What is Bloom Fertilizer?
It is crucial to clarify what is meant by "Bloom" fertilizer, as the name applies to a few different products in the market. The primary product in question is Bloom®, a soil amendment and fertilizer produced by DC Water from Class A Exceptional Quality biosolids. This is not the same as generic horticultural "bloom" fertilizers designed to boost flowers, nor is it related to the popular "Bloom Greens" dietary supplement. The Bloom from DC Water is made using an advanced thermal hydrolysis process that treats wastewater solids with high heat and pressure to create a nutrient-rich, earthy-smelling product that acts similarly to compost.
The Source of Biosolids
Biosolids are the solid organic material that remains after treating domestic wastewater. While the vast majority of wastewater comes from residential sources, some may contain industrial discharge. It is this industrial flow, albeit a small percentage, that contributes trace amounts of heavy metals to the wastewater system. Because of this, regulations are in place to control industrial pollutants at the source, preventing them from contaminating the wastewater to unacceptable levels. The subsequent intensive treatment process further minimizes contaminants.
EPA Regulations and Exceptional Quality Biosolids
The U.S. Environmental Protection Agency (EPA) heavily regulates the use and disposal of sewage sludge, including biosolids, under the Part 503 Rule. This rule sets strict standards for heavy metal content, pathogen reduction, and management practices to protect public health and the environment.
Key EPA Classifications for Biosolids:
- Class A: Achieves a high level of pathogen reduction, making it safe for general use, including home lawns and gardens.
- Exceptional Quality (EQ): Meets the most stringent standards for both pathogen and heavy metal content. EQ biosolids have very low levels of metals and pose the lowest risk to human health and the environment.
DC Water's Bloom product is specifically certified as "Exceptional Quality Class A," confirming it meets the EPA's most rigorous safety criteria. The EPA establishes maximum concentration limits for ten heavy metals, including arsenic, cadmium, lead, and mercury, that can be present in land-applied biosolids. Bloom's production process ensures it falls well within these limits.
Does Bloom Contain Heavy Metals?
Yes, but in extremely low, safe concentrations. As Bloom Soil confirms, the final product does contain trace amounts of heavy metals. However, their presence is similar to what is naturally found in typical soils and is far below levels known to pose a risk to human health. The EPA's robust, risk-based Part 503 rule, based on extensive research, is designed to ensure safety even with these trace elements. The rigorous pretreatment programs and advanced thermal hydrolysis process used to produce Bloom are designed to manage and minimize these levels.
Factors Affecting Metal Availability in Soil
It's important to understand that the total amount of a heavy metal in the soil is not the only factor determining its potential risk. Another crucial aspect is its "bioavailability"—how easily it can be absorbed by plants or animals. Factors influencing bioavailability include:
- Soil pH: More acidic soils (lower pH) can increase the solubility and availability of heavy metals.
- Organic Matter: The high organic matter content in Bloom and other composts can actually bind to heavy metals, making them less available for plant uptake.
- Other Nutrients: The presence of other nutrients, like phosphorus, can also affect metal lability in soil.
Comparison: Bloom (Biosolids) vs. Other Compost
| Feature | Bloom (Exceptional Quality Biosolids) | Typical Organic Compost | Notes |
|---|---|---|---|
| Raw Material Source | Primarily domestic wastewater solids from homes and businesses. | Varies widely; can include yard waste, food scraps, and manure. | Source impacts potential contaminants. |
| Heavy Metal Levels | Contains trace heavy metals, but strictly regulated and tested to meet EPA EQ standards. | Can contain trace heavy metals depending on source materials (e.g., manures, waste products). | Regulation level is a key difference. |
| Federal Regulation | Governed by stringent EPA Part 503 rules for both metal content and pathogen destruction. | Less federal oversight regarding metal content; regulations may vary by state. | Ensures consistent, high-quality product. |
| Treatment Process | Advanced processes like thermal hydrolysis and digestion ensure pathogen removal and stability. | Standard aerobic composting, which varies in effectiveness depending on method. | High-tech process ensures safety and consistency. |
| USDA Organic Status | Not permitted for use in USDA-certified organic farming due to source. | If made from clean, organic feedstocks, can be used in organic farming. | Important distinction for organic gardeners. |
Conclusion
In summary, while Bloom fertilizer does contain heavy metals, their concentration is so low that the product meets the highest safety standards set by the EPA for residential use. Its production involves advanced treatment to minimize contaminants and eliminate pathogens, resulting in a product that is safe for home and garden applications. The presence of these trace elements is a reality of many natural soil amendments, including some standard composts. The rigorous testing and regulation mandated by the EPA's Exceptional Quality classification provide a robust safety net. Ultimately, for gardeners seeking a sustainable, nutrient-rich soil amendment, Bloom represents a safe and environmentally friendly option, provided it is used according to manufacturer and regulatory guidelines.
For more information on the EPA's biosolids standards, visit the official page on the U.S. Environmental Protection Agency website.
The Bottom Line on Bloom
- Bloom from DC Water is made from Class A Exceptional Quality biosolids.
- It is strictly regulated by the EPA, with metal levels well below federal limits.
- The low concentrations of heavy metals found are comparable to those in natural soils.
- The product undergoes advanced thermal treatment to ensure pathogen destruction and safety.
- It is safe for use in home vegetable and flower gardens when applied correctly.
References
- U.S. Environmental Protection Agency,
Guide to the Biosolids Risk Assessments for the EPA Part 503 Rule. - DC Water,
FAQs - Bloom Soil. - Virginia Biosolids Council,
Metals in Biosolids. - ScienceDirect.com,
A review on the fate and effects of contaminants in biosolids applied .... - Bloom Soil,
Facts about Bloom.
