Brownfield Remediation: Solutions for Urban Agriculture

Conclusions

Brownfield remediation is an emerging field, and as such, substantial research has yet to be done related to the feasibility for community groups of pursuing remediation options to prepare land for planting. Thus far, very few grassroots organizations that have undertaken such endeavours and of the few community groups who have in fact remediating, most are simply experimenting with process and have rarely planted crops for consumption post-remediation. Remediating contaminated land remains a domain largely in the hands of industry and government.

There are no straightforward solutions to the problem of brownfield remediation for urban agriculture. Feasibility issues including accessibility, cost, timeframe, effectiveness to remediate soil to agricultural standards and environmental effects. The selection of an appropriate technique will depend on the needs, capabilities and constraints of individual groups as well as the particular soil characteristics, and the type and degree of contamination present. There is no technique that will be suitable to all groups and to all sorts of contamination problems. In light of these limitations, we have identified excavation as the most appropriate option for community groups to pursue at this time. Because of the high health risk in the ingestion of food cultivated in contaminated soil, we recommend that community groups exercise the precautionary principle and employ excavation, the only feasible solution guaranteed to provide nutritious produce grown in a contaminant-free environment. It is accessible, cost- and time-effective, and represents the least amount of risk in bringing soil up to agricultural standards as well as maintaining these standards over the long term.

In light of this recommendation, we recognize the great future potential of biological methods such as microbial and phytoremediation. Microbial remediation and phytoremediation are very effective in removing the majority of contamination in a given plot. They are also both cost-effective and accessible to community groups. However, both techniques have demonstrated difficulty in removing the final pollutants required to achieve agricultural-grade soil. With more research and time, these methods have the prospective of being risk-free and even more cost-effective than excavation, presenting exciting options for the future.

Finally, by thinking creatively, community groups may wish to recast the problem of brownfield remediation for urban agriculture as "brownfields for urban agriculture" and pursue options that are not affected by urban soil contamination at all. Examples include container gardening and aquaponics. These techniques enable groups to achieve urban gardens, but without the cost, time requirements and risk of soil remediation at this time. Exploring such options makes urban agriculture feasible in the interim while research into remediation for small-scale, low budget urban projects develops and matures.