It’s time to shift the burden of proof, from scientists, back to the chemical industry
Video published on 5 June 2019, by UCSF Program on Reproductive Health and the Environment.
And how to reduce exposure to toxic chemicals worldwide ?
It’s time to shift the burden of proof, from scientists, back to the chemical industry
Video published on 5 June 2019, by UCSF Program on Reproductive Health and the Environment.
Analysis of individual and combined estrogenic effects of bisphenol, nonylphenol and diethylstilbestrol in immature rats with mathematical models
Traditional toxicological studies focus on individual compounds. However, this single-compound approach neglects the fact that the mixture exposed to human may act additively or synergistically to induce greater toxicity than the single compounds exposure due to their similarities in the mode of action and targets. Mixture effects can occur even when all mixture components are present at levels that individually do not produce observable effects. So the individual chemical effect thresholds do not necessarily protect against combination effects, an understanding of the rules governing the interactive effects in mixtures is needed. The aim of the study was to test and analyze the individual and combined estrogenic effects of a mixture of three endocrine disrupting chemicals (EDCs), bisphenol A (BPA), nonylphenol (NP) and diethylstilbestrol (DES) in immature rats with mathematical models.
In the present study, the data of individual estrogenic effects of BPA, NP and DES were obtained in uterotrophic bioassay respectively, the reference points for BPA, NP and DES were derived from the dose-response ralationship by using the traditional no observed adverse effect (NOAEL) or lowest observed adverse effect level (LOAEL) methods, and the benchmark dose (BMD) method. Then LOAEL values and the benchmark dose lower confidence limit (BMDL10) of single EDCs as the dose design basis for the study of the combined action pattern. Mixed prediction models, the 3 × 2 factorial design model and the concentration addition (CA) model, were employed to analyze the combined estrogenic effect of the three EDCs.
From the dose-response relationship of estrogenic effects of BPA, NP and DES in the model of the prepuberty rats, the BMDL10(NOAEL) of the estrogenic effects of BPA, NP and DES were 90(120) mg/kg body weight, 6 mg/kg body weight and 0.10(0.25) μg/kg body weight, and the LOAEL of the the estrogenic effects of three EDCs were 240 mg/kg body weight, 15 mg/kg body weight and 0.50 μg/kg body weight, respectively. At BMDL10 doses based on the CA concept and the factorial analysis, the mode of combined effects of the three EDCs were dose addition. Mixtures in LOAEL doses, NP and DES combined effects on rat uterine/body weight ratio indicates antagonistic based on the CA concept but additive based on the factorial analysis. Combined effects of other mixtures are all additive by using the two models.
Our results showed that CA model provide more accurate results than the factorial analysis, the mode of combined effects of the three EDCs were dose addition, except mixtures in LOAEL doses, NP and DES combined effects indicates antagonistic effects based on the CA model but additive based on the factorial analysis. In particular, BPA and NP produced combination effects that are larger than the effect of each mixture component applied separately at BMDL doses, which show that additivity is important in the assessment of chemicals with estrogenic effects. The use of BMDL as point of departure in risk assessment may lead to underestimation of risk, and a more balanced approach should be considered in risk assessment.
Plastic leachates impair growth and oxygen production in Prochlorococcus, the ocean’s most abundant photosynthetic bacteria
Plastic pollution is a global threat to marine ecosystems. Plastic litter can leach a variety of substances into marine environments; however, virtually nothing is known regarding how this affects photosynthetic bacteria at the base of the marine food web.
To address this, we investigated the effect of plastic leachate exposure on marine Prochlorococcus, widely considered the most abundant photosynthetic organism on Earth and vital contributors to global primary production and carbon cycling.
Two strains of Prochlorococcus representing distinct ecotypes were exposed to leachate from common plastic items: high-density polyethylene bags and polyvinyl chloride matting.
We show leachate exposure strongly impairs Prochlorococcus in vitro growth and photosynthetic capacity and results in genome-wide transcriptional changes. The strains showed distinct differences in the extent and timing of their response to each leachate.
Consequently, plastic leachate exposure could influence marine Prochlorococcus community composition and potentially the broader composition and productivity of ocean phytoplankton communities.
Endocrine Disruption of Androgenic Activity by Perfluoroalkyl Substances: Clinical and Experimental Evidence, 2019
Perfluoroalkyl compounds (PFCs) are a class of organic molecules that are used in many everyday products such as oil and water repellents, coatings for cookware, carpets, and textiles.
The crucial emerging role of PFCs as pollutants of water, soil, and air and their persistent level in males warrant for more investigation on the mechanisms of PFC toxicity in humans.
There is a new reason to be concerned about toxic chemicals used in nonstick pans, waterproof products, and firefighting foam: PFCs impair male reproductive health, according to a recent study, the intercept reports.
Considerable attention has been paid to perfluoroalkyl compounds (PFCs) because of their worldwide presence in humans, wildlife, and environment. A wide variety of toxicological effects is well supported in animals, including testicular toxicity and male infertility. For these reasons, the understanding of epidemiological associations and of the molecular mechanisms involved in the endocrine-disrupting properties of PFCs on human reproductive health is a major concern.
To investigate the relationship between PFC exposure and male reproductive health.
This study was performed within a screening protocol to evaluate male reproductive health in high schools.
This is a cross-sectional study on 212 exposed males from the Veneto region, one of the four areas worldwide heavily polluted with PFCs, and 171 nonexposed controls.
Main Outcome Measures
Anthropometrics, seminal parameters, and sex hormones were measured in young males from exposed areas compared with age-matched controls. We also performed biochemical studies in established experimental models.
We found that increased levels of PFCs in plasma and seminal fluid positively correlate with circulating testosterone (T) and with a reduction of semen quality, testicular volume, penile length, and anogenital distance. Experimental evidence points toward an antagonistic action of perfluorooctanoic acid on the binding of T to androgen receptor (AR) in a gene reporter assay, a competition assay on an AR-coated surface plasmon resonance chip, and an AR nuclear translocation assay.
This study documents that PFCs have a substantial impact on human health as they interfere with hormonal pathways, potentially leading to male infertility.
PFAS Pollution across the Middle East and Asia, 2019 IPEN Report
Decades after DuPont and 3M first discovered that the perfluorinated chemicals making them fortunes could be transmitted from mothers to babies, millions of women around the world are passing dangerous amounts of these toxic compounds to their children, according to a new IPEN document, the intercept reports.
Per- and polyfluoroalkyl substances (PFAS) is a large class of more than 4,500 fluorinated chemicals that have received significant public and media attention in Australia, EU, and the US, in part due to their toxicity, extreme persistence, and documented water pollution. However, information about PFAS in other parts of the world is largely lacking and the information which is available is difficult to access.
In 2019, IPEN participating organizations in twelve Middle Eastern and Asian countries conducted surveys to explore possible PFAS uses and pollution sources, scientific studies and government actions, including under the Stockholm Convention. Countries covered include: Bangladesh, Egypt, India, Indonesia, Japan, Jordan, Lebanon, Malaysia, Nepal, Sri Lanka, Thailand, and Vietnam.
From Legacies to Innovative Solutions: Implementing the 2030 Agenda for Sustainable Development
The Global Chemicals Outlook II – From Legacies to Innovative Solutions: Implementing the 2030 Agenda for Sustainable Development, mandated by the UN Environment Assembly in 2016, seeks to alert policymakers and other stakeholders to the critical role of the sound management of chemicals and waste in sustainable development. It takes stock of global trends as well as progress made and gaps in achieving the global goal to minimize the adverse impacts from chemicals and waste by 2020. The Global Chemicals Outlook II finds that the global goal to minimize adverse impacts of chemicals and waste will not be achieved by 2020. Solutions exist, but more ambitious worldwide action by all stakeholders is urgently required.
Towards Sound Management of Chemicals
The Global Chemicals Outlook: Towards Sound Management of Chemicals was published in February 2013 and assembled scientific, technical and socio-economic information on the sound management of chemicals. It covered trends and indicators for chemical production, transport, use and disposal, and associated health and environmental impacts; economic implications of these trends, including costs of inaction and benefits of action; and instruments and approaches for sound management of chemicals. Decision 27/12, adopted by the Governing Council of the United Nations Environment Programme in 2013, recognized the significance of the findings of the Global Chemicals Outlook.
Chemicals are an integral part of modern daily life. There is hardly any industry where chemical substances are not used and there is no single economic sector where chemicals do not play an important role. Millions of people throughout the world lead richer, more productive and more comfortable lives because of the thousands of chemicals on the market today. These chemicals are used in a wide variety of products and processes and, while they are major contributors to national and world economies, their sound management throughout their lifecycle is essential in order to avoid significant and increasingly complex risks to human health and ecosystems and substantial costs to national economies.
Industries producing and using these substances have a significant impact on employment, trade and economic growth worldwide, but the substances can have adverse effects on human health and the environment. A variety of global economic and regulatory forces influence changes in chemical production, transport, import, export, use and disposal over time. In response to the growing demand for chemical-based products and processes, the international chemical industry has grown dramatically since the 1970s. Global chemical output was valued at US$ 171 billion in 1970; by 2010, it had grown to US$ 4.12 trillion.
Many national governments have enacted laws and established institutional structures for managing the hazards of this growing volume of chemicals. Leading corporations have adopted chemical management programmes and there are now many international conventions and institutions for addressing these chemicals globally. However, the increasing complexity of the background mix of chemicals and the ever longer and more intricate chemical supply chain including wastes reveal varied gaps, lapses and inconsistencies in government and international policies and corporate practices. They feed growing international concerns over the threat that poor management of chemicals pose to the health of communities and ecosystems and over the capacity to achieve the Johannesburg Plan of Implementation goal that, by 2020, chemicals will be produced and used in ways that minimize significant adverse impacts on the environment and human health.
These concerns are important to all countries but are particularly salient in industrializing economies that face pressing needs to achieve development, national security and poverty eradication objectives. Developing countries and countries with economies in transition can learn lessons from the fragmented sector-by-sector chemical management approaches that have characterized conventional chemicals policies in developed countries. To protect human health and the environment and to fully benefit from the value that chemicals can yield, all countries must include in their economic and social development priorities the means to manage chemicals soundly.
Using Lipstick, Moisturizers During Pregnancy Linked To Motor Skill Deficiencies In Kids
Previous reports suggest that prenatal phthalate exposure is associated with lower scores on measures of motor skills in infants and toddlers. Whether these associations persist into later childhood or preadolescence has not been studied.
In a follow up study of 209 inner-city mothers and their children the concentrations of mono-n-butyl phthalate (MnBP), monobenzyl phthalate (MBzP), monoisobutyl phthalate (MiBP), monomethyl phthalate (MEP), mono-carboxy-isooctyl phthalate (MCOP), and four di-2-ethylhexyl phthalate metabolites (ΣDEHP) were measured in spot urine sample collected from the women in late pregnancy and from their children at ages 3, 5, and 7 years. The Bruininks-Oseretsky Test of Motor Proficiency short form (BOT-2) was administered at child age 11 to assess gross and fine motor skills.
The total number of children included in the study was 209. Of the 209 children, 116(55.5%) were girls and 93 were (45%) boys. Among girls, prenatal MnBP(b=−2.09; 95%CI: [−3.43, −0.75]), MBzP (b=−1.14; [95%CI: −2.13, −0.14]), and MiBP(b=−1.36; 95%CI: [−2.51, −0.21] and MEP(b=−1.23 [95%CI: −2.36, −0.11]) were associated with lower total BOT-2 composite score. MnBP (b= –1.43; 95% CI: [–2.44, –0.42]) was associated with lower fine motor scores and MiBP(b = –0.56; 95% CI: [–1.12, –0.01]) and MEP (b = –0.60; 95% CI: [–1.14, −0.06])was associated with lower gross motor scores. Among boys, prenatal MBzP (b = –0.79; 95% CI: [–1.40, −0.19]) was associated with lower fine motor composite score.
The associations between MEP measured at age 3 and the BOT-2 gross motor, fine motor and total motor score differed by sex. In boys, there was an inverse association between ΣDEHP metabolites measured in childhood at ages 3 (b = –1.30; 95% CI: [–2.34, −0.26]) and 7 years (b = –0.96; 95% CI: [–1.79, −0.13]), and BOT-2 fine motor composite scores.
Higher prenatal exposure to specific phthalates was associated with lower motor function among 11- year old girls while higher postnatal exposure to ΣDEHP metabolites was associated with lower scores among boys. As lower scores on measures of motor development have been associated with more problems in cognitive, socioemotional functioning and behavior, the findings of this study have implications related to overall child development.
Comment les firmes chimiques ont mis la main sur le contrôle de leurs produits
Depuis les années 1960, d’ambitieux dispositifs réglementaires promettent de contrôler les produits chimiques auxquels nous sommes exposés quotidiennement. Pourtant, les rares « interdictions » prononcées sont systématiquement assorties de dérogations permettant de continuer à les utiliser. Pourquoi les États semblent-ils incapables de prononcer des décisions fermes ? Comment la commercialisation de substances toxiques est-elle devenue « légale » ?
Ce livre montre comment les grandes entreprises chimiques ont inscrit dans le droit l’impossibilité d’interdire leurs molécules, si toxiques soient-elles. Depuis 2006, le règlement REACH encadre leur commercialisation en Europe. Ce texte promettait de résoudre la méconnaissance des effets de dizaines de milliers de substances présentes sur le marché et d’améliorer leur contrôle. Finalement, les entreprises sont au cœur de la fabrique de l’expertise et les agences publiques se retrouvent à évaluer les risques de produits pour lesquels elles n’ont aucune donnée solide. En suivant la trajectoire de trois molécules dangereuses – un sel métallique, un solvant et un plastifiant –, l’enquête de l’auteur montre comment REACH organise leur maintien sur le marché.
L’histoire retracée dans ce livre est caractéristique de la manière dont certaines grandes réformes contemporaines masquent en fait un désengagement de l’État sans précédent. L’expertise est externalisée, les données fournies sont insuffisantes, les procédures dérogatoires multiples. Les firmes maîtrisent, plus que jamais, les ressorts de cette bureaucratie industrielle.
Phthalates exposure and uterine fibroid burden among women undergoing surgical treatment for fibroids: a preliminary study
A pilot study published in the journal Fertility and Sterility suggests that exposure to certain harmful chemicals called phthalates may lead to an increased burden of fibroids, uterine tumors that can cause heavy bleeding, pain, infertility, and other serious reproductive problems.
To examine the association between phthalate exposure and two measures of uterine fibroid burden: diameter of largest fibroid and uterine volume.
Pilot, cross-sectional study.
Academic medical center.
Fifty-seven premenopausal women undergoing either hysterectomy or myomectomy for fibroids.
Main Outcome Measure(s)
The diameter of the largest fibroid and uterine dimensions were abstracted from medical records. Spot urine samples were analyzed for 14 phthalate biomarkers using mass spectrometry. We estimated associations between fibroid outcomes and individual phthalate metabolites, sum of di(2-ethylhexyl) phthalate metabolites (∑DEHP), and a weighted sum of anti-androgenic phthalate metabolites (∑AA Phthalates) using linear regression, adjusting for age, race/ethnicity, and body mass index. Fibroid outcomes were also examined dichotomously (divided at the median) using logistic regression.
Most women were of black ethnicity, overweight or obese, and college educated. In multivariable models, higher levels of mono-hydroxyisobutyl phthalate, monocarboxyoctyl phthalate, monocarboxynonyl phthalate, mono(2-ethylhexyl) phthalate, mono(2-ethyl-5-hydroxyhexyl phthalate) (MEHHP), mono(2-ethyl-5-oxohexyl) phthalate (MEOHP), and mono(2-ethyl-5-carboxypentyl) phthalate (MECPP), ∑DEHP, and ∑AA Phthalates were positively associated with uterine volume. Associations were most pronounced for individual DEHP metabolites (MEHHP, MEOHP, MECPP), ∑DEHP, and ∑AA Phthalates. For example, a doubling in ∑DEHP and ∑AA Phthalates was associated with 33.2% (95% confidence interval 6.6–66.5) and 26.8% (95% confidence interval 2.2–57.4) increase in uterine volume, respectively. There were few associations between phthalate biomarkers and fibroid size.
Exposure to some phthalate biomarkers was positively associated with uterine volume, which further supports the hypothesis that phthalate exposures may be associated with fibroid outcomes. Additional studies are needed to confirm these relationships.
The George Washington University press release.