Water and sediment pesticide contamination on indigenous lands surrounded by oil palm plantations in the Brazilian Amazon.

Large-scale oil palm cultivation with intensive pesticide use has been growing worldwide and reached the Brazilian Amazon. The rapid expansion of this crop over the last decade has reached vast areas, including the boundaries of different indigenous lands. This study aimed at assessing the occurrence of pesticide residues in surface and ground waters as well as drainage sediments in the Turé-Mariquita Indigenous Territory, in addition to other nearby indigenous villages in the northeastern state of Pará. Thirty-three (33) water samples were collected from streams, springs and from active and abandoned wells at 19 sampling points, as well as 16 sediment samples at 9 sampling sites both during dry and rainy seasons. In total, 49 environmental samples were taken during fieldworks and subsequently analyzed by means of liquid chromatography and mass-mass spectrometry. The analytical determination of pesticide residues showed the occurrence of three pesticides in the water both from streams and from wells, two of them knowingly used by the oil palm company: glyphosate-based herbicides (GBHs) and endosulfan insecticides. Although the highest glyphosate and endosulfan levels as well as the maximum concentration of glyphosate found in ground water are within the Brazilian environmental regulatory guidelines, all the values for human consumption found in the glyphosate-containing samples are well above the European Union regulatory standards. Our results draw the attention to the risks of biota contamination and human exposure to multiple-pesticide residues.

Levels of organochlorine pesticides in Amazon turtle (Podocnemis unifilis) in the Xingu River, Brazil.

Due to the toxicity and high environmental persistence of organochlorine pesticides in aquatic organisms, turtles have been studied as environment biomonitors. These animals are important sources of protein for the riverside and indigenous peoples of the Brazilian amazon. In the present study, organochlorine pesticide contamination was investigated in Podocnemis unifilis. Liver, muscle and fatty tissue samples were removed from 50 specimens collected from five sampling points located in the Xingu River basin. Fourteen organochlorine pesticides were analysed via gas chromatography with an electron capture detector (CG-ECD). Eight organochlorine pesticides were detected with average concentrations of ∑DDT, ∑Endossulfan and ∑HCH which were 26.17 ± 26.35, 14.38 ± 23.77 and 1.39 ± 8.46 ng g-1 in moisture content, respectively. DDT compounds were the most predominant, with a greater concentration of pp'-DDT in the liver and pp'-DDD in the muscle. Significant differences were noted between the types of tissues studied, and the concentration of OCPs varied between sampling sites.

Seasonal assessment of trace element contamination in intertidal sediments of the meso-macrotidal Hooghly (Ganges) River Estuary with a note on mercury speciation.

The spatial and seasonal distribution of trace elements (TEs) (n=16) in surficial sediment were examined along the Hooghly River Estuary (~175km), India. A synchronous elevation of majority of TEs concentration (mgkg-1) was encountered during monsoon with the following descending order: Al (67070); Fe (31300); Cd (5.73); Cr (71.17); Cu (29.09); Mn (658.74); Ni (35.89). An overall low and homogeneous concentration of total Hg (THg=17.85±4.98ngg-1) was recorded in which methyl mercury (MeHg) shared minor fraction (8-31%) of the THg. Sediment pollution indices, viz. geo-accumulation index (Igeo) and enrichment factor (EF) for Cd (Igeo=1.92-3.67; EF=13.83-31.17) and Ba (Igeo=0.79-5.03; EF=5.79-108.94) suggested high contamination from anthropogenic sources. From factor analysis it was inferred that TEs primarily originated from lithogenic sources. This study would provide the latest benchmark of TE pollution along with the first record of MeHg in this fluvial system which recommends reliable monitoring to safeguard geochemical health of this stressed environment.

Assessment of DDT and Metabolites in Soil and Sediment of Potentially Contaminated Areas of Belém, Amazon Region, Brazil.

The aim of this study was to evaluate the distribution of DDT and metabolites in surface soils and soil profiles from two areas containing deposits of obsolete pesticides in Belém, Amazon Region, Brazil. DDT and metabolites were extracted by microwave assisted extraction and analyzed by gas chromatography with electron capture detection. Concentrations of total DDT in surface soil samples ranged from 64.22 mg kg-1 in area 1 (A1) to 447.84 mg kg-1 in area 2 (A2). Lower levels were found in soil profiles than at the surface (6.21-21.17 mg kg-1 in A1 and 36.13-113.66 mg kg-1 in A2). pp'-DDT, pp'-DDE and pp'-DDD were detected in sediments at levels of 2.01, 0.96 and 0.35 mg kg-1, respectively. The ratio (DDE + DDD)/ΣDDT was low indicating the recent introduction of DDT to the environment in the two study areas, through the volatilization and atmospheric deposition of the obsolete pesticides.