Anomalous enrichment of soil elements (especially heavy metals) has aroused popular attention in China. In order to discuss distribution characteristics and analyze sources of elements in brown soil, field investigation and sample collection were carried out under different vegetation (cherry, apple, bamboos and pine) in Qixia, a typical apple production base in China. Element contents, pH, electrical conductivity (EC) and magnetic susceptibility (MS) were tested. Results showed that element concentrations were about roughly 2.48 times as China's background values, while significantly lower than the class ii of National soil Environment Quality Standard (Ni excepted). Meanwhile, vertical distribution and accumulation characteristics of elements in typical brown soil were significantly different under different vegetation. In detail, elements (Zn excepted) of Pine soil accumulated in surface, while they (Cd, Arsenic excepted) increased with depth under other vegetation. Moreover, pH and EC changed like elements, while MS was exactly opposite. It was found that those differences above were mainly caused by human activities (such as improper use of fertilizer, pesticide and inadequate use of organic fertilizer, etc.). Additionally, differences in composition and decomposition rate of vegetation litter also resulted in vertical differentiations of soil elements under different vegetation.

The influence of large rivers on the Subei littoral plain area requires more research than the results that have been available up to now. Thus, specific diagnostic indices of detrital mica are successfully applied for the first time to identify the detritus of the Yangtze River and the ancient Yellow River and to analyze their influence on the coast in the Subei littoral plain area. Based on field investigation and sample collection, detrital mica minerals within the 0.063–0.125 mm grain size fraction were selected and identified. Their content/ratio differentiations and possible origins were analyzed. Moreover, specific diagnostic indices were evaluated for detritus identification considering these two large rivers in addition to their provenance influences on the Subei littoral plain area. The results indicate that the detrital mica contents in the Yangtze River Estuary differed from those in the ancient Yellow River Estuary. The mass percentage in the former (average value of 32.2%) was much higher than that in the latter (average value of 13.1%). The former contained abundant weathered mica, with a particle percentage of approximately 50.6%, while the latter contained abundant biotite (with a particle percentage of approximately 40.9%). Differences, including but not limited to those above, could be attributed to basic geological, climatic and hydrodynamic conditions. In particular, the mica indices were clearly distinguished between these two river estuaries. These indices constitute specific diagnostic indices for differentiating river detritus and quantitative contribution analysis of detritus provenance in the Subei littoral plain area. Finally, the changes and quantitative contributions of four diagnostic indices demonstrated that in the Subei littoral plain area, northward from the Yangtze River Estuary to sample site SBY11 located in Yangkou town, Rudong County, detrital micas were mainly affected by the Yangtze River, and southward from the ancient Yellow River Estuary to sample site SBY12 located in Bengcha town, Rudong County, detrital micas were largely affected by the ancient Yellow River. The main mixing area should be located between these two towns. This study provides both a good example and an efficient approach to the application of detrital mica in detritus identification, mixed zone determination, sediment provenance analysis and transport tracing.

Beachrock offers a unique geochemical record of palaeoenvironmental change, relative sea-level (RSL) oscillations, and anthropogenic impact, etc. This paper synthesises major, trace, rare earth element (REE), and stable isotope (δ ¹³ C, δ ¹⁸ O) data across three frameworks: (i) palaeoclimatic reconstruction, (ii) Holocene RSL history, and (iii) coastal pollution monitoring. Relative to the upper crust, beachrock is enriched in CaO (20–50 wt%) and MgO (∼2 to >10 wt%) and depleted in SiO ₂ , Al2O ₃ , Na ₂ O, K ₂ O, and TiO ₂ , indicating carbonate dominance. Trace-element proxies (Sr/Ba, V/Cr, V/(V+Ni), Rb/K) constrain palaeosalinity and palaeoredox, placing formation in suboxic-oxic transitional settings. REE patterns (Lan/Ybn=1.2–3.5; Ce/Ce*=0.75–0.95; Eu/Eu*≈0.60–0.75; Y/Ho≈45) provide seawater-like signatures, with peloidal microbially mediated cements as the most robust archives. Cement δ13C and δ18O yield palaeotemperatures (21–32°C in tropics), fluid-mixing histories, and diagenetic overprint. Beachrock sequesters metals (loid) (Cu, Zn, Pb, Cd, As, Cr), organic pollutants, and microplastics at the land-sea interface, establishing a stratigraphic sentinel for Anthropocene contamination. MICP pathways also suggest nature-based coastal resilience potential. We advocate standardised protocols, global databases, and multi-proxy integration to unlock beachrock’s full potential.

Taking acidified Cd contaminated brown soil in Yantai as the research object, based on different exogenous salinity (NaCl) gradient (0%, 0.3%, 0.6%, 0.9%, 1.5%, 2% and 5%), indoor simulation experiments of Cd release were carried out after field investigation. Results showed that there was a significantly positive relation (r>0.90) between Cd release concentration/amount/ratio and exogenous salt (NaCl). Besides, the more exogenous salt (NaCl) was added; maximum release concentration/amount of Cd appeared the earlier. It was found that exogenous salt (NaCl) addition could obviously promote Cd release from acidified Cd contaminated brown soil. It was believed that this could be mainly due to the cation exchange between Cd²⁺ and Na⁺, together with the dissociation and/or complexation between Cl^- and Cd²⁺. In addition, available adsorption sites reduction by exchange base in soil causing Cd changed from solid state to soil solution was also a probable reason.