دوشنبه ۲۶ شهریور ۰۳ | ۲۰:۴۱ ۶ بازديد
Review
Introduction
Nickel is a nutritionally essential trace metal for at
least several animal species, micro-organisms and plants,
and therefore either deficiency or toxicity symptoms can
occur when, respectively, too little or too much Ni is taken
up. Although a number of cellular effects of nickel have
been documented, a deficiency state in humans has not
been described [1-6]. Nickel and nickel compounds have
many industrial and commercial uses, and the progress
of industrialization has led to increased emission of pol-
lutants into ecosystems. Although Ni is omnipresent and
is vital for the function of many organisms, concentra-
tions in some areas from both anthropogenic release and
naturally varying levels may be toxic to living organisms
[6-8].
Inhalation exposure in occupational settings is a prima-
ry route for nickel-induced toxicity, and may cause toxic
effects in the respiratory tract and immune system [9]. The
exposure of the general population to nickel mainly con-
cerned oral intake, primarily through water and food, as a
contaminant in drinking water or as both a constituent and
contaminant of food [7, 10]. It is also known to affect non-
occupationally exposed individuals, especially those han-
dling stainless steel and nickel-plated articles of everyday
use, because nickel is a common sensitizing agent with a
high prevalence of allergic contact dermatitis [1, 11, 12].
This paper presents a current overview of the occur-
rence and sources of nickel in different parts of the envi-
ronment (air, water, soil, food) with particular emphasis
on polish measurements, as well as the effect of nickel on
living organisms.
Nickel: A Review of Its Sources and Environmental
Toxicology
M. Cempel, G. Nikel
Department of Environmental Toxicology, Interfaculty Institute of Maritime and Tropical Medicine,
Medical university of Gdańsk, powstania styczniowego 9B, 81-519 Gdynia, poland
Received: September 23, 2005
Accepted: December 27, 2005
Abstract
Nickel is a metal of widespread distribution in the environment: there are almost 100 minerals of which
it is an essential constituent and which have many industrial and commercial uses. Nickel and nickel com-
pounds belong to the classic noxious agents encountered in industry but are also known to affect non-oc-
cupationally exposed individuals. The general population may be exposed to nickel in the air, water and
food. Inhalation is an important route of occupational exposure to nickel in relation to health risks. Most
nickel in the human body originates from drinking water and food; however, the gastrointestinal route is of
lesser importance, due to its limited intestinal absorption. The toxicity and carcinogenicity of some nickel
compounds (in the nasal cavity, larynx and lungs) in experimental animals, as well as in the occupationally
exposed population, are well documented.
The objective of this paper is to summarize the current overview of the occurrence and sources of nickel
in the environment, and the effect of this metal and its compounds on living organisms. As this topic is very
broad, this review is briefly concerned with the toxicokinetics of nickel, its health effects and biological
monitoring.
Keywords: nickel, environment, sources, toxicokinetics, pollution
Polish J. of Environ. Stud. Vol. 15, No. 3 (2006), 375-382
Introduction
Nickel is a nutritionally essential trace metal for at
least several animal species, micro-organisms and plants,
and therefore either deficiency or toxicity symptoms can
occur when, respectively, too little or too much Ni is taken
up. Although a number of cellular effects of nickel have
been documented, a deficiency state in humans has not
been described [1-6]. Nickel and nickel compounds have
many industrial and commercial uses, and the progress
of industrialization has led to increased emission of pol-
lutants into ecosystems. Although Ni is omnipresent and
is vital for the function of many organisms, concentra-
tions in some areas from both anthropogenic release and
naturally varying levels may be toxic to living organisms
[6-8].
Inhalation exposure in occupational settings is a prima-
ry route for nickel-induced toxicity, and may cause toxic
effects in the respiratory tract and immune system [9]. The
exposure of the general population to nickel mainly con-
cerned oral intake, primarily through water and food, as a
contaminant in drinking water or as both a constituent and
contaminant of food [7, 10]. It is also known to affect non-
occupationally exposed individuals, especially those han-
dling stainless steel and nickel-plated articles of everyday
use, because nickel is a common sensitizing agent with a
high prevalence of allergic contact dermatitis [1, 11, 12].
This paper presents a current overview of the occur-
rence and sources of nickel in different parts of the envi-
ronment (air, water, soil, food) with particular emphasis
on polish measurements, as well as the effect of nickel on
living organisms.
Nickel: A Review of Its Sources and Environmental
Toxicology
M. Cempel, G. Nikel
Department of Environmental Toxicology, Interfaculty Institute of Maritime and Tropical Medicine,
Medical university of Gdańsk, powstania styczniowego 9B, 81-519 Gdynia, poland
Received: September 23, 2005
Accepted: December 27, 2005
Abstract
Nickel is a metal of widespread distribution in the environment: there are almost 100 minerals of which
it is an essential constituent and which have many industrial and commercial uses. Nickel and nickel com-
pounds belong to the classic noxious agents encountered in industry but are also known to affect non-oc-
cupationally exposed individuals. The general population may be exposed to nickel in the air, water and
food. Inhalation is an important route of occupational exposure to nickel in relation to health risks. Most
nickel in the human body originates from drinking water and food; however, the gastrointestinal route is of
lesser importance, due to its limited intestinal absorption. The toxicity and carcinogenicity of some nickel
compounds (in the nasal cavity, larynx and lungs) in experimental animals, as well as in the occupationally
exposed population, are well documented.
The objective of this paper is to summarize the current overview of the occurrence and sources of nickel
in the environment, and the effect of this metal and its compounds on living organisms. As this topic is very
broad, this review is briefly concerned with the toxicokinetics of nickel, its health effects and biological
monitoring.
Keywords: nickel, environment, sources, toxicokinetics, pollution
Polish J. of Environ. Stud. Vol. 15, No. 3 (2006), 375-382
Occurrence and Sources
Nickel (Ni) is the 24th most abundant element in the
Earth’s crust, comprising about 3% of the composition of
the earth. It is the 5th most abundant element by weight
after iron, oxygen, magnesium and silicon. It is a mem-
ber of the transition series and belongs to group VIII B
of the periodic table along with iron, cobalt, palladium,
platinum and five other elements. Nickel is a naturally oc-
curring element that can exist in various mineral forms.
As a member of the transition metal series, it is resistant
to corrosion by air, water and alkali, but dissolves readily
in dilute oxidizing acids. Natural nickel is a mixture of
five stable isotopes; nineteen other unstable isotopes are
known. Although it can exist in several different oxidation
states, the prevalent oxidation state under environmental
conditions is Ni(II), nickel in the +2 valence state. other
valences (-1, +1, +3, and +4) are also encountered, though
less frequently [9, 10, 13].
Nickel and nickel compounds have many industrial
and commercial uses. Most nickel is used for the produc-
tion of stainless steel and other nickel alloys with high
corrosion and temperature resistance. Nickel metal and
its alloys are used widely in the metallurgical, chemical
and food processing industries, especially as catalysts and
pigments. The nickel salts of greatest commercial impor-
tance are nickel chloride, sulphate, nitrate, carbonate, hy-
droxide, acetate and oxide [14, 15].
Nickel is one of many trace metals widely distributed in
the environment, being released from both natural sources
and anthropogenic activity, with input from both station-
ary and mobile sources. It is present in the air, water, soil
and biological material. Natural sources of atmospheric
nickel levels include wind-blown dust, derived from the
weathering of rocks and soils, volcanic emissions, forest
fires and vegetation. Nickel finds its way into the ambi-
ent air as a result of the combustion of coal, diesel oil and
fuel oil, the incineration of waste and sewage, and mis-
cellaneous sources [10, 14-18]. Environmental sources of
lower levels of nickel include tobacco, dental or orthopae-
dic implants, stainless steel kitchen utensils and inexpen-
sive jewellery [4]. Tobacco smoking is another, not neg-
ligible, source of non-occupational exposures to nickel. It
has been estimated that each cigarette contains nickel in
a quantity of 1.1 to 3.1 µg and that about 10-20% of the
nickel inhaled is present in the gaseous phase. According
to some authors, nickel in tobacco smoke may be present
in the form of nickel carbonyl, a form which is extremely
hazardous to human health. pipe tobacco, cigarettes and
other types of tobacco products do not greatly differ one
from another in the content of nickel [1, 16].
Air
Nickel concentrations in ambient air vary consider-
ably and the highest values have been reported from high-
ly industrialized areas. Typical average levels of airborne
nickel are: 0.00001-0.003 µg/m3 in remote areas; 0.003-
0.03 µg/m3 in urban areas having no metallurgical indus-
try; 0.07-0.77 µg/m 3 in nickel processing areas. In poland
the recommended nickel concentration in the atmospheric
air is set as 0.025 µg/m3 [1, 18, 19].
occupational exposure to nickel compounds is depen-
dent upon industrial processing and is usually substantially
higher than work-unrelated nickel exposure. The form of
nickel to which workers are exposed differs in the various
industries in which nickel is used and occurs through inha-
lation or dermal contact (inhalation is the primary route of
exposure), with ingestion taking place where there are poor
industrial hygiene practices [10, 20]. It usually involves the
inhalation of one of the following substances: dust of rela-
tively insoluble nickel compounds, aerosols derived from
nickel solutions (soluble nickel) and gaseous forms con-
taining nickel (usually nickel carbonyl) [16]. Many mea-
surements conducted at various workplaces at risk (cast-
ing, welding, battery manufacture etc.) have revealed that
the occupational concentrations may vary in a wide range
from micrograms to milligrams of nickel per m3 of air [1].
In nickel-producing or nickel-using industries, about 0.2%
of the work force may be exposed to considerable amounts
of airborne nickel, which may lead to the retention of 100
µg of nickel per day [1, 10, 14, 16, 20].
Water
Drinking water generally contains nickel at concentra-
tions less than 10 µg/l. Assuming a daily intake of 1.5 l of
water and a level of 5-10 µgNi/l, the mean daily intake of
nickel from water for adults would be between 7.5 and
15.0 µg. Tests conducted in the usA have revealed that
97% of the 2053 drinking water samples tested had nickel
concentrations below 20 µg/l and 80% of the samples had
less than 10 µg/l. In exceptional cases, values up to 75
µg/l are found and those as high as 200 µg/l were record-
ed only in the nickel ore mining areas. The incidence of
health impairments due to higher nickel intakes in drink-
ing water is extremely infrequent [16, 21].
The mean Ni content in 80 samples of drinking wa-
ter in Poland collected from an area affected by industrial
emissions (stalowa wola area) was 17 µg/l and in most of
the analyzed water samples did not exceed the allowable
concentration of 20 µg/l [22, 23].
The concentration of Ni in cold and hot water depends
on the quality of the pipes. In the case of metal pipes,
the level of Ni in hot water is lower than in cold water.
However, when pVC pipes are used the concentrations
are opposite [24].
soft drinking water and acidic beverages may dissolve
nickel from pipes and containers. leaching or corrosion
processes may contribute significantly to oral nickel in-
take, occasionally up to 1 mg/day. Nickel concentration
in screened households’ drinking water decreased signifi-
cantly after 10 min. of flushing in the morning from aver-
age 10.79 µg/l to 7.23 µg/l, respectively [14, 25].
The major sources of trace metal pollution in aquatic
ecosystems, including the ocean, are domestic wastewater
effluents (especially As, Cr, Cu, Mn and Ni) and non-fer-
rous metal smelters (Cd, Ni, pb and se). Nickel is easily
accumulated in the biota, particularly in the phytoplank-
ton or other aquatic plants, which are sensitive bioindica-
tors of water pollution. It can be deposited in the sediment
by such processes as precipitation, complexation and ad-
sorption on clay particles and via uptake by biota [16, 26,
27].
In lakes, the ionic form and the association with or-
ganic matter are predominant. on the basis of complex
investigations on lakes (more than 100 km distant from
the nearest source of pollution – enterprises of the copper-
nickel industry), it was discovered that there is intensive
precipitation of heavy metals and acid oxides within the
catchment area of lake kochejavr. levels of precipitation
of Ni of 0.9 mg/m2/year over long periods were found to
be dangerous for biological systems of fresh water catch-
ments [28].
In rivers, nickel is transported mainly as a precipitated
coating on particles and in association with organic mat-
ter. The concentrations of nickel in the biggest and only
navigable river in the South of Iran (River Karoon) were
from 69.3 to 110.7 µg/l in winter, and from 41.0 to 60.7
µg/l in spring, respectively. The results show that the pol-
lution has increased along the river, down to the estuary
at persian Gulf [8]. part of the nickel is transported via
rivers and streams into the ocean. In poland, nickel is gen-
erally transported via rivers into the Baltic Sea and in this
way the average value of anthropogenic Ni input is 57%.
Generally, in sea water nickel is present at concentrations
of 0.1- 0.5 µg/l [1, 16, 17, 29].
Soil
Nickel is generally distributed uniformly through the
soil profile but typically accumulates at the surface from
deposition by industrial and agricultural activities. Nickel
may present a major problem in land near towns, in indus-
trial areas, or even in agricultural land receiving wastes
such as sewage sludge. Its content in soil varies in a wide
range from 3 to 1000 mg/kg [1, 6, 17]. Nickel can exist
in soils in several forms: inorganic crystalline minerals
or precipitates, complexed or adsorbed on organic cation
surfaces or on inorganic cation exchange surfaces, water-
soluble, free-ion or chelated metal complexes in soil solu-
tion [6, 16, 21].
This metal apparently does not seem to be a major con-
cern outside urban areas at this time but may eventually
become a problem as a result of decreased soil pH caused
by reduced use of soil liming in agriculture and mobiliza-
tion as a consequence of increased acid rain [1, 6]. Mielke
et al. [30] investigated the effect of anthropogenic met-
als on the geochemical quality of urban soils. The median
nickel content was 3.9 µg/g for fresh alluvium samples
and 9.8 µg/g for urban alluvial soils (New orleans and
stratified by census tracts). overall, significantly higher
metal values occur in the inner city and lower values oc-
cur in outlying areas.
In poland, the level of nickel in 60 samples of the soil
collected from the stalowa wola area, which is affected
by industrial emissions, was higher (average 17.20 mg/kg)
than that in the reference samples (average 9.72 mg/kg).
All the values, however, were below the highest allowable
concentration [31]. similarly, nickel content in soils in al-
lotment gardens in post-flooded industrialized areas of the
Dolnośląski Region during 2000-01 also did not exceed
the highest allowable concentration [32, 33]. According to
the current polish regulation the allowable limit for nickel
in the soil depends on many factors, and for not industrial-
ized areas is set as 50 mg/kg d.w. [27, 34].
Food
Nickel is considered to be a normal constituent of
the diet and its compounds are generally recognized as
safe when used as a direct ingredient in human food [35].
little is known about the actual chemical forms of nickel
in various foods or whether dietary nickel has distinct “or-
ganic” forms with enhanced bioavailability analogous to
those of iron and chromium. Nickel levels in foodstuffs
generally range from less than 0.1 mg/kg to 0.5 mg/kg. A
few foods may have obtained nickel during the manufac-
turing process but in most it apparently occurred naturally
[16, 36].
Food processing methods apparently add to the nick-
el levels already present in foodstuffs via: 1. leaching
from nickel-containing alloys in food processing equip-
ment made from stainless steel; 2. the milling of flour; 3.
catalytic hydrogenation of fats and oils by use of nickel
catalysts [15, 17]. Rich food sources of nickel include oat-
meal, dried beans and peas, nuts, dark chocolate and soya
products, and consumption of these products in larger
amounts may increase the nickel intake to 900 µg/person/
day or more [37].
A requirement for nickel has not been conclusively
demonstrated in humans. Scattered studies indicate a
highly variable dietary intake of nickel but typical daily
intake of this metal from food ranges from 100-300 µg/
day in most countries. In France, the estimated weekly
intake for the general population of nickel from wine con-
sumption was, on the basis of 66 l/year/resident, 30.6 µg/
week (4.37 µg/day) [10, 14, 38].
Many measurements of nickel levels in several food
products were performed in poland. In 1990, a survey
was conducted on twenty-seven whole-day alimentary
rations at canteens in lublin and warsaw, as well as the
food rations of manual workers’ families in several pol-
ish towns. It was observed that daily nickel intake values,
according to the current dietary recommendations, may
be considered as safe (187-302 µg/day for the canteen ra-
tions and 183-341 µg/day for the family rations) [39]. Ac-
cording to leszczyńska and Gambuś [40], in 1996-1998
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