This book proposes a framework for a national-scale program to monitor changes
in mercury concentrations in the environment following the reduction of atmospheric
mercury emissions. The book is the product of efforts initiated at a workshop held
in Pensacola, Florida, in September 2003, involving more than 30 experts in the
fields of atmospheric mercury transport and deposition, mercury cycling in terrestrial
and aquatic ecosystems, and mercury bioaccumulation in aquatic food webs and
This is a dangerous combination. The persistence and mobility of POPs means that they
are literally everywhere in the world, even in the Arctic,Antarctica, and remote Pacific islands.
Their attraction to fatty tissue, known as "bioaccumulation", means that even though a
poison is first dispersed widely and thinly it gradually starts to concentrate as organisms
consume other organisms as they move up the food chain.
Water pollution is the introduction into fresh or ocean waters of chemical, physical, or biological material that degrades the quality of the water and affects the organisms living in it. This process ranges from simple addition of dissolved or suspended solids to discharge of the most insidious and persistent toxic pollutants (such as pesticides, heavy metals, and nondegradable, bioaccumulative, chemical compounds).
The Bioaccumulation of
Mercury, Methylmercury, and Other Toxic Elements into Pelagic and Benthic Organisms - Rất nhiều yếu tố độc hại đối với sinh vật, nhưng thường chỉ trong một hình thức hóa học cụ thể. Ví dụ, mặc dù vô cơ thủy ngân (Hg) là độc hại cho sinh vật ở nồng độ thấp, nó là hình thức hữu cơ của Hg, monomethylmercury (mmHg), đó là cao bioaccumulative và tài khoản cho những mối quan tâm động vật hoang dã và sức khỏe từ việc tiêu thụ cá cao mmHg burdens.
This is a frightening development. There are traces within you – or, depending on your
circumstances and exposures, more than traces – of several hundred man-made chemicals.
Many are harmless (or at least are so far thought to be). Others, however, may cause cancer
and damage the nervous systems, reproductive systems, immune systems, or livers of animals.
Mounting scientific evidence is confirming long-term suspicions that they do the same to
Define ecological biochemistry. • Explain biochemical adaptation and the roles of secondary compounds. • Describe detoxification and the primary metabolic pathways in plants and animals. • Explain the key processes and factors involved in biotransformation & biodegradation. • Explain the concepts of sequestration, bioaccumulation, and biomagnification. • Contrast different forms of ecological biochemical interaction.
Two samples were also analysed for polychlorinated dioxins and
furans (PCDD/Fs), a class of chemical that can be formed during the
combustion of materials present in e-waste. Soil from an open
burning site was moderately contaminated, while sediment from the
Agbogbloshie lagoon contained a very high level of these highly toxic,
highly persistent and bioaccumulative chemicals, at a level just below
the threshold defined as being indicative of serious contamination for
sediments in the Netherlands.
an effort to ensure the wise use of taxpayers’ money, the federal government
has undertaken major initiatives to evaluate the performance and results
of federally funded programs, including research and development (R&D) programs.
The initiatives include the Government Performance and Results Act of
1993 and the Office of Management and Budget (OMB) Program Assessment
Rating Tool (PART), developed in 2002. The latter was designed in the context
of “performance budgeting” and “performance measurement” and focused on
evaluating the efficiency of programs.
The Minamata poisoning episode provided local researchers with the hard evidence that first linked
mercury discharges to its bioaccumulation in the environment. Cats in Minamata were the first to show
signs of mercury poisoning, although at the time the unusual behaviour exhibited by the cats was
unexplained. The disease was known locally as “dancing cat disease” in reference to the uncontrollable
muscle spasms and tremors seen in the poisoned cats.
Inorganic mercury is toxic when humans or
wildlife are exposed to high levels for a short peri-
od of time. Organic methylmercury has a greater
tendency to accumulate in the body over time,
eventually causing harm, even in small amounts.
Methylmercury has the three properties that make
substances particularly harmful to humans and
other organisms — it persists, it bioaccumulates,
and it is toxic to most life forms. The health effects
of mercury are described in more detail in the next
chapter of this primer.
In recent years, awareness of the vulnerability of the environment has increased, as evidenced
by new and developing international policies for environmental protection, starting with the
Rio Declaration of 1992. In the context of ionizing radiation, the existing international
approach is largely based on providing for the protection of humans, but this is being
critically reviewed in several international fora.
The hazards of methylmercury poisoning received modern international attention in 1956 when many
of the residents of Minamata, Japan, became seriously ill, or died, after eating the fish and shellfish in
Minamata Bay. A chemical plant that used methylmercury to manufacture plastic (acetaldehyde) was
dumping methylmercury-contaminated wastes into Minamata Bay. The mercury built up or bioaccumulated
in the fish and shellfish, which were a major part of the residents’ diets. A similar tragedy
unfolded in the nearby town of Nigata, Japan.
Copper fungicides are environmentally unfriendly. They are very toxic to fish and aquatic
invertebrates, such as crab, shrimp and oysters. There are cases where most animal life in soil,
including large earthworms, have been eliminated by the extensive use of copper-containing
fungicides in orchards. It is strongly bioaccumulated and is very persistent. Once a soil is
contaminated with copper, there is no practical way to remove it.
The organic insecticide rotenone has been found to be toxic to pigs, rats and dogs and is is very
toxic to fish. It causes skin and eye irritations.