Horsefly River Roundtable Discussion Paper on Biosolids
Watershed Considerations and Knowledge Gaps
This discussion concerns balancing agricultural benefits with environmental
stewardship within a salmon-bearing watershed. Nutrifor, derived from treated
municipal biosolids, is currently being applied within the Horsefly River watershed.
While biosolids meet existing regulatory requirements and can provide agronomic
benefits, they are also known to contain trace levels of persistent and emerging
substances of concern, including per – and polyfluoroalkyl (PFAS) and
perfluoroocatanesulfonic acid (PFOS), certain pharmaceuticals, heavy metals, and
micro-plastics.
Scientific literature has identified potential health and ecological effects associated with
specific PFAS/PFOS compounds, including links to certain cancers and immune and
reproductive disruption. Regulatory responses internationally are evolving, with various
jurisdictions phasing out or restricting certain compounds. However, environmental
behaviour, cumulative loading, and long-term transport of complex contaminant
mixtures within cold-climate, high-flow watersheds remain areas of ongoing research.
From a watershed management perspective, the key question is not limited to
compliance at the point of application, but whether specific local conditions create
credible transport pathways. Within the Horsefly watershed, relevant considerations
include:
• Surface application practices
• Storage location and duration prior to spreading
• Fall application timing and overwinter exposure
• Soil saturation conditions
• Spring freshet as the primary annual transport window
During freshet, soils are often cold and biologically less active, reducing assimilation
capacity while increasing runoff potential. This period also coincides with sensitive
salmon life stages present in spawning gravels and nearshore habitats.
Monitoring for certain emerging contaminants can be analytically complex and costly,
and routine regulatory sampling may not capture peak-flow transport events. A
watershed-scale screening approach focused on runoff timing and perimeter drainages
may provide clearer understanding of potential movement under high-flow conditions.
The Roundtable’s objective is to better understand site-specific hydrologic pathways
and monitoring gaps so that land application practices reflect both agricultural
productivity and long-term watershed resilience.
Version
Biosolid Chemicals and Global Actions – Forever Chemicals
These are the most pressing concern right now because they persist in the
environment forever. PFAS don’t break down in wastewater treatment and accumulate in biosolids. They can then transfer to soil, crops, and groundwater.
Here’s what countries around the world are doing:
Europe
Leading Regulatory Action
The European Union is taking the most aggressive stance:
PFAS Restrictions:
∙ In April 2025, EU Member States formally adopted a sectorspecific
restriction banning PFAS in firefighting foams
∙ Denmark, Germany, the Netherlands, Norway and Sweden
have proposed restricting around 10,000 types of PFAS under
REACH regulations, with the European Chemicals Agency aiming to complete its scientific evaluation by the end of 2026
∙ France adopted legislation in February 2025 banning PFAS in
cosmetics, textiles and ski wax from 2026, extending to all textiles
by 2030
Drinking Water:
∙ The EU recast Drinking Water Directive limits 20 individual
PFAS to roughly 100 parts per trillion and total PFAS to 500 parts
per trillion, with stricter country-specific measures in Denmark
(2ppt), Sweden (4ppt), and Germany (20ppt by 2028)
Germany
Is phasing out agricultural use of sewage sludge since 2017. They are
banning direct agricultural application for larger wastewater treatment
plans.
United States
State-led actions
Since there are no federal biosolids limits:
∙ Maine became the first state in 2022 to ban all land
application of sludge and sludge-derived compost following severe
contamination cases and some dairy farms have been closed due
to PFAS contamination from biosolids impacting milk
∙ Michigan set thresholds where biosolids containing 100 ppb
or more PFOS and an additional group called perfluorooctanoic
acid (PFOA) cannot be land-applied, while those with 20-100 ppb
face reduced application rates
∙ In April 2024, the EPA set legally enforceable drinking water
limits: 4 parts per trillion for PFOA and PFOS, and 10 parts per
trillion for several others
Australia & New Zealand
∙ Version 3.0 of the PFAS National Environmental Management
Plan includes trigger levels for PFOS and another group called
Perfluorohexane sulfonic acid (PFHxS) in biosolids in the low
microgram per kilogram range, though it’s not legally binding unless
other legislation gives it force
∙ Although there is no ban on PFAS in biosolids, national and
state-level guidelines for PFAS levels in land-applied sludge have
been introduced
Asia
Many Asian countries are still in the early stages of addressing
PFAS, with primary focus on drinking water standards and limited
discussion so far on biosolids reuse
The key global challenge is that few countries have implemented action
on biosolids and there is no consensus on the approach to setting limits
for use . The responses range from complete bans (Maine) to risk-based
management (Australia) to concentration limits (Michigan, Germany).
Canada
PFAS specific actions at the federal level affecting BC:
∙ The Canadian Food Inspection Agency announced plans to
implement an interim standard for PFAS in biosolids used as
fertilizers, set at 50 parts per billion ppb of PFAS.
∙ Biosolids in Canada contained total PFAS concentrations ranging
from 200 to 900 ppb (dry weight), and several provinces are now
considering restrictions or enhanced monitoring requirements.
Here’s a link to a blog that discusses Canadas actions dated March 2025:
https://www.bennettjones.com/Insights/Blogs/Federal-Governmentpublishes-
State-of-PFAS-Report-and-Risk-Management-Approach
Closer to home, we know that the prairie provinces allow sewage sludge to be used on agricultural lands where it is either injected five to 10 centimetres below ground level or surface application must be tilled as soon as possible after application.
All provinces are starting to test for forever chemicals, and have
been testing for specific heavy metals. They are not yet testing for
pharmaceuticals or nanoplastics, but these concerns are being examined in
Ontario. Quebec has 2023 guidelines that define biosolids classes and assign varying PFAS and PFOS ppb limits and has implemented a temporary
moratorium on agricultural application of sewage sludge imported from the
United States. Halifax, Nova Scotia the biosolids program is voluntarily not used on food crops. Other East Coast Provinces have modelled their biosolids management programs like Calgary’s.
BC Regulations manage biosolids through the Organic Matter Recycling
Regulation (OMRR), which has been in place since 2002. The province has been reviewing these regulations since 2018, their amendments were expected last year including new standards for Class A biosolids.
We encourage you to get involved and read more here:
https://www2.gov.bc.ca/gov/content/environment/waste-management/food-and-organic-waste/regulations-guidelines
Here is some information on the state of current testing in BC. Some BC
facilities are already testing for PFAS. For example, the Capital Regional District tests biosolids at their Residuals Treatment Facility for PFAS compliance with the federal standard, be it right or wrong.
The challenges are that the current BC OMRR primarily regulates pathogens and heavy metals but does not yet have specific limits for PFAS, pharmaceuticals, or nanoplastics, a regulatory gap that is highly concerning.
The research and significant knowledge gap in BC, given global concerns about
PFAS, pharmaceuticals, nanoplastics, and heavy metals, is that there is no
recent published research examining how these contaminants in biosolids
specifically affect these smallest organisms in the food web
∙ BC’s native earthworm species
∙ BC reptiles (snakes, turtles, lizards)
∙ Amphibians exposed to biosolids in BC watersheds
This absence of data is concerning as these organisms are often the first
indicators of environmental contamination and are critical parts of the food web.
There is some global research on earthworms (Annelida) exposed to PFAS in
bioaccumulation factors and uptake kinetics for PFOS and PFOA . Recent work has documented PFAS biomagnification in terrestrial food webs, including small mammals like bank voles, showing extremely high PFOS concentrations and potential health effects. However, reptile studies are limited, with toxicity data
described as insufficient to develop robust assessments, though some
amphibian data exists.
Pharmaceuticals
Pharmaceuticals from biosolids enter terrestrial ecosystems, with over 4,000
pharmaceuticals used globally that can partition to biosolids and be applied to agricultural land . Research on pharmaceuticals has focused heavily on birds, with significant knowledge gaps regarding amphibians, reptiles, and mammals .
Studies have shown antimicrobials from biosolids can transfer through food chains to secondary and tertiary consumers, and earthworms bioaccumulate various pharmaceuticals from biosolid-amended soils .
Nanoplastics
Microplastics contaminate agricultural soils through biosolids application, with concentrations varying globally from 0.7 to 240 MPs per gram in different nations . Earthworm studies are extensive, showing nanoplastics exhibit higher toxicity than microplastics, with concentrations above 1000 ppb causing growth
inhibition and reduced survival . Effects on fish, birds, and mammals have been documented, though terrestrial vertebrate research is less developed.
Heavy Metals
Small mammal studies examining heavy metal bioaccumulation from
contaminated soils exist, with research on shrews and mice showing tissue accumulation and histopathological effects including liver and kidney damage .
Reptiles remain underrepresented in ecotoxicological research despite being threatened by chemical pollution, with some studies on alligators, turtles, and
lizards .
The gap in all of this research is that it is mostly developed for earthworms
across all types of contaminant types, while reptile studies remain notably
sparse for all contaminants. Small mammal research exists but is less
comprehensive than invertebrate work.
Global Actions for Forever Chemicals
The Stockholm Convention
The Stockholm Convention is the primary international mechanism for
stopping PFAS production worldwide. The Stockholm Convention is a
global treaty signed by over 180 countries to eliminate or restrict the most dangerous persistent organic pollutants:
Already Banned Globally:
∙ PFOS, its salts and perfluorooctane sulfonyl fluoride were
listed in 2009
∙ PFOA (perfluorooctanoic acid), its salts and PFOA-related
compounds were added in 2019
∙ PFHxS, its salts and PFHxS-related compounds were listed
in 2022
NEW – Just Added in 2025:
∙ Long-chain perfluorinated carboxylic acids (C9-21 PFCAs),
their salts and related substances were included in May 2025
∙ The ban on production and use of long-chain PFCAs takes
effect across countries party to the Stockholm Convention on
January 1, 2026
This means that countries signing on to the Stockholm Convention must
eliminate production and use of these chemicals (not just restrict them).
This creates legally binding obligations, the challenge is adding a new substance to the Stockholm Convention takes at least three years, and the Convention was not designed to handle thousands of chemicals, but
rather to regulate a handful of highly hazardous ones.
There are an estimated 10,000-14,000 different PFAS chemicals, and only
a handful have been banned so far. As soon as one is banned,
manufacturers can simply switch to a slightly different molecular structure
that isn’t yet regulated.
The other major global challenge is that China and the United States – the
world’s two largest manufacturers – are not among the more than 150
signatories to the Stockholm Convention.
European Union
Most Aggressive Approach:
∙ Germany, Denmark, the Netherlands, Norway, and Sweden
proposed broader PFAS restrictions in January 2023, currently under
review From January 2026, ban on manufacture, import, export, and sale
of PFAS-containing textiles, footwear, and waterproofing agents for
consumers
∙ On July 8, 2025, the European Commission presented an Action
Plan for the Chemicals Industry, including a revision of the REACH
Regulation by Q4 2025 and a proposal to restrict PFAS comprehensively
∙ A legislative proposal to ban the production and use of all PFAS
compounds at the EU level could come to fruition by 2026
France – Leading National Action:
∙ French law bans the production, import or sale from January 2026
of any product for which an alternative to PFAS already exists
In January 2025 investigation revealed a coordinated lobbying and
misinformation campaign by the chemical industry aimed at weakening the EU’s
proposed PFAS ban.
United States
State-by-State:
∙ The EPA has eliminated exemptions for low-volume PFAS and
requires detailed risk assessments before approval
∙ Multiple states implementing bans, but no comprehensive federal
production ban
∙ TSCA reporting requirements force manufacturers to report PFAS
use dating back to 2011
Canada
In March 2025, Canada announced its plan to phase out PFAS in many
products starting in 2027, first in firefighting foams, followed by
cosmetics, food packaging, textiles, medicines, and medical devices. The
innovation vs. industry debate continues as industry lobbies claim there are no alternatives, but proponents argue that setting clear and binding rules creates the right conditions for research and development of safer
solution, alternatives are available for all potential applications, including
both fluorinated and non-fluorinated substances as well as alternative
technical solutions.
