Page 107 - Environmental Control in Petroleum Engineering

94 Environmental Control in Petroleum Engineering

hydrocarbons in sediments, and all species expected to be in the area
were indeed present. Fish feeding around the seeps did show high
levels of enzyme activity needed to break down and digest the toxic
oil compounds (American Petroleum Institute, 1984b).

Impact on Human Health

The impact of hydrocarbons on human health depends somewhat
on whether exposure was from ingestion, inhalation, or dermal (skin)
contact and on whether the exposure was acute (short-term) or chronic
(long-term).
The acute effects of ingestion may include irritation to the mouth,
throat, and stomach, and digestive disorders and/or damage. Small
amounts of hydrocarbons can be drawn into the lungs, either from
swallowing or vomiting, and may cause respiratory impact such as
pulmonary edema or bronchopneumonia.
The chronic effects of ingestion may include kidney, liver, or
gastointestinal tract damage, or abnormal heart rhythms. Prolonged
and/or repeated exposure to aromatics like benzene may cause damage
to the blood-producing system and serious blood disorders, includ-
ing leukemia. The metabolism of aromatic hydrocarbons after
ingestion can result in the creation of mutagenic or carcinogenic
derivatives, even if the original hydrocarbon is relatively nontoxic.
(National Research Council, 1985). A number of PAHs have been
linked to cancer of the skin, lung, and other sites on the body. There
is no epidemiologic evidence for human cancer from intake of PAH-
contaminated food, however. Most human exposure to PAHs comes
from nonpetroleum sources, including cigarette smoke, fossil fuel
combustion products, and food.
The acute symptoms of hydrocarbon exposure by inhalation may
include irritation of the nose, throat, and lungs, headaches and dizziness,
anesthetic effects, and other central nervous system depression effects.
These symptoms can occur at air concentrations of 0.5 mg/1 for 30
minutes (Hastings et al., 1984). Epileptic-type seizures may occur
months after a high acute exposure to gasoline vapors, and permanent
brain damage has been reported. Acute toxic effects are not commonly
observed, however, in gas station attendants and auto mechanics.
Chronic effects of inhalation exposure to hydrocarbons containing
high concentrations of aromatic compounds, including gasoline, can