Wastewater exposure and health--a comparative study of two occupational groups

The impact of endocrine disrupting compounds and carcinogens in wastewater: Implications for breast cancer

The incidence of breast cancer is often associated with geographic variation which indicates that a person's surrounding environment can be an important etiological factor in cancer development. Environmental risk factors can include exposure to sewage- or wastewater, which consist of a complex mixture of pathogens, mutagens and carcinogens. Wastewater contains primarily carbonaceous, nitrogenous and phosphorus compounds, however it can also contain trace amounts of chemical pollutants including toxic metal cations, hydrocarbons and pesticides. More importantly, the contamination of drinking water by wastewater is a potential source of exposure to mammary carcinogens and endocrine disrupting compounds. Organic solvents and other pollutants often found in wastewater have been detected in various tissues, including breast and adipose tissues. Furthermore, these pollutants such as phenolic compounds in some detergents and plastics, as well as parabens and pesticides can mimic estrogen. High estrogen levels are a well-established risk factor for estrogen-receptor (ER) positive breast cancer. Therefore, exposure to wastewater is a risk factor for the initiation, progression and metastasis of breast cancer. Carcinogens present in wastewater can promote tumourigenesis through various mechanisms, including the formation of DNA adducts, gene mutations and oxidative stress. Lastly, the presence of endocrine disrupting compounds in wastewater can have negative implications for ER-positive breast cancers, where these molecules can activate ERα to promote cell proliferation, survival and metastasis. As such, strategies should be implemented to limit exposure, such as providing funding into treatment technologies and implementation of regulations that limit the production and use of these potentially harmful chemicals.

Wastewater aerosols produced during flushing toilets, WWTPs, and irrigation with reclaimed municipal wastewater as indirect exposure to SARS-CoV-2

The detection of SARS-CoV-2 RNA in raw and treated wastewater can open up a fresh perspective to waterborne and aerosolized wastewater as a new transmission route of SARS-CoV-2 RNA during the current pandemic. The aim of this paper is to discuss the potential transmission of SARS-CoV-2 RNA from wastewater aerosols formed during toilet flushing, plumbing failure, wastewater treatment plants, and municipal wastewater reuse for irrigation. Moreover, how these aerosols might increase the risk of exposure to this novel coronavirus (SARS-CoV-2 RNA). This article supplies a review of the literature on the presence of SARS-CoV-2 RNA in untreated wastewater, as well as the fate and stability of SARS-CoV-2 RNA in wastewater. We also reviewed the existing literatures on generation and transmission of aerosolized wastewater through flush a toilet, house's plumbing networks, WWTPs, wastewater reuse for irrigation of agricultural areas. Finally, the article briefly studies the potential risk of infection with exposure to the fecal bioaerosols of SARS-CoV-2 RNA for the people who might be exposed through flushing toilets or faulty building plumbing systems, operators/workers in wastewater treatment plants, and workers of fields irrigated with treated wastewater - based on current knowledge. Although this review highlights the indirect transmission of SARS-CoV-2 RNA through wastewater aerosols, no research has yet clearly demonstrated the role of aerosolized wastewater in disease transmission regarding the continuation of this pandemic. Therefore, there is a need for additional studies on wastewater aerosols in transmission of COVID-19.

Temporal changes in gene expression and genotype frequency of the ornithine decarboxylase gene in native silverside Basilichthys microlepidotus: Impact of wastewater reduction due to implementation of public policies

Human activity has caused a deterioration in the health and population size of riverine species; thus, public policies have been implemented to mitigate the anthropogenic impacts of water use, watercourse transformation, and pollution. We studied the Maipo River Basin, one of the most polluted with untreated wastewater in Chile, for a period of 12 years (2007-2019). Since the implementation of new public policies, including the operation of a wastewater collector (2012), the Maipo River Basin is currently much less polluted by untreated water than before. To analyze the impact of wastewater reduction in this river basin, we studied the native silverside (Basilichthys microlepidotus), which inhabits both polluted and unpolluted areas of the river basin. Previous studies reported the overexpression of the ornithine decarboxylase (odc) gene, heterozygote deficit, and high frequency of a homozygote odc genotype in silverside populations that inhabit wastewater-polluted sites, suggesting a phenotypic change and genotypic selection in response to pollution. Here, a population affected and another population unaffected by wastewater were studied before and after implementing the wastewater collector. The physicochemical data of water samples, changes in odc expression and microsatellite variability, and odc genotype frequencies were analyzed. The results showed physicochemical changes in the affected site before and after the operation of the wastewater collector. The microsatellite loci showed no changes in either population. The odc expression in the affected site was higher before the operation of the wastewater collector. Significant changes in the genotype frequencies of the odc gene before and after the wastewater collector operation were detected only at the affected site, wherein the homozygous dominant genotype decreased from >59% to <25%. Our results suggest that public policies aimed at mitigating aquatic pollution can indirectly affect both gene expression and genotype frequencies of important functional genes.

Issue of Compliance with Use of Personal Protective Equipment among Wastewater Workers across the Southeast Region of the United States

Wastewater workers are exposed to different occupational hazards such as chemicals, gases, viruses, and bacteria. Personal protective equipment (PPE) is a significant factor that can reduce or decrease the probability of an accident from hazardous exposures to chemicals and microbial contaminants. The purpose of this study was to examine wastewater worker’s beliefs and practices on wearing PPE through the integration of the Health Belief Model (HBM), identify the impact that management has on wastewater workers wearing PPE, and determine the predictors of PPE compliance among workers in the wastewater industry. Data was collected from 272 wastewater workers located at 33 wastewater facilities across the southeast region of the United States. Descriptive statistical analysis was conducted to present frequency distributions of participants’ knowledge and compliance with wearing PPE. Univariate and multiple linear regression models were applied to determine the association of predictors of interest with PPE compliance. Wastewater workers were knowledgeable of occupational exposures and PPE requirements at their facility. Positive predictors of PPE compliance were perceived susceptibility and perceived severity of contracting an occupational illness (p < 0.05). A negative association was identified between managers setting the example of wearing PPE sometimes and PPE compliance (p < 0.05). Utilizing perceived susceptibility and severity for safety programs and interventions may improve PPE compliance among wastewater workers.

Launaea taraxacifolia (Willd.) Amin ex C. Jeffrey inhibits oxidative damage and econucleotidase followed by increased cellular ATP in testicular cells of rats exposed to metropolitan polluted river water

BACKGROUND

Humans are directly/indirectly exposed to hazardous chemicals from the aquatic environment. We investigated the protection of the Launea taraxacifolia methanolic extract (LTME) on the hydroxyl steroid dehydrogenases [(∆5-3β-hydroxyl steroid dehydrogenase (∆5-3β-HSD) and the ∆5-17β-hydroxyl steroid dehydrogenase (∆5-17β-HSD), testicular 5'-nucleotidase and lactate dehydrogenase (LDH)] activities as well as the key indicators of oxidative stress in germinal epithelial cells of rats induced with surulere polluted river water (SPRW).

METHODS

The animals were divided into six groups (n=8). Group I was given 1 mL of distilled water only, Group II received 1 mL of SPRW only, Group III received 200 mg/kg LTME before+1 mL of SPRW after, Group IV received 200 mg/kg LTME+1 mL of SPRW, Group V received 1 mL of SPRW before+200 mg/kg LTME after and Group VI received 200 mg/kg LTME only. The treatment was done via oral administration for 28 days.

RESULTS

The HPLC results showed the abundance of quercetin and quercitrin. The SPRW increased 5'-nucleotidase with the concomitant decrease of ∆5-3β-HSD, ∆5-17β-HSD and LDH activities in rats exposed in relation to the control. Similarly, the administration of the SPRW caused a systemic oxidative damage along with adverse histopathological changes in germinal epithelial cells.

CONCLUSIONS

Interestingly, these alterations were differentially reversed by LTME via the elevation of steroidogenic enzymes and cellular ATP.

Acute invasive pulmonary aspergillosis, shortly after occupational exposure to polluted muddy water, in a previously healthy subject

Invasive pulmonary aspergillosis (IPA) predominantly occurs in severely neutropenic immunocompromised subjects. The occurrence of acute IPA after brief but massive exposure to Aspergillus conidia in previously healthy subjects has been documented, although only six such cases have been reported. The diagnosis was delayed in all six of the affected patients, five of whom died. We report the case of a 50-year-old HIV-negative male, a water pipeline maintenance worker, who presented with acute-onset dyspnea and fever one day after working for 2 h in a deep pit containing polluted, muddy water. Over a one-month period, his general condition deteriorated markedly, despite antibiotic therapy. Imaging showed bilateral diffuse nodules with cavitation, some of which were surrounded by ground-glass opacity suggestive of a halo sign (a hallmark of IPA). Cultures (of sputum/bronchial aspirate samples) and serology were positive for Aspergillus fumigatus. After being started on itraconazole, the patient improved. We conclude that massive exposure to Aspergillus conidia can lead to acute IPA in immunocompetent subjects.

Impacts of soil and water pollution on food safety and health risks in China

Environmental pollution and food safety are two of the most important issues of our time. Soil and water pollution, in particular, have historically impacted on food safety which represents an important threat to human health. Nowhere has that situation been more complex and challenging than in China, where a combination of pollution and an increasing food safety risk have affected a large part of the population. Water scarcity, pesticide over-application, and chemical pollutants are considered to be the most important factors impacting on food safety in China. Inadequate quantity and quality of surface water resources in China have led to the long-term use of waste-water irrigation to fulfill the water requirements for agricultural production. In some regions this has caused serious agricultural land and food pollution, especially for heavy metals. It is important, therefore, that issues threatening food safety such as combined pesticide residues and heavy metal pollution are addressed to reduce risks to human health. The increasing negative effects on food safety from water and soil pollution have put more people at risk of carcinogenic diseases, potentially contributing to 'cancer villages' which appear to correlate strongly with the main food producing areas. Currently in China, food safety policies are not integrated with soil and water pollution management policies. Here, a comprehensive map of both soil and water pollution threats to food safety in China is presented and integrated policies addressing soil and water pollution for achieving food safety are suggested to provide a holistic approach.

Mortality analysis on wastewater exposure in Shijiazhuang, Hebei, China, from 2007 to 2011

The study investigated the age-adjusted mortality rate and disease odds among deceased residents living in areas exposed to wastewater and cleanwater from 2007 to 2011, in Shijiazhuang, China. Mortality data for eight villages exposed to wastewater and 16 villages not exposed to wastewater were collected and crosschecked from multiple sources. Overall mean age-adjusted mortality rate for wastewater areas was 798/105 (95% Confidence Interval (CI) = ± 68), insignificantly higher than the mean mortality rate for cleanwater area, 726/105 (95% CI = ± 46), p > 0.05. Malignant neoplasms and respiratory mortality and disease odds were higher in wastewater areas than in cleanwater areas, OR = 1.7 (95% CI = 1.3-2.2, p < 0.01) and OR = 1.9 (95% CI = 1.1-3.4, p < 0.05), respectively. Wastewater area mortality and disease odds for Lung and Stomach cancers after adjustments were OR = 1.6 (95% CI = 1.1-2.4, p < 0.05) and OR = 1.8 (95% CI = 1.2-2.7, p < 0.01), respectively, significantly higher than those of cleanwater areas. There is a possibility that exposure to wastewater might be associated with cancer and respiratory disease mortality. The study recommends that the use of wastewater be limited, discouraged, or discontinued.

Exposure to airborne endotoxins among sewer workers: an exploratory study

Exploratory bioaerosol sampling was performed in order to assess exposure to airborne endotoxins during sewer work. Personal samples were collected in underground sewer pipes using 37-mm closed-face cassettes containing fibreglass filters (CFC-FG method) or polycarbonate filters (CFC-PC method). Endotoxins were quantified using the limulus amoebocyte lysate assay. Concentrations of airborne endotoxins at sewer workplaces (16-420 EU m(-3)) were higher than those measured outside the sewer network (0.6-122 EU m(-3)). Sewer worker exposure to airborne endotoxins depended on the workplace and on the tasks. Exposure levels were the highest for tasks involving agitation of water and matter, especially for 'chamber cleanup' and 'pipes cleanup' with a high-pressure water jet. Airborne endotoxin levels at the workplace tended to be higher when CFC-FG was used as the sampling method rather than CFC-PC. The adjusted mean of the measured concentrations for CFC-PC represents 57% of the mean observed with CFC-FG. The number of samples collected in the descriptive study was too low for drawing definitive conclusions and further exposure investigations are needed. Therefore, our exploratory study provides new exposure data for the insufficiently documented sewer working environment and it would be useful for designing larger exposures studies.

Integrated exposure assessment of sewage workers to genotoxicants: an urinary biomarker approach and oxidative stress evaluation

BACKGROUND

Sewage workers are exposed to multiple chemicals among which many are suspected genotoxicants. Therefore, they might incur DNA damage and oxidative stress. We aimed to explore integrated urinary biomarkers, assessing the overall urine genotoxicity by in vitro comet and micronucleus assays and measuring urinary 8-oxo-2'-deoxyguanosine.

METHODS

During three consecutive working days, polycyclic aromatic hydrocarbons and volatile organic compounds were sampled in workplace air of 34 sewage and 30 office workers, as indicators of airborne exposure. The last day, subjects collected their 24 hours urine. Genotoxicity of urinary extracts was assessed by comet and micronucleus assays on a HepG2 cell line. Using competitive enzymatic immunoassay we evaluated the 24 hours urinary 8-oxo-2'-deoxyguanosine excretion. Benzo(a)pyrene toxicity equivalent factors and inhalation unit risk for Benzo(a)pyrene and benzene were used to give an estimate of cancer risk levels.

RESULTS

Workplace air concentrations of polycyclic aromatic hydrocarbons (e.g. 23.7 [range 2.4-104.6] ng.m-3 for fluoranthene) and volatile organic compounds (e.g. 19.1 ± 2.9 [standard error] μ.m-3 for benzene) were elevated in sewage compared to office workplaces (P < 0.01) and corresponded to an increased lifetime cancer risk. The urinary extracts of sewage workers showed higher genotoxicity (P < 0.001) than office workers.

CONCLUSIONS

The integrated and non-specific urinary biomarkers of exposure showed that sewage workers experience exposure to mixtures of genotoxicants in the workplace.

Cancer incidence in the wastewater treatment plant of a large chemical company

OBJECTIVES

To evaluate cancer incidence among employees assigned to BASF's wastewater treatment plant.

METHODS

We conducted a retrospective cohort study including 477 male employees who had ever worked in the facility for at least 1 year since the start of operations in 1974. Cancers were identified by review of occupational medical records and a standardized questionnaire completed by the participants or their next of kin. Confirmation through hospital records was sought for all reported cases after obtaining informed consent. Standardized incidence ratios (SIR) and 95% confidence intervals (CI) were computed using comparison data provided by the Saarland Cancer Registry. Further comparisons were made between three different subgroups of employees, working in maintenance, wastewater processing, and sewage sludge treatment.

RESULTS

A total of 50 cancers were observed (SIR 1.14, CI 0.85-1.51). Colorectal (1.14, 0.42-2.48), bronchial (1.40, 0.67-2.57) and prostate (1.15, 0.42-2.50) were the most frequently observed cancers. Five cases of bladder cancer were found in the total cohort (1.75, 0.57-4.09), with four of them occurring in the sewage sludge treatment area (6.82, 1.86-17.46). Allowing for a 10-year lag did not significantly change the results.

CONCLUSIONS

The overall cancer experience among employees of the wastewater treatment plant was similar to that of the corresponding general population. The finding of an excess risk for bladder cancer in one subgroup of workers was unexpected with regard to the available literature. There is no straightforward explanation for this finding, and it may be due to chance. An extended follow-up of this cohort will take place after 5 years. Annual bladder cancer screening is offered to active and retired employees from this plant for the time being. The current working conditions and work practices have been re-assessed by occupational hygienists and deemed to be safe.

Biomonitoring of complex occupational exposures to carcinogens: the case of sewage workers in Paris

Background

Sewage workers provide an essential service in the protection of public and environmental health. However, they are exposed to varied mixtures of chemicals; some are known or suspected to be genotoxics or carcinogens. Thus, trying to relate adverse outcomes to single toxicant is inappropriate. We aim to investigate if sewage workers are at increased carcinogenic risk as evaluated by biomarkers of exposure and early biological effects.

Methods/design

This cross sectional study will compare exposed sewage workers to non-exposed office workers. Both are voluntaries from Paris municipality, males, aged (20–60) years, non-smokers since at least six months, with no history of chronic or recent illness, and have similar socioeconomic status. After at least 3 days of consecutive work, blood sample and a 24-hour urine will be collected. A caffeine test will be performed, by administering coffee and collecting urines three hours after. Subjects will fill in self-administered questionnaires; one covering the professional and lifestyle habits while the a second one is alimentary. The blood sample will be used to assess DNA adducts in peripheral lymphocytes. The 24-hour urine to assess urinary 8-oxo-7, 8-dihydro-2'-deoxy-Guanosine (8-oxo-dG), and the in vitro genotoxicity tests (comet and micronucleus) using HeLa S3 or HepG2 cells. In parallel, occupational air sampling will be conducted for some Polycyclic Aromatic Hydrocarbons and Volatile Organic Compounds. A weekly sampling chronology at the offices of occupational medicine in Paris city during the regular medical visits will be followed. This protocol has been accepted by the French Est III Ethical Comitee with the number 2007-A00685-48.

Discussion

Biomarkers of exposure and of early biological effects may help overcome the limitations of environmental exposure assessment in very complex occupational or environmental settings.

Mortality among Paris sewage workers

OBJECTIVES

To describe the mortality of Paris sewage workers.

METHODS

A cohort of all Paris sewage workers since 1970 was established and followed up in mortality until 1999. The causes of death were determined by matching with a national database. The mortality rates were compared to the rates of a local reference population.

RESULTS

A large excess in mortality (standardised mortality ratio (SMR) = 1.25; 530 cases, 95% CI 1.15 to 1.36) and in particular mortality from cancer (SMR = 1.37, 235 cases) was detected which was particularly important in the subgroup of subjects who had left employment because they resigned or were laid off (SMR = 1.77; 50 cases). The excess mortality is to a large extent due to alcohol related diseases (SMR = 1.65, 122 cases) especially malignant (SMR = 1.85, 16 cases) and non-malignant (SMR = 1.68, 38 cases) liver diseases, lung cancer (SMR = 1.47, 68 cases), and infectious diseases (SMR = 1.86, 25 cases). The SMRs for some diseases (all cancers, cancers of the oesophagus and lung, all alcohol related diseases) seem to increase with duration of employment as a sewage worker. Other than lung cancer, smoking related diseases were not in excess.

CONCLUSION

The increased mortality by both malignant and non-malignant liver diseases is probably due to excessive alcohol consumption, but could be partially the result of occupational exposure to chemical and infectious agents and interactions of these factors. The excess lung cancer is unlikely to be due to an increased smoking prevalence.

Hepatitis E, Helicobacter pylori, and gastrointestinal symptoms in workers exposed to waste water

BACKGROUND

Workers exposed to sewage may have an increased risk of infection by Helicobacter pylori and hepatitis E virus (HEV).

AIMS

To assess the prevalence of clinical hepatitis E (HE) and peptic ulcer disease as well as the seroprevalence of antibodies to H pylori and HEV in workers with and without sewage exposure and to look for symptoms due to exposure to endotoxin.

METHODS

In the first year of a prospective cohort study 349 sewage exposed workers and 429 municipal manual workers (participation: 61%) underwent a complete medical examination. Travelling to endemic areas, socioeconomic level, age, country in which childhood was spent, and number of siblings were considered as the main confounding factors.

RESULTS

Peptic ulcer disease and clinical HE did not occur more often in workers exposed to sewage. Prevalence of antibodies to HEV was 3.3% and overall prevalence of IgG antibodies to H pylori was 42% with large differences between subgroups. Logistic regression did not show an increased risk of seropositivity or antibodies to parietal cells in sewage exposed workers, but disentangling the effect of exposure from that of confounders was extremely difficult. No increase of symptoms due to exposure to endotoxin was found in sewage workers, with the exception of diarrhoea.

CONCLUSIONS

No clear increased risk of infection by H pylori or by HEV in workers exposed to sewage was found in this cross-sectional study, but these results need to be confirmed by follow up.