Surface sediment and water samples were collected from Daihai Lake to study the biogeochemical characteristics of nitrogen and phosphorus, to estimate the loads of these nutrients, and to assess their effects on water quality. The contents and spatial distributions of total phosphorus (TP), total nitrogen (TN), and different nitrogen forms in sediments were analyzed. The results showed that concentrations of TN and TP in surface sediments ranged from 0.27 to 1.78 g/kg and from 558.31 to 891.29 mg/kg, respectively. Ratios of C : N ranged between 8.2 and 12.1, which indicated that nitrogen accumulated came mainly from terrestrial source. Ratios of N : P in all sampling sites were below 10, which indicated that N was the limiting nutrient for algal growth in this lake. Effects of environment factors on the release of nitrogen and phosphorus in lake sediments were also determined; high pH values could encourage the release of nitrogen and phosphorus. Modified Carlson's trophic state index (TSIM) and comprehensive trophic state index (TSIC) were applied to ascertain the trophic classification of the studied lake, and the values of TSIM and TSIC ranged from 53.72 to 70.61 and from 47.73 to 53.67, respectively, which indicated that the Daihai Lake was in the stage of hypereutropher.

The spatial variability and temporal trend in concentrations of the organochlorine pesticides (OCPs), hexachlorocyclohexane (HCH) and dichlorodiphenyltrichloroethane (DDT), in soils and agricultural corps were investigated on an intensive horticulture area in Hohhot, North-West China, from 2008 to 2011. The most frequently found and abundant pesticides were the metabolites of DDT (p,p'-DDE, p,p'-DDT, o,p'-DDT and p,p'-DDD). Total DDT concentrations ranged from ND (not detectable) to 507.41 ng/g and were higher than the concentration of total HCHs measured for the range of 4.84-281.44 ng/g. There were significantly positive correlations between the ∑DDT and ∑HCH concentrations (r (2)>0.74) in soils, but no significant correlation was found between the concentrations of OCPs in soils and clay content while a relatively strong correlation was found between total OCP concentrations and total organic carbon (TOC). β-HCH was the main isomer of HCHs, and was detected in all samples; the maximum proportion of β-HCH compared to ∑HCHs (mean value 54%) was found, suggesting its persistence. The α/γ-HCH ratio was between 0.89 and 5.39, which signified the combined influence of technical HCHs and lindane. Low p,p'-DDE/p,p'-DDT in N1, N3 and N9 were found, reflecting the fresh input of DDTs, while the relatively high o,p'-DDT/p,p'-DDT ratios indicated the agricultural application of dicofol. Ratios of DDT/(DDE+DDD) in soils do not indicate recent inputs of DDT into Hohhot farmland soil environment. Seasonal variations of OCPs featured higher concentrations in autumn and lower concentrations in spring. This was likely associated with their temperature-driven re-volatilization and application of dicofol in late spring.

Chlorophylls (Chls), the green pigments responsible for photosynthesis in plants, algae and bacteria, are also part of the daily diet of herbivorous feeders. Chl degradation occurs during leaf senescence and fruit ripening but is also noticed as a response to biotic and abiotic stresses. Besides the programmed degradation during senescence different factors such as high temperature, extreme pH values, enzymatic actions, molecular oxygen, and light initiate the degradation of Chl. To gain more information on Chl degradation in the gut of plant-feeding insects, regurgitate and frass of Spodoptera littoralis caterpillars were analysed for late Chl catabolites by using LC-MS, UV, Fluorescence and NMR spectroscopy. The major metabolites were determined in fresh leaves of the food plant lima bean (Phaseoluslunatus), and were compared with digestive products. The observed spectrum of metabolites can be attributed to the combined action of esterolytic gut enzymes and the strongly alkaline milieu in the digestive tract. Interestingly, linear Chl catabolites were not detected in the gut of the larvae of S. littoralis. Substantial amounts of Chl catabolites were found to be macrocyclic rings opened in the senescent food plants, but also in the aged frass. We studied two primary fluorescent chlorophyll catabolites in senescent leaves of lima bean. One of the primary fluorescent chlorophyll catabolites that have been found in the frass of S. littoralis might be generating opened tetrapyrroles of Chl, only after being exposed to the air and light.

Groundwater is not a nutrient-rich environment for microorganisms to grow and thrive, but it is polluted by many environmental factors. These nutrients can exceed the permissible levels in drinking water and can be a reason for spreading highly infectious diseases in the population. Therefore, there is a need to monitor the quality of water from deep wells in ger areas, to study certain correlations, to prevent people from various infectious diseases, to protect the environment, to use water resources properly, and to provide citizens with accurate information on drinking water. Within the framework of the study, samples were taken from 135 deep wells used for drinking and household purposes in the Bayanzurkh, Bayangol, and Sukhbaatar districts of Ulaanbaatar city. The water quality was analyzed for some hydrochemical (NO3 -) and six main microbiological parameters. Due to microbiological parameters, 42 samples (30.6%) from the surveyed deep wells did not meet the requirements of MNS 0900:2018, the national drinking water standard of Mongolia, and 31 samples (21.9%) exceeded the nitrate ion content described in above the standard. In the Bayangol district, 88% of the surveyed sources found that the number of bacterial contaminants in 100 mL of water exceeded the limit. But in the Sukhbaatar district's summer camp region which is a relatively low populated area was shown a relatively low level of microbiological contamination and nutrient pollution compared to the permissible level in water samples.According to correlation studies, the nitrate ion concentrations of 12.6% samples over the permissible value (more than 50 mg/L) and high level of bacterial contamination in drinking water, showed a weak correlation.