Cadmium (Cd) is a widespread environmental toxic contaminant, which causes serious health-related problems. In this study, human intestinal cell line (Caco-2 cells) and normal human liver cell line (HL-7702 cells) were used to investigate the toxicity and bioavailability of Cd to both cell lines and to validate these cell lines asin vitromodels for studying Cd accumulation and toxicity in human intestine and liver. Results showed that Cd uptake by both cell lines increased in a dose-dependent manner and its uptake by Caco-2 cells (720.15 µg mg⁻¹cell protein) was significantly higher than HL-7702 cells (229.01 µg mg⁻¹cell protein) at 10 mg L⁻¹. A time- and dose-dependent effect of Cd on cytotoxicity assays (LDH release, MTT assay) was observed in both Cd-treated cell lines. The activities of antioxidant enzymes and differentiation markers (SOD, GPX, and AKP) of the HL-7702 cells were higher than those of Caco-2 cells, although both of them decreased significantly with raising Cd levels. The results from the present study indicate that Cd above a certain level inhibits cellular antioxidant activities and HL-7702 cells are more sensitive to Cd exposure than Caco-2 cells. However, Cd concentrations <0.5 mg L⁻¹pose no toxic effects on both cell lines.

The minimum concentration of cadmium (Cd), by Chinese cabbage grown on Cd contaminated soils that can initiate toxicity in human liver cells using in vitro digestion coupled with Caco-2/HL-7702 cell models was studied. Cadmium bioaccessibility in the gastric phase for yellow soil (YS) cabbage (40.84%) and calcareous soil (CS) cabbage (21.54%) was significantly higher than small intestinal phase with the corresponding values of 21.2% and 11.11%, respectively. Cadmium bioavailability was higher in YS cabbage (5.27%–14.66%) than in CS cabbage (1.12%–9.64%). Cadmium concentrations (>0.74 μg) transported from YS and CS cabbage were able to induce oxidative (MDA, H₂O₂) stress by inhibiting antioxidant (SOD, GPx) enzyme activities in human liver cells (HL-7702). Additionally the study revealed that the ingestion of Cd contaminated Chinese cabbage grown in acidic soil (yellow soil) weakened the antioxidant defense system under all levels of contamination (2, 6, and 9 mg·kg⁻¹) which ultimately escalated the oxidative stress in liver cells; however, in case of CS cabbage, a marked oxidative stress was observed only at 9 mg kg⁻¹Cd level of soil. Therefore, it is necessary to monitor Cd concentrations in leafy vegetables grown on acidic soils to minimize human health risk.

Tetracycline (TC) contamination has become hot research topic, but little attention has been paid to its ecotoxicological monitoring. The primary objective of this study is to investigate the impact of TC on human normal liver cells (HL-7702) and find indicators for monitoring their ecotoxicity. The cytotoxicity of TC, at concentrations ranging from 0 to 1000 μg L⁻¹, was assessed on HL-7702 cells. The results showed that TC significantly inhibited the cell viability at a high concentration (1000 μg L⁻¹). The TC at exposure levels ≥ 50–100 μg L⁻¹ significantly increased the levels of extracellular catalase (CAT), malondialdehyde (MDA), alanine transaminase (ALT), and aspartate transaminase (AST), and a significantly positive correlation between the TC concentrations and the values of the above parameters was observed. Swelling of the mitochondrial cristae (MC) and rough endoplasmic reticulum (RER) and the loss of ribosomes in HL-7702 cells, were observed at high TC levels. There was a positive correlation between soil TC concentration and ALT activities. The above results suggest that TC is cytotoxic to HL-7702 cells and that extracellular ALT activities can be used as a sensitive bioindicator for monitoring soil TC contamination. We, therefore, propose that the HL-7702 cell line can be a novel tool for early antibiotics toxicity monitoring.

Tetracyclines (TCs) pollution in vegetable fields is a widely recognized concern, yet the health and ecological risks of TCs residues in the soil–cabbage food chain remain unclear. This study used enzyme-linked immunosorbent assay (ELISA) to investigate the health risks associated with TCs contamination in soil–cabbage (Brassica campestris L. ssp. chinensis) systems to better understand TCs accumulation in soil–cabbage and its impact on human health. The human health risks of the edible parts of Chinese cabbage and the ecological risks of TCs-contaminated soils were assessed using the health risk quotient method (RQ) and risk quotient method, respectively. The results showed that after 65 days of tetracycline (TC), chlortetracycline (CTC), and oxytetracycline (OTC) treatments, the degradation rates of TCs in soil were higher in black soil than in purplish clay soil, following the order of OTC > CTC > TC. As the three types of TCs concentration increased (0–20 mg kg⁻¹), their accumulation in the leaves and roots of Chinese cabbage in purplish clay soil was generally higher than in black soil. The health risk values of the three types of TCs in Chinese cabbage were also higher in purplish clay soil than in black soil, following the order of TC > CTC > OTC. Under controlled pot experimental conditions, the TC content in Chinese cabbage grown in purplish clay soil posed moderate risks to children aged 1–6 years (0.1 < HQ < 1.0), while the CTC and OTC contents in Chinese cabbage leaves indicated low risks to both adults and children (HQ ≤ 0.1). Additionally, all three TCs in both soils posed high ecological risks (RQ ≥ 1.0), with risk values being higher in purplish clay soil than in black soil, following the order of TC > CTC > OTC. Consequently, more fertile soils can help mitigate the impact of TCs pollution on human health and ecological safety.