Global Chemicals Outlook - UNEP

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state, when combined, these together can form an increasingly
signifi cant and complex overall mix of chemicals not present fi fty
years ago. As this chemical intensity increases, the prospects
for widespread and multifaceted exposures of humans and the
environment to chemicals of high and unknown concern also
arise.
Of the tens of thousands of chemicals on the market, only a
fraction has been thoroughly evaluated to determine their effects
on human health and the environment. Even as progress is being
made to develop better information on the effects of chemicals,
for example through data submission under the European Union’s
REACH programme, United States Toxic Substances Control Act
(TSCA), Canada’s Chemicals Management Plan (CMP) and the
Japanese Chemical Substances Control Law, this data remains
limited to individual chemicals. Real-life exposures are rarely
limited to a single chemical and very little information is available
on the health and environmental effects of chemical mixtures.
Nevertheless, many of these chemicals in widespread use have
been associated with well-established risks to human health
and the environment. Exposure to toxic chemicals can cause or
contribute to a broad range of health outcomes. These include
eye, skin, and respiratory irritation; damage to organs such as the
brain, lungs, liver or kidneys; damage to the immune, respiratory,
cardiovascular, nervous, reproductive or endocrine systems; and
birth defects and chronic diseases, such as cancer, asthma, or
diabetes. The vulnerability and effects of exposure are much
greater for children, pregnant women and other vulnerable groups.
Workers in industries using chemicals are especially vulnerable
through exposure to toxic chemicals and related health effects.
These include an increased cancer rate in workers in electronics
facilities; high blood lead levels among workers at lead-acid battery
manufacturing and recycling plants; fl ame retardant exposures
among workers in electronic waste recycling; mercury poisoning
in small-scale gold miners; asbestosis among workers employed
in asbestos mining and milling; and acute and chronic pesticide
poisoning among workers in agriculture in many countries.
Toxicological research has also revealed that for a range of
chemicals, very low levels of exposure can infl uence disease
risk and that both dose and timing of exposure are important.
For example, human exposure to certain chemical toxicants at
low levels during periods of rapid growth and cell differentiation
(e.g., foetal life through puberty) can be important factors that
infl uence disease risk. Individuals living in poverty are particularly
vulnerable, both because their exposures may be particularly
high, and because poor nutrition and other risk factors can
increase susceptibility to the effects of toxic exposures. Due to
their size, children’s responses to small doses of toxic chemicals
are disproportionately large compared to adults. Because their
metabolic pathways are immature, children are also slower to
detoxify and excrete many environmental chemicals and thus
toxins may remain active in their bodies for longer periods of
time (table 3). Research has also made clear that the elderly
are among those particularly susceptible to health effects from a
range of chemical contaminants.
CHEMICAL IMPACTS ON FISHERIES
Fisheries, an important source of protein and of economic value for populations around the world, can be severely affected by
chemicals. Persistent organic pollutants can accumulate in fi sh, especially those high in the food chain. As a result, the value of
this otherwise excellent protein source is diminished or lost completely.
Industrial and agricultural run-off can lead to large-scale fi sh kills, and lower-level chemical contamination of water bodies can
decimate fi sh populations over time. Chemical contamination is also associated with disease in fi sh populations, including
cancers and increased vulnerability to infectious agents.