Use free word association for “pollutant” and the first several things that probably come to mind are “lead”, “petroleum”, “PCBs” or “dioxins”. Or use the Clean Air Act definition for the six most common pollutants and you might associate pollutant with smog, ozone, carbon monoxide, sulfur oxides, nitrogen oxides, or lead. How you slice it does not matter. A pollutant is simply something that is unwanted and not originally present in the environment that might cause adverse damages. Sediment is usually not thought of as a pollutant and doesn’t make the list. However, more and more sediment is being tendered on environmental insurance claims and causing potential high exposure to pollution-based policies for cleanup. With or without commingled contamination, sediment can still cause devastating damages as it makes its way to rivers, lakes, wetlands and oceans.
Globally, almost every major harbor or coastal region, subject to urban land runoff, suffers from sediment contamination that may include PCBs, dioxins, pesticides, and heavy metals. In a recent study conducted by the United States Environmental Protection Agency (USEPA), it was observed that almost every port in the U.S. suffers from moderate-to-severe sediment contamination which may lead to human health and ecological damages. Dioxins and pesticides commingled with fish eggs that lie in sediments are known to disrupt human reproductive functions and factor in genetic mutations.
Every year the U.S. Army Corp of Engineers (USACE) plans to dredge 400 million tons of sediments to keep navigation channels open for commerce. However, increasingly, the USACE must decide whether their dredging operations will disturb sediments in these contaminated areas which may become suspended in the water column – creating more harm than good to the fishing and tourism industries. In total, sediment pollution has been reported to cause approximately $16 billion in environmental damages annually in the U.S.
Erosion
Erosion is the key process that drives sedimentation pollution where loose sand, clay, and silt are carried by wind, water and ice to settle at the bottom of waterways. USEPA estimates that only 30% of worldwide sedimentation comes from natural erosion; while 70% is produced by humans through the disturbance of soil from activities such as road building, home building, and agricultural operations. Soil erosion can occur anytime barren soil is exposed and may be exacerbated when vegetation and plant roots are removed.
Sediment Effects to Waterways
Sediment as a physical pollutant can enter stormwater runoff and degrade the quality of the water column for drinking, wildlife, and the land surrounding streams in two primary ways:
- High levels of turbidity can limit or prevent sunlight in the water column impeding the growth of aquatic plants, and
- Sediments introduced to streams can raise the level of the stream bed, reducing the depth of a navigational channel.
The overall environmental impacts of sedimentation to waterways can include:
- Loss of important or sensitive aquatic habitat
- Decrease in fishery resources and changes to fish migration patterns
- Loss of recreational attributes
- Human health concerns, such as potential adverse impacts to potable water intakes
- Increased loss of wetland areas
- Nutrient imbalances
- Increases in turbidity and decreases in oxygen
Complications from Contaminated Sediments
Unusual damages can occur when commingled contaminated sediments interact with high-velocity floodwaters. Such was the case shortly after Hurricane Katrina’s floodwaters receded in New Orleans’ Lower Ninth Ward, when a layer of very fine-grained, crusty, dark sediment invaded local neighborhoods, homes and businesses. The material was traced back to nearby industrial canals and Lake Pontchartrain that had known contamination of sediments containing heavy metals, arsenic and other contaminants. Of special interest was the winnowing or filtering process that squeezed only very fine particles through small cracks in doors and windows and made their way inside homes, where they subsequently settled out during the stagnation of the floodwaters in the week after Katrina’s landfall. These fine particles were often associated with the highest loading of metals and organic contaminants and deposited high concentrations of arsenic, cadmium, lead, vanadium, and other contaminants into homes – creating severe health-risk issues for returning residents and first responders, including complications with disposal of debris as hazardous waste in some cases.
Insurance Case Example
In Ortega Rock Quarry v. Golden Eagle Insurance Corp., the USEPA issued an administrative order to the operator of the rock quarry which alleged that an operator had discharged sediment and fill materials from their operation into a nearby creek and covered a main access road to the quarry that had been previously washed out during storm events. Some of the sediment materials had eroded into the creek. USEPA directed the quarry operator to cease the discharge, submit an erosion control plan, and restore the creek – stating they believed the sediments were pollutants and a violation of the Clean Water Act. The quarry operator tendered defense to its commercial general liability (CGL) insurance carrier; however the insurers denied coverage based on the pollution exclusion. The quarry operator argued sediment is a naturally occurring material, should not be considered a pollutant, and did not reflect the definition of a pollutant in the Clean Water Act. On appeal, the court ruled in favor of the insurers and stated that sediment materials are pollutants when placed in waters of the United States from an unnatural location.
Minimization of Sedimentation
The good news is that sedimentation can be prevented or minimized. For construction projects, tried-and-true methods – including stabilization of slopes with mats or hay bales and silt fencing around construction sites – can go a long way to minimize impacts from potential sedimentation. Planting of shrubs, trees and vegetation can also have a long-term impact. For the average homeowner, simple measures such as sweeping sidewalks and driveways instead of using water can keep sedimentation from running off-property. Weed-free mulch, reseeding bare lawn spots, and use of compost can help keep soil from washing away. Washing your car at a commercial car wash that recycles its water is better than doing it yourself at home.
In Conclusion
Sediments, not normally on the common list of pollutants, are starting to show up as primary drivers of pollution conditions on tendered claims on CGL and pollution-based policies. While sedimentation is a natural process from erosion, sediments commingled with other contaminants can cause additional damages to land and water bodies – producing unusual secondary pollution issues and changes to hydraulic characteristics, creating downstream ecological and human health risks. Hurricanes and storms can drive sediments with pollutants to areas beyond normal conditions, increasing exposure to Natural Resource Damages. Proper planning and erosion control measures, including stabilization of slopes and other techniques, can minimize downgradient damages caused by human activities (such as construction activities).
HETI…Help with Sedimentation Issues
HETI can assist companies involved with earth work planning or other operations that have the potential to disturb sediments with proper erosion control planning and implementation of measures to minimize off-site damages. We can also assist insurance underwriters with engineering surveys of potential insureds to evaluate whether their erosion control procedures and planning can help mitigate the risk of potential off-site or third-party claims. And, should claims associated with sedimentation pollution happen, HETI offers services to quantify the damages and determine the most cost-effective cleanup actions.
To find out more information about this and other HETI environmental services, please contact us.