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Air Quality Criteria for Lead Volume II of II - (NEPIS)(EPA) - US ...

Air Quality Criteria for Lead Volume II of II - (NEPIS)(EPA) - US ...

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metals over nonessential metals. This is demonstrated by the relatively consistent concentrations<br />

<strong>of</strong> Cu, Mn, and Zn that were reported <strong>for</strong> the abalone samples (Arai et al., 2002).<br />

Other Physiological Effects<br />

Increased levels <strong>of</strong> Pb in water were found to increase fish production <strong>of</strong> mucus: excess<br />

mucus coagulates were observed over the entire body <strong>of</strong> fishes. Buildup was particularly high<br />

around the gills, and in the worst cases, interfered with respiration and resulted in death by<br />

anoxia (Aronson, 1971; National Research Council <strong>of</strong> Canada., 1973).<br />

AX7.2.3.4 Factors That Modify Organism Response to <strong>Lead</strong><br />

A great deal <strong>of</strong> research has been undertaken recently to better understand the factors that<br />

modify aquatic organism response to metals including lead. A discussion <strong>of</strong> research on the<br />

many factors that can modify aquatic organism response to Pb is provided in this section.<br />

Influence <strong>of</strong> Organism Age and Size on <strong>Lead</strong> Uptake and Response<br />

It is generally accepted that Pb accumulation in living organisms is controlled, in part, by<br />

metabolic rates (Farkas et al., 2003). Metabolic rates are, in-turn, controlled by the physiological<br />

conditions <strong>of</strong> an organism, including such factors as size, age, point in reproductive cycle,<br />

nutrition, and overall health. Of these physiological conditions, size and age are the most<br />

commonly investigated in relation to heavy metal uptake. This section reviews recent research<br />

focusing on relationships between body size, age, and Pb accumulation in aquatic invertebrates<br />

and fish.<br />

Invertebrates<br />

MacLean et al. (1996) investigated bioaccumulation kinetics and toxicity <strong>of</strong> Pb in the<br />

amphipod Hyalella azteca. Their results indicated that body size did not greatly influence Pb<br />

accumulation in H. azteca exposed to 50 or 100 µg/L <strong>of</strong> PbCl2 <strong>for</strong> 4 days. Canli and Furness<br />

(1993) found similar results in the Norway lobster Nephrops norvegicus exposed to 100 µg/L <strong>of</strong><br />

Pb(NO3)2 <strong>for</strong> 30 days. No significant sex- or size-related differences were found in<br />

concentrations <strong>of</strong> Pb in the tissue. The highest tissue burden was found in the carapaces (42%).<br />

Several studies have determined that Pb can bind to the exoskeleton <strong>of</strong> invertebrates and<br />

AX7-162

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