A Natural Resource Management Guide for the County of Morris A ...

Impacts From Natural Hazards
In Morris County, threats from geologic natural hazards are varied in intensity. Though the county is still
shaken occasionally by a minor earthquake, risk to human health and property is relatively small. Plate 3
provides an historical perspective of seismic activity in the county. Other hazards, however, such as cave-ins,
erosion, and radon present significant issues justifying management intervention.
Sinkholes: Limestone formations are often prolific ground water suppliers. The very hydraulic
characteristics that enable excellent aquifer recharge and ground water availability, also allow vulnerability
to ground water contamination. When overlying land is disturbed, subsequent stormwater runoff may enlarge
fractures, forming cavities and ultimately sinkholes.
Cave-ins: Remnants of a previously active mining industry have produced serious cave-in threats, if not
actual incidences (e.g. Mine Hill) posing serious safety concerns for overlying structures and inhabitants.
Radon: An odorless, tasteless, and invisible radioactive gas, radon is produced during the decay of Uranium.
Sources can be found in soils and rocks containing uranium, granite, shale, phosphate, and pitchblende, typical
in the Highlands. A natural component in the atmosphere, radon does not pose a threat when outdoors. It can,
however, pose a danger when concentrated in a confined environment. Generally, the greater the exposure
to radon, the greater the risk for developing lung cancer.
Typical human exposure to Radon occurs in the home, particularly the basement or ground level. Access
points normally are dirt floors, cracks in concrete floors and walls, floor drains, sumps, tiny cracks or pores
in hollow-block walls, and water supply pipes. Indoor Radon concentrations can vary from day to day, season
to season, and within different parts of a home. A person's total accumulated radon exposure from a particular
home depends on several factors including:
average concentration of radon in the home
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number of years a person has lived in the home
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amount of time spent at home each day 1
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Radon is practically ubiquitous in New Jersey, although concentration reflects the underlying geology. New
Jersey Department of Environmental Protection’s 1987 Overview of Initial Results Statewide Scientific Study
of Radon reported on the testing of approximately 5300 homes for naturally occurring radon. Average indoor
Radon concentrations fluctuated widely based on geographic distribution:
Average concentration of 8.1 pCi/l was found in the Highlands region (Reading Prong).
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Average concentration in the Piedmont region was 4.2 pCi/L.
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Whether remediation measures need to be taken or not, steps to safeguard your environment include:
increase ventilation in your ! home
limit the amount of time spent in the areas of highest ! concentration
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stop smoking and discourage smoking in your home
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Geologic History of Morris County