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Persistent organic pollutants (POPs) are a global issue. The recently signed Stockholm POP convention requires information from signatory countries regarding sources and environmental levels. In eastern and western South American countries, this information is not always easily accessible, and therefore an effort toward collection of updated information is required. This review attempts to fulfill these requirements by analyzing the existing information regarding environmental levels of POPs in eight countries of South America.

A regional trend for environmental POP information is the uneven contribution among countries, which reflects the different patterns of economic, technical, and scientific development. In general terms, the available information is strongly biased toward those countries with scientists, and technical facilities for performing research in POP-related issues. Data related to environmental levels and spatial patterns principally come from the densely populated areas along major rivers such as the Amazon, Paraná, and Río de la Plata. The database is thus strongly biased toward freshwater environments to the detriment of coastal marine areas, which have received proportionally less attention.

POP monitoring in air is infrequent in the Region. Data represent a few geographical areas within the Region. PCB levels in air from some urban areas in Argentina, Brazil, and Chile are low to moderate (0.7–6.5 ng/m) but considerably higher than those reported for the remote Falkland Islands (Islas Malvinas) (5 pg/m). POP monitoring in soils is also limited within the Region. There are no regional monitoring programs, and most data refer to agricultural areas in Chile and urban hot spots in Brazil. Chilean soil data from agricultural areas indicate generally low levels of chlorinated pesticides in spite of a relatively high detection frequency.

Overall, several high pesticide levels for freshwater in the Region suggest a complex situation, but the narrow coverage of the data requires a cautious interpretation. Usually, only suspected contaminated ecosystems are monitored, and large-scale regional water monitoring programs have never been undertaken. The few PCB reports indicate generally low to moderate levels (7–22 ng/L), higher than recommended guidelines in urbanized estuaries and rivers such as the Río de la Plata (Argentina) and Biobio (Chile). Pesticide levels show high variability (0.6–14, 160 ng/L), reflecting distinct ecosystem conditions from less-impacted environments to severely polluted streams located in densely populated areas near Buenos Aires and Sao Paulo. Heptachlor, HCHs, aldrin, and DDTs are the most frequently reported pesticides in water, accounting for more than 60% of the total database.

Regional POP information for sediments is also dominated by chlorinated pesticides, but presents a more balanced contribution of PCBs with a few reports for PCDD/F. Overall, as observed for waters, sediment data indicate a complex situation in densely populated areas affected by urban-industrial inputs that have high POP levels. The most frequently reported POPs are DDTs, HCHs, PCBs, and heptachlors. The concentrations show a large variability, principally introduced by some highly contaminated sites in Argentina and Brazil with levels 4–5 orders of magnitude higher.

Aquatic organisms are by far the most studied organisms in the region, among them principally bivalves and fish. As observed for other environmental receptors, the regional distribution of data is uneven, heavily centered in coastal environments and in some countries (Argentina, Brazil, Chile, and Peru). The most comprehensive POP monitoring program in the South American coastal environment is the Mussel Watch. Among the POPs studied, PCBs predominate, followed by DDTs and chlordanes. Baseline PCB concentrations range from 200 to 700 μg/kg lipids in unpolluted sites, from 1,000 to 3,000 μg/kg in moderately contaminated sites, and from 4,000 to 13,000 μg/kg lipids in most affected bivalves from the Río de la Plata (Argentine side), Recife (Brazil), and Punta Arenas (Chile). DDT averages in bivalves are an order of magnitude lower than those of PCBs, below the 5 ppm guideline, and follow a similar spatial pattern.

Other organisms that have been analyzed for POPs in the Region are crabs (), dolphins (), and porpoises () from the Atlantic Argentine coast and continental shelf. PCBs show the highest levels (averages, 296, 1980 and 3300 μg/kg lipid in crabs, dolphins, and porpoises, respectively) closely followed by DDTs (170, 1670, and 4320 μg/kg lipid). PCDD/Fs analyzed in the omnivorous blue crab () collected in the Santos Bay area (Brazil) showed total TEQ values of 1.5 pg/g wet weight with the predominance of octachlor dioxins, followed by heptachlor congeners. POP data in crustaceans and gastropods from the Valdivia area (southern Chile) show generally low levels, basically of DDTs and DRINs (0.8–5 ng/g ww), whereas very few data from organisms collected in the Peruvian coast show low DDT (1–10 ng/g), and PCB levels (0.12–17.8 ng/g).

The situation of most of the Argentine rivers is very serious due to the amount and range of pollutants, principally as a consequence of industrial development with an inadequate regulatory framework and a deficit of decades in matters of sanitary substructure and waste treatment.

Freshwater quality monitoring in Argentina was based on water chemistry and bacteriology, with measurements of only the main variables required for the determination of quality indexes. A multidisciplinary approach considering simultaneous evaluation of a number of factors and processes that in an integrative picture determine its characteristics was poorly developed or lacking. The use of biota for monitoring the aquatic environments has been relatively uncommon compared to abiotic variables.

The Reconquista River is a typical lowland watercourse situated in the Buenos Aires Province. Located in a temperate subtropical region, it flows into an international river, Río de la Plata, which is part of the second largest hydrogeographic system of South America, after the Amazon, and the fifth largest in the world. The river receives the output of 80 small tributaries, and one of them, the Morón creek, should be highlighted as it marks the limit between the medium and the lower sections of the river. During the dry season the entire stream is composed of sewage and industrial wastes and known as an “open sewer.”

The river is the second most polluted waterway of Argentina. There is a great variety of industrial activities settled on its basin. Some 10,000 plants, most of them located on the margins of the river, discharge their untreated effluents into the river and use large quantities of water in processing, cooling, and cleaning. Approximately 20% of these industries discharge a total BOD load of approximately 150,000 kg d, which is equivalent to an organic loading capacity of 2.5 million population.

To monitor water quality of the main course of the Reconquista River, the following principal approaches have been adopted: (a) measurement of approximately 30 physical and chemical variables, (b) determination of biological parameters (phytoplankton and zooplankton abundance, diversity, and community structure, microbiology), (c) acute and prolonged and laboratory toxicity tests with algae, tadpoles, and fish (fry and juveniles) as sentinel organisms, (d) monitoring of alterations in specific physiological and biochemical markers of exposure in fish, and (e) determination of water quality indexes based on the physicochemical profile of the samples.

The studies were carried out during a span of 15 years on samples regularly taken in three to five sites covering the length of the river’s main bed. The most relevant outcomes of the study can be summarized as follows.

Spatial variation of the DO was from 7–8 mg L in S1 down to 0-0.3 mg L in S5, indicating water in Bancalari was in permanent anoxia.

COD/BOD ratios oscillated between 11 (in S1) and 4 (in S4–S5), suggesting the presence of important amounts of nonbiodegradable organic matter.

The presence of domestic sewage indicators and municipal wastes as chlorides, orthophosphates, inorganic N compounds (NH, NO, NO) and phenols were found in all samples, with a clear-cut increase in concentration down river up to values well above MPQs.

Total heavy metal concentrations always exceeded widely MPQs established by Argentine law for protection of freshwater life. At all locations organochlorine insecticide levels varied between 40- and 400 fold above legal limits.

When considering physicochemical parameters altogether in a spatial and temporal perspective, it becomes evident that there was a progressive but sustained alteration of the water quality downriver, especially after the confluence of the Morón creek, and, that the deterioration increased with time.

River water showed an alarming degree of bacterial pollution, which was temporally and spatially highly variable.

Environmental physicochemical toxicity data were closely correlated with the results of both acute and sublethal chronic toxicity bioassays.

It was concluded that only an integrated analysis of chemical and biological parameters coupled with toxicity tests will offer a realistic view of the state of water quality in the Reconquista River.

The pulp and paper manufacturing industry generates large quantities of wastewater and has been described as a significant pollutant of the aquatic environment for many decades. The majority of pulp mills are located in the U.S. and Canada, and these countries are therefore subject to the greatest environmental impact. Some form of toxicity following exposure to mill effluent has been documented in numerous species, both aquatic and terrestrial, and the compounds present in effluents can affect multiple physiological processes, including hepatic mechanisms, reproduction and development, and endocrine function. Although the effects of PME on wildlife have been known for some time, the detection of chlorinated organic compounds generated substantial concern to humans because of the potential risk of exposure to these highly toxic compounds through environmental persistence and bioaccumulation. Government regulations were imposed on the pulping industry in an effort to prevent further contamination and reduce the toxic potential of pulp mill effluent to both humans and wildlife.

Included among these regulations was the elimination of bleaching processes that utilized organic chlorine in favor of elemental chlorine free (ECF) and totally chlorine free (TCF) bleaching processes. There is little in the peer-reviewed literature describing the advantages of TCF over ECF, and many Internet sources claim that the differences between the two are small, although ECF is better economically. The USEPA has listed ECF as one of the best available technologies (BAT) within the Cluster Rule. However, because the mechanisms of MFO activity are unclear and reproductive effects have been observed following effluent exposure, and because some of these same effects have been reported in areas minimally compromised by PME, it is difficult to assess the true improvements that these processes are attaining. Other methods of bleaching continue to be tested and each has its own beneficial aspects. However, negative elements still seem to arise, either through chemical persistence, the formation of previously undetected compounds, or the conversion from one toxicant to another. Certainly, the elimination of elemental chlorine in pulping and bleaching processes will improve the quality of effluents with respect to chlorinated organics, but further research is necessary to determine the actual benefits of all processes and to determine how the toxicity that remains can be eliminated.

Lead is a very toxic environmental pollutant that affects people living or working in contaminated areas or ingesting this element. Since the beginning of lead use, it has left evidence of lead poisoning with dramatic effects on the destiny of ancient civilizations. It was recently proposed that this toxicity can also contribute to the decline of current societies through lead-induced impairment of intelligence, increased tendency to abuse of drugs, psychological and behavioral changes, and increase in delinquent behavior.

The effects of chronic exposure to lead in adolescents or adults may be reversed, at least in part, after a decrease in the blood lead levels. In contrast, in children, especially at earlier ages, the effects are irreversible, may persist through life, and some of them may be induced by the mechanism of imprinting. Exposure to lead during the perinatal period of life may occur in mothers previously exposed to the metal, presenting increased concentration of lead in bones; fetuses and newborns are most vulnerable to the toxic effects of lead because the damage persists throughout life.

The various sources of lead exposure in Chile as well as the evolution of regulations and mitigation measures are reviewed. An important source of contamination with lead was the existence of paints with high lead content, used to paint house walls, children’s furniture, and toys, among other objects. The highest content of lead in paints was not in those bearing Chilean trademark names, but from a foreign trademark with formulas licensed to produce in Chile, although the same products in the country of origin (U.S.) did not present measurable lead levels. From 1997 on, new legislation regulated lead content in paints. Many houses, furniture, children’s toys, and other objects painted before 1997 are still an important source of exposure to lead, mainly for children.

Formerly, the widest source of lead contamination in Chile was the use of leaded gasoline, mainly in greatly populated cities. There has been a progressive decrease in lead content in leaded gasoline, which was banned in April 2001. Lead pollution still persists in highly populated cities as city soil, home soil, and as soil contamination near highways.

Clusters of different magnitude originated from point sources, of which the most relevant in magnitude was that which occurred in Ñuble with the use of wheat flour contaminated with lead, caused by the use of a mill whose stone was repaired by lead welding. Several other clusters of smaller magnitude are frequently caused by the widespread practice of battery repair and recovery by small enterprises or as a familial productive activity, affecting all the family group and occasionally persons living in the vicinity.

Two special cases of very important environmental contamination occurred, affecting the population of two major cities. The most dramatic case was the storage of powdered lead mineral concentrates at the ports or the railroad terminals within the cities of Arica and Antofagasta, where it usually remained until shipped to other countries. Lead from this source is the most relevant source of exposure in the cities of Arica and Antofagasta. Another source of lead, which affected the population of Arica, originated from toxic wastes imported by Promel from the Swedish company Boliden Metal, stored without protection in Arica suburbs, where a few years later new dwellings were constructed and residents were exposed for more than 10 years.

Occupational exposure frequently occurs in painters, welders, and mining or smelting workers. Various degrees of food lead contamination may increase exposure to the metal. Vegetables grown in or near highly populated areas, lead pipes in old dwellings or copper pipes welded with lead, and formerly lead from canned food, especially those that had been accidentally deformed or were opened and the food stored in those cans.

Little information exists on lead content in soil. There are sites where lead concentrations are increased from anthropogenic sources. In regions known to have abundant lead minerals, soil is not contaminated in the vicinity of rivers, suggesting that raw lead minerals do not dissolve in water and do not affect the soil.

Human nails are extensively employed for monitoring exposure to excessive levels of elements. Nails can be studied easily and economically in subjects of residential areas and industrial workers and patients, and sometimes may indicate that high concentrations of elements are related to various illnesses. Deficiency of certain elements (Se and Fe) can also be determined with use of nails of subjects with specific or unknown deficiencies. Although nails are different from other biological samples in bioaccumulation, physiological activities may be partially due to chemical properties of the elements. Comparison of multielements between nails and other samples is relevant and found significant, because of the status of chronic exposure to high levels of elements. However, comparison of multielements between nails and other samples results in inconsistencies when exposure to elements is acute or unpredictable, or the subject is deficient in the elements being measured. Studies associated with elemental speciation, supplementation, interaction, and deficiency of essential elements (Zn, Cu, Mn, Mo,etc.), although rarely available, may enhance the growing use of nails. In many other research fields nail levels of elements and other associated factors or parameters are being investigated for further expansion of their application.