Tracking pollution from fur farms using forensic paleolimnology

Area of Science:

• Environmental Science
• Paleolimnology
• Geochemistry

Background:

• Eutrophication poses a global threat to water quality, especially in agricultural regions.
• Fur farming, predominantly mink, is a significant agricultural activity in southwest Nova Scotia, Canada.
• Assessing long-term pollution drivers in lakes is crucial for effective water quality management.

Purpose of the Study:

• To investigate the long-term drivers of potential pollution inputs into lakes in southwest Nova Scotia.
• To correlate changes in sediment geochemistry with the expansion of mink farming in the region.
• To apply geochemical fingerprinting as a tool for forensic paleolimnology.

Main Methods:

• Utilized a before-after-control-impact (BACI) study design.
• Collected and analyzed sediment cores from 14 lakes near mink farms.
• Combined economic data, mink fecal samples, and geochemical markers (sterols, δ¹⁵N, chlorophyll-a, heavy metals).

Main Results:

• Sterol biomarkers (cholesterol, β-sitosterol) and heavy metals (As, Cu, Sr) were elevated near mink farms.
• Increased mink-related sterols, δ¹⁵N, and chlorophyll-a occurred in the 1980s, coinciding with a 400% rise in mink farms.
• Agricultural impacts were less pronounced than mink farming impacts in most studied lakes.

Conclusions:

• Mink farming has demonstrably impacted lake sediment geochemistry and water quality in southwest Nova Scotia.
• Geochemical fingerprinting provides a valuable multi-proxy approach for assessing historical pollution in lake ecosystems.
• This methodology offers promising applications for environmental pollution assessments in other lake systems.