Melwani, A. R., Gregorio, D., Jin, Y., Stephenson, M., Ichikawa, G.,
Siegel, E., Crane, D., Lauenstein, G., and Davis, J. A., (in press).
Mussel watch update: long-term trends in selected contaminants
from coastal California, 1977–2010. Marine Pollution Bulletin.
http://dx.doi.org/10.1016/j.marpolbul.2013.04.025
Cross-references
Bioavailability
Biomagnification
BIOAVAILABILITY
Monica Ferreira da Costa
1
, Helena do Amaral Kehrig
2 and
Isabel Maria Neto da Silva Moreira
3
1
Oceanography Department, Federal University of
Pernambuco, Recife, Pernambuco, Brazil
2
Laboratório de Ciências Ambientais, CBB,
Universidade Estadual do Norte Fluminense, Rio de
Janeiro, Brazil
3
Departamento de Química, Pontifícia Universidade
Católica do Rio de Janeiro, Rio de Janeiro, Brazil
Definition
An ecological property presented by chemical elements
and compounds in the environment (chemical agents) that
determines if they will be more, or less, efficiently assimilated by the biota that enters in contact (is exposed to)
with them.
Fundamentals
The bioavailability of a chemical corresponds to the
amount of the element that can be absorbed by the living
organisms from the environment (Chen et al., 2012). It is
a parameter directly associated with the chemical species
of this element present in each biogeochemical compartment (Hoffman et al., 2012; Sinoir et al., 2012). This characteristic of chemical agents in the environment can then
be time and space dependent as water quality changes
along ecological gradients and seasons. Bioavailability is
a descriptive property of chemical elements, chemical species, and compounds determined by a relatively complex
group of factors, indicating their own chemical characteristics, the chemical and physical characteristics of the
medium they are distributed in, metabolism rates, and
the type of exposure the biota has (skin, breathing, feeding). Bioavailability can increase or decrease according
to the combination of these factors (Chen et al., 2012;
Hoffman et al., 2012; Sinoir et al., 2012). The same chemical can have its bioavailability change with the presence
and concentration of Cl
À ions, as in seawater, for example,
or due to changes in water temperature, organic particulate
loads, or dissolved oxygen. In the same way, bioavailability varies if an element changes its oxidative state
(e.g., Cr
+3 vs. Cr
+6 ). Chemical agents must be bioavailable
in the environment in order to be assimilated,
bioaccumulated, and possibly biomagnified in the biotic
compartment. Usually, once a chemical agent enters the
trophic web, it becomes readily available for all its subsequent levels. Contaminated food is a common form of bioavailability (Chen et al., 2012).
Bibliography
Chen, C. Y., Evers, D. C., Mason, R. P., Schoeny, R., Sunderland,
E. M., Serrell, N., and Rardin, L. R. (eds.), 2012. Mercury in
marine ecosystems: sources to seafood consumers. Environmental Research, 119, 1.
Hoffmann, L. J., Breitbarth, E., Boyd, P. W., and Hunter, K. A.,
2012. Influence of ocean warming and acidification on
trace metal biogeochemistry. Marine Ecology Progress Series,
470, 191.
Sinoir, M., Butler, E. C. V., Bowie, A. R., Mongin, M., Nesterenko,
P. N., and Hassler, C. S., 2012. Zinc marine biogeochemistry in
seawater: a review. Marine and Freshwater Research, 63, 644.
Cross-references
Bioaccumulation
Biomagnification
BIOCHEMICAL OXYGEN DEMAND
Manuel Flores Montes
Department of Oceanography, Federal University of
Pernambuco, Recife, Pernambuco, Brazil
Synonyms
Biological oxygen demand
Definition
Biochemical oxygen demand (BOD) is the amount of
molecular oxygen required to oxidize organic matter into
a stable inorganic form through aerobic microbial
decomposition.
Description
The biochemical oxygen demand (BOD) is determined
by empirical testing in which standardized laboratory
procedures yield the relative oxygen requirements of
wastewaters, effluents, and polluted waters (APHA,
1999). Five days at 20
C is often used to oxidize the
carbonaceous organic matter, being referred to as
“BOD 5, 20 .”
Importance: This test is important for pollution control. Heterotrophic microbial metabolism transforms biodegradable organic compounds into stable or mineralized
end products, including water, carbon dioxide, sulfates,
phosphates, ammonia, and nitrates. The BOD test is
widely used to assess the level of domestic or industrial
sewage pollution discharged in estuaries. Dissolved
oxygen (DO) consumption by bacteria during organic
BIOCHEMICAL OXYGEN DEMAND
75
Siegel, E., Crane, D., Lauenstein, G., and Davis, J. A., (in press).
Mussel watch update: long-term trends in selected contaminants
from coastal California, 1977–2010. Marine Pollution Bulletin.
http://dx.doi.org/10.1016/j.marpolbul.2013.04.025
Cross-references
Bioavailability
Biomagnification
BIOAVAILABILITY
Monica Ferreira da Costa
1
, Helena do Amaral Kehrig
2 and
Isabel Maria Neto da Silva Moreira
3
1
Oceanography Department, Federal University of
Pernambuco, Recife, Pernambuco, Brazil
2
Laboratório de Ciências Ambientais, CBB,
Universidade Estadual do Norte Fluminense, Rio de
Janeiro, Brazil
3
Departamento de Química, Pontifícia Universidade
Católica do Rio de Janeiro, Rio de Janeiro, Brazil
Definition
An ecological property presented by chemical elements
and compounds in the environment (chemical agents) that
determines if they will be more, or less, efficiently assimilated by the biota that enters in contact (is exposed to)
with them.
Fundamentals
The bioavailability of a chemical corresponds to the
amount of the element that can be absorbed by the living
organisms from the environment (Chen et al., 2012). It is
a parameter directly associated with the chemical species
of this element present in each biogeochemical compartment (Hoffman et al., 2012; Sinoir et al., 2012). This characteristic of chemical agents in the environment can then
be time and space dependent as water quality changes
along ecological gradients and seasons. Bioavailability is
a descriptive property of chemical elements, chemical species, and compounds determined by a relatively complex
group of factors, indicating their own chemical characteristics, the chemical and physical characteristics of the
medium they are distributed in, metabolism rates, and
the type of exposure the biota has (skin, breathing, feeding). Bioavailability can increase or decrease according
to the combination of these factors (Chen et al., 2012;
Hoffman et al., 2012; Sinoir et al., 2012). The same chemical can have its bioavailability change with the presence
and concentration of Cl
À ions, as in seawater, for example,
or due to changes in water temperature, organic particulate
loads, or dissolved oxygen. In the same way, bioavailability varies if an element changes its oxidative state
(e.g., Cr
+3 vs. Cr
+6 ). Chemical agents must be bioavailable
in the environment in order to be assimilated,
bioaccumulated, and possibly biomagnified in the biotic
compartment. Usually, once a chemical agent enters the
trophic web, it becomes readily available for all its subsequent levels. Contaminated food is a common form of bioavailability (Chen et al., 2012).
Bibliography
Chen, C. Y., Evers, D. C., Mason, R. P., Schoeny, R., Sunderland,
E. M., Serrell, N., and Rardin, L. R. (eds.), 2012. Mercury in
marine ecosystems: sources to seafood consumers. Environmental Research, 119, 1.
Hoffmann, L. J., Breitbarth, E., Boyd, P. W., and Hunter, K. A.,
2012. Influence of ocean warming and acidification on
trace metal biogeochemistry. Marine Ecology Progress Series,
470, 191.
Sinoir, M., Butler, E. C. V., Bowie, A. R., Mongin, M., Nesterenko,
P. N., and Hassler, C. S., 2012. Zinc marine biogeochemistry in
seawater: a review. Marine and Freshwater Research, 63, 644.
Cross-references
Bioaccumulation
Biomagnification
BIOCHEMICAL OXYGEN DEMAND
Manuel Flores Montes
Department of Oceanography, Federal University of
Pernambuco, Recife, Pernambuco, Brazil
Synonyms
Biological oxygen demand
Definition
Biochemical oxygen demand (BOD) is the amount of
molecular oxygen required to oxidize organic matter into
a stable inorganic form through aerobic microbial
decomposition.
Description
The biochemical oxygen demand (BOD) is determined
by empirical testing in which standardized laboratory
procedures yield the relative oxygen requirements of
wastewaters, effluents, and polluted waters (APHA,
1999). Five days at 20
C is often used to oxidize the
carbonaceous organic matter, being referred to as
“BOD 5, 20 .”
Importance: This test is important for pollution control. Heterotrophic microbial metabolism transforms biodegradable organic compounds into stable or mineralized
end products, including water, carbon dioxide, sulfates,
phosphates, ammonia, and nitrates. The BOD test is
widely used to assess the level of domestic or industrial
sewage pollution discharged in estuaries. Dissolved
oxygen (DO) consumption by bacteria during organic
BIOCHEMICAL OXYGEN DEMAND
75