250) were used to compare the four media (pyrogen-free water [PFW], PFW-Tween 20, PFW-Tris, and PFW-triethyl-amine- phosphate [TAP]) and an extraction time of 10 or 60 min. A subset of the extracts in PFW or PFW-Tween (n = 40) were analyzed in parallel LAL assays with PFW or PFW-Tween as the assay medium. The results produced by a shorter extraction time or the presence of Tris were similar to the results for the reference procedure (PFW and 60 min of shaking). The use of PFW-TAP showed overall lower yields and a deviant calibration curve. The presence of Tween in the extraction medium resulted in significantly (P < 0.05) higher endotoxin yields from all dust types, independent of the effect of Tween in the assay. Tween in the LAL assay, however, also strongly inhibited the reactivity of the lipopolysaccharide (LPS) standard, thus shifting the calibration curve to higher values. The inhibition of LPS in test samples was less pronounced and varied between dust sources, resulting in enhanced calculated concentrations. This assay effect could be circumvented by diluting extracts at least 50-fold before the LAL assay. In conclusion, of the media tested, only Tween enhances the efficiency of endotoxin extraction from airborne dust samples in a consistent manner. We recommend extraction in PFW-Tween combined with dilution and LAL analysis in PFW. Copyright © 2008, American Society for Microbiology. All Rights Reserved. Chemicals / CAS: polysorbate 20, 12244-25-6, 9005-64-5; triethylamine, 121-44-8; water, 7732-18-5; Culture Media; Endotoxins; Ethylamines; Polysorbates; triethylamine, 121-44-8; Tromethamine, 77-86-1

Suzanne Spaan

Papers

Exposure to inhalable dust and endotoxins in agricultural industries

Overview of Personal Occupational Exposure Levels to Inhalable Dust, Endotoxin, β(1→3)-Glucan and Fungal Extracellular Polysaccharides in the Waste Management Chain

Endotoxin exposure and symptoms in wastewater treatment workers

Optimization of airborne endotoxin exposure assessment: effects of filter type, transport conditions, extraction solutions, and storage of samples and extracts.

Effect of extraction and assay media on analysis of airborne endotoxin