Environmental impact of leatherleaf fern farms in Costa Rica

Leatherleaf ferns are the fifth leading agricultural export product in Costa Rica. Non-traditional agricultural export products (NTAE), such as leatherleaf ferns, flowers, melons, and pineapples, have received government subsidies in the form of tax exemptions and cash rebates as part of the structural adjustments prescribed by the U.S. Agency for International Development and World Bank during the 1980s regional economic crisis. Although ferns are touted as one of the most successful NTAE, due to the sector's impressive growth and high revenues, there was concern about the heavy use of pesticides and the location of farms in aquifer recharge areas. This study used an interdisciplinary approach to evaluate the potential impact of ornamental plant production, including flowers but relying mostly on leatherleaf fern data, given the much larger area dedicated to fern cultivation as compared to flowers. I focused on the ecotoxicological impacts in the local watersheds including groundwater, the social impacts at the community level, and the macroeconomic policies effects at the local and national levels. Ten out of sixty-nine pesticides reportedly used in flower and fern farms were detected in surface water samples between November 1999 and April 2000: chlorothalonil (0.13 mg/L), diazinon (0.8 μg/L), dimethoate (0.91 μg/L), malathion (1.5 μg/L), pirimiphos-methyl (2.7 μg/L), α-endosulfan (9.3 g/L), β-endosulfan (8.9 g/L), pirimicarb (0.09 μg/L), prochloraz (5.5 mg/L), propiconazole (0.1 μg/L), and vinclozolin (0.08 μg/L). Two out of ten groundwater samples tested positive in Ceriodaphnia dubia chronic toxicity tests. No pesticide residues were detected in groundwater samples. However, our chemical analysis only covered 22% of the compounds used in the sector.; Workers in ornamental plant are at significant risk of acute or chronic pesticide poisoning due to low education, lack of training, and inadequate protection.; Externalities identified in this study included water contamination and depletion, workers' pesticide exposure, deforestation and soil degradation.; I suggest some environmental and social standards for a certification program, as a market-incentive strategy to mitigate the negative impacts generated by the sector.