Tropical ecotoxicology: Status and needs

Abstract

Abstract-Ecotoxicology has focused almost exclusively on countries and ecosystems in temperate zones. Tropical ecosystems, which combined contain as much as 75% of the global biodiversity, have been neglected. Tropical ecosystems are under increasing threat of development and habitat degradation from population growth and urbanization, agricultural expansion, deforestation, and mining. Some of these activities also lead to the release of toxic substances into the environment. Little research in ecotoxicology has been carried out in tropical environments. Techniques and procedures developed for temperate environments are often applied, even though physical and chemical environmental parameters in the tropics can be very different. Most research has focused on water quality and aquatic toxicology. The regulatory environment also varies among countries. We present a review of the literature on tropical ecotoxicology, with an emphasis on Latin America and the Caribbean. We also address priority areas for immediate research in the tropics. These include large-scale agricultural activities, especially banana, pineapple, and soybean farming, and gold mining with the associated heavy use of mercury. We outline the special issues that must be addressed as the field of tropical ecotoxicology progresses.

Effects of malathion and carbendazim on Amazonian freshwater organisms: comparison of tropical and temperate species sensitivity distributions

“…The applicability of threshold concentrations derived from SSDs for protecting tropical freshwater ecosystems still requires further investigation. The higher diversity of tropical ecosystems implies that the number of species potentially affected by pesticides should also be greater (Lacher and Goldstein 1997), and that, for example, the number of potentially affected species under the 5% cut-off value (HC5) of the sensitivity distribution should also be higher. Thus, when assuming the degree of contamination that is considered acceptable for temperate ecosystems (with 5% of species affected) the structure of tropical ecosystems may be threatened, affecting a considerable number of species.…”

“…Ecotoxicological research into the fate and effects of agrochemicals on aquatic ecosystems surrounding agricultural fields has mainly focused on temperate countries (i.e., EU, USA), while little information is available for tropical ecosystems (Castillo et al 1997; Lacher and Goldstein 1997; Daam and Van den Brink 2010). The lack of toxicity studies for tropical species has forced scientists from tropical countries to perform ecological risk assessment studies based on toxicity data and water quality criteria (WQC) derived for the risk assessment of pesticides in temperate regions.…”

“…The lack of toxicity studies for tropical species has forced scientists from tropical countries to perform ecological risk assessment studies based on toxicity data and water quality criteria (WQC) derived for the risk assessment of pesticides in temperate regions. Several authors have hypothesized that the extrapolation of temperate toxicity data for tropical hazard assessments may place tropical ecosystems at undue risks, since differences between temperate and tropical ecosystems in terms of environmental conditions and species sensitivity are not normally taken into account (Castillo et al 1997; Lacher and Goldstein 1997; Kwok et al 2007; Römbke et al 2008). It has been demonstrated that different thermal conditions and water quality parameters can influence the toxicity of pesticides to freshwater organisms.…”

Effect of Parathion-Methyl on Amazonian Fish and Freshwater Invertebrates: A Comparison of Sensitivity with Temperate Data

“…Due to a lack of site-specific toxicity data, in many tropical and subtropical countries like Brazil, the ecological risk assessment and the calculation of safe environmental concentrations for the control and monitoring of pesticides in the aquatic ecosystems have relied on European and North American single-species toxicity bioassays (Kwok et al 2007; Lacher and Goldstein 1997). Consequently, acceptable environmental concentrations for pesticides (i.e., parathion-methyl) used in the Brazilian Amazon are based on the extrapolation of toxicity data derived in the temperate region; hence, differences in environmental parameters and species sensitivity are not being taken into account (Römbke et al 2008).…”

“…Consequently, acceptable environmental concentrations for pesticides (i.e., parathion-methyl) used in the Brazilian Amazon are based on the extrapolation of toxicity data derived in the temperate region; hence, differences in environmental parameters and species sensitivity are not being taken into account (Römbke et al 2008). Differences in sensitivity between species should be assessed and incorporated in the risk assessment, because an extrapolation of temperate data to tropical conditions without a scientific base could lead to a potential risk for tropical freshwater ecosystems (Henriques et al 1997; Lacher and Goldstein 1997). The differences in sensitivity to pesticides between freshwater species from different climatic regions have been already studied by several authors (Daam et al 2008, 2009; Dyer et al 1997; Kwok et al 2007; Maltby et al 2005).…”