Chile's agricultural research institute plant tissue analysis dataset.

This dataset holds 9,175 entries that report the nitrogen, phosphorus, potassium, calcium, magnesium, zinc, manganese, copper and boron contents of various plant species, with a focus on crops. The dataset accounts data of 94 plant species, and present nutrient concentration of 14 different plant tissues. The data are derived from the Soil and Plant Nutrition Lab of the Chilean Agricultural Research Institute, which provided services to farmers in the Chilean Central Valley between 2006 and 2020. The analytical methods used to generate these data were consistent across all years, ensuring the reliability of the information. Specifically, nitrogen content was determined using the Kjeldahl method, while all other analytes were quantified via colorimetry (phosphorus and boron) or atomic absorption spectrometry following high-temperature oxidation and dilution of the ashes with hydrochloric acid. The dataset has numerous potential applications, including the estimation of crop nutrient extraction rates, the identification of nutrient deficiencies or excesses, and the provision of reference or prior information for researchers studying plant physiology. The dataset includes 21 Chilean endemic species, which might be of particular interest to researchers studying the biodiversity and ecology of Chile's Central Valley.

Microplastics occurrence and frequency in soils under different land uses on a regional scale.

The growing evidence of microplastic pollution in terrestrial ecosystems reveals adverse effects of microplastics on soil biota and plant growth. However, since large scale assessments are lacking, it is possible that the laboratory based experiments conducted have assumed unrealistic microplastic concentrations in soils. In this paper we present regional scale data on the presence of microplastics in soils under different land uses in the central valley of Chile, which is characterized by urbanization, agricultural, and mining operations. We identified microplastics in soils under four different land use systems having different management intensities (crop lands, pastures, rangelands, and natural grasslands), and all somewhat prone to accumulate microplastics from different sources. We analyzed 240 soil samples from Chile's central valley, trying to identify the most probable sources of the microplastics. Our hypothesis was that microplastics were ubiquitous in the environment and that their concentration peaks follow the intensity of fertilizer use (phosphorus), soil heavy metals concentrations derived from nearby mining operations (Zn and Cu), and distance to roads and urban areas. We did find evidence of microplastic pollution in crop lands and pastures (306 ± 360 and 184 ± 266 particles kg-1, respectively), but we did not observe pollution of rangelands and natural grasslands. Distance to mining operations, roads, or urban areas did not increase the microplastic particles count. Our observations contradict the common belief that microplastics are ubiquitous in the environment and relate the pollution problem more to agricultural activities. However, our data do not provide sufficient evidence to identify the pollution source. This is the first study that reports on microplastic occurrence in soils at a broad geographical scale. For greater insight on this topic more studies that contribute monitoring data about microplastics in soils are urgently needed.

Sewage sludge application as a vehicle for microplastics in eastern Spanish agricultural soils.

Microplastic pollution is becoming a major challenge with the growing use of plastic. In recent years, research about microplastic pollution in the environment has become a field of study with increased interest, with ever expanding findings on sources, sinks and pathways of microplastics. Wastewater treatment plants effectively remove microplastics from wastewater and concentrate them in sewage sludge which is often used to fertilise agricultural fields. Despite this, quantification of microplastic pollution in agricultural fields through the application of sewage sludge is largely unknown. In light of this issue, four wastewater treatment plants and 16 agricultural fields (0-8 sewage sludge applications of 20-22 tons ha-1 per application), located in the east of Spain, were sampled. Microplastics were extracted using a floatation and filtration method, making a distinction between light density microplastics (ρ < 1 g cm-3) and heavy density microplastics (ρ > 1 g cm-3). Sewage sludge, on average, had a light density plastic load of 18,000 ± 15,940 microplastics kg-1 and a heavy density plastic load of 32,070 ± 19,080 microplastics kg-1. Soils without addition of sewage sludge had an average light density plastic load of 930 ± 740 microplastics kg-1 and a heavy density plastic load of 1100 ± 570 microplastics kg-1. Soils with addition of sewage sludge had an average light density plastic load of 2130 ± 950 microplastics kg-1 and a heavy density plastic load of 3060 ± 1680 microplastics kg-1. On average, soils' plastic loads increased by 280 light density microplastics kg-1 and 430 heavy density microplastics kg-1 with each successive application of sewage sludge, indicating that sewage sludge application results in accumulation of microplastics in agricultural soils.

Evidence of microplastic accumulation in agricultural soils from sewage sludge disposal.

Microplastics are emerging as a steadily increasing environmental threat. Wastewater treatment plants efficiently remove microplastics from sewage, trapping the particles in the sludge and preventing their entrance into aquatic environments. Treatment plants are essentially taking the microplastics out of the waste water and concentrating them in the sludge, however. It has become common practice to use this sludge on agricultural soils as a fertilizer. The aim of the current research was to evaluate the microplastic contamination of soils by this practice, assessing the implications of successive sludge applications by looking at the total count of microplastic particles in soil samples. Thirty-one agricultural fields with different sludge application records and similar edaphoclimatic conditions were evaluated. Field records of sludge application covered a ten year period. For all fields, historical disposal events used the same amount of sludge (40 ton ha-1 dry weight). Extraction of microplastics was done by flotation and particles were then counted and classified with the help of a microscope. Seven sludge samples were collected in the fields that underwent sludge applications during the study period. Soils where 1, 2, 3, 4, and 5 applications of sludge had been performed had a median of 1.1, 1.6, 1.7, 2.3, and 3.5 particles g-1 dry soil, respectively. There were statistical differences in the microplastic contents related to the number of applications that a field had undergone (1, 2, 3 < 4, 5). Microplastic content in sludge ranged from 18 to 41 particles g-1, with a median of 34 particles g-1. The majority of the observed microplastics were fibers (90% in sludge, and 97% in soil). Our results indicate that microplastic counts increase over time where successive sludge applications are performed. Microplastics observed in soil samples stress the relevance of sludge as a driver of soil microplastic contamination.

Predicting soil microplastic concentration using vis-NIR spectroscopy.

Microplastic accumulation in soil may have a detrimental impact on soil biota. The lack of standardized methods to identify and quantify microplastics in soils is an obstacle to research. Existing techniques are time-consuming and field data are seldom collected. To tackle the problem, we explored the possibilities of using a portable spectroradiometer working in the near infrared range (350-2500 nm) to rapidly assess microplastic concentrations in soils without extraction. Four sets of artificially polluted soil samples were prepared. Three sets had only one polymer polluting the soil (low-density polyethylene (LDPE), polyethylene terephthalate (PET), or polyvinyl chloride (PVC)). The fourth set contained random amounts of the three polymers (Mix). The concentrations of microplastics were regressed on the reflectance observed for each of the 2150 wavelengths registered by the instrument, using a Bayesian approach. For a measurement range between 1 and 100 g kg-1, results showed a root-mean-squared-deviation (RMSD) of 8, 18, and 10 g kg-1 for LDPE, PET, and PVC. The Mix treatment presented an RMSD of 8, 10, and 5 g kg-1 for LDPE, PET, and PVC. The repeatability of the proposed method was 0.2-8.4, 0.1-5.1, and 0.1-9.0 g kg-1 for LDPE, PET, and PVC, respectively. Overall, our results suggest that vis-NIR techniques are suitable to identify and quantify LDPE, PET, and PVC microplastics in soil samples, with a 10 g kg-1 accuracy and a detection limit ≈ 15 g kg-1. The method proposed is different than other approaches since it is faster because it avoids extraction steps and can directly quantify the amount of plastic in a sample. Nevertheless, it seems to be useful only for pollution hotspots.

Effects of maize cultivation on nitrogen and phosphorus loadings to drainage channels in Central Chile.

There are concerns about the impact of maize cultivation with high applications of nitrogen (N) and phosphorus (P) on water quality in surface waters in Mediterranean Central Chile. This study estimated the contribution of N and P from maize fields to nearby drainage channels and evaluated the effects in water quality. An N and P budget was drawn up for three fields managed with a maize-fallow system, El Maitén (20.7 ha), El Naranjal (14.9 ha) and El Caleuche (4.2 ha), and water quality variables (pH, EC, dissolved oxygen, total solids, turbidity, NO3-N, NH4-N, PO4(3-), COD, total N, total P and sulphate) were monitored in nearby drainage channels. The N and P balances for the three fields indicated a high risk of N and P non-point source pollution, with fertiliser management, soil texture and climate factors determining the temporal variations in water quality parameters. Elevated levels of NH4-N and PO4(3-) in the drainage channels were usually observed during the winter period, while NO3- concentrations did not show a clear tendency. The results suggest that excessive slurry application during winter represents a very high risk of N and P runoff to drainage channels. Overall, great emphasis must be placed on good agronomic management of fields neighbouring drainage channels, including accurately calculating N and P fertiliser rates and establishing mitigation measures.

BRCA1 expression in triple negative sporadic breast cancers.

OBJECTIVE: To study how to identify patients with "triple negative" sporadic breast cancers (BCs) having BRCA1 silenced or down-regulated due to epigenetic BRCA1 inactivation. STUDY DESIGN: We selected, from our database, patients diagnosed with BC between 1995 and 2001 with tumors exhibiting the "triple negative" phenotype. "Triple positive" tumors were used as controls. BRCA1 protein expression was determined by immunohistochemistry. Methylation specific polymerase chain reaction (PCR) and bisulfite sequencing on genomic DNA were used to assess BRCA1 promoter methylation. BRCA1 m-RNA expression analysis was conducted by real-time PCR. RESULTS: Forty-four triple negative and 68 controls (triple positive) were eligible for our analysis. BRCA1 promoter methylation was present in 31.8% of triple negative and in 20.6% of triple positive cases. BRCA1 was inactivated (absent BRCA1 m-RNA expression and lack of BRCA1 protein) in 21.4% of tumors with BRCA1 promoter methylation, as compared with 6% of non-methylated ones (p = 0.0453). CONCLUSION: BRCA1 inactivation due to promoter methylation could play an important role in some sporadic BC cases. Patients with this signature could represent the basis for prospective studies aiming to compare clinical response to different drugs.

CAT25 is a mononucleotide marker to identify HNPCC patients.

Mismatch repair mutations are the cause of generalized genomic instability and are particularly evident at microsatellite loci, which is known as microsatellite instability (MSI). MSI is present in 85% to 90% of colorectal cancers and occurs in hereditary non-polyposis colorectal cancer (HNPCC). The National Cancer Institute recommends the "Bethesda panel" for MSI screening. Recently, a novel T(25) mononucleotide marker was described, termed CAT25. This microsatellite marker displays a quasi-monomorphic pattern in normal tissues. The aim of our study was to evaluate the performance of CAT25 in HNPCC patients and to compare its reliability with the results of the Bethesda panel. We tested 55 tumor tissues from HNPCC patients using both the Bethesda panel and the CAT25 mononucleotide marker. One hundred healthy blood donors were used as controls. The CAT25 microsatellite was found to be altered in all 13 colorectal cancers classified as MSI-H using the standard Bethesda panel. Colorectal tumors that showed a stable Bethesda pattern did not show altered CAT25 repeats. Additionally, CAT25 showed a monomorphic allele pattern in all tissue samples. In our series, the concordance between the Bethesda panel and CAT25 in identifying colorectal cancers with high MSI reached 100%. Our results suggest that the CAT25 microsatellite represents a sensitive and specific marker for MSI and could be, at least, included in the panel of markers for the identification of HNPCC patients.