13.02.2013 Views

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

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

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

SHOW MORE
SHOW LESS

Create successful ePaper yourself

Turn your PDF publications into a flip-book with our unique Google optimized e-Paper software.

Algae<br />

The 1986 <strong>Lead</strong> AQCD (U.S. Environmental Protection Agency, 1986a) reported that<br />

some algal species (e.g., Scenedesmus sp.) were found to exhibit physiological changes when<br />

exposed to high lead or organolead concentrations in situ. The observed changes included<br />

increased numbers <strong>of</strong> vacuoles, de<strong>for</strong>mations in cell organelles, and increased autolytic activity.<br />

Increased vacuolization was assumed to be a tolerance mechanism by which lead was<br />

immobilized within cell vacuoles.<br />

Aquatic Vertebrates<br />

The 1986 <strong>Lead</strong> AQCD (U.S. Environmental Protection Agency, 1986a) reported that<br />

hematological and neurological responses were the most commonly reported effects in aquatic<br />

vertebrates. These effects include red blood cell destruction and inhibition <strong>of</strong> the enzyme<br />

ALAD, required <strong>for</strong> hemoglobin synthesis. At high lead concentrations, neurological responses<br />

included neuromuscular distortion, anorexia, muscle tremor, and spinal curvature (e.g., lordosis).<br />

The lowest reported exposure concentration causing either hematological or neurological effects<br />

was 8 µg/L (U.S. Environmental Protection Agency, 1986a).<br />

Aquatic Invertebrates<br />

Numerous studies were cited on the effects <strong>of</strong> lead to aquatic invertebrates in the 1986<br />

<strong>Lead</strong> AQCD (U.S. Environmental Protection Agency, 1986a). In general, lead concentrations in<br />

aquatic invertebrates were found to be correlated closely with concentrations in water rather than<br />

food. Freshwater snails were found to accumulate lead in s<strong>of</strong>t tissue, <strong>of</strong>ten in granular bodies <strong>of</strong><br />

precipitated lead. Mortality and reproductive effects were reported to begin at 19 µg Pb/L <strong>for</strong> the<br />

freshwater snail Lymnea palutris and 27 µg Pb/L <strong>for</strong> Daphnia sp.<br />

The review <strong>of</strong> the NAAQS <strong>for</strong> Pb (U.S. Environmental Protection Agency, 1990) made<br />

only one recommendation reported in the sections <strong>of</strong> the 1986 <strong>Lead</strong> AQCD dealing with effects<br />

to aquatic biota. This was the need to consider the impact <strong>of</strong> water hardness on Pb<br />

bioavailability and toxicity, to be consistent with the recommendations <strong>of</strong> the AWQC <strong>for</strong> the<br />

protection <strong>of</strong> aquatic life (U.S. Environmental Protection Agency, 1985).<br />

AX7-176

Hooray! Your file is uploaded and ready to be published.

Saved successfully!

Ooh no, something went wrong!