Ambiente & Água - An Interdisciplinary Journal of Applied Science ISSN 1980-993X – doi:10.4136/1980-993X www.ambi-agua.net E-mail: ambi.agua@gmail.com This is an Open Access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Heavy metals in waters used for human consumption and crop irrigation ARTICLES doi:10.4136/ambi-agua.1999 Received: 03 Sep. 2016; Accepted: 17 May 2018 Laercio Santos Silva1; Izabel Cristina de Luna Galindo2; Clístenes Wilians Araújo do Nascimento2; Romário Pimenta Gomes1; Ludmila de Freitas1; Ivanildo Amorim de Oliveira1; Milton César Costa Campos3*; José Maurício da Cunha4 1Universidade Estadual Paulista "Júlio de Mesquita Filho" (UNESP), Jaboticabal, SP, Brasil Departamento de Solos e Adubos (FCAV/UNESP). E-mail: laerciosantos18@gmail.com, rpgagronomia@gmail.com, ludmilafreitas84@gmail.com, ivanildoufam@gmail.com 2Universidade Federal Rural de Pernambuco (UFRPE), Recife, PE, Brasil Departamento de Agronomia. E-mail: agromccc@yahoo.com.br, cwanascimento@yahoo.com 3Universidade Federal do Amazonas (UFAM), Humaitá, AM, Brasil Colegiado de Agronomia. E-mail: mcesarsolos@gmail.com 4Universidade Federal do Amazonas (UFAM), Humaitá, AM, Brasil Colegiado de Ciências: Física e Matemática. E-mail: maujmc@gmail.com *Corresponding author ABSTRACT The consumption of contaminated water is a major source of heavy metal contamination in humans and animals. This study therefore aimed to assess Cd, Cu, Mn, Ni, Pb, and Zn levels in water used for human and animal consumption and vegetable crop irrigation in Camocim de São Félix, Pernambuco, Brazil. Water samples were collected on the studied farms from an artesian well and reservoirs used for human and animal consumption as well as for crop irrigation. The results showed that concentrations of Cd (> 0.001 mg L-1), Ni (> 0.025 mg L-1) and Pb (> 0.01 mg L-1) were above the maximum allowable limits established under Brazilian law, indicating the need for a preventive monitoring program and immediate intervention initiatives aimed at the sources of contamination. The results demonstrate the need to quantify heavy metal content in vegetable crops, since their contamination by irrigation water may make them harmful to human health. Rainfall has a seasonal effect on heavy metal concentrations in water, showing a significant effect on Pb levels, whereas Cd and Ni content was less dependent on seasonal variation. Keywords: agrochemicals, cadmium, diffuse pollution, lead, trace elements. Metais pesados em águas utilizadas para consumo humano e irrigação de culturas RESUMO O consumo de águas contaminadas representa uma das principais vias de contaminação humana e animal por metais pesados. Neste sentido, o objetivo deste trabalho foi determinar as concentrações de Cd, Cu, Mn, Ni, Pb e Zn em águas utilizadas para consumo humano e animal http://www.ambi-agua.net/seer/index.php/ambi-agua/index http://dx.doi.org/10.4136/1980-993X http://dx.doi.org/10.4136/1980-993X http://www.ambi-agua.net/splash-seer/ http://www.ambi-agua.net/splash-seer/ https://doi.org/10.4136/ambi-agua.1999 mailto:laerciosantos18@gmail.com mailto:rpgagronomia@gmail.com mailto:ludmilafreitas84@gmail.com mailto:ivanildoufam@gmail.com mailto:agromccc@yahoo.com.br mailto:cwanascimento@yahoo.com mailto:mcesarsolos@gmail.com Rev. Ambient. Água vol. 13 n. 4, e1999 - Taubaté 2018 2 Laercio Santos Silva et al. e na irrigação de hortaliças no município de Camocim de São Félix (PE). Nas propriedades agrícolas, as amostras de água analisadas foram coletadas de poço artesiano e de reservatórios destinados ao consumo humano, animal e irrigação das lavouras. Os resultados demonstraram que as águas analisadas no presente estudo apresentaram concentrações de Cd (> 0,001 mg L-1), Ni (> 0,025 mg L-1) e Pb (> 0,01 mg L-1) superiores aos teores máximos permitidos indicados pela legislação brasileira, sinalizando a necessidade de um programa de monitoramento preventivo e ações de intervenção imediata das fontes de contaminação. Os resultados indicam a necessidade de quantificação das concentrações de metais pesados nas hortaliças, visto que contaminadas pelas águas de irrigação podem ser uma fonte nociva à saúde humana. A precipitação pluviométrica tem influência sobre a variação sazonal dos teores dos metais nas águas, com maior efeito na concentração de Pb e influência moderada nas concentrações de Cd e Ni. Palavras-chave: agroquímicos, cádmio, chumbo, elementos-traço, poluição difusa. 1. INTRODUCTION Heavy metals can affect crop development and compromise the health of humans and animals by contaminating the food chain (Lee et al., 2006; Amin et al., 2013). In aquatic ecosystems, metals can occur naturally or be introduced by human activity. Natural occurrence is through atmospheric deposition and rainfall, or the release and transport of heavy metals from sediment or soil, in the case of soil erosion (Bezerra et al., 2014). Anthropogenic sources include raw sewage in urban areas and the discharge of industrial effluents and agricultural waste that widely contaminate basin areas (Gomes and Sato, 2011). Agriculture is one of the most important sources of heavy metal pollution of bodies of water, largely through fertilizers (Cd, Cr, Pb, Zn) and pesticides (Cu, Pb, Mn, Zn) (Mendes et al., 2006, Silva et al., 2016). In this respect, although agrochemicals are a decisive factor in increasing yields, they can also cause heavy metal contamination (Mendes et al., 2010). For example, fertilizers made from phosphate rocks can increase levels of heavy metals such as Cd, Cu, Mn, Ni, Pb and Zn in the soil (Freitas et al., 2009). In order to protect human health and ecosystems, monitoring agencies have established maximum allowable limits for heavy metals in water (CETESB, 2005; CONAMA, 2005). A study of water samples from the Caetés watershed in Paty de Alferes, Rio de Janeiro (RJ), found Mn, Cd and Pb levels higher than the allowable limits stipulated by the National Environmental Council (CONAMA, 2005), attributed to atmospheric deposition and agricultural activities (fertilizers and agrochemicals) (Ramalho et al., 2000). Cunha Filho et al. (2014) analyzed crop irrigation water for the heavy metals Fe, Mn, Zn, Cu, Pb, Cd and Cr and found that only Fe content (0.908 mg L-1) exceeded the allowable limit of 0.3 mg. L-1 (CONAMA, 2005). In Pernambuco state, vegetable cultivation is concentrated in municipalities in the rural region, particularly Camocim de São Félix, where vegetable farming is the main economic activity. However, farmers in this area have used fertilizers without following technical criteria for at least 30 years, causing N and P contamination and eutrophication of water used for irrigation as well as human and animal consumption (Silva et al., 2001). In this context, the present study measured levels of the heavy metals Cd, Cu, Mn, Ni, Pb and Zn in water used to irrigate vegetable crops and for human and animal consumption, in the municipality of Camocim de São Félix (PE), and compared them to the maximum allowable limits for these elements. Additionally, seasonal variations in water levels of these metals due to rainfall were also assessed. 3 Heavy metals in waters used for human … Rev. Ambient. Água vol. 13 n. 4, e1999 - Taubaté 2018 2. MATERIAL AND METHODS The study was conducted in vegetable farming areas in the municipality of Camocim de São Félix, located in the southern rural region of Pernambuco state, in the Brejo Pernambucano microregion. Annual rainfall in the area is between 900 and 1300 mm and altitudes range from 600 to 1000 m. Water samples were taken from small dams in five vegetable farming areas along the slope. Samples were collected in loco and based on information obtained by the rural farmers and the Pernambuco Agronomic Institute (IPA). Each area had its own reservoir (R-1, R-2, R-3, R-4 and R-5), from which samples were taken of water used for crop irrigation as well as for human and animal consumption. Samples were also collected directly from a residential water source (artesian well). The reservoirs and residential well were georeferenced and the coordinates are shown in Table 1. The areas containing the reservoirs are farmed using similar agricultural management systems, and exhibit an average 33% slope and consecutive annual vegetable crops. The farmers in this region use preventive and corrective irrigation and fertilizer/pesticide application during the different crops cycles. In this study, 200 mL of water was collected from the reservoirs each month, in addition to samples of the water used for human consumption, over a 12-month period (January to December 2010). Table 1. Altitude, geographic coordinates and area of the bodies of water studied. Reservations: Altitude (m) Coordinates Body of water (m2) aR-1 643 S 8°22’34.5” and W 35°45’59.4”* 7600 R-2 640 S 8°22’37.0” and W 35°46’02.5” 8100 R-3 646 S 8°20’39.3” and W 35°45’04.9” 5250 R-4 656 S 8°20’36.7” and W 35°45’00.2” 5950 R-5 665 S 8°20’49.9” and W 35°44’58.1” 6300 Homeb 699 S 8°21’50.2” and W 35°45’44.2” --- aR = reservoir; b = artesian well. *data on altitude, coordinates and the bodies of water were obtained using a Garmin eTREX VISTA HCx GPS device. Collections were performed between the 5th and the 8th of each month (January to December 2010) at different points of the reservoirs, avoiding areas with murky water or suspended material. At the residence, water was collected from a water outlet on the artesian well. An average of five subsamples were collected to form a 200 mL sample. The containers used for sampling were previously immersed in acidic solution (3% HCl) for 24 hours. The samples were immediately acidified with dilute nitric acid, at 1 mL of HNO3 for every 100 mL of sample. Once sealed, the flasks were kept in coolers and transported to the laboratory. On the same day they were collected, the samples were filtered in the laboratory using slow-filtering qualitative filter paper to prevent the release of low levels of the elements from the particulate material into the solution and stored in a refrigerator at 4°C. Concentrations of Cd, Cu, Mn, Ni, Pb were determined by flame atomic absorption spectrometry (Perkin Elmer AAnalyst 800), with detection limits for Cd (0.002), Cu (0.005), Mn (0.05), Ni (0.002), Pb (0.003) and Zn (0.002). For quality control purposes, samples of multielement standard solutions (spikes) were used, prepared based on 1000 mg L-1 standards (TITRISOL®, Merck), with concentration equal to the central point of the calibration curve of the device, for each chemical element. The results were compared to the parameters established by Resolution 357 (CONAMA, 2005), which addresses the classification of bodies of water and their relevant environmental guidelines, as well as conditions and standards for effluent discharge. The resolution also Rev. Ambient. Água vol. 13 n. 4, e1999 - Taubaté 2018 4 Laercio Santos Silva et al. stipulates quality parameters for water for human and animal consumption, as well as irrigation of vegetables consumed raw and/or fruit that grows close to the ground and is eaten raw without removing the peel. Monthly rainfall data for 2010 and the previous 10 years in the municipality of Camocim de São Félix were obtained from the Pernambuco Institute of Technology (Figure 1), to determine whether rainfall influenced heavy metal levels in the water analyzed (ITEP and LAMEPE, 2010). Figure 1. Mean monthly rainfall (January to December 2010) and historic mean in the municipality of Camocim de São Félix-PE. Source: Data provided by ITEP/LAMEPE, Camocim de São Félix Weather Station; * monthly rainfall in 2010 and 10-year average. 3. RESULTS AND DISCUSSION No Cu, Mn or Zn was detected in water from the reservoirs and artesian well studied. These results are similar to those reported by Sobral et al. (2007), who recorded Cu, Mn and Zn levels below the detection limit in water from the Cabedelo River (Rio Cabedelo), in the Mangabeira industrial district of João Pessoa (Paraíba state - PB). Cd levels in the water samples varied from 0.041 to 0.058 mg L-1 (Table 2 and Figure 2), with all samples found to be above the established standard (CONAMA, 2005) of 0.001 mg L-1, indicating contamination of these water sources; a similar situation was reported by Paty do Alferes (RJ) (Ramalho et al., 2000) in Barra do Choça (Bahia state - BA). Cd is highly toxic and can cause poisoning when ingested in water or food (McGrath et al., 2006). The element is carcinogenic and can occur in agriculture through the use of pesticides and fertilizers (Sharma et al., 2007; Manzini et al., 2010). Cd contamination in the water samples may be due to excessive use of phosphate fertilizers (Nacke et al., 2013; Gonçalves Júnior. et al., 2014; Benson et al., 2014; Balkhair and Ashraf, 2016). Around 60% of the Cd in triple superphosphate comes from phosphate rock. Bizarro et al. (2008) found Cd in the acidified P sources single and triple superphosphate, ranging from 2 to 13 and 3 to 33 mg kg-1, respectively. These values are relatively low; however, intensive http://www.ncbi.nlm.nih.gov/pubmed/?term=Balkhair%20KS%5Bauth%5D 5 Heavy metals in waters used for human … Rev. Ambient. Água vol. 13 n. 4, e1999 - Taubaté 2018 farming using agrochemicals (fertilizers and pesticides) can increase heavy metal concentrations in the soil-water-plant system, especially in the case of elements poorly retained by the soil and easily lost to leaching (Singh and Agrawal, 2008; Freitas et al., 2009; Silva et al., 2016). Table 2. Heavy metals in water samples from five reservoirs and an artesian well used to irrigate vegetable crops and for human and animal consumption in the municipality of Camocim de São Félix-PE. Areas Months Jan Feb Mar Apr May Jun Jul Aug Sept Oct Nov Dec Mean bCd mg L-1 aR-1 0.05 0.04 0.04 0.04 0.04 0.04 0.04 0.04 0.04 0.04 0.04 0.04 0.04 R-2 0.05 0.05 0.05 0.04 0.04 0.04 0.04 0.05 0.04 0.04 0.05 0.04 0.04 R-3 0.04 0.05 0.04 0.04 0.05 0.04 0.04 0.04 0.04 0.04 0.05 0.04 0.04 R-4 0.04 0.04 0.04 0.04 0.04 0.05 0.05 0.05 0.05 0.05 0.06 0.05 0.05 R-5 0.05 0.05 0.05 0.05 0.05 0.05 0.05 0.05 0.05 0.05 0.05 0.05 0.05 Home 0.05 0.05 0.05 0.05 0.05 0.06 0.06 0.06 0.05 0.06 0.06 0.05 0.05 CONAMA Nº 357/05* 0.001 cNi mg L-1 R-1 1.95 2.18 2.14 2.47 2.73 2.59 2.57 2.48 2.51 2.7 2.41 2.07 2.4 R-2 2.26 2 1.87 2.02 2.23 2.09 2.35 2.23 2.32 2.44 2.43 2.06 2.19 R-3 2.45 2.58 2.22 2.44 2.19 2.14 2.62 2.57 2.33 2.57 2.17 1.85 2.34 R-4 2.67 1.97 2.3 2.58 2.38 2.46 2.72 2.96 2.56 2.5 2.69 2.62 2.53 R-5 2.78 2.25 2.45 2.47 2.55 2.89 2.62 2.61 2.9 2.75 2.75 2.52 2.63 Home 2.32 2.71 2.53 2.58 2.49 2.95 2.88 2.9 3.17 3.28 3.31 3.25 2.86 CONAMA Nº 357/05* 0.025 dPb mg L-1 R-1