**1. Introduction**

196 Pesticides in the Modern World - Risks and Benefits

Sorvari, J, E. Schultz, E. Rossi, H. Lehtinen, A Joutti, K. Vaajasaari, and T. Kauppila (2007),

Styblo, M., L. M. Del Razo, L. Vega, D. R. Germolec, E. L. LeCluyse, G. A. Hamilton, W.

Sun, G. X., P. N. Williams, A. M. Carey, Y. G. Zhu, C. Deacon, A. Raab, J. Feldmann, R. M.

Vahidnia, A., der van, V, and F. A. de Wolff (2007), "Arsenic neurotoxicity--a review,"

Von Hyman J.Zimmerman. (1999), *Hepatoxicity: the adverse effects of drugs and other chemicals* 

Wang, S. L., J. M. Chiou, C. J. Chen, C. H. Tseng, W. L. Chou, C. C. Wang, T. N. Wu, and L.

Wang, S. X., Z. H. Wang, X. T. Cheng, J. Li, Z. P. Sang, X. D. Zhang, L. L. Han, X. Y. Qiao, Z.

Watanabe, C., A. Kawata, N. Sudo, M. Sekiyama, T. Inaoka, M. Bae, and R. Ohtsuka (2004),

Waxman, S. and K. C. Anderson (2001), "History of the development of arsenic derivatives

Wong, S. S., K. C. Tan, and C. L. Goh (1998b), "Cutaneous manifestations of chronic arsenicism: review of seventeen cases," *J.Am.Acad.Dermatol.*, 38(2 Pt 1), 179-85. Wong, S. S., K. C. Tan, and C. L. Goh (1998a), "Cutaneous manifestations of chronic arsenicism: review of seventeen cases," *J.Am.Acad.Dermatol.*, 38(2 Pt 1), 179-85. Wong, S. S., K. C. Tan, and C. L. Goh (1998d), "Cutaneous manifestations of chronic arsenicism: review of seventeen cases," *J.Am.Acad.Dermatol.*, 38(2 Pt 1), 179-85. Wong, S. S., K. C. Tan, and C. L. Goh (1998c), "Cutaneous manifestations of chronic arsenicism: review of seventeen cases," *J.Am.Acad.Dermatol.*, 38(2 Pt 1), 179-85. Yang, H. T., H. J. Chou, B. C. Han, and S. Y. Huang (2007), "Lifelong inorganic arsenic

Finland," Finland: Finnish Environment Institute Esko Rossi Oy.

trioxide," *N.Engl.J.Med.*, 339(19), 1341-8.

cells," *Arch.Toxicol.*, 74(6), 289-99.

*Hum.Exp.Toxicol.*, 26(10), 823-32.

*on the liver*. Lippincott Williams & Wilkins.

*Environ.Health Perspect.*, 115(4), 643-7.

*Toxicol.Appl.Pharmacol.*, 198(3), 272-82.

*Toxicol.Appl.Pharmacol.*, 198(3), 243-52.

*Chem.Toxicol.*, 46(11), 3506-11.

45(12), 2479-87.

in cancer therapy," *Oncologist.*, 6 Suppl 2 3-10.

areas in Taiwan," *Environ.Health Perspect.*, 111(2), 155-9.

6.

"Complete remission after treatment of acute promyelocytic leukemia with arsenic

"Risk Assessment of Natural and Anthropogenic Arsenic in the Pirkanmaa Region,

Reed, C. Wang, W. R. Cullen, and D. J. Thomas (2000), "Comparative toxicity of trivalent and pentavalent inorganic and methylated arsenicals in rat and human

Islam, and A. A. Meharg (2008), "Inorganic arsenic in rice bran and its products are an order of magnitude higher than in bulk grain," *Environ.Sci.Technol.*, 42(19), 7542-

W. Chang (2003), "Prevalence of non-insulin-dependent diabetes mellitus and related vascular diseases in southwestern arseniasis-endemic and nonendemic

M. Wu, and Z. Q. Wang (2007), "Arsenic and fluoride exposure in drinking water: children's IQ and growth in Shanyin county, Shanxi province, China,"

"Water intake in an Asian population living in arsenic-contaminated area,"

compounds consumption affected blood pressure in rats," *Food Chem.Toxicol.*,

to arsenic via the drinking water: dose-response relationships in review,"

biochemical perturbations in rats: ameliorating effect of curcumin," *Food* 

Yoshida, T., H. Yamauchi, and Sun G. Fan (2004), "Chronic health effects in people exposed

Yousef, M. I., F. M. El-Demerdash, and F. M. Radwan (2008), "Sodium arsenite induced

#### **1.1 Levels of organisation in biological systems and their relationships**

Scales in nature can be difficult to define and understand because several ecological factors can interact. The study of different biological scales contributes to information that varies in its quality and significance for humans. Observations at the ecosystem scale are of great ecological significance but can be of low quality or provide little information about causes; at the other extreme, molecular studies that provide exact determinations of causes can have very little relevance to effects at a larger scale (Figure 1). In the middle of these extremes are observations that provide more or less significant and relevant information. Increasing the level of biological complexity in our observations can lead to an unexpected increase in the number of variables to be considered, requiring the consideration of n-adimensional conditions.

Fig. 1. Relationship between spatial and temporal scales with the quality information obtained

Each level of study is influenced by the level below it, and each level affects the level above it, which is mediated by interspecific relationships that influence ecosystem structure, and this can vary according to the heterogeneity of an ecosystem. When biological complexity

Freshwater Decapods and Pesticides: An Unavoidable Relation in the Modern World 199

different formulations available. In addition, the creation of new compounds, the genetic modification of plants to withstand pesticides, and the improved effectiveness of the methods of pesticide application have had substantial economic support for research and development. Unfortunately, studies of the damage caused by these chemicals have not had

Fig. 2. Land use in South America indicating the surface of Orinoco, Amazon and La Plata basins, approximately. A) urban development and level (A) farm and industrial activities (B). Scale indicates differences in the intensities of the activities (modifies of Collins et al., in

Thus, the man invades and uses natural systems, intensively modifying them, and the fauna suffers extreme stress. Aquatic systems, although generally not targeted by direct application of pesticides, are impacted as a result of runoff after rain. This water, with all the elements that may be associated with it, goes into rivers or depressed areas. Groundwater may also be contaminated by percolation after rainfall. This mobility of elements occurs

Moreover, the higher populations in cities have caused an increase in the urban area required to accommodate people and their families. This, together with increased biocide use and the increased area of impermeable surfaces in cities has meant that household chemicals and waste products are transported rapidly to aquatic systems during rains (José

Watersheds are continually being impacted, and care must be taken to ensure their quality control because these watersheds provide people with water to live. In South America, there are three major basins with water flows ranging from 18.000 m-3s-1 to approximately 220.000 m-3s-1 (Bonetto & Waiss, 1995; Lewis et al., 1995). These basins are the Amazon, Orinoco and La Plata. Of these three, the most densely populated watershed, with the greatest number of agricultural enterprises and the largest number of factories, is La Plata Basin (Figure 2)

more intensively when the fields have no vegetative cover.

similar financial support.

press).

de Paggi et al., 2008).

(Collins et al., in press).

increases, it is important to consider that temporal and spatial dimensions are interconnected, e.g., molecular reactions occur in spaces smaller than one-hundredth of a millimetre and at reaction times of less than one second. At the same time, the effects of the predation of one species on the populations of other species may play out in spaces at the scale of kilometres and at timescales that can exceed a year. According to the heterogeneity of a system, its component species and the processes involved, variations in the time and space involved in a given process can be very important (Figure 1).

## **1.2 Fauna in aquatic systems**

Year after year, the quality of aquatic environments is recognised as a priority for humanity, with particular emphasis on the quantity and quality of freshwater.

Among the faunal components of aquatic environments, decapods, an order of crustaceans, are an interesting group that possesses biological characteristics useful in assessing the quality of inland aquatic systems. In addition, some species of decapods may be used as food by humans and are part of the food chain of other species used by humans as food, mainly fish and birds.

Five decapod families occur in southern South America and east of the Andes. Some of these decapods are endemic at the family level, others at the genus level and still others at the species level. These families include prawns and shrimp (Palaemonidae and Sergestidae), crabs (Trichodactylidae), pseudocrabs (Aeglidae) and crayfish (Parastacidae) (Collins et al., 2007).

Some of these families live in burrows constructed of fine sediment (some Trichodactylidae and Parastacidae). Others live in the background using clasts, rocks or tree trunks for hide under this cover (Aeglidae). Some decapod families live among aquatic vegetation (some Trichodactylidae and Palaemonidae), while others live all or part of their lives in the water column (some Palaemonidae and Sergestidae). Thus, the habitats used by this group are very diverse, and different taxa have different relationships to the land environment. The densities of decapods can be very high at certain times of year and may exceed 500 animals per square meter (e.g., Palaemonidae). Their diets are varied and may include plant matter (e.g., aquatic plants and phytoplankton debris), microinvertebrates (e.g., protozoa, cladocerans, rotifers, and copepods), macroinvertebrates (Palaemonidae insect larvae, oligochaetes, molluscs) and vertebrates (fish). The trophic resource used by decapods is mainly composed of live animals, but dead animals are also commonly fed upon. Consumption intensities are very high, transferring energy and material from various bottom levels (e.g., oligochaetes, chironomid larvae, zooplankton, and vegetal remains) to the top trophic levels (e.g., fish, mammals, reptiles, birds) (Collins & Paggi, 1998; Collins 1999; Williner & Collins, 2002; Collins 2005; Collins et al., 2006).

Since the industrial revolution, the human population has been growing rapidly and has therefore required more intensive management of natural environments. This need for intensive management has included the use of more land for growing food, causing the conversion of forests, jungles, and grasslands, among other ecosystems, into farmland. Subsequently, different poisons (e.g., herbicides, insecticides, fungicides) have been employed with the aim of eliminating those plants and animals that could use the crop resources (cereal or other crops), which humans call "pests". The use of these chemicals grew during the last century in an unprecedented manner in both volume of use and in the

increases, it is important to consider that temporal and spatial dimensions are interconnected, e.g., molecular reactions occur in spaces smaller than one-hundredth of a millimetre and at reaction times of less than one second. At the same time, the effects of the predation of one species on the populations of other species may play out in spaces at the scale of kilometres and at timescales that can exceed a year. According to the heterogeneity of a system, its component species and the processes involved, variations in the time and

Year after year, the quality of aquatic environments is recognised as a priority for humanity,

Among the faunal components of aquatic environments, decapods, an order of crustaceans, are an interesting group that possesses biological characteristics useful in assessing the quality of inland aquatic systems. In addition, some species of decapods may be used as food by humans and are part of the food chain of other species used by humans as food,

Five decapod families occur in southern South America and east of the Andes. Some of these decapods are endemic at the family level, others at the genus level and still others at the species level. These families include prawns and shrimp (Palaemonidae and Sergestidae), crabs (Trichodactylidae), pseudocrabs (Aeglidae) and crayfish (Parastacidae) (Collins et al.,

Some of these families live in burrows constructed of fine sediment (some Trichodactylidae and Parastacidae). Others live in the background using clasts, rocks or tree trunks for hide under this cover (Aeglidae). Some decapod families live among aquatic vegetation (some Trichodactylidae and Palaemonidae), while others live all or part of their lives in the water column (some Palaemonidae and Sergestidae). Thus, the habitats used by this group are very diverse, and different taxa have different relationships to the land environment. The densities of decapods can be very high at certain times of year and may exceed 500 animals per square meter (e.g., Palaemonidae). Their diets are varied and may include plant matter (e.g., aquatic plants and phytoplankton debris), microinvertebrates (e.g., protozoa, cladocerans, rotifers, and copepods), macroinvertebrates (Palaemonidae insect larvae, oligochaetes, molluscs) and vertebrates (fish). The trophic resource used by decapods is mainly composed of live animals, but dead animals are also commonly fed upon. Consumption intensities are very high, transferring energy and material from various bottom levels (e.g., oligochaetes, chironomid larvae, zooplankton, and vegetal remains) to the top trophic levels (e.g., fish, mammals, reptiles, birds) (Collins & Paggi, 1998; Collins

Since the industrial revolution, the human population has been growing rapidly and has therefore required more intensive management of natural environments. This need for intensive management has included the use of more land for growing food, causing the conversion of forests, jungles, and grasslands, among other ecosystems, into farmland. Subsequently, different poisons (e.g., herbicides, insecticides, fungicides) have been employed with the aim of eliminating those plants and animals that could use the crop resources (cereal or other crops), which humans call "pests". The use of these chemicals grew during the last century in an unprecedented manner in both volume of use and in the

space involved in a given process can be very important (Figure 1).

with particular emphasis on the quantity and quality of freshwater.

1999; Williner & Collins, 2002; Collins 2005; Collins et al., 2006).

**1.2 Fauna in aquatic systems** 

mainly fish and birds.

2007).

different formulations available. In addition, the creation of new compounds, the genetic modification of plants to withstand pesticides, and the improved effectiveness of the methods of pesticide application have had substantial economic support for research and development. Unfortunately, studies of the damage caused by these chemicals have not had similar financial support.

Fig. 2. Land use in South America indicating the surface of Orinoco, Amazon and La Plata basins, approximately. A) urban development and level (A) farm and industrial activities (B). Scale indicates differences in the intensities of the activities (modifies of Collins et al., in press).

Thus, the man invades and uses natural systems, intensively modifying them, and the fauna suffers extreme stress. Aquatic systems, although generally not targeted by direct application of pesticides, are impacted as a result of runoff after rain. This water, with all the elements that may be associated with it, goes into rivers or depressed areas. Groundwater may also be contaminated by percolation after rainfall. This mobility of elements occurs more intensively when the fields have no vegetative cover.

Moreover, the higher populations in cities have caused an increase in the urban area required to accommodate people and their families. This, together with increased biocide use and the increased area of impermeable surfaces in cities has meant that household chemicals and waste products are transported rapidly to aquatic systems during rains (José de Paggi et al., 2008).

Watersheds are continually being impacted, and care must be taken to ensure their quality control because these watersheds provide people with water to live. In South America, there are three major basins with water flows ranging from 18.000 m-3s-1 to approximately 220.000 m-3s-1 (Bonetto & Waiss, 1995; Lewis et al., 1995). These basins are the Amazon, Orinoco and La Plata. Of these three, the most densely populated watershed, with the greatest number of agricultural enterprises and the largest number of factories, is La Plata Basin (Figure 2) (Collins et al., in press).

Freshwater Decapods and Pesticides: An Unavoidable Relation in the Modern World 201

on the chemical nature of the pesticide involved. Matsumura (1977) summarised the specific properties that influence uptake into aquatic organisms: lipid and water solubility, chemical stability against degradative action by biological systems (biotransformation), and the molecular weight of the chemical. These physicochemical properties determine the affinities of toxic compounds for the materials comprising the arthropod cuticle and plasma

Because lipids constitute a substantial part of the plasma membrane, lipid solubility is a very significant factor determining the rate of penetration of many toxic compounds (such as organochlorine pesticides) by passive diffusion through the non-polar portion of the membranes. Lipid solubility is usually characterised by the octanol/water partition coefficient (Kow). In other cases, both facilitated diffusion and active transport are required for the passage of toxic into the cell through channel proteins and via their association with carrier proteins, respectively (Newman & Unger, 2003). The passage through a protein channel occurs down a concentration gradient that may be subject to saturation kinetics, and it is influenced by the size of the molecule, which determines a lower permeability of the membrane with increasing molecular size (Zitko, 1980). Moreover, the uptake of several pesticide compounds requires an active process with an expenditure of metabolic energy in living tissue. Through these pathways, toxicants enter cells and cause alterations in the physicochemical properties of the cytoplasm and the pH of the medium, destruction of the membranes of the organelles, disruption of the normal functioning of the cell proteins, and

Because in multicellular organisms the distribution of toxicants occurs in more than one compartment, within the crustacean body, haemolymph circulation may be involved in the transport of these chemicals to their sites of action and even more so if it is an open system that flows around the organs. In other arthropods, such as insects, Brooks (1974) reported that phosphoric acid penetrates the cuticle more rapidly than organochlorine insecticides, and having passed this barrier, the toxicant enters the haemolymph and may be transported to all parts of the organism in solution, if water soluble, or bound to proteins or dissolved in lipid particles, if lipophilic. The relatively hydrophilic molecules are much more likely to remain in this circulatory fluid than small, hydrophobic molecules, which are rapidly distributed in several organs and stored in lipid tissue (Hartley & Graham-Bryce, 1980).

The adverse effects of toxic products on crustaceans depend on its concentration and affinity, activity (intrinsic toxicity, which is function of molecular structure) and chemical biotransformations (James, 1987) and the acclimation responses of the individual (Klerks, 1999). For biocides, such as organophosphates and carbamate anticholinesterases (anti-ChEs), intrinsic toxicity can be judged by measuring the inhibition of cholinesterase and

While some organic compounds are sufficiently water-soluble (hydrophilic) for excretion and can be eliminated rapidly, many lipophilic components cannot be directly excreted and would accumulate if not processed to more polar derivatives. Because the unaltered toxicant and any of its transformation products (metabolites) may be excreted, excretion represents a possible protective mechanism against the toxicant (Newman & Unger, 2003). Usually, organic pesticides are subject to modifications through enzyme-catalysed biotransformations leading to *detoxification* or *activation* (Figure 4). Chemical

propagation of action potentials on synaptic transmission (see biomarkers section).

inhibition of the actions of the enzymes (Sohna et al., 2004; Collins, 2010).

membrane of the cell (Hartley & Graham-Bryce, 1980).

**2.2 Toxicity and biotransformation** 

#### **1.3 Biocides**

The variety of active ingredients used as biocides and their commercial formulations, solvents and coadjuvants or related chemicals is immense. All of them are used by application with agricultural aircraft, sprayers, hand-held units, or trucks that carry the spraying equipment, according to the extension land, application protocols, crop types and soil characteristics. Studies on native fauna are scarce, and only for very few taxa have the biological effects of biocides been studied. Studies on the interrelationships among the fauna components in relation to pesticide use have also been scarce. The actions of each biocide cause different biological responses, e.g., cypermethrin provokes an increase in metabolic activity and glyphosate a decrease (Collins et al., in press). The action of each pesticide is different, and the scarce information in their effects makes it very difficult to recognise the magnitude of the harm caused by these biocides on non-target species and on aquatic environments. The studies that have been conducted have focused on assays involving the active ingredient; however, it is not only the active ingredients that cause damage to the environment but also those compounds that are in the formulation and are considered inert. These compounds can increase the toxicity of the active ingredient, facilitating its ingression in biological systems, or may be toxic by themselves. It is therefore necessary for studies not to ignore commercial formulations, because they may include several compounds that can affect aquatic systems.

Fig. 3. Structure of typical area more affect by biocides through of sprayer with airplane, runoff after rain or groundwater potentially contaminated
