Environmental Hormones and Dioxins

Homepage: http://www.nies.go.jp/edc/index-e.html

The NIES Endocrine Disruptors and Dioxins Research Project, utilizing the new Endocrine Disruptor Research Laboratory, is conducting research using four approaches:
(1) development of measurement methods, (2) evaluation of the current status of environmental pollution, (3) hazard and effect assessment, and (4) development of countermeasures and integrated assessment technologies.

Endocrine Disrupting Chemicals (EDCs)
The term "environmental hormone is a general term that refers to chemical substances present in the environment that disrupt the endocrine functions of humans and animals (Endocrine Disrupting Chemicals, EDCs). They may also impede reproductive and other functions. However, only recently has full-scale research looked at the effects of these substances on living things and the environment. Many crucial scientific questions remain unanswered.

Liquid chromatograph/mass spectrometer used for analysis of EDCs

EDCs, also known as endocrine disruptors, may have significant and irreversible effects on humans and ecosystems. Urgent action must be taken to ascertain the actual state of pollution from these substances, to understand their mechanisms, and to develop preventive strategies.

NIES is conducting research to develop technologies that allow highly sensitive measurements of the amounts of environmental hormones in all environmental media; to develop various methodologies such as screening methods to measure the endocrine-disrupting potential of substances; and to develop "biomarkers" to measure the levels of exposure in humans, other animals, and plants.

In addition, NIES is conducting research such as field studies and laboratory biological experiments, in order to clarify the relationship between EDCs and reproductive abnormalities in humans and living organisms that make up ecosystems such as fish, amphibians, birds and invertebrates. NIES is also working to clarify the impact mechanisms. In addition, we are developing diagnostic imaging methods that use magnetic resonance imaging (MRI) to clarify the impacts of EDCs on human brains, nervous systems and immune systems. We are also conducting research on laboratory animals using techniques involving behavioral sciences, neurology, molecular biology and systems sciences.

Rock shell (Thais clavigera)

Rock shell (with shell removed)
LEFT: male CENTER: female RIGHT: imposex-exhibiting female, which has male sexual organs, such as penis and vas deferens
The specimens in the center and on the right were originally females. The center specimen is a normal female, while the one on the right has both a penis and a vas deferens about the same size as the male's, but it is unable to spawn as its vaginal opening is blocked. This phenomenon is known as imposex in snails, a super-imposition of male sexual organs on female snails.

Decrease in the total catch of the ivory shell snail fishery and difficulty of seed/seedling production (artificial hatching/incubation and release of juveniles)
The total catch of the ivory shell (Babylonia japonica) in one prefecture dropped dramatically starting in 1984. Here, imposex has been observed in the ivory shell since 1982. At hatcheries, the egg production by parent ivory shells decreased in the latter half of the 1980s. In line with this, the number of juvenile shells released to the sea also decreased, and the declining trend of the catch continued. This phenomenon is thought to have been brought about due to reproductive failure accompanied with imposex induced by organitin compounds from antifouling paints. Parent ivory shells were introduced from other prefectures starting in 1992 because natural egg production did not increase. Thanks to this measure it later increased.

Dioxins
Dioxin pollution has become a issue of concern in society, not only in Japan but worldwide. The main current source of dioxins in Japan is thought to be the process of combustion in incinerators. Research has detected new sources, making more studies on dioxin sources and response actions urgently needed.

In 1999, Japan established environmental quality standards for water, air and soil. Standards for exhaust gases and effluent were also revised. Epidemiological studies have suggested that if dioxins accumulate in a pregnant woman's body the fetus could be affected and that this could hinder later neurological development. Studies also suggested that co-planar PCBs may increase the risk of breast cancer. In this light, it is increasingly important to conduct research for risk assessment on laboratory animals, as well as assessments of direct risks on human health.

NIES is conducting comprehensive research to improve quality control and standardization of analytical methods to measure the amounts of dioxins in environmental (in air, water, soil, incineration ashes, food, etc.) and human (in blood, tissue, urine, etc.) samples. Information from such measurements is essential for development of dioxin countermeasures and for risk assessments.
In addition, research is being conducted relating to monitoring and exposure assessments for various types of dioxins, developing a better understanding of dioxin pollution on a global scale, assessing ecosystem impacts of dioxins (including impacts on various species), and responses to related new substances.

In addition, with the aim of assessing the health risks of dioxins, particularly to assess the risk of effects on reproduction and their occurrence we are conducting research on the amounts of dioxin exposure in humans, assessments of human body burden of dioxin, the availability of biomarkers, the search for and development of new biomarkers, and the elucidation at the molecular level of the factors that determine susceptibility to dioxins, etc.

In concert with this research there is a need to clarify the fate of EDCs and dioxins in the environment, and to develop response technologies and risk management methodologies. NIES is carrying out a variety of research in this regard. We are studying the environmental fate of these substances, developing technologies that use plants to remediate polluted soil, designing integrated risk management system based on geographical information systems (GIS) for environmental fate and environmental information in order to assess and control pollution, and developing a database to assess the impacts of EDCs.

Presently, there are many things unknown about endocrine disruptors and dioxins. What phenomena are occurring? What is causing them? What responses can be taken? Through integrated research, this project is attempting to find the answers to such questions.

Global monitoring of dioxin pollution using cuttlefish

Detection of environmental hormone (estrogen) using genetically modified yeast
NIES developed a easily and highly sensitive testing method to detect estrogen-like substances, using modified the yeast two-hybrid assay system that had been genetically modified with the estrogen receptors. It is used to study estrogen activation estrogenic activities in environmental samples. This sample shows 5 ppt in estradiol equivalent.

Geographical information system (GIS) map of dioxin emissions and soil concentrations

Research in the NIES Hazardous Chemical Control Area using laboratory animals given doses of dioxins