Microplastics: Human exposure assessment through air, water, and food.

BACKGROUND: Microplastics (MP) are plastic particles with dimension up to 5 mm. Due to their persistence, global spread across different ecosystems and potential human health effects, they have gained increasing attention during the last decade. However, the extent of human exposure to MP through different pathways and their intake have not been elucidated. OBJECTIVES: The objective of this review is to provide an overview on the pathways of exposure to MP through inhalation, ingestion, and dermal contact considering data from the open bibliography on MP in air, dust, food, water and drinks. METHODS: A bibliographic search on Scopus and PubMed was conducted using keywords on MP in outdoor and indoor air, indoor dust, food including beverages and water and human intake (n = 521). Articles were sorted by their title and abstract (n = 213), and only studies reporting MP identification and quantification techniques were further considered (n = 168). A total of 115 articles that include quality assurance and quality control (QA/QC) procedures are finally discussed in the present review. Based on MP concentration data available in literature, we estimated the potential inhaled dose (ID), dust intake (DI), the estimated daily intake (EDI) via food and beverages. Finally, the total daily intake (TDI) considering both inhalation and ingestion routes are provided for adults, infants and newborns. RESULTS: The concentrations of MP in outdoor and indoor air, dust, and in food and water are provided according to the bibliography. Human exposure to MP through dust ingestion, inhalation of air and food/drinks consumption revealed that indoor air and drinking waters were the main sources of MP. CONCLUSIONS: This study reveals that humans are constantly exposed to MP, and that the indoor environment and the food and water we ingest decisively contribute to MP intake. Additionally, we highlight that infants and newborns are exposed to high MP concentrations and further studies are needed to evaluate the presence and risk of MP in this vulnerable age-population.

BPA toxicity during development of zebrafish embryo / Toxicidade do BPA durante o desenvolvimento de embriões de Zebrafish

Bisphenol A (BPA) is a monomer used in the production of polycarbonate, a polymer commonly found in plastics, epoxy resins and thermal papers. The presence of BPA in food, water, air and dust has been of great concern in recent years not only due to environmental and ecological issues but also because of its supposed risk to public health related to its mutagenic and carcinogenic potential. In this study we evaluated the toxicity of bisphenol A in zebrafish embryos (Danio rerio) and determined the 50% lethal concentration (LC50) of this chemical. BPA was used at concentrations ranging from 1 µM to 100 µM in E3 medium/0.5% dimethylsulfoxide (DMSO) from previously prepared stock solutions in 100% DMSO. Controls included embryos exposed only to E3 medium or supplemented with 0.5% DMSO. Camptothecin (CPT), a known inhibitor of cell proliferation was used as positive control at a concentration of 0.001 µM in E3 medium/0.5% DMSO. Adults zebrafish were placed for breeding a day before the experimental set up, then, viable embryos were collected and selected for use. Experiments were carried out in triplicates, according to specifications from Organization for Economic Cooperation and Development (OECD). One embryo/well (25 embryos per concentration) was distributed in 96 well microplates in presence or absence of the chemicals. The plates were kept in BOD incubators with a controlled temperature of 28.5 ºC and with photoperiod of 14 h light:10 h dark. After 24h, 48h, 72h and 96h exposure, the exposed embryos were evaluated according to the following parameters: mortality, coagulation, rate of heartbeat, hatching and presence of morphological abnormalities. Photography was obtained by photomicroscopy. Apoptosis was evaluated by DNA ladder assay. DNA was extracted by phenol:chloroform method and analyzed by 2% agarose gel electrophoresis. DNA fragments were visualized after ethidium bromide staining in ultraviolet transilluminator. The LC50 determined for BPA was 70 µM after 24 hours, 72 µM after 48 hours, 47 µM after 72 hours and 31 µM after 96 hours exposure. BPA induced morphological and physiological alterations such as yolk sac and pericardial edema, hatching delay or inhibition, spine deformation, decreasing in heartbeat rate and mortality. In conclusion, this study demonstrated that BPA induced marked malformations in zebrafish embryos at concentrations above 25 µM corroborating the current concerns related to the widespread presence of BPA in the air, food and water used by humans as well as in the bodily fluids and tissues.

Bisfenol A (BPA) é um monômero utilizado na produção de policarbonato, um polímero comumente encontrado em plásticos, resinas epóxi e papéis térmicos. A presença de BPA em alimentos, água, ar e poeira tem sido motivo de grande preocupação nos últimos anos, não só devido a questões ambientais e ecológicas, mas também ao suposto risco para a saúde pública relacionado ao seu potencial mutagênico e carcinogênico. Neste estudo avaliamos a toxicidade do bisfenol A em embriões de peixe-zebra (Danio rerio) e determinamos a concentração letal 50% (LC50) deste composto químico. O BPA foi usado na faixa de concentração entre 1 µM e 100µM em meio E3/0,5% de dimetilsulfóxido (DMSO), preparado a partir de soluções estoques em 100% DMSO. Os controles negativos incluíram embriões expostos apenas ao meio E3 ou suplementado com 0,5% DMSO. Camptotecina (CPT), um conhecido inibidor da proliferação celular, foi usado como controle positivo a uma concentração de 0,001 µM em meio E3/0,5% DMSO. Peixes-zebra adultos foram colocados para reprodução um dia antes da montagem experimental, em seguida, embriões viáveis foram coletados e selecionados para uso. Os experimentos foram realizados em triplicata, de acordo com as especificações da Organização para Cooperação e Desenvolvimento Econômico (OCDE). Um embrião/ poço (25 embriões por concentração) foi distribuído em microplacas de 96 poços na presença ou ausência dos compostos químicos. As placas foram mantidas em incubadoras BOD com temperatura controlada de 28,5 ºC e com fotoperíodo de 14h claro:10h escuro. Após 24h, 48h, 72h e 96h, os embriões expostos foram avaliados de acordo com os seguintes parâmetros: mortalidade, presença de coagulação, taxa do batimento cardíaco, eclosão e presença de anormalidades morfológicas. Fotografias foram obtidas por fotomicroscopia. A apoptose foi avaliada pelo ensaio de DNA ladder. O DNA foi extraído pelo método fenol:clorofórmio e analisado por eletroforese em gel de agarose a 2%. Fragmentos de DNA foram visualizadas após coloração com brometo de etídio em um transiluminador ultravioleta. A LC50 determinada para o BPA foi 70 µM após 24 horas, 72 µM após 48 horas, 47 µM após 72 horas e 31 µM após exposição por 96 horas. O BPA induziu alterações morfológicas e fisiológicas como edema de saco vitelino e edema pericárdico, atraso no tempo ou inibição da eclosão, deformação da coluna vertebral, diminuição da taxa de batimentos cardíacos e mortalidade. Em conclusão, este estudo demonstrou que o BPA induziu grande número de malformações em embriões de peixe-zebra em concentrações acima de 25 µM, corroborando as preocupações atuais relacionadas a presença generalizada do BPA no ar, alimento e água usados pelos seres humanos bem como nos fluidos e tecidos corporais.

Overview of Legal and Policy Framework Approaches for Plastic Bag Waste Management in African Countries.

Plastic bag waste is a major challenge in several African countries. As a way of reducing the detrimental effects posed by plastic bags, governments have adopted various approaches for plastic bag waste management that include levies, bans and or the combination of the two. Despite the adoption of anti-plastic bag policies in several African countries, there has been limited investigation regarding their effectiveness. Thus, the present paper reviews the effectiveness of legal and policy framework approaches for plastic bag waste management in African countries. This systematic review covers legal and policy framework approaches for plastic bag waste management in African countries since 2004 with a view to find their effectiveness. Data sources included peer-reviewed journal articles, websites, books, reports, and dissertations. The databases from which literature was retrieved included Elsevier, Taylor, Springer, institutional repository, and Google Scholar. The current paper argues that poorly enforced plastic bag legislation, resistance from stakeholders, and limited effective substitutes are major factors hindering effective plastic bag waste management in Africa. A six-step model developed by Patton and Sawicki assisted in evaluating plastic bag policies in varied African nations. The study concluded that the key to effective legislation is hinged on consistent enforcement and educating the public to attain environmental buy-in. African countries should adopt and implement the Patton and Sawicki six-step rationalist model to achieve effective plastic bag legislation. African governments should enlighten consumers about other alternatives that are more specific to African countries, especially bags made of raffia and leaves. The findings are limited in that there may be other relevant articles (beyond published articles) about policy and legal approaches for plastic bag waste management, which are not available in the public domain. Therefore, data reviewed may not be exhaustible.

Assessment the effect of exposure to microplastics in Nile Tilapia (Oreochromis niloticus) early juvenile: I. blood biomarkers.

There is a scarcity of knowledge about the impacts of microplastics (MPs) on the early juvenile stage of freshwater fish. The current study aims to inspect the exposure and post-exposure recovery of microplastics (MPs) on accumulation and blood biomarkers of Nile Tilapia (Oreochromis niloticus) early juvenile. Four groups of fishes were used; the first group was the control group, the second group was exposed to (1 mg/L of MPs), the third group was exposed to (10 mg/L of MPs), and the fourth group was exposed to (100 mg/L of MPs) for 15 days and 15 days of recovery. The results showed that significantly higher numbers of microplastics were observed in microplastics-exposed groups compared to control group. Biochemical parameters (creatinine, uric acid, AST, ALT, ALP, glucose, cholesterol, total protein, albumin, globulin, and A/G ratio) showed significant increment after exposure to microplastics for 15 days compared to control group in dose dependent manner. The hematological indices (RBC's count, Hb, Ht, MCHC, Platelets, WBC's count, and monocytes) showed a significant decline after exposure to microplastics for 15 days compared to control group, while MCV and MCH showed a significant increase after exposure to microplastics for 15 days. After the recovery period, microplastics accumulations, hemato-biochemical alterations were still detected in microplastics exposed groups compared to the control group except for WBC's count and MCV which return to normal levels. MPs caused anemia and perturbations in hemato-biochemical parameters which may cause mortality of tilapia early juvenile and should be considered in a program for monitoring hazard materials in the ecosystem.

Understanding plastics pollution: The role of economic development and technological research.

Our world is awash with plastic. The massive increase in plastics production, combined with a shift to single-use, disposable plastics and widespread mismanagement of plastic waste, has created a huge "tragedy of the commons" (Hardin, 1968) in our oceans, seas and waterways. Plastics pollution is now a global externality that damages ecosystems, curtails biodiversity and ultimately has the potential to affect everyone on the planet. Although waste output is often modelled separately from environmental pollution in research, in the case of plastics, the waste problem has become one of global pollution. In this paper, we model the relationship between mismanaged plastic waste1 and income per capita for 151 countries, and for the first time find empirical support for the environmental Kuznets curve using plastics pollution data. Further, we find support for the hypothesis that a key instrument for reducing plastics pollution is investment in scientific and technological research. The paper concludes with a discussion of the results, limitations, and implications for future research and practice.

Phthalate pollution driven by the industrial plastics market: a case study of the plastic market in Yuyao City, China.

In attempts to evaluate the environmental risk produced by plastic markets, the levels and congener profiles of phthalate esters (PAEs) in soil, vegetable, and sediment samples collected from the plastic market in China, where numerous plastic products are exchanged every year, were investigated. The concentrations of ∑22PAEs ranged from 2131 to 27,805 ng g-1 in agricultural soils, from 8023 to 37,556 ng g-1 in vegetables and from 9031 to 87,329 ng g-1 in sediments. The predominant PAE pollutants were di-(2-ethylhexyl) phthalate (DEHP), di-n-butyl phthalate (DnBP), di-isobutyl phthalate (DiBP), and dibenzyl phthalate (DBzP). The mean percentages of the predominant PAEs in the soil, vegetable, and sediment samples accounted for 98.4%, 97.3%, and 99.5% of the total PAEs, respectively. The concentrations of PAEs at the sites around the plastic market were significantly higher than those at other pollution sites, such as sites contaminated by agricultural plastic film, electronic waste (e-waste) recycling sites, and industrial parks, indicating that the plastic market was an important pollution source. The DEHP concentrations in the soils, vegetables, and sediments and the DnBP concentrations in the vegetables all exceeded the environmental risk levels (ERL) or the environmental allowable levels (EAL), indicating that the plastic market posed potential environmental risks.

Exposure assessment of monoterpenes and styrene: a comparison of air sampling and biomonitoring.

BACKGROUND: Within- and between-worker variance components have seldom been reported for both environmental and biological data collected from the same persons. AIMS: To estimate these variance components and their ratio for air contaminants and urinary metabolites in two different work environments and to predict the attenuation of exposure-response relationships based on these measures. METHODS: Parallel measurements of air and urine were performed among workers exposed to monoterpenes in sawmills (urinary metabolite: verbenol) and styrene in reinforced plastics factories (urinary metabolite: mandelic acid). RESULTS: Among the sawmill workers, variance components of the air and urinary verbenol results were similar; for the reinforced plastics workers the estimated between-worker variance component was greater for styrene in air than mandelic acid in urine. This suggests that attenuation bias would be about equal if air or biological monitoring were employed for monoterpene exposures, but would be greater if urinary mandelic acid were used instead of airborne styrene in an investigation of styrene exposure. CONCLUSIONS: Personal air samplers provide data with similar or superior quality to urinary metabolites as measures of exposure to these monoterpenes in sawmills and styrene in reinforced plastics factories.

Exposure assessment in epidemiologic studies of birth defects by industrial hygiene review of maternal interviews.

In epidemiologic studies of birth defects, occupational titles have frequently been used as surrogates for exposure. To avoid the error associated with such proxy exposure measures, we have designed a process in which an industrial hygienist systematically imputes exposures derived from maternal interviews. In response to a structured questionnaire, mothers of cases and controls recalled occupational and nonoccupational tasks performed or products used around the time of conception. Maternal exposures were then assigned to several a priori defined categories by an industrial hygienist. The central exposure category consists of 74 chemical families, e.g., alcohols, lead compounds. Other exposure categories are individual chemical compounds; nonchemical agents, e.g., ionizing radiation, infectious diseases; and product end-use categories, e.g., insecticides, combustion products. A detailed description of this approach and its exposure assessment potential is presented using exposure data from 220 maternal interviews.

Assessment of colorectal cancer incidence among polypropylene pilot plant employees.

Our recent study reported a colorectal cancer excess among workers involved in the manufacture of polypropylene. To follow up on this finding, we initiated a study of colorectal cancer incidence among polypropylene pilot plant workers within the same company. The purpose of this investigation was to determine whether colorectal cancer incidence was elevated among workers who may have had exposures similar to those experienced on the commercial production unit. The study population included 183 employees who worked at least 6 months on either of two pilot plants. Overall, there were three observed colorectal cases v. 3.3 expected (standardized incidence ratio = 0.9, 90% confidence interval 0.3 to 2.3). Analyses for the process, mechanic, and laboratory subgroup showed rates consistent with expected values (3 observed, 2.8 expected; standardized incidence ratio = 1.1, 90% confidence interval 0.3 to 2.8). Analyses by duration of employment and latency did not show patterns consistent with the colorectal cancer excess previously reported. The likelihood of lower or different exposures on the pilot plant than would be found on commercial production units is discussed along with the need for studies of workers in other polypropylene manufacturing environments.

Assessment of colorectal cancer screening outcomes among workers involved in polypropylene manufacture.

To follow up on a previous finding of an elevated colorectal cancer incidence rate among Exxon employees on a unit devoted to the manufacture of polypropylene (the polyolefin unit [POU]), a company-sponsored screening program was offered to all former and present POU workers. Overall participation was 52.5%, with lower participation among older workers and workers who had retired or were no longer employed by the company. Evaluation of polyp prevalence rates for POU workers v rates for non-Exxon employees screened at the same clinic showed a general pattern of elevated rates for POU employees, especially for mechanical and process workers. This pattern was most marked for polyps at least 0.5 cm in diameter, but findings were less clear for adenomatous polyps. The effect of factors that might bias evaluation of colorectal polyp prevalence rates (eg, selection bias, observation bias, genetic susceptibility) is discussed, but none of these factors seemed a likely explanation for the findings observed in this study.

Injuries caused by plastic bullets compared with those caused by rubber bullets.

The injuries sustained by 99 people struck by plastic bullets, were compared with those sustained by 90 people struck by rubber bullets. Plastic bullets struck the head and chest less often than rubber bullets and caused fewer serious injuries to the face and chest, but tended to cause more serious skull and brain injuries.

Use of disposable products in surgical practice.

Disposable products today are an important part of the multibillion dollar health devices industry. A few heavy-usage and low-usage examples of disposable products used by surgeons are chosen to demonstrate that in a 1,000-bed hospital, economy is rarely, if ever, a reason for converting from reusables to disposables. The actual reasons are more closely related to individual preference, availability, convenience, dependability, safely, and, in some cases, manufacturer's promotion. In a 24-hospital study of surgical apparel, it was found that only caps, masks, shoe covers, and other small items approached partly in cost between disposable and reusable items, where as the per-use cost of reusable larger items such as gowns and drapes was still much lower than that of their disposable counterparts. However, each hospital must make its own decisions based on all factors, not on economy alone.