Dangerous toys
After calls from environmental groups, in 1999 the EPA first began investigating the use and prevalence of environmental hormones in Taiwan. Wang Cheng-hsung states that of the chemicals listed as environmental hormones in Japan, more than half are insecticides and fungicides. Because these substances are acutely toxic to the environment and to humans, they were long ago subjected to controls in Taiwan too, under legislation regulating agrochemicals, environmental agents and poisons.
But the 70 suspected environmental hormones also include nine plasticizers, used in making plastics. Because they do not pose a direct threat to human health they are not covered by the poisons regulations, or, at present, by any other legislation.
Although plastic products can last for years without breaking or wearing out, for many years well informed people have vigorously advocated following the example of Western European countries by banning or restricting them. But Taiwan is known as a petrochemicals kingdom, where plastic products are cheap to make and cheap to buy. The overuse of plastics in Taiwan is world famous, and the EPA estimates that plastics account for more than 30% of Taiwanese household waste. But most plasticizers of the family phthalates act as environmental hormones to some extent. European studies have shown that when children chew toys made of PVC containing phthalates, the chemicals may enter their saliva. Some European countries have banned the use of phthalates as additives in plastic toys. "Plastic tableware, medical syringes and toys all need to be thoroughly checked," says Wang Cheng-hsung, who notes that after experiments by scientists in Taiwan, at the beginning of this year the EPA for the first time announced a ban on the use of two plasticizers.
Nevertheless, a survey by Soochow University reveals that phthalates are widely distributed in the mud at the bottom of Taiwan's rivers.
Triple risk
Another environmental hormone that has environmentalists worried is the estrogen-like compound bisphenol A (BPA), which may leach out of the shatterproof, heat-resistant plastic melamine, and of the resin coatings used inside steel and aluminum drinks cans. US experiments in 1998 showed that BPA causes great reductions in sperm motility, and increased growth of breast cancer cells. In 1999, the Japanese physician H. Takada isolated BPA from the umbilical cords of women giving birth at a clinic. In a previous incident, most primary and secondary schools in Nara, Japan stopped using melamine tableware after intense protests from parents, even though the manufacturer had established that the plates and bowls would not release BPA if the children did not scratch them with their cutlery.
"BPA, plasticizers and nonylphenols are the three major types of environmental hormone that the EPA has expended the greatest effort on in recent times," says Chen Yeong-ren, who notes that due to lack of regulation, the levels of residues of these three groups of compounds in the environment are a cause for concern. In April, the chemistry department at National Central University announced that 40% of cleaning products sold in Taiwan contain surfactants that break down into alkylphenols, which are compounds very similar to human estrogens.
In response to environmental demands, in recent years most large factories have begun to treat their effluent, and many factories use the treated effluent to water flowers or raise fish. But when effluent containing alkylphenols undergoes microbiological secondary treatment, as if by magic it comes out containing the environmental hormones nonylphenols.
A survey by Associate Professor Ding Wang-hsien of NCU's chemistry department showed that over half of Taiwan's rivers, including the Tanshui, Touchien, Putsu and Tungkang Rivers, contain nonylphenols, with residual concentrations far higher than in Europe and North America.
Mythical purity
The National Institute of Environmental Analysis also confirms that nonylphenols are already disrupting the endocrine systems of male carp in Taiwan's rivers. People in Taiwan do not eat much river fish, but "according to overseas reports, nonylphenols can be absorbed into the human body through food, drink, contact or injection, and inadequate sewage treatment can allow drinking water to the polluted." In a report entitled "Survey of nonylphenol residues and their biological effects on male carp" the institute suggests that in view of the relatively low coverage of sewage systems in Taiwan, the mandatory water quality tests for drinking water and released effluents should be expanded to test not only for anionic surfactants as at present, but also for nonylphenols derived from non-ionic surfactants.
Because alkylphenols are not themselves toxic, at present they are used in large quantities for industrial cleansing processes. Also, says Ding Wang-hsien, "most household cleaning products that are touted as powerful cleansers, especially for jobs like washing socks or collars and cuffs, contain alkylphenols." The EPA has discussed the possibility of controls, but as Chen Yeong-ren points out, "It's not that simple to change the law to introduce controls on chemical substances." Because of the large number of chemicals we use in our daily lives, the impact on society of banning them would be so great that one cannot do so just on the strength of suspicions. Ample evidence is needed to convince both manufacturers and consumers.
Chen notes that it will take the participation of public health agencies, medical workers, and even the Ministry of Economic Affairs (which is responsible for the regulation of commercial products) and the National Science Council (which sponsors research) before it will be possible to establish a comprehensive network to monitor environmental hormones in Taiwan.
No turning back the clock
There is an urgent need to track and understand the status of environmental hormones that are not yet subject to controls, but the fact that compounds such as dioxins, tributyltin and PCBs are already listed and regulated under the Toxic Chemical Substances Control Act, does not mean that we no longer need to worry about them.
For example, dioxins can disrupt endocrine functions even at concentrations as low as one part in 10 billion. Unlike other environmental hormones, dioxins are not manufactured deliberately, but are mostly byproducts of processes such as waste incineration. Although the limits on dioxin emissions imposed by Taiwan's Air Pollution Control Act are the strictest anywhere in the world, we can never eliminate dioxins from incinerator emissions completely unless we can stop generating waste that contains chlorine. Waste separation has thus far never been properly implemented in Taiwan, and attempts to ban plastic bags made of chlorinated plastics have repeatedly failed. Hence despite continuous improvements in incinerator burn efficiency, residents near incinerators are still exposed to the nightmare of dioxins.
Although organochlorines such as PCBs and DDT have been banned, the residues left behind from the organochlorines used during decades of economic development are still silently eating away at the health of Taiwan's land and people.
For instance, with regard to PCBs, Professor Guo Yue-liang of NCKU has long been following up the aftereffects of the PCB-contaminated cooking oil incident that rocked Taiwanese society in 1979. In 2000 and 2002, articles co-authored by him were published in the leading British medical periodical The Lancet.
The victims of the incident, which occurred in Changhua, ate oil contaminated with PCBs, leading to symptoms such as neuritis, skin reactions, weakness of the limbs, and impaired liver function. PCBs have an affinity for fats, and are therefore not readily eliminated from the body. Women who were poisoned gave birth to babies with slow development, low body weight and congenital abnormalities.
In 1990, NCKU began following up these children who were poisoned in the womb and comparing them with children of the same age from the same neighborhoods. After allowing for other causes, they discovered that males who were below age 20 when poisoned have an abnormally high proportion of girl children. The normal ratio is 51% boys to 49% girls, but among these men's children only 45.8% are boys. This is consistent with PCBs' ability to "feminize" organisms.
Compared with the control group, the male children of the poisoning victims also showed an increase of around 50% in sperm abnormalities, their sperm motility was reduced by around 40%, and their sperm's ability to combine with eggs was reduced by 10%. Guo Yue-liang, who has taken part in the program for 12 years, says: "Environmental hormones represent a long-term hidden problem, the effects of which only become apparent in the second and third generations. If health care professionals do not take the initiative to investigate them, we have no chance of understanding the true level of disease."
Stolen future
In 1998, Associate Professor Hsu Kuang-hung of the health care management department at Chang Gung University also published a report on the epidemiology of endometriosis. Endometriosis is an often painful condition in which womb lining tissue grows outside the womb. Hsu discovered that among 300,000 women who sought medical help due to endometriosis during a six-month period, the numbers in the Chiayi, Taitung and Penghu areas were markedly higher than elsewhere. "These geographical differences in the incidence of disease may be connected with the contamination of agricultural land with heavy metals such as mercury and cadmium," wrote Hsu. Cadmium is one of three heavy metals listed as environmental hormones in the USA and Japan.
"Because there is no hospital reporting system, in fact nobody knows how serious the overall effects of environmental hormones on reproductive health are in Taiwan." Although over time a number of doctors have begun to get involved in environmental hormone research, Guo Yue-liang believes that the data exist in the hospitals, but there is a need for statistical analysis and better understanding of causation, and therefore the government should provide greater incentives for physicians and researchers to investigate the mechanisms by which environmental hormones affect human health.
In 1995, the US book Our Stolen Future for the first time described in detail the terrifying nature of environmental hormones. The book was regarded at the time as "presenting political and social issues that go far beyond its importance for health and scientific research." Today, only six or seven years later, the environmental changes happening around us, and the growth in human reproductive diseases, are forcing people to take the threat of environmental hormones seriously. Can we put the lid back on this chemical Pandora's box? How individuals can improve their knowledge of environmental hormones, remain alert to the dangers they pose and avoid them in their daily lives, will be a pressing challenge for humankind.
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